Knockdown of OsHox33, a member of the class III homeodomain-leucine zipper gene family, accelerates leaf senescence in rice

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• 作者：WeiJiang Luan (1)
  Ao Shen (1)
  ZhiPing Jin (2)
  SuSheng Song (3)
  ZhengLong Li (1)
  AiHua Sha (4)
  
• 关键词：HD ; Zip III ; leaf senescence ; rice
• 刊名：Science China Life Sciences
• 出版年：2013
• 出版时间：December 2013
• 年：2013
• 卷：56
• 期：12
• 页码：1113-1123
• 全文大小：
• 作者单位：WeiJiang Luan (1)
  Ao Shen (1)
  ZhiPing Jin (2)
  SuSheng Song (3)
  ZhengLong Li (1)
  AiHua Sha (4)
  
  1. College of Life Sciences, Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Normal University, Tianjin, 300387, China
  2. Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
  3. School of Life Science, Tsinghua University, Beijing, 100084, China
  4. Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
  
• ISSN：1869-1889

文摘

The class III homeodomain-leucine zipper (HD-Zip III) gene family plays important roles in plant growth and development, including regulation of apical embryo patterning, embryonic shoot meristem formation, leaf polarity, vascular development, and meristem function, with a particularly crucial function in leaf development. Although HD-Zip III members are highly conserved in land plants, previous studies, such as genetic analyses based on multiple mutants in Arabidopsis and other plants, suggest that various HD-Zip III family genes have evolved with distinct functions and pleiotropic effects on plant growth and development. In this study, we analyzed a HD-Zip III member, OsHox33, and demonstrated that it plays an important role in age-dependent leaf senescence in rice. We constructed two specific RNAi vectors derived from the 5′-end region and 3′-UTR of OsHox33 to knockdown its expression. Transgenic plants harboring either RNAi construct displayed similar phenotypes of precocious leaf senescence symptoms, suggesting that knockdown of OsHox33 accelerates leaf senescence in rice. pOsHox33::GUS fusion expression and RT-PCR revealed that OsHox33 is highly expressed in young organs, especially in young meristems such as shoot apical meristems, intercalary meristems, and young callus. In addition, real-time PCR indicated that OsHox33 was more highly expressed in young leaves than in old leaves. To further investigate OsHox33 function, we analyzed chloroplast ultrastructure in different-aged leaves of RNAi plants, and found that OsHox33 knockdown accelerated chloroplast degradation, which is consistent with RNAi phenotypes. Finally, real-time PCR studies showed that OsHox33 can regulate the expression of GS1 and GS2, two senescence-associated genes. Taken together, the work presented here provides new insights into the function of HD-Zip III members in plants.