过表达水稻OsPIN2通过减弱地上部重力反应增大分蘖角度  

Overexpression of OsPIN2 increases tiller angle by reducing shoot gravitropic response in rice

作　　者：吴佳俊 涂燃冉 张秋丽[1] 邹沁雯 孙志豪 王宏[1] 何光华[1] WU Jia-Jun;TU Ran-Ran;ZHANG Qiu-Li;ZOU Qin-Wen;SUN Zhi-Hao;WANG Hong;HE Guang-Hua(Rice Research Institute,Southwest University/Academy of Agricultural Sciences,Southwest University/Key Laboratory of Crop Molecular Im-provement,Chongqing 400715,China)

机构地区：[1]西南大学水稻研究所/西南大学农业科学研究院/作物分子改良重庆市重点实验室,重庆400715

出　　处：《作物学报》2024年第12期2962-2970,共9页Acta Agronomica Sinica

基　　金：重庆市自然科学基金创新群体(cstc2021jcyj-cxttX0004);重庆市现代农业产业技术体系水稻创新团队项目(CQMAITS202301)资助。

摘　　要：地上部向重力性与分蘖角度形成紧密相关,解析其调控机制有助于合理设计分蘖角度,从而促进作物株型改良。在水稻生长素输出载体基因OsPIN2过表达株系中鉴定到2个分蘖角度显著增大的株系OE-OsPIN2-1/2。扫描电镜观察显示OE-OsPIN2-1/2分蘖基部的近地端与远地端近乎对称生长。向重力性检测发现OE-OsPIN2-1/2幼苗地上部重力反应降低,且重力刺激后生长素标志基因OsIAA20和WUSCHEL相关同源盒基因WOX6/11不对称表达减弱,表明过表达OsPIN2减弱重力作用下的生长素不对称分布。此外,OE-OsPIN2-1/2分蘖基部参与重力反应的正调控基因下调表达而负调控基因上调表达,进一步表明过表达OsPIN2能够减弱地上部重力反应。本研究结果揭示了OsPIN2通过调控地上部向重力性从而控制水稻分蘖角度的机制,为深入研究植物地上部重力反应提供理论依据。Shoot gravitropism is closely related to the formation of the tiller angle,and understanding its regulatory mechanism is crucial for rationally designing tiller angles to improve crop plant architecture.In the rice auxin efflux carrier gene OsPIN2 overexpression lines,two lines with significantly increased tiller angles,OE-OsPIN2-1 and OE-OsPIN2-2,were identified.Scanning electron microscopy revealed that the near-ground and far-ground parts of the tiller bases in OE-OsPIN2-1/2 grew nearly symmetrically.Shoot gravitropism assays indicated that the shoot gravitropic responses of OE-OsPIN2-1/2 seedlings were reduced,and the asymmetric expression of the auxin marker gene OsIAA20 and WUSCHEL RELATED HOMEOBOX6/11(WOX6/11)was weakened upon gravistimulation.This suggests that overexpression of OsPIN2 attenuates the asymmetric distribution of auxin following gravistimulation.Furthermore,the expressions of positive regulators involved in the gravitropic response at the tiller base in OE-OsPIN2-1/2 lines were downregulated,while the expressions of negative regulators were upregulated.This further indicates that overexpression of OsPIN2 leads to a reduced shoot gravitropic response.This study elucidates the mechanism by which OsPIN2 controls rice tiller angle by regulating shoot gravitropism,providing a theoretical basis for in-depth studies of shoot gravitropic responses.

关 键 词：水稻 OsPIN2 分蘖角度 地上部向重力性 

分 类 号：S511[农业科学—作物学]