Carbon Starved Anther modulates sugar and ABA metabolism to protect rice seed germination and seedling fitness.
Carbon Starved Anther modulates sugar and ABA metabolism to protect rice seed germination and seedling fitness.
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DOI：
10.1093/plphys/kiab391
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发表时间：
2021-08
期刊：
影响因子：
7.4
通讯作者：
Linlin Sun;Zheng Yuan;Duoxiang Wang;Jingbin Li;Jin Shi;Yangyang Hu;Jing Yu;Xiaofei Chen
中科院分区：
文献类型：
--
作者：
Linlin Sun;Zheng Yuan;Duoxiang Wang;Jingbin Li;Jin Shi;Yangyang Hu;Jing Yu;Xiaofei Chen
种子萌发是植物生存和农业生产的关键，种子萌发受种子内部因素和外部环境条件的影响。然而，作物早期种子萌发的遗传基础和潜在的分子机制仍不清楚。在这里，我们报告，R2 R3 MYB转录因子碳饥饿花药（CSA）的特异性表达在水稻胚和糊粉响应种子吸胀，峰值在3-6小时，吸胀后24小时检测不到。CSA种子萌发速度比野生型水稻种子，有较高水平的淀粉酶活性，葡萄糖，和非活性脱落酸-葡萄糖酯（ABA-GE），但阿坝水平较低。通过分析CSA相关的转录组和CSA与下游靶基因的结合，我们确定了两个糖酵解基因作为CSA的直接靶点。CSA抑制淀粉酶3A表达以限制淀粉产生葡萄糖，并激活0 s3 BGlu 6表达以促进ABA-GE与阿坝的解缀合;这些功能用于减缓发芽并提高幼苗在生长的前3周对非生物胁迫的恢复力。因此，本研究揭示了CSA在早期种子萌发过程中通过平衡葡萄糖和阿坝代谢来优化种子萌发和胁迫响应适应性的保护机制。
Seed germination is critical for plant survival and agricultural production, which is affected by both internal seed factors and external environmental conditions. However, the genetic basis and underlying molecular mechanisms of early seed germination in crops remain largely unclear. Here, we report that R2R3 MYB transcription factor Carbon Starved Anther (CSA) is expressed specifically in Oryza sativa embryo and aleurone in response to seed imbibition, peaking at 3-6 h and undetectable by 24-h post-imbibition. CSA seeds germinated more quickly than wild-type rice seeds and had higher levels of amylase activity, glucose, and inactive abscisic acid-glucose ester (ABA-GE), but lower levels of ABA. Through analyzing the CSA-associated transcriptome and CSA binding to downstream target genes, we identified two glycolytic genes as direct CSA targets. CSA inhibits Amylase 3A expression to limit glucose production from starch and activates Os3BGlu6 expression to promote de-conjugation of ABA-GE to ABA; these functions serve to slow germination and improve seedling resilience to abiotic stress in the first 3 weeks of growth. Therefore, this study unveils a protection mechanism conferred by CSA during early seed germination by balancing glucose and ABA metabolism to optimize seed germination and stress response fitness.