生长素调控水稻颖花开放的效应研究  

Study of regulating effect of auxin on floret opening in rice

作　　者：何永明 张芳 HE Yong-Ming;ZHANG Fang(Jiangxi Agricultural University/Key Laboratory of Crop Physiology,Ecology and Genetic Breeding,Ministry of Education/Jiangxi Key Laboratory of Crop Physiology,Ecology and Genetic Breeding,Nanchang 330045,Jiangxi,China)

机构地区：[1]江西农业大学/作物生理生态与遗传育种教育部重点实验室/江西省作物生理生态与遗传育种重点实验室,江西南昌330045

出　　处：《作物学报》2023年第6期1690-1698,共9页Acta Agronomica Sinica

基　　金：国家自然科学基金项目(31360295,31801272);江西省自然科学基金项目(20212BAB205006,20202BABL215001)资助

摘　　要：颖花开放由浆片膨大所启动,对水稻授粉受精具有直接影响。生长素是调节花药开裂、花粉育性和种子起始等生殖发育过程的重要激素。为阐明生长素在水稻颖花开放中的调控作用,本研究以粳稻品种中花11为试验材料,调查了外源生长素及其抑制剂对颖花开放的影响,以及内源生长素水平和生长素信号通路基因表达的动态变化。结果表明,IAA(10~20 mmol L^(-1))、NAA(0.05~0.50 mmol L^(-1))浸穗处理将推迟水稻颖花开放,其中高浓度(0.5 mmol L^(-1))NAA能使颖花开放推迟3 d,并表现出颖花张开时间延长和结实率下降的现象。IAA极性运输抑制剂TIBA及其作用抑制剂PCIB也抑制颖花开放。NAA预处理后,增施茉莉酸甲酯(MeJA)能有效恢复颖花开放。水稻颖花中IAA含量在自然开放前2 h迅速下降,比开颖前1 d、2 d分别降低了65.85%、74.27%。与IAA水平变化相对应,颖花开放时浆片IAA生物合成基因(OsTAR2、OsYUCCA3/4/8)表达下调,而催化IAA结合失活的酶基因(OsGH3.2、OsGH3.8)、IAA输出载体基因(OsPIN1、OsPIN1a)以及IAA极性运输正向调节因子BG1基因均显著上调表达。此外,我们也鉴定到13个差异表达的IAA早期响应基因(OsAUX/IAAs、OsARF15、OsSAURs),其中10个上调表达,3个下调表达。综上表明,水稻颖花开放受内源生长素调控,但提高浆片生长素水平则抑制其开放。Floret opening which is driven by swelling of lodicules has a direct effect on rice pollination and fertilization.Auxin is an essential phytohormone in regulating reproductive development processes such as anther dehiscence,pollen fertility,and seed initiation.To elucidate the role of auxin in floret opening,the effects of exogenous auxin and its inhibitors on floret opening,and dynamic changes of endogenous auxin levels,and gene relative expression levels of auxin pathway in florets and lodicules were investigated in japonica cultivar Zhonghua 11.The results showed that the panicles soaked with IAA(10-20 mmol L^(-1))or NAA(0.05-0.50 mmol L^(-1))delayed significantly floret opening.Under high concentration of NAA(0.5 mmol L^(-1)),compared with the water-treated panicles,the floret opening was postponed by three days.The prolonged opening duration of single floret and decreased seed-setting rate were also observed after IAA and NAA treatments.Treatments with IAA polar transport inhibitor TIBA and function inhibitor PCIB delayed florets opening as well.Furthermore,the application of methyl jamonate(MeJA)could restore effectively floret opening which was retared by NAA pretreatments.A sharp decline of IAA levels was detected two hours before floret opening in natural condition.Compared to that at 1 d and 2 d before opening,IAA level in florets at 2 hours before opening was decreased by 65.85%and 74.27%,respectively.Corresponding to the changes of IAA levels in florets,the relative expression levels of IAA biosynthetic genes(OsTAR2,OsYUCCA3/4/8)in the lodicules were down-regulated during floret opening,while the expressions of catabolic genes(OsGH3.2/OsGH3.8)in formation of inactive IAA conjugates,IAA efflux transport genes(OsPIN1,OsPIN1a),and its positive regulator BG1 gene were significantly up-regulated.13 differentially expressed early auxin response genes(OsAUX/IAAs,OsARF15,OsSAURs)were also identified,among which,10 were up-regulated and 3 down-regulated.In conclusion,rice floret opening was regulated by endoge

关 键 词：水稻 颖花开放 生长素 抑制效应 

分 类 号：S511[农业科学—作物学]