拟南芥调控胚乳发育和种子大小的基因
|
摘要
种子对人类来说,代表了食物和工业原料的重要来源。种子大小是影响作物产量的重要因素之一。而胚乳又占谷类植物种子的大部分体积,决定了种子的大小。因此,在当前人口越来越膨胀、资源越来越紧缺的形势下,加强对胚乳发育的研究,对于农业生产乃至人类社会的科学可持续发展具有特别重大的战略意义。
前人研究(Garcia等；Luo等)表明,拟南芥早期胚乳和种子大小至少受到三个基因IKU1、IKU2和MINI3控制。它们的突变体均表现为胚乳数量减少和种子变小。这三个基因作用于同一个遗传途径。IKU2编码LRR受体激酶；MINI3编码WRKY家族蛋白WRKY10,是调控胚乳增殖的转录因子。但对IKU1基因了解甚少。
本文使用分子生物学、遗传学、细胞生物学、生物信息学、生殖生物学的方法对与胚乳发育有关的拟南芥孢子体隐性突变体——ikul (haikul)基因进行了较为深入的研究。应用了遗传标记定位技术、显微镜技术、蛋白研究技术、基因克隆、突变技术、生物信息学等技术来分离IKU1基因、研究IKU1的功能,取得了突出进展,为早期胚乳的发育和种子大小控制的机理贡献了新的知识,对农业生产中的小麦、水稻等种子发育研究有重要的参考价值。
本研究利用遗传标记、PCR技术和基因测序技术把IKU1定位在At2g35230基因上。带有At2g35230全部基因信息的互补载体弥补了iku1突变体的基因缺陷,使iku1突变体表现型恢复为野生型大种子。分析其T1、T2种子的表现型和基因型,从遗传学角度证实了IKU1基因功能发生在胚乳中,验证了拟南芥的卵细胞和中央细胞可以通过花器浸泡分别转化。IKU1编码的蛋白包含了植物中特有的VQmotif。在检验IKU1蛋白功能区的遗传互补试验中,带有VQ motif突变的IKU1基因不能使iku1突变体种子恢复野生型大小,而删除了重复区域45个氨基酸的突变仍可以使突变体种子恢复野生型大小,说明VQ motif对于IKU1基因影响种子发育的功能十分重要。高表达启动子35S作用下的GFP∷IKU1蛋白在根尖细胞、茎表皮细胞、叶片绒毛细胞、气孔保卫细胞、种皮细胞的细胞核以及洋葱表皮细胞的细胞核中表达,但核仁中没有GFP信号。同时,也发现35S::GFP::IKU1在其转化株后代中,会出现基因沉默现象。而IKU1启动子作用下的GFP::IKU1仍具有IKU1在胚乳中的功能,可以使ikul突变体的种子恢复野生型性状,同时也揭示了IKU1在植株中真实表达形式。其T1植株中,GFP::IKU1表达在根尖、茎表皮、花柄、荚果隔膜、种皮和中央细胞及受精后不同阶段的胚乳细胞细胞核中,但是蛋白表面没有亮点(speckle),卵细胞和胚的细胞中也没有GFP::IKU1信号。IKU1是一个未知功能的蛋白,它与At1g32610及其它来自毛果杨、蓖麻、棉花、葡萄的VQ motif蛋白处于同一进化组群。大多数编码VQ motif蛋白的基因都没有内含子。Atlg32610与IKU1蛋白序列十分相似,它们某些功能的可能重叠也许导致我们观察不到iku1突变体在种子以外的组织器官中的表现型。双突变体种子重量的分析结果说明了IKU1和MINI3作用于同一个影响种子发育的遗传途径。酵母双杂交等试验结果也揭示,IKU1极可能与MINI3/WRKY10,一个WRKY家族的转录因子存在相互作用,形成蛋白复合体。
在本试验和前人研究的基础上,提出了一个关于IKU1-MINI3/WRKY10的种子发育途径模式。在野生型植株中,IKU1、MINI3/WRKY10先形成蛋白复合体,由复合体参与调节一个控制种子大小的基因——IKU2,最终产生野生型大种子。iku1突变体造成IKU1-MINI3/WRKY10转录结合体不稳定,作为反馈,MINI3/WRKY10抑制MINI3基因的表达；同时,IKU2的表达下调,最终产生小种子。
Seed represents an important source of food, feed, and industrial raw material for mankind. Seed size is one of the significant factors affecting crop production. Endosperm accounts for most of the bulk of cereal seed and determines the seed size. It will be strategically significant for the sustainable development of the agricultural production and the human society to support the research on reproductive biology, because of the resource shortage and expanding population in the world.
The reproductive process in plants is an important area in biology, which still requires substantial genetic and molecular investigation to elucidate the complex process. Angiosperms, or higher plants, have a unique seed forming process, double fertilization: the egg cell is fused with a sperm nucleus and the central cell fuses to another sperm nucleus both coming from the same pollen grain. This leads to the formation of the embryo and endosperm. Three mutants ikul, iku2and mini3have been shown to give small seed size because of the reduction of endosperm growth. The expression levels of MINI3and IKU2were decreased in the ikul-1mutant. IKU2expression was reduced in a miniS-1background whereas MINI3expression levels were unaltered in the iku2-3mutant. These observation suggest the successive action of the three genes IKU1, IKU2and MINI3in the same genetic pathway of seed development. In this pathway, MINI3encodes WRKY10, a WRKY class transcription factor; IKU2encodes a LRR KINASE (At3g19700). But the identity of IKU1remains unknown.
In this study, the integrated approaches involving classic genetic, molecular, cellular methodologies were used to investigate the molecular identity of IKU1. We reported here the cloning of IKU1gene which controls the seed size in Arabidopsis using map-based strategy. It was shown that IKU1is At2g35230which encodes a novel protein containing VQ motif. VQ motif contains a core sequence of unknown function and is specific in plant species. The genetic complementation of ikul phenotype suggests that IKU1gene functions in endosperm. It was also confirmed that the endosperm and the embryo of Arabidopsis thaliana are independently transformed through infiltration by Agrobacterium tumefaciens. The mutation in IKU1only causes obvious phenotype in seed, though IKU1is expressed widely. The genomic construct carrying mutations in VQ motif failed to complement the ikul seed lesion, suggesting an essential role of the VQ motif in IKU1functioning. There is evidence that the mutations in other parts of genes are not important for IKU1function. We found that IKU1is nuclear-localized, organized into speckles and led to gene silencing under35S. When driven by its native promoter, the GFP::IKU1without any speckle, able to complement the mutant phenotype, was detected in the nuclear of the early endosperm as well as other vegetative organs. The physical interaction between IKU1and MINI3/WRKY10suggests that the IKU1is a co-transcription factor of MTNI3/WRKY10. A model has been proposed to explain how the IKU1and MINI3/WRKY10regulate endosperm development and seed size. In wild type Arabidopsis, IKU1interacts with MINI3/WRKY10to form a complex which regulates the IKU2and consequently wild-type seeds will be produced. Seeds in ikul or miniS mutants become small, because IKU2is repressed. Further, in ikul mutants the IKU1-MINI3/WRKY10transcription complex becomes unstable and the un-associated MINI3/WRKY10protein starts to repress the expression of MINIS genes as a feedback mechanism. In the same time IKU2expression is down-regulated, which leads the formation of small seeds.
前人研究(Garcia等；Luo等)表明,拟南芥早期胚乳和种子大小至少受到三个基因IKU1、IKU2和MINI3控制。它们的突变体均表现为胚乳数量减少和种子变小。这三个基因作用于同一个遗传途径。IKU2编码LRR受体激酶；MINI3编码WRKY家族蛋白WRKY10,是调控胚乳增殖的转录因子。但对IKU1基因了解甚少。
本文使用分子生物学、遗传学、细胞生物学、生物信息学、生殖生物学的方法对与胚乳发育有关的拟南芥孢子体隐性突变体——ikul (haikul)基因进行了较为深入的研究。应用了遗传标记定位技术、显微镜技术、蛋白研究技术、基因克隆、突变技术、生物信息学等技术来分离IKU1基因、研究IKU1的功能,取得了突出进展,为早期胚乳的发育和种子大小控制的机理贡献了新的知识,对农业生产中的小麦、水稻等种子发育研究有重要的参考价值。
本研究利用遗传标记、PCR技术和基因测序技术把IKU1定位在At2g35230基因上。带有At2g35230全部基因信息的互补载体弥补了iku1突变体的基因缺陷,使iku1突变体表现型恢复为野生型大种子。分析其T1、T2种子的表现型和基因型,从遗传学角度证实了IKU1基因功能发生在胚乳中,验证了拟南芥的卵细胞和中央细胞可以通过花器浸泡分别转化。IKU1编码的蛋白包含了植物中特有的VQmotif。在检验IKU1蛋白功能区的遗传互补试验中,带有VQ motif突变的IKU1基因不能使iku1突变体种子恢复野生型大小,而删除了重复区域45个氨基酸的突变仍可以使突变体种子恢复野生型大小,说明VQ motif对于IKU1基因影响种子发育的功能十分重要。高表达启动子35S作用下的GFP∷IKU1蛋白在根尖细胞、茎表皮细胞、叶片绒毛细胞、气孔保卫细胞、种皮细胞的细胞核以及洋葱表皮细胞的细胞核中表达,但核仁中没有GFP信号。同时,也发现35S::GFP::IKU1在其转化株后代中,会出现基因沉默现象。而IKU1启动子作用下的GFP::IKU1仍具有IKU1在胚乳中的功能,可以使ikul突变体的种子恢复野生型性状,同时也揭示了IKU1在植株中真实表达形式。其T1植株中,GFP::IKU1表达在根尖、茎表皮、花柄、荚果隔膜、种皮和中央细胞及受精后不同阶段的胚乳细胞细胞核中,但是蛋白表面没有亮点(speckle),卵细胞和胚的细胞中也没有GFP::IKU1信号。IKU1是一个未知功能的蛋白,它与At1g32610及其它来自毛果杨、蓖麻、棉花、葡萄的VQ motif蛋白处于同一进化组群。大多数编码VQ motif蛋白的基因都没有内含子。Atlg32610与IKU1蛋白序列十分相似,它们某些功能的可能重叠也许导致我们观察不到iku1突变体在种子以外的组织器官中的表现型。双突变体种子重量的分析结果说明了IKU1和MINI3作用于同一个影响种子发育的遗传途径。酵母双杂交等试验结果也揭示,IKU1极可能与MINI3/WRKY10,一个WRKY家族的转录因子存在相互作用,形成蛋白复合体。
在本试验和前人研究的基础上,提出了一个关于IKU1-MINI3/WRKY10的种子发育途径模式。在野生型植株中,IKU1、MINI3/WRKY10先形成蛋白复合体,由复合体参与调节一个控制种子大小的基因——IKU2,最终产生野生型大种子。iku1突变体造成IKU1-MINI3/WRKY10转录结合体不稳定,作为反馈,MINI3/WRKY10抑制MINI3基因的表达；同时,IKU2的表达下调,最终产生小种子。
Seed represents an important source of food, feed, and industrial raw material for mankind. Seed size is one of the significant factors affecting crop production. Endosperm accounts for most of the bulk of cereal seed and determines the seed size. It will be strategically significant for the sustainable development of the agricultural production and the human society to support the research on reproductive biology, because of the resource shortage and expanding population in the world.
The reproductive process in plants is an important area in biology, which still requires substantial genetic and molecular investigation to elucidate the complex process. Angiosperms, or higher plants, have a unique seed forming process, double fertilization: the egg cell is fused with a sperm nucleus and the central cell fuses to another sperm nucleus both coming from the same pollen grain. This leads to the formation of the embryo and endosperm. Three mutants ikul, iku2and mini3have been shown to give small seed size because of the reduction of endosperm growth. The expression levels of MINI3and IKU2were decreased in the ikul-1mutant. IKU2expression was reduced in a miniS-1background whereas MINI3expression levels were unaltered in the iku2-3mutant. These observation suggest the successive action of the three genes IKU1, IKU2and MINI3in the same genetic pathway of seed development. In this pathway, MINI3encodes WRKY10, a WRKY class transcription factor; IKU2encodes a LRR KINASE (At3g19700). But the identity of IKU1remains unknown.
In this study, the integrated approaches involving classic genetic, molecular, cellular methodologies were used to investigate the molecular identity of IKU1. We reported here the cloning of IKU1gene which controls the seed size in Arabidopsis using map-based strategy. It was shown that IKU1is At2g35230which encodes a novel protein containing VQ motif. VQ motif contains a core sequence of unknown function and is specific in plant species. The genetic complementation of ikul phenotype suggests that IKU1gene functions in endosperm. It was also confirmed that the endosperm and the embryo of Arabidopsis thaliana are independently transformed through infiltration by Agrobacterium tumefaciens. The mutation in IKU1only causes obvious phenotype in seed, though IKU1is expressed widely. The genomic construct carrying mutations in VQ motif failed to complement the ikul seed lesion, suggesting an essential role of the VQ motif in IKU1functioning. There is evidence that the mutations in other parts of genes are not important for IKU1function. We found that IKU1is nuclear-localized, organized into speckles and led to gene silencing under35S. When driven by its native promoter, the GFP::IKU1without any speckle, able to complement the mutant phenotype, was detected in the nuclear of the early endosperm as well as other vegetative organs. The physical interaction between IKU1and MINI3/WRKY10suggests that the IKU1is a co-transcription factor of MTNI3/WRKY10. A model has been proposed to explain how the IKU1and MINI3/WRKY10regulate endosperm development and seed size. In wild type Arabidopsis, IKU1interacts with MINI3/WRKY10to form a complex which regulates the IKU2and consequently wild-type seeds will be produced. Seeds in ikul or miniS mutants become small, because IKU2is repressed. Further, in ikul mutants the IKU1-MINI3/WRKY10transcription complex becomes unstable and the un-associated MINI3/WRKY10protein starts to repress the expression of MINIS genes as a feedback mechanism. In the same time IKU2expression is down-regulated, which leads the formation of small seeds.
引文
1. Drews GN, Lee D, Christensen CA. (1998). Genetic analysis of female gametophyte development and function. Plant Cell 10(1):5-17. Review.
2. Chaudhury AM, Koltunow A, Payne T, Luo M, Tucker MR, Dennis ES, Peacock WJ. (2001). Control of early seed development. Annu Rev Cell Dev Biol.17:677-99. Review.
3. Scott RJ, Spielman M, Bailey J, Dickinson HG.(1998). Parent-of-origin effects on seed development in Arabidopsis thaliana. Development 125:3329-3341
4. Jurgens G, Mayer U, Busch M. Lukowitz W, Laux T. (1995). Pattern formation in the Arabidopsis embryo:a genetic perspective. Philos Trans R Soc Lond B Biol Sci.350(1331):19-25. Review.
5. Boisnard-Lorig C, Colon-Carmona A, Bauch M, Hodge S, Doerner P, Bancharel E, Dumas C, Haseloff J, Berger F. (2001). Dynamic analyses of the expression of the HISTONE::YFP fusion protein in Arabidopsis show that syncytial endosperm is divided in mitotic domains. Plant Cell 13:495-509.
6. Frederic Berger.1999. Endosperm developmen. Plant Biology,2:28-32
7. Lin BY. (1984). Ploidy barrier to endosperm development in maize. Genetics 107, 103-115.
8. Kinoshita T, Yadegari R, Harada JJ, Goldberg RB, Fischer RL. (1999). Imprinting of the MEDEA polycomb gene in the Arabidopsis endosperm. Plant Cell 11(10):1945-52.
9. Vielle-Calzada JP, Baskar R, Grossniklaus U. (2000). Delayed activation of the paternal genome during seed development. Nature 404(6773):91-4.
10. Grossniklaus U, Vielle-Calzada JP, Hoeppner MA, Gagliano WB. (1998). Maternal control of embryogenesis by MEDEA, a Polycomb group gene in Arabidopsis. Science 280,446-450.
11. Luo M, Bilodeau P, Koltunow A, Dennis ES, Peacock WJ, Chaudhury AM (1999) Genes controlling fertilization-independent seed development in Arabidopsis thaliana. Proc Natl Acad Sci USA 96:296-301
12. Ohad N, Yadegari R, Margossian L, Hannon M, Michaeli D, Harada JJ, Goldberg RB, Fischer RL. (1999). Mutations in FIE, a WD polycomb group gene, allow endosperm development without fertilization. Plant Cell 11(3):407-16.
13. Ramin Yadegari andGaryN. Drews.(2004). Female Gametophyte Development. ThePlantCell,16:S133-S141
14. Cory A. Christensen, Edward J.King, John R.Jordan and G. N.Drews. (1997). Megagametogenesis in Arabidopsis wild type and the Gf mutant. Sex. Plant Reprod, 10:49-64
15. Schneitz K, Hulskamp M, Pruitt RE. (1995). Wild-type ovule development in Arabidopsis thaliana:a light microscope study of cleared whole-mount tissue. Plant J 7,731-749.
16. Erik Vollbrecht, and Sarah C. Hake. (1995). Deficiency analysis of female gametogenesis in maize. Developmental Genetics 16,44-63.
17. Mansfield SG, Briarty LG, Erni, S. (1991). Early embryogenesis in Arabidopsis thaliana. I. The mature embryo sac. Can. J. Bot,69,447-460.
18. Frieman W. E. (1998).The evolution of double fertilization and endosperm:an historical perspective. Sexual plant reproduction,11,6-11
19. Jensen K., Fisher D. B. (1968). Cotton embryogenesis:The entrance and discharge of the pollen tube in the embryo sac. Planta 78,158-183
20. Thomas Laux and Gerd Jurgens. (1997). Embryogenesis:a new start in life. The Plant cell,9:989-1000
21. Ray, S., Golden, T., and Ray, A. (1996). Maternal effects of the short integument mutation on embryo development in Arabidopsis. Dev. Biol.180,365-369
22. Golden TA, Schauer SE, Lang JD, Pien S, Mushegian AR, Grossniklaus U, Meinke DW, Ray A. (2002) SHORT INTEGUMENTS1/SUSPENSOR1/CARPEL FACTORY, a Dicer homolog, is a maternal effect gene required for embryo development in Arabidopsis. Plant Physiol.130(2):808-22.
23. Busch M, Mayer U, Jurgens G. (1996). Molecular analysis of the Arabidopsis pattern formation of gene GNOM:gene structure and intragenic complementation. Mol Gen Genet.,250(6):681-91
24. Torres-Ruiz RA, Lohner A, Jurgens G. (1996). The GURKE gene is required for normal organization of the apical region in the Arabidopsis embryo. Plant J 10(6):1005-16.
25. Takada S, Hibara K, Ishida T, Tasaka M. (2001). The CUP-SHAPED COTYLEDON1 gene of Arabidopsis regulates shoot apical meristem formation. Development 128(7):1127-35.
26. Aida M, Vernoux T, Furutani M, Traas J, Tasaka M. (2002). Roles of PIN-FORMED1 and MONOPTEROS in pattern formation of the apical region of the Arabidopsis embryo. Development 129(17):3965-74.
27. Lotan T, Ohto M, Yee KM, West MA, Lo R, Kwong RW, Yamagishi K, Fischer RL, Goldberg RB, Harada JJ.(1998). Arabidopsis LEAFY COTYLEDON1 is sufficient to induce embryo development in vegetative cells. Cell 93(7):1195-205.
28. Stone SL, Kwong LW, Yee KM, Pelletier J, Lepiniec L, Fischer RL, Goldberg RB, Harada JJ. (2001). LEAFY COTYLEDON2 encodes a B3 domain transcription factor that induces embryo development. Proc Natl Acad Sci USA 98(20):11806-11.
29. Kwong RW, Bui AQ, Lee H, Kwong LW, Fischer RL, Goldberg RB, Harada JJ. (2003). LEAFY COTYLEDON1-LIKE defines a class of regulators essential for embryo development. Plant Cell 15(1):5-18.
30. Joe Ogas, Jin-Chen Cheng, Z. Renee Sung, Chris Somerville. (1997). Cellular Differentiation Regulated by Gibberellin in the Arabidopsis thaliana pickle Mutant. Science,277:91-94
31. Ogas J, Kaufmann S, Henderson J, Somerville C. (1999). PICKLE is a CHD3 chromatin-remodeling factor that regulates the transition from embryonic to vegetative development in Arabidopsis. Proc Natl Acad Sci USA.96:13839-13844
32. Kim Boutilier, Remko Offringa, Vijay K. Sharma, Henk Kieft, Therese Ouellet, Lemin Zhang, Jiro Hattori, Chun-Ming Liu, Andre A. M. van Lammeren, Brian L. A. Miki, Jan B. M. Custers, and Michiel M. van Lookeren Campagne.(2002). Ectopic Expression of BABY BOOM Triggers a Conversion from Vegetative to Embryonic Growth. Plant Cell,14(8):1737-1749
33. Hecht V, Vielle-Calzada JP, Hartog MV, Schmidt ED, Boutilier K, Grossniklaus U, de Vries SC. (2001). The Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR KINASE 1 gene is expressed in developing ovules and embryos and enhances embryogenic competence in culture. Plant Physiol.127(3):803-16.
34. Olsen OA, Linnestad C, Nichols SE. (1999). Developmental biology of the cereal endosperm. Trends Plant Sci.4(7):253-257.
35. Olsen OA. (2001). ENDOSPERM DEVELOPMENT:Cellularization and Cell Fate Specification. Annu Rev Plant Physiol Plant Mol Biol.52:233-267.
36. Boisnard-Lorig C, Colon-Carmona A, Bauch M, Hodge S, Doerner P, Bancharel E, Dumas C, Haseloff J, Berger F (2001) Dynamic analyses of the expression of the HISTONE:YFP fusion protein in Arabidopsis show that syncytial endosperm is divided in mitotic domains. Plant Cell 13:495-509
37. Brown RC, Lemmon BE, Nguyen H, Olsen OA. (1999). Development of endosperm in Arabidopsis thaliana. Sex Plant Reprod 12:32-42.
38. Young TE, Gallie DR, DeMason DA. (1997). Ethylene-madiated programmed cell death during maize endosperm development of wild type and shrunken2 genotypes. Plant physiol.115:737-751
39. Young TE, Gallie DR. (2000). Programmed cell death during endosperm development. Plant Mol Biol 44(3):283-301.
40. Lopes MA, Larkins BA. (1993). Endosperm origin, development, and function. Plant Cell 5(10):1383-99. Review.
41. van Hengel AJ, Guzzo F, van Kammen A, de Vries SC. (1998). Expression pattern of the carrot EP3 endochitinase genes in suspension cultures and in developing seeds. Plant physiol.117:43-53
42. Opsahl-Ferstad HG, Le Deunff E, Dumas C, Rogowsky PM. (1997). ZmEsr, a novel endosperm-specific gene expressed in a restricted region around the maize embryo. Plant J.12(1):235-46.
43. Tzafrir I, McElver JA, Liu Cm CM, Yang LJ, Wu JQ, Martinez A, Patton DA, Meinke DW. (2002). Diversity of TITAN functions in Arabidopsis seed development. Plant Physiol 128:38-51
44. McElver J, Patton D, Rumbaugh M, Liu C, Yang LJ, Meinke D. (2000). The TITAN5 gene of Arabidopsis encodes a protein related to the ADP ribosylation factor family of GTP binding proteins. Plant Cell 12:1379-1392
45. Maitz M, Santandrea G, Zhang Z. Lal S, Hannah LC, Salamini F, Thompson RD. (2000). rgfl, a mutation reducing grain filling in maize through effects on basal endosperm and pedicel development. Plant J 23(1):29-42.
46. Becraft PW, Kang SH, Suh SG. (2001). The maize CRINKLY4 receptor kinase controls a cell-autonomous differentiation response. Plant Physiol 127(2):486-96.
47. Sorensen MB, Mayer U, Lukowitz W, Robert H, Chambrier P, Jurgens G, Somerville C, Lepiniec L, Berger F. (2002). Cellularisation in the endosperm of Arabidopsis thaliana is coupled to mitosis and shares multiple components with cytokinesis. Development 129(24):5567-5576.
48. Lauber MH, Waizenegger I, Steinmann T, Schwarz H, Mayer U, Hwang I, Lukowitz W, Jurgens G. (1997). The Arabidopsis KNOLLE protein is a cytokinesis-specific syntaxin. J Cell Biol.139(6):1485-93.
49. Chaudhury AM, Ming L, Miller C, Craig S, Dennis ES, Peacock WJ. (1997). Fertilization-independent seed development in Arabidopsis thaliana. Proc Natl Acad Sci USA 94(8):4223-8.
50. Ohad N, Margossian L, Hsu YC, Williams C, Repetti P, Fischer RL. (1996). A mutation that allows endosperm development without fertilization. Proc Natl Acad Sci USA 93(11):5319-24.
51. Grossniklaus U, Vielle-Calzada JP, Hoeppner MA, Gagliano WB (1998) Maternal control of embryogenesis by MEDEA, a polycomb group gene in Arabidopsis. Science 280:446-450
52. Luo M, Bilodeau P, Koltunow A, Dennis ES, Peacock WJ, Chaudhury AM. (1999). Genes controlling fertilization-independent seed development in Arabidopsis thaliana. Proc Natl Acad Sci USA 96(1):296-301.
53. Luo M, Bilodeau P, Dennis ES, Peacock WJ, Chaudhury A. (2000). Expression and parent-of-origin effects for FIS2, MEA, and FIE in the endosperm and embryo of developing Arabidopsis seeds. Proc Natl Acad Sci USA 97(19):10637-42.
54. Spillane C, MacDougall C, Stock C, Kohler C, Vielle-Calzada JP, Nunes SM, Grossniklaus U, Goodrich J. (2000). Interaction of the Arabidopsis polycomb group proteins FIE and MEA mediates their common phenotypes. Curr Biol. 10(23):1535-8.
55. Sorensen MB, Chaudhury AM, Robert H, Bancharel E, Berger F. (2001). Polycomb group genes control pattern formation in plant seed. Curr Biol 11(4),277-81.
56. Kinoshita T, Harada JJ, Goldberg RB, Fischer RL. (2001). Polycomb repression of flowering during early plant development. Proc Natl Acad Sci USA 98(24):14156-61.
57. Brink R A, Cooper D C. (1947) The endosperm in seed development. Bot Rev,13, 423-541
58. Bhatnagar SP, Sawhney V. (1981). Endosperm:its morphology, ultrastructure, and histochemistry. Int. Rev. Cytol 73,55-102.
59. Vijayaraghavan MR, Prabhakar K. (1984). The endosperm. In Embryology of Angiosperm. Edited by BM John. Berlin, Springer-Verlag,319-376
60. Lopes MA, Larkins BA (1993) Endosperm origin, development, and function. Plant Cell 5:1383-1399
61. Johnston SA, den Nijs TPM, Peloquin SJ, Hanneman REJ. (1980). The significance of genie balance to endosperm development in interspecific crosses. Theor. Appl. Genet 57,5-9.
62. Haig D, Westoby M. (1991). Genomic imprinting in endosperm:Its effect on seed development in crosses between species, and between defferent ploidies of the same species, and its implications for the evolution of apomixis. Philos Trans R Soc Lond,333(1),1-13
63. Birchler JA. (1993). Dosage analysis of maize endosperm development. Ann. Rev. Genet.27,181-204.
64. Haig D, Westoby M. (1989). Parent-specific gene expression and the triploid endosperm. Am Nat,134,147-155
65. Feil, R and Berger, F. (2007). Convergent evolution of genomic imprinting and plants and mammals. Trends in Genetics 23(4):192-9
66. Sanford JP, Clark HJ, Chapman VM, Rossant J. (1987). Differences in DNA methylation during oogenesis and spermatogenesis and their persistence during early embryogenesis in the mouse. Genes Dev.1(10):1039-46.
67. El Kharroubi A, Piras G, Stewart CL. (2001). DNA demethylation reactivates a subset of imprinted genes in uniparental mouse embryonic fibroblasts. J Biol Chem.276(12):8674-80.
68. Kaffer CR, Grinberg A, Pfeifer K. (2001). Regulatory mechanisms at the mouse Igf2/H19 locus. Mol Cell Biol.21(23):8189-96.
69. Jullien, P., Kinoshita, T., Ohad, N., and Berger, F. (2006a). Maintenance of DNA methylation during the Arabidopsis life cycle is essential for parental imprinting. Plant Cell 18,1360-1372
70. Jullien, P, Katz, A, Oliva, M, Ohad, N and Berger, F. (2006b). PcG group complexes self-regulate imprinting of the PcG group gene MEDEA in Arabidopsis. Current Biology 16(5):486-92
71. Xiao, W., Gehring, M., Choi, Y., Margossian, L., Pu, H., Harada, J. J., Goldberg, R. B., Pennell, R. I. and Fischer, R. L. (2003). "Imprinting of the MEA PcG gene is controlled by antagonism between MET1 methyltransferase and DME glycosylase." Developmental Cell 5:891-901.
72. Gehring M, Huh JH, Hsieh TF, Penterman J, Choi Y, Harada JJ, Goldberg RB, Fischer RL. (2006). DEMETER DNA glycosylase establishes MEDEA PcG gene self-imprinting by allele-specific demethylation. Cell 124(3):495-506.
73. Jullien, PE., Mosquna, A., Ingouff, M., Sakata, T., Ohad, N. and Berger F. (2008). Retinoblastoma and its binding partner MSI1 control imprinting in Arabidopsis. Plos Biology 6(8):e194
74. Haun, W., Laoueille-Duprat, S., O'connell, M., Spillane, C., Grossniklaus, U., Phillips, A., Kaeppler, S., and Springer, N. (2007). Genomic imprinting, methylation and molecular evolution of maize Enhancer of zeste (Mez) homologs. Plant Journal 49,325-337
75. Gutierrez-Marcos JF, Costa LM, Dal Pra M, Scholten S, Kranz E, Perez P, Dickinson HG. (2006). Epigenetic asymmetry of imprinted genes in plant gametes. Nature Genetics 38(8):876-8.
76. Rodrigues, JCM; Luo, M; Berger, F and Koltunow, AMG. PcG group gene function and imprinting requirements for sexual and asexual seed development in Angiosperms. (in press)
77. Haun WJ, Danilevskaya ON, Meeley RB, Springer NM. (2009). Disruption of imprinting by mutator transposon insertions in the 5'proximal regions of the Zea mays Mezl locus. Genetics 181 (4):1229-37
78. Adams S, Vinkenoog R. Spielman M, Dickinson HG, Scott RJ. (2000). Parent-of-origin effects on seed development in Arabidopsis thaliana require DNA methylation. Development 127(11):2493-502.
79. Harper JL, Loveli PH, Moore KG. (1970) The shapes and sizes of seeds. Annu. Rev. Ecol. Syst.1,327-356.
80. Silvertown J. (1989). The paradox of seed size and adaption. Trends Ecol. Evol.4, 24-26.
81. Roach D, Wulff R. (1987). Maternal effects in plants. Annu. Rev. Ecol. Syst.18, 209-235.
82. Prioul, JL, Quarrie S, Causse, M, Devienne D. (1997). Dissecting complex physiological functions through the use of molecular quantitative genetics. J. Exp. Bot.48,1151-1163.
83. Lu C, Shen L, Tan Z, Xu Y, He P, Chen Y, Zhu L. (1997). Comparative mapping of QTLs for agronomic traits of rice across environments by using a double haploid population. Theor. Appl. Genet.94,145-150.
84. Maughan PJ, Saghai Maroof MA, Buss GR. (1996) Molecular marker analysis of seed-weight:Genomic locations. gene action, and evidence for orthologous evolution among three legume species. Theor. Appl. Genet.93,574-579.
85. Paterson AH, Lin YR, Li Z, Schertz KF, Doebley JF, Pinson SRM, Liu, SC, Stansel JW, Irvine JE. (1995) Convergent domestication of cereal crops by independent mutations at corresponding genetic loci. Science 269,1714-1718.
86. Alonso-Blanco C, Blankestijn-de Vries H, Hanhart CJ, Koornneef M. (1999). Natural allelic variation at seed size loci in relation to other life history traits of Arabidopsis thaliana. Proc Natl Acad Sci USA 96(8):4710-7.
87. Krizek BA. (1999). Ectopic expression of AINTEGUMENTA in Arabidopsis plants results in increased growth of floral organs. Dev Genet.25(3):224-36.
88. Mizukami Y, Fischer RL. (2000). Plant organ size control:AINTEGUMENTA regulates growth and cell numbers during organogenesis. Proc Natl Acad Sci USA 97(2):942-7.
89. Li Y, Zheng L, Corke F, Smith C, Bevan MW. (2008). Control of final seed and organ size by the DAI gene family in Arabidopsis thaliana.Genes Dev., 22(10),1331-6
90. H.S. Lee and Z.J. Chen, (2001).Protein-coding genes are epigenetically regulated in Arabidopsis polyploids. Proc Natl Acad Sci USA 98,6753-6758
91. Schruff MC, Spielman M, Tiwari S, Adams S, Fenby N, Scott RJ. (2006) The AUXIN RESPONSE FACTOR 2 gene of Arabidopsis links auxin signalling, cell division, and the size of seeds and other organs. Development,133(2):251-61
92. Ohto, M.A., Fischer, R.L., Goldberg, R.B., Nakamura, K., and Harada, J.J. (2005). Control of Seed Mass by APETALA2. Proc Natl Acad Sci U S A 102:3123-3128.
93. Garcia D, Saingery V, Chambrier P, Mayer U, Jurgens G, Berger F. (2003). Arabidopsis haiku mutants reveal new controls of seed size by endosperm. Plant Physiol.131(4),1661-70.
94. Garcia D, Fitz Gerald JN, Berger F (2005) Maternal control of integument cell elongation and zygotic control of endosperm growth are coordinated to determine seed size in Arabidopsis. Plant Cell 17:52-60
95. Luo M, Dennis ES, Berger F, Peacock WJ, Chaudhury A. (2005). MINISEED3 (MINI3), a WRKY family gene, and HAIKU2 (IKU2), a leucine-rich repeat (LRR) KINASE gene, are regulators of seed size in Arabidopsis. Proc Natl Acad Sci USA 102:17531-17536
96. Zhou Y, Zhang X, Kang X, Zhao X. Zhang X, Ni M. (2009). SHORT HYPOCOTYL UNDER BLUE1 Associates with MINISEED3 and HAIKU2 promoters in vivo to regulate Arabidopsis seed development. The Plant Cell 21:106-117
97. Cesar Llave, Kristin D. Kasschau, and James C. Carrington (2000). Virus-encoded suppressor of posttranscriptional gene silencing targets a maintenance step in the silencing pathway. PNAS,97:13401-13406
98. Andreasson E, Jenkins T, Brodersen P, Thorgrimsen S, Petersen NH, Zhu S, Qiu JL, Micheelsen P, Rocher A, Petersen M, Newman M-A, Nielsen HB, Hirt H, Somssich I, Mattsson O and Mundy J. (2005). The MAP kinase substrate MKS1 is a regulator of plant defense responses. EMBO J.,24:2579-2589
99. Morikawa K, Shiina T, Murakami S. Toyoshima Y. (2002) Novel nuclear-encoded proteins interacting with a plastid sigma factor, Sigl, in Arabidopsis thaliana. FEBS Lett.,514:300-304
100. Pan D, Zhang L. (2009).Burst of young retrogenes and independent retrogene formation in mammals.PLoS ONE,4(3):e5040
101.Nicole Bechtold, Sylvie Jolivet, Roger Voisin & Georges Pelletier. (2002) The endosperm and the embryo of Arabidopsis thaliana are independently transformed through infiltration by Agrobacterium tumefaciens.Transgenic Research 12:509-517
102. Citovsky, V., Lee, L.Y., Vyas, S., Glick, E., Chen, M.H., Vainstein, A., Gafni, Y, Gelvin, S.B.,& Tzfira, T. (2006) Identification of subcellular localization of interacting proteins by bimolecular fluorescence complementation in planta. J. Mol. Biol.362,1120-1131.
2. Chaudhury AM, Koltunow A, Payne T, Luo M, Tucker MR, Dennis ES, Peacock WJ. (2001). Control of early seed development. Annu Rev Cell Dev Biol.17:677-99. Review.
3. Scott RJ, Spielman M, Bailey J, Dickinson HG.(1998). Parent-of-origin effects on seed development in Arabidopsis thaliana. Development 125:3329-3341
4. Jurgens G, Mayer U, Busch M. Lukowitz W, Laux T. (1995). Pattern formation in the Arabidopsis embryo:a genetic perspective. Philos Trans R Soc Lond B Biol Sci.350(1331):19-25. Review.
5. Boisnard-Lorig C, Colon-Carmona A, Bauch M, Hodge S, Doerner P, Bancharel E, Dumas C, Haseloff J, Berger F. (2001). Dynamic analyses of the expression of the HISTONE::YFP fusion protein in Arabidopsis show that syncytial endosperm is divided in mitotic domains. Plant Cell 13:495-509.
6. Frederic Berger.1999. Endosperm developmen. Plant Biology,2:28-32
7. Lin BY. (1984). Ploidy barrier to endosperm development in maize. Genetics 107, 103-115.
8. Kinoshita T, Yadegari R, Harada JJ, Goldberg RB, Fischer RL. (1999). Imprinting of the MEDEA polycomb gene in the Arabidopsis endosperm. Plant Cell 11(10):1945-52.
9. Vielle-Calzada JP, Baskar R, Grossniklaus U. (2000). Delayed activation of the paternal genome during seed development. Nature 404(6773):91-4.
10. Grossniklaus U, Vielle-Calzada JP, Hoeppner MA, Gagliano WB. (1998). Maternal control of embryogenesis by MEDEA, a Polycomb group gene in Arabidopsis. Science 280,446-450.
11. Luo M, Bilodeau P, Koltunow A, Dennis ES, Peacock WJ, Chaudhury AM (1999) Genes controlling fertilization-independent seed development in Arabidopsis thaliana. Proc Natl Acad Sci USA 96:296-301
12. Ohad N, Yadegari R, Margossian L, Hannon M, Michaeli D, Harada JJ, Goldberg RB, Fischer RL. (1999). Mutations in FIE, a WD polycomb group gene, allow endosperm development without fertilization. Plant Cell 11(3):407-16.
13. Ramin Yadegari andGaryN. Drews.(2004). Female Gametophyte Development. ThePlantCell,16:S133-S141
14. Cory A. Christensen, Edward J.King, John R.Jordan and G. N.Drews. (1997). Megagametogenesis in Arabidopsis wild type and the Gf mutant. Sex. Plant Reprod, 10:49-64
15. Schneitz K, Hulskamp M, Pruitt RE. (1995). Wild-type ovule development in Arabidopsis thaliana:a light microscope study of cleared whole-mount tissue. Plant J 7,731-749.
16. Erik Vollbrecht, and Sarah C. Hake. (1995). Deficiency analysis of female gametogenesis in maize. Developmental Genetics 16,44-63.
17. Mansfield SG, Briarty LG, Erni, S. (1991). Early embryogenesis in Arabidopsis thaliana. I. The mature embryo sac. Can. J. Bot,69,447-460.
18. Frieman W. E. (1998).The evolution of double fertilization and endosperm:an historical perspective. Sexual plant reproduction,11,6-11
19. Jensen K., Fisher D. B. (1968). Cotton embryogenesis:The entrance and discharge of the pollen tube in the embryo sac. Planta 78,158-183
20. Thomas Laux and Gerd Jurgens. (1997). Embryogenesis:a new start in life. The Plant cell,9:989-1000
21. Ray, S., Golden, T., and Ray, A. (1996). Maternal effects of the short integument mutation on embryo development in Arabidopsis. Dev. Biol.180,365-369
22. Golden TA, Schauer SE, Lang JD, Pien S, Mushegian AR, Grossniklaus U, Meinke DW, Ray A. (2002) SHORT INTEGUMENTS1/SUSPENSOR1/CARPEL FACTORY, a Dicer homolog, is a maternal effect gene required for embryo development in Arabidopsis. Plant Physiol.130(2):808-22.
23. Busch M, Mayer U, Jurgens G. (1996). Molecular analysis of the Arabidopsis pattern formation of gene GNOM:gene structure and intragenic complementation. Mol Gen Genet.,250(6):681-91
24. Torres-Ruiz RA, Lohner A, Jurgens G. (1996). The GURKE gene is required for normal organization of the apical region in the Arabidopsis embryo. Plant J 10(6):1005-16.
25. Takada S, Hibara K, Ishida T, Tasaka M. (2001). The CUP-SHAPED COTYLEDON1 gene of Arabidopsis regulates shoot apical meristem formation. Development 128(7):1127-35.
26. Aida M, Vernoux T, Furutani M, Traas J, Tasaka M. (2002). Roles of PIN-FORMED1 and MONOPTEROS in pattern formation of the apical region of the Arabidopsis embryo. Development 129(17):3965-74.
27. Lotan T, Ohto M, Yee KM, West MA, Lo R, Kwong RW, Yamagishi K, Fischer RL, Goldberg RB, Harada JJ.(1998). Arabidopsis LEAFY COTYLEDON1 is sufficient to induce embryo development in vegetative cells. Cell 93(7):1195-205.
28. Stone SL, Kwong LW, Yee KM, Pelletier J, Lepiniec L, Fischer RL, Goldberg RB, Harada JJ. (2001). LEAFY COTYLEDON2 encodes a B3 domain transcription factor that induces embryo development. Proc Natl Acad Sci USA 98(20):11806-11.
29. Kwong RW, Bui AQ, Lee H, Kwong LW, Fischer RL, Goldberg RB, Harada JJ. (2003). LEAFY COTYLEDON1-LIKE defines a class of regulators essential for embryo development. Plant Cell 15(1):5-18.
30. Joe Ogas, Jin-Chen Cheng, Z. Renee Sung, Chris Somerville. (1997). Cellular Differentiation Regulated by Gibberellin in the Arabidopsis thaliana pickle Mutant. Science,277:91-94
31. Ogas J, Kaufmann S, Henderson J, Somerville C. (1999). PICKLE is a CHD3 chromatin-remodeling factor that regulates the transition from embryonic to vegetative development in Arabidopsis. Proc Natl Acad Sci USA.96:13839-13844
32. Kim Boutilier, Remko Offringa, Vijay K. Sharma, Henk Kieft, Therese Ouellet, Lemin Zhang, Jiro Hattori, Chun-Ming Liu, Andre A. M. van Lammeren, Brian L. A. Miki, Jan B. M. Custers, and Michiel M. van Lookeren Campagne.(2002). Ectopic Expression of BABY BOOM Triggers a Conversion from Vegetative to Embryonic Growth. Plant Cell,14(8):1737-1749
33. Hecht V, Vielle-Calzada JP, Hartog MV, Schmidt ED, Boutilier K, Grossniklaus U, de Vries SC. (2001). The Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR KINASE 1 gene is expressed in developing ovules and embryos and enhances embryogenic competence in culture. Plant Physiol.127(3):803-16.
34. Olsen OA, Linnestad C, Nichols SE. (1999). Developmental biology of the cereal endosperm. Trends Plant Sci.4(7):253-257.
35. Olsen OA. (2001). ENDOSPERM DEVELOPMENT:Cellularization and Cell Fate Specification. Annu Rev Plant Physiol Plant Mol Biol.52:233-267.
36. Boisnard-Lorig C, Colon-Carmona A, Bauch M, Hodge S, Doerner P, Bancharel E, Dumas C, Haseloff J, Berger F (2001) Dynamic analyses of the expression of the HISTONE:YFP fusion protein in Arabidopsis show that syncytial endosperm is divided in mitotic domains. Plant Cell 13:495-509
37. Brown RC, Lemmon BE, Nguyen H, Olsen OA. (1999). Development of endosperm in Arabidopsis thaliana. Sex Plant Reprod 12:32-42.
38. Young TE, Gallie DR, DeMason DA. (1997). Ethylene-madiated programmed cell death during maize endosperm development of wild type and shrunken2 genotypes. Plant physiol.115:737-751
39. Young TE, Gallie DR. (2000). Programmed cell death during endosperm development. Plant Mol Biol 44(3):283-301.
40. Lopes MA, Larkins BA. (1993). Endosperm origin, development, and function. Plant Cell 5(10):1383-99. Review.
41. van Hengel AJ, Guzzo F, van Kammen A, de Vries SC. (1998). Expression pattern of the carrot EP3 endochitinase genes in suspension cultures and in developing seeds. Plant physiol.117:43-53
42. Opsahl-Ferstad HG, Le Deunff E, Dumas C, Rogowsky PM. (1997). ZmEsr, a novel endosperm-specific gene expressed in a restricted region around the maize embryo. Plant J.12(1):235-46.
43. Tzafrir I, McElver JA, Liu Cm CM, Yang LJ, Wu JQ, Martinez A, Patton DA, Meinke DW. (2002). Diversity of TITAN functions in Arabidopsis seed development. Plant Physiol 128:38-51
44. McElver J, Patton D, Rumbaugh M, Liu C, Yang LJ, Meinke D. (2000). The TITAN5 gene of Arabidopsis encodes a protein related to the ADP ribosylation factor family of GTP binding proteins. Plant Cell 12:1379-1392
45. Maitz M, Santandrea G, Zhang Z. Lal S, Hannah LC, Salamini F, Thompson RD. (2000). rgfl, a mutation reducing grain filling in maize through effects on basal endosperm and pedicel development. Plant J 23(1):29-42.
46. Becraft PW, Kang SH, Suh SG. (2001). The maize CRINKLY4 receptor kinase controls a cell-autonomous differentiation response. Plant Physiol 127(2):486-96.
47. Sorensen MB, Mayer U, Lukowitz W, Robert H, Chambrier P, Jurgens G, Somerville C, Lepiniec L, Berger F. (2002). Cellularisation in the endosperm of Arabidopsis thaliana is coupled to mitosis and shares multiple components with cytokinesis. Development 129(24):5567-5576.
48. Lauber MH, Waizenegger I, Steinmann T, Schwarz H, Mayer U, Hwang I, Lukowitz W, Jurgens G. (1997). The Arabidopsis KNOLLE protein is a cytokinesis-specific syntaxin. J Cell Biol.139(6):1485-93.
49. Chaudhury AM, Ming L, Miller C, Craig S, Dennis ES, Peacock WJ. (1997). Fertilization-independent seed development in Arabidopsis thaliana. Proc Natl Acad Sci USA 94(8):4223-8.
50. Ohad N, Margossian L, Hsu YC, Williams C, Repetti P, Fischer RL. (1996). A mutation that allows endosperm development without fertilization. Proc Natl Acad Sci USA 93(11):5319-24.
51. Grossniklaus U, Vielle-Calzada JP, Hoeppner MA, Gagliano WB (1998) Maternal control of embryogenesis by MEDEA, a polycomb group gene in Arabidopsis. Science 280:446-450
52. Luo M, Bilodeau P, Koltunow A, Dennis ES, Peacock WJ, Chaudhury AM. (1999). Genes controlling fertilization-independent seed development in Arabidopsis thaliana. Proc Natl Acad Sci USA 96(1):296-301.
53. Luo M, Bilodeau P, Dennis ES, Peacock WJ, Chaudhury A. (2000). Expression and parent-of-origin effects for FIS2, MEA, and FIE in the endosperm and embryo of developing Arabidopsis seeds. Proc Natl Acad Sci USA 97(19):10637-42.
54. Spillane C, MacDougall C, Stock C, Kohler C, Vielle-Calzada JP, Nunes SM, Grossniklaus U, Goodrich J. (2000). Interaction of the Arabidopsis polycomb group proteins FIE and MEA mediates their common phenotypes. Curr Biol. 10(23):1535-8.
55. Sorensen MB, Chaudhury AM, Robert H, Bancharel E, Berger F. (2001). Polycomb group genes control pattern formation in plant seed. Curr Biol 11(4),277-81.
56. Kinoshita T, Harada JJ, Goldberg RB, Fischer RL. (2001). Polycomb repression of flowering during early plant development. Proc Natl Acad Sci USA 98(24):14156-61.
57. Brink R A, Cooper D C. (1947) The endosperm in seed development. Bot Rev,13, 423-541
58. Bhatnagar SP, Sawhney V. (1981). Endosperm:its morphology, ultrastructure, and histochemistry. Int. Rev. Cytol 73,55-102.
59. Vijayaraghavan MR, Prabhakar K. (1984). The endosperm. In Embryology of Angiosperm. Edited by BM John. Berlin, Springer-Verlag,319-376
60. Lopes MA, Larkins BA (1993) Endosperm origin, development, and function. Plant Cell 5:1383-1399
61. Johnston SA, den Nijs TPM, Peloquin SJ, Hanneman REJ. (1980). The significance of genie balance to endosperm development in interspecific crosses. Theor. Appl. Genet 57,5-9.
62. Haig D, Westoby M. (1991). Genomic imprinting in endosperm:Its effect on seed development in crosses between species, and between defferent ploidies of the same species, and its implications for the evolution of apomixis. Philos Trans R Soc Lond,333(1),1-13
63. Birchler JA. (1993). Dosage analysis of maize endosperm development. Ann. Rev. Genet.27,181-204.
64. Haig D, Westoby M. (1989). Parent-specific gene expression and the triploid endosperm. Am Nat,134,147-155
65. Feil, R and Berger, F. (2007). Convergent evolution of genomic imprinting and plants and mammals. Trends in Genetics 23(4):192-9
66. Sanford JP, Clark HJ, Chapman VM, Rossant J. (1987). Differences in DNA methylation during oogenesis and spermatogenesis and their persistence during early embryogenesis in the mouse. Genes Dev.1(10):1039-46.
67. El Kharroubi A, Piras G, Stewart CL. (2001). DNA demethylation reactivates a subset of imprinted genes in uniparental mouse embryonic fibroblasts. J Biol Chem.276(12):8674-80.
68. Kaffer CR, Grinberg A, Pfeifer K. (2001). Regulatory mechanisms at the mouse Igf2/H19 locus. Mol Cell Biol.21(23):8189-96.
69. Jullien, P., Kinoshita, T., Ohad, N., and Berger, F. (2006a). Maintenance of DNA methylation during the Arabidopsis life cycle is essential for parental imprinting. Plant Cell 18,1360-1372
70. Jullien, P, Katz, A, Oliva, M, Ohad, N and Berger, F. (2006b). PcG group complexes self-regulate imprinting of the PcG group gene MEDEA in Arabidopsis. Current Biology 16(5):486-92
71. Xiao, W., Gehring, M., Choi, Y., Margossian, L., Pu, H., Harada, J. J., Goldberg, R. B., Pennell, R. I. and Fischer, R. L. (2003). "Imprinting of the MEA PcG gene is controlled by antagonism between MET1 methyltransferase and DME glycosylase." Developmental Cell 5:891-901.
72. Gehring M, Huh JH, Hsieh TF, Penterman J, Choi Y, Harada JJ, Goldberg RB, Fischer RL. (2006). DEMETER DNA glycosylase establishes MEDEA PcG gene self-imprinting by allele-specific demethylation. Cell 124(3):495-506.
73. Jullien, PE., Mosquna, A., Ingouff, M., Sakata, T., Ohad, N. and Berger F. (2008). Retinoblastoma and its binding partner MSI1 control imprinting in Arabidopsis. Plos Biology 6(8):e194
74. Haun, W., Laoueille-Duprat, S., O'connell, M., Spillane, C., Grossniklaus, U., Phillips, A., Kaeppler, S., and Springer, N. (2007). Genomic imprinting, methylation and molecular evolution of maize Enhancer of zeste (Mez) homologs. Plant Journal 49,325-337
75. Gutierrez-Marcos JF, Costa LM, Dal Pra M, Scholten S, Kranz E, Perez P, Dickinson HG. (2006). Epigenetic asymmetry of imprinted genes in plant gametes. Nature Genetics 38(8):876-8.
76. Rodrigues, JCM; Luo, M; Berger, F and Koltunow, AMG. PcG group gene function and imprinting requirements for sexual and asexual seed development in Angiosperms. (in press)
77. Haun WJ, Danilevskaya ON, Meeley RB, Springer NM. (2009). Disruption of imprinting by mutator transposon insertions in the 5'proximal regions of the Zea mays Mezl locus. Genetics 181 (4):1229-37
78. Adams S, Vinkenoog R. Spielman M, Dickinson HG, Scott RJ. (2000). Parent-of-origin effects on seed development in Arabidopsis thaliana require DNA methylation. Development 127(11):2493-502.
79. Harper JL, Loveli PH, Moore KG. (1970) The shapes and sizes of seeds. Annu. Rev. Ecol. Syst.1,327-356.
80. Silvertown J. (1989). The paradox of seed size and adaption. Trends Ecol. Evol.4, 24-26.
81. Roach D, Wulff R. (1987). Maternal effects in plants. Annu. Rev. Ecol. Syst.18, 209-235.
82. Prioul, JL, Quarrie S, Causse, M, Devienne D. (1997). Dissecting complex physiological functions through the use of molecular quantitative genetics. J. Exp. Bot.48,1151-1163.
83. Lu C, Shen L, Tan Z, Xu Y, He P, Chen Y, Zhu L. (1997). Comparative mapping of QTLs for agronomic traits of rice across environments by using a double haploid population. Theor. Appl. Genet.94,145-150.
84. Maughan PJ, Saghai Maroof MA, Buss GR. (1996) Molecular marker analysis of seed-weight:Genomic locations. gene action, and evidence for orthologous evolution among three legume species. Theor. Appl. Genet.93,574-579.
85. Paterson AH, Lin YR, Li Z, Schertz KF, Doebley JF, Pinson SRM, Liu, SC, Stansel JW, Irvine JE. (1995) Convergent domestication of cereal crops by independent mutations at corresponding genetic loci. Science 269,1714-1718.
86. Alonso-Blanco C, Blankestijn-de Vries H, Hanhart CJ, Koornneef M. (1999). Natural allelic variation at seed size loci in relation to other life history traits of Arabidopsis thaliana. Proc Natl Acad Sci USA 96(8):4710-7.
87. Krizek BA. (1999). Ectopic expression of AINTEGUMENTA in Arabidopsis plants results in increased growth of floral organs. Dev Genet.25(3):224-36.
88. Mizukami Y, Fischer RL. (2000). Plant organ size control:AINTEGUMENTA regulates growth and cell numbers during organogenesis. Proc Natl Acad Sci USA 97(2):942-7.
89. Li Y, Zheng L, Corke F, Smith C, Bevan MW. (2008). Control of final seed and organ size by the DAI gene family in Arabidopsis thaliana.Genes Dev., 22(10),1331-6
90. H.S. Lee and Z.J. Chen, (2001).Protein-coding genes are epigenetically regulated in Arabidopsis polyploids. Proc Natl Acad Sci USA 98,6753-6758
91. Schruff MC, Spielman M, Tiwari S, Adams S, Fenby N, Scott RJ. (2006) The AUXIN RESPONSE FACTOR 2 gene of Arabidopsis links auxin signalling, cell division, and the size of seeds and other organs. Development,133(2):251-61
92. Ohto, M.A., Fischer, R.L., Goldberg, R.B., Nakamura, K., and Harada, J.J. (2005). Control of Seed Mass by APETALA2. Proc Natl Acad Sci U S A 102:3123-3128.
93. Garcia D, Saingery V, Chambrier P, Mayer U, Jurgens G, Berger F. (2003). Arabidopsis haiku mutants reveal new controls of seed size by endosperm. Plant Physiol.131(4),1661-70.
94. Garcia D, Fitz Gerald JN, Berger F (2005) Maternal control of integument cell elongation and zygotic control of endosperm growth are coordinated to determine seed size in Arabidopsis. Plant Cell 17:52-60
95. Luo M, Dennis ES, Berger F, Peacock WJ, Chaudhury A. (2005). MINISEED3 (MINI3), a WRKY family gene, and HAIKU2 (IKU2), a leucine-rich repeat (LRR) KINASE gene, are regulators of seed size in Arabidopsis. Proc Natl Acad Sci USA 102:17531-17536
96. Zhou Y, Zhang X, Kang X, Zhao X. Zhang X, Ni M. (2009). SHORT HYPOCOTYL UNDER BLUE1 Associates with MINISEED3 and HAIKU2 promoters in vivo to regulate Arabidopsis seed development. The Plant Cell 21:106-117
97. Cesar Llave, Kristin D. Kasschau, and James C. Carrington (2000). Virus-encoded suppressor of posttranscriptional gene silencing targets a maintenance step in the silencing pathway. PNAS,97:13401-13406
98. Andreasson E, Jenkins T, Brodersen P, Thorgrimsen S, Petersen NH, Zhu S, Qiu JL, Micheelsen P, Rocher A, Petersen M, Newman M-A, Nielsen HB, Hirt H, Somssich I, Mattsson O and Mundy J. (2005). The MAP kinase substrate MKS1 is a regulator of plant defense responses. EMBO J.,24:2579-2589
99. Morikawa K, Shiina T, Murakami S. Toyoshima Y. (2002) Novel nuclear-encoded proteins interacting with a plastid sigma factor, Sigl, in Arabidopsis thaliana. FEBS Lett.,514:300-304
100. Pan D, Zhang L. (2009).Burst of young retrogenes and independent retrogene formation in mammals.PLoS ONE,4(3):e5040
101.Nicole Bechtold, Sylvie Jolivet, Roger Voisin & Georges Pelletier. (2002) The endosperm and the embryo of Arabidopsis thaliana are independently transformed through infiltration by Agrobacterium tumefaciens.Transgenic Research 12:509-517
102. Citovsky, V., Lee, L.Y., Vyas, S., Glick, E., Chen, M.H., Vainstein, A., Gafni, Y, Gelvin, S.B.,& Tzfira, T. (2006) Identification of subcellular localization of interacting proteins by bimolecular fluorescence complementation in planta. J. Mol. Biol.362,1120-1131.