Temporal control of the Aux/IAA genes BnIAA32 and BnIAA34 mediates Brassica napus dual shade responses  

作　　者：Yafei Li Yiyi Guo Yue Cao Pengguo Xia Dongqing Xu Ning Sun Lixi Jiang Jie Dong 

机构地区：[1]Institute of Crop Science,College of Agriculture and Biotechnology,Zhejiang University,Hangzhou 310058,China [2]Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province,College of Life Sciences and Medicine,Zhejiang Sci-TechUniversity,Hangzhou310018,China [3]State Key Laboratory of Crop Genetics and Germplasm Enhancement,College of Agriculture,Nanjing Agricultural University,Nanjing 210095,China [4]Key Laboratory of Growth Regulation and Transformation Research of Zhejiang Province,School of Life Sciences,Westlake University,Hangzhou 310024,China

出　　处：《Journal of Integrative Plant Biology》2024年第5期928-942,共15页植物学报（英文版）

基　　金：supported by the Scientific Innovation 2030 Project(2022ZD0400801);the National Key R&D Program of China(2022YFD1200400);the National Natural Science Foundation of China(32100190);the National Natural Science Fund for Excellent Young Scientists Fund Program(Overseas).

摘　　要：Precise responses to changes in light quality are crucial for plant growth and development.For example,hypocotyls of shade-avoiding plants typically elongate under shade conditions.Although this typical shade-avoidance response(TSR)has been studied in Arabidopsis(Arabidopsis thaliana),the molecular mechanisms underlying shade tolerance are poorly understood.Here we report that B.napus(Brassica napus)seedlings exhibit dual shade responses.In addition to the TSR,B.napus seedlings also display an atypical shade response(ASR),with shorter hypocotyls upon perception of early-shade cues.Genome-wide selective sweep analysis indicated that ASR is associated with light and auxin signaling.Moreover,genetic studies demonstrated that phytochrome A(BnphyA)promotes ASR,whereas BnphyB inhibits it.During ASR,YUCCA8 expression is activated by early-shade cues,leading to increased auxin biosynthesis.This inhibits hypocotyl elongation,as young B.napus seedlings are highly sensitive to auxin.Notably,two non-canonical AUXIN/INDOLE-3-ACETIC ACID(Aux/IAA)repressor genes,BnIAA32 and BnIAA34,are expressed during this early stage.BnIAA32 and BnIAA34 inhibit hypocotyl elongation under shade conditions,and mutations in BnIAA32 and BnIAA34 suppress ASR.Collectively,our study demonstrates that the temporal expression of BnIAA32 and BnIAA34 determines the behavior of B.napus seedlings following shade-induced auxin biosynthesis.

关 键 词：Brassica napus high-density planting IAA32/34 light signal transduction shade response temporal gene expression 

分 类 号：S565.4[农业科学—作物学]