Loss-of-function mutations of the rice GAMYB gene impair α-amylase expression in aleurone and flower development
Loss-of-function mutations of the rice GAMYB gene impair α-amylase expression in aleurone and flower development
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DOI：
10.1105/tpc.017327
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发表时间：
2004-01-01
期刊：
影响因子：
11.6
通讯作者：
Matsuoka, M
中科院分区：
文献类型：
--
作者：
Kaneko, M;Inukai, Y;Matsuoka, M
在大麦糊粉层细胞中，GAMYB是赤霉素（GA）依赖的α-淀粉酶表达的一个正转录调节因子，其分子和生化特性已得到很好的表征。然而，在工厂的其他地方的GAMYB的作用还没有得到很好的理解。为了研究的分子功能的糊粉层细胞外的GAMYB，我们分离的功能丧失的突变体从一个面板的水稻突变体的插入反转录转座子，Tos 17。利用水稻GAMYB（OsGAMYB）和Tos 17的引物进行PCR筛选，分离到3个Tos 17插入到外显子区域的独立突变等位基因。在这些突变体中，响应于GA处理，胚乳中没有α-淀粉酶的表达被诱导，这表明Tos 17插入已经敲除了OsGAMYB功能。在营养生长阶段，我们没有发现突变体的生长和发育的显着缺陷。然而，在向生殖阶段过渡后，观察到节间缩短和花器官发育缺陷，特别是花粉发育缺陷。另一方面，在开花时间上没有检测到差异。OsGAMYB在花药的糊粉层细胞、花序茎尖、雄蕊原基和绒毡层细胞中有高水平表达，在营养生长期的器官和伸长的茎中有低水平表达。这些结果表明，除了在糊粉层中诱导α-淀粉酶的作用之外，OsGAMYB还对花器官发育和花粉发育至关重要。
GAMYB was first isolated as a positive transcriptional regulator of gibberellin (GA)-dependent alpha-amylase expression in barley aleurone cells, and its molecular and biochemical properties have been well characterized. However, the role of GAMYB elsewhere in the plant is not well understood. To investigate the molecular function of GAMYB outside of the aleurone cells, we isolated loss-of-function mutants from a panel of rice mutants produced by the insertion of a retrotransposon, Tos17. Through PCR screening using primers for rice GAMYB (OsGAMYB) and Tos17, we isolated three independent mutant alleles that contained Tos17 inserted in the exon region. No alpha-amylase expression in the endosperm was induced in these mutants in response to GA treatment, indicating that the Tos17 insertion had knocked out OsGAMYB function. We found no significant defects in the growth and development of the mutants at the vegetative stage. After the phase transition to the reproductive stage, however, shortened internodes and defects in floral organ development, especially a defect in pollen development, were observed. On the other hand, no difference was detected in flowering time. High-level OsGAMYB expression was detected in the aleurone cells, inflorescence shoot apical region, stamen primordia, and tapetum cells of the anther, but only low-level expression occurred in organs at the vegetative stage or in the elongating stem. These results demonstrate that, in addition to its role in the induction of alpha-amylase in aleurone, OsGAMYB also is important for floral organ development and essential for pollen development.