LAZY3 interacts with LAZY2 to regulate tiller angle by modulating shoot gravity perception in rice |
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Authors: | Yueyue Cai Linzhou Huang Yuqi Song Yundong Yuan Shuo Xu Xueping Wang Yan Liang Jie Zhou Guifu Liu Jiayang Li Wenguang Wang Yonghong Wang |
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Affiliation: | 1. Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China;2. College of Advanced Agricultural Sciences, Zhejiang A&F University, Hangzhou, China;3. State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an, China |
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Abstract: | Starch biosynthesis in gravity-sensing tissues of rice shoot determines the magnitude of rice shoot gravitropism and thus tiller angle. However, the molecular mechanism underlying starch biosynthesis in rice gravity-sensing tissues is still unclear. We characterized a novel tiller angle gene LAZY3 (LA3) in rice through map-based cloning. Biochemical, molecular and genetic studies further demonstrated the essential roles of LA3 in gravity perception of rice shoot and tiller angle control. The shoot gravitropism and lateral auxin transport were defective in la3 mutant upon gravistimulation. We showed that LA3 encodes a chloroplast-localized tryptophan-rich protein associated with starch granules via Tryptophan-rich region (TRR) domain. Moreover, LA3 could interact with the starch biosynthesis regulator LA2, determining starch granule formation in shoot gravity-sensing tissues. LA3 and LA2 negatively regulate tiller angle in the same pathway acting upstream of LA1 to mediate asymmetric distribution of auxin. Our study defined LA3 as an indispensable factor of starch biosynthesis in rice gravity-sensing tissues that greatly broadens current understanding in the molecular mechanisms underlying the starch granule formation in gravity-sensing tissues, and provides new insights into the regulatory mechanism of shoot gravitropism and rice tiller angle. |
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Keywords: | tiller angle shoot gravitropism starch biosynthesis auxin LAZY3 rice |
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