Abstract
Precise responses to changes in light quality are crucial for plant growth and development.For ex-ample,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 re-sponses.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 in-dicated 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 hypo-cotyl 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 fol-lowing shade-induced auxin biosynthesis.
基金项目
Scientific Innovation 2030 Project(2022ZD0400801)
National Key R&D Program of China(2022YFD1200400)
National Natural Science Foundation of China(32100190)
National Natural Science Fund for Excellent Young Scientists Fund Program(Overseas)()
维普
万方数据