The Preliminary Function Analysis On OsNCED3 Gene In Rice(Orazy Sativa L.)

Abscisic acid(ABA)is one of the five hormones of plants that has a wide range of physiological effects in plants embryo development,seed germination,maturity and dormancy,plants and fruit ripening,response to rtress.ABA synthesis has a close relationship with 9-cis-epoxycarotenoid dioxygenase(NCED).The grown of rice may be affected by abiotic stresses such as cold,heat and drought.The study of OsNCED3 will help to understand the response to various abiotic stresses in rice and provide evidences for improved stress tolerance in rice by genetic breeding method.In this study,we study physiological functions of OsNCED3 in response of abiotic stress with materials of Nipponbare as wild-type and Osnced3 mutant by CRISPR/Cas9 mediated gene knockout,The main results are as follows:1)we obtained a Osnced3 homozygous mutant line of 53bp deletion by CRISPR/Cas9 mediated gene knockout and agrobacterium-mediated genetic transformation.2)Under abscisic acid(1,3,5 pM)condition the reduced rate of shoot length of Osnced3 transgenic lines were 52.75%,60.44%and 89.01%respectively.The reduced rate of shoot length of wild type were 9.52%,19.05%and 71.43%.The reduced rate of shoot length of Osnced3 transgenic lines was higher than that of wild type.The reduced rate of root length of Osnced3 transgenic lines were 52.95%,54.44%,69.12%respectively.The reduced rate of root length of wild type were 9.52%,19.05%and 71.43%.The reduce rate of root length of Osnced3 transgenic lines was higher than that ofwild type.3)The withered degree of Osnced3 transgenic lines under 150mM NaCl condition was higher than that of wild type.After the treatment of 150mM NaCl condition the survival rate of Osnced3 transgenic lines was 59.41%while wild type was 89.01%.The survival rate of Osnced3 transgenic lines was lower than that of wild type.4)The withered degree of Osnced3 transgenic lines under 250mM Mannitol condition was higher than that of wild type.Under 250mM Mannitol condition the survival rate of Osnced3 transgenic lines was 64.37%and the survival rate of wild type was 86.34%.The survival rate of Osnced3 transgenic lines was lower than that of wild type.5)The withered degree of Osnced3 transgenic lines under 20%PEG condition was higher than that of wild type.After 20%PEG condition the survival rate of Osnced3 transgenic lines was 76.15%and the survival rate of wild type was 93.93%.The survival rate of Osnced3 transgenic lines was lower than wild type.6)The withered degree of Osnced3 transgenic lines under drought condition comed from soil was higher than that of wild type.After drought condition the relative electrical conductivity in leaves of Osnced3 transgenic lines was higher than that of wild type.7)The water loss rate in leaves of Osnced3 transgenic lines was similar with wild type within 1h,and higher than that of wild type within 1 to 4h,and similar with wild type at last within 4h to 5h.The above results showed that knockout OsNCED3 gene in Rice can reduce the drought and salt tolerance of transgenic plants.It is evidence that OsNCED3 is related with drought and salt tolerance in Rice.OsNCED3 may plays an important role in response to abiotic stress in rice.