An orchestrated ethylene-gibberellin signaling cascade contributes to mesocotyl elongation and emergence of rice direct seeding  

作　　者：Yusong Lyu Xinli Dong Shipeng Niu Ruijie Cao Gaoneng Shao Zhonghua Sheng Guiai Jiao Lihong Xie Shikai Hu Shaoqing Tang Xiangjin Wei Peisong Hu 

机构地区：[1]State Key Laboratory of Rice Biology and Breeding,China National Center for Rice Improvement,China National Rice Research Institute,Hangzhou 310006,China [2]College of Agriculture and Biotechnology,Zhejiang University,Hangzhou 310058,China

出　　处：《Journal of Integrative Plant Biology》2024年第7期1427-1439,共13页植物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(32188102 and 32101763);Zhejiang Provincial Science and Technology Project(2020R51007);the Key Research and Development Program of Zhejiang province(2022C02011);the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CACB-202402).

摘　　要：A mechanized direct seeding of rice with less labor and water usage,has been widely adopted.However,this approach requires varieties that exhibit uniform seedling emergence.Mesocotyl elongation(ME)offers the main drive of fast emergence of rice seedlings from soils;nevertheless,its genetic basis remains unknown.Here,we identify a major rice quantitative trait locus Mesocotyl Elongation1(qME1),an allele of the Green Revolution gene Semi-Dwarf1(SD1),encoding GA20-oxidase for gibberellin(GA)biosynthesis.ME1 expression is strongly induced by soil depth and ethylene.When rice grains are direct-seeded in soils,the ethylene core signaling factor OsEIL1 directly promotes ME1 transcription,accelerating bioactive GA biosynthesis.The GAs further degrade the DELLA protein SLENDER RICE 1(SLR1),alleviating its inhibition of rice PHYTOCHROME-INTERACTING FACTOR-LIKE13(OsPIL13)to activate the downstream expansion gene OsEXPA4 and ultimately promote rice seedling ME and emergence.The ancient traits of long mesocotyl and strong emergence ability in wild rice and landrace were gradually lost in company with the Green Revolution dwarf breeding process,and an elite ME1-R allele(D349H)is found in some modern Geng varieties(long mesocotyl lengths)in northern China,which can be used in the direct seeding and dwarf breeding of Geng varieties.Furthermore,the ectopic and high expression of ME1 driven by mesocotyl-specific promoters resulted in rice plants that could be direct-seeded without obvious plant architecture or yield penalties.Collectively,we reveal the molecular mechanism of rice ME,and provide useful information for breeding new Green Revolution varieties with long mesocotyl suitable for direct-seeding practice.

关 键 词：rice(Oryza sativa L.) direct seeding Green Revolu-tion mesocotyl elongation ETHYLENE GIBBERELLIN semi-dwarf1(SD1) 

分 类 号：S511[农业科学—作物学]