The Auxin-Deficient Defective Kernel18 (dek18) Mutation Alters the Expression of Seed-Specific Biosynthetic Genes in Maize

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• 作者：Jamila Bernardi ; Qin-Bao Li ; Yangbin Gao ; Yunde Zhao…
• 刊名：Journal of Plant Growth Regulation
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：35
• 期：3
• 页码：770-777
• 全文大小：957 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Plant Sciences
  Cell Biology
  Agriculture
  Forestry
  
• 出版者：Springer New York
• ISSN：1435-8107
• 卷排序：35

文摘

The dek18 mutant of maize was previously classified as a collapsed kernel mutant named cp*-931A, which has a decreased auxin content in kernels. Molecular and functional characterization of this mutant line offers the possibility to better understand auxin biology during maize seed development. Seeds of the dek18 mutants are smaller compared to wild-type seeds and the vegetative development of dek18 is delayed. Here we analyzed the expression of several auxin-related genes in dek18 homozygous seeds and normal-sized seeds (Dek18/-) segregating on the same ear. Three genes related to auxin biosynthesis ZmAlliinase/Tar3, ZmTar1, and ZmYuc1 were highly downregulated in the mutant compared to the wild type. Sequence analysis of these genes revealed that no nucleotide difference is present in dek18 homozygous seeds compared to Dek18/-, except for ZmYuc1. Two different ZmYuc1 cDNAs sequences are produced: a normal-sized sequence of 1197 bp and a shorter coding sequence lacking the third exon. Ectopic expression of ZmYuc1 cDNAs in Arabidopsis indicates that (i) the ZmYuc1 gene is functional in Arabidopsis and (ii) the third exon is required for the enzymatic activity of the YUCCA1 protein. Because ZmYuc1, ZmTar1, and ZmAlliinase are barely expressed in dek18 homozygous seeds, it is proposed that the mutation responsible for the dek18 phenotype alters the upstream regulation of the auxin biosynthetic pathway.KeywordsSeedAuxinYucca1AlliinaseTar1Zea mays