Knock-Down the Expression of Brassinosteroid Receptor TaBRI1 Reduces Photosynthesis, Tolerance to High Light and High Temperature Stresses and Grain Yield in Wheat
Knock-Down the Expression of Brassinosteroid Receptor TaBRI1 Reduces Photosynthesis, Tolerance to High Light and High Temperature Stresses and Grain Yield in Wheat
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DOI：
10.3390/plants9070840
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发表时间：
2020-07-01
期刊：
影响因子：
4.5
通讯作者：
Tong, Yiping
中科院分区：
文献类型：
--
作者：
Fang, Jingjing;Zhu, Weiqi;Tong, Yiping
油菜素内酯（BR）缺失或不敏感突变体表现出改变植株结构的潜在影响产量，其潜在的生理和分子机制仍有待探索。本研究从六倍体小麦（Triticum estivum L.）并进一步从总受体TaBRI 1表达显著降低的品种小偃81、TaBRI 1-A1和TaBRI 1-D1的离子束诱导突变体中分离TaBRI 1-A1、TaBRI 1-D1缺失突变体。TaBRI 1敲低突变体表现出相对直立的叶片和显着降低的千粒重。进一步的研究表明，TaBRI 1敲低突变体在整个灌浆期表现出光合速率的显著降低。通过TaBRI 1-A1、TaBRI 1-D1缺失或使用病毒诱导的基因沉默产生的TaBRI 1敲除植物表现出光系统II（PSII）效率（Fv/Fm、Phi（PSII）和电子传递速率（ETR））的降低，尤其是在强光和高温胁迫下。24-表油菜素（EBR）处理增加了正常和强光高温胁迫条件下野生型的CO2同化速率，但在TaBRI 1敲低突变体中没有观察到这种增加效应。同时，在EBR处理后的TaBRI 1敲低突变体中，包括TaDWARF 4、TaCPD 1和TaCPD 90 C1的BR生物合成基因的表达水平没有降低或降低程度较小。这些结果表明TaBRI 1是维持光合作用和对强光和高温胁迫的耐受性所必需的，这两者对于籽粒产量都是重要的，并且将是控制植物光合作用和小麦产量的可能的工程靶标。
Brassinosteroid (BR)-deficient or -insensitive mutants exhibited altered plant architecture with the potential to impact yield, the underlying physiological and molecular mechanisms are still to be explored. In this study, we cloned three BR receptor homologous genes TaBRI1-A1, -B1 and -D1 from hexaploid wheat (Triticum estivum L.) and further isolated the TaBRI1-A1, TaBRI1-D1 deletion mutants from the ion beam-induced mutants of variety Xiaoyan81, TaBRI1-Al and TaBRI1-D1 in which the expression of total receptor TaBRI1 was significantly decreased. The TaBRI1 knock-down mutants exhibited relatively erect leaves and a significant decrease in the 1000-grain weight. Further studies showed that TaBRI1 knock-down mutants showed a significant reduction in photosynthetic rate during the whole grain-filling stage. TaBRI1 knock-down plants generated by TaBRI1-Al, TaBRI1-D1 deletion or using virus-induced gene silencing exhibited the reduction in the efficiency of photosystem II (PSII) (Fv/Fm, Phi(PSII) and electron transport rate, ETR) especially under high light and high temperature stresses. The 24-epibrassinolide (EBR) treatment increased CO2 assimilation rate in the wild type under both normal and high light and high temperature stresses conditions, but this increasing effect was not observed in the TaBRI1 knock-down mutants. Meanwhile, the expression levels of BR biosynthetic genes including TaDWARF4, TaCPD1 and TaCPD90C1 is not decreased or decreased to a lesser extent in the TaBRI1 knock-down mutants after EBR treatment. These results suggested that TaBRI1 is required for maintaining photosynthesis and tolerance to high light and high temperature stresses both of which are important for grain yield and will be a possible engineered target to control plant photosynthesis and yields in wheat.