Study On Application Of Rice OsCOI3 Gene To Improve Stress Resistance Of Crops

Rice(Oryza sativa L.)is one of the main food crops in China.It faced with many adversities,especially drought,salt and other abiotic stresses during its growth.Therefore,it is very necessary to improve the ability to cope with various abiotic environmental stress to ensure food security in rice.Studies have shown that Arabidopsis coronatine insensitive protein 1(COI1)is a jasmonic acid receptor,participates in jasmonic acid signal transduction pathway,and plays an indispensable role in plant growth and development and stress.As a homologous gene of Arabidopsis COI1 in rice,the function of OsCOI3 has not been reported.In this paper,the function of OsCOI3 in rice growth and abiotic stress response was studied by using the functional deletion mutant of OsCOI3(hereinafter referred to as oscoi3):(1)Evolutionary analysis of OsCOI3.Similar to its family members,OsCOI3 also contains conserved amino acid residues interacting with coronatine or JAZs,but located in different evolutionary branches,suggesting that it may differentiate functionally.(2)Spatio-temporal expression pattern and subcellular localization of OsCOI3 in rice tissues and organs.The results of Genevestigator analysis showed that OsCOI3 was expressed in all tissues and organs of rice,especially in the primary root tip,pistil style and ovary.RT-q PCR results showed that the expression level of OsCOI3 in the root is higher than shoot.Subcellular localization analysis shows that OsCOI3 protein was mainly located in the nucleus.(3)The mutation of OsCOI3 improves salt tolerance in rice.The experiment of soil salt stress showed that the curling and yellowing speed of wild type(HY)leaves was faster than that of oscoi3 under the same treatment.The results of medium salt stress test showed that the shoot and primary root of oscoi3 was higher than that of wild type.The malondialdehyde(MDA)content and relative conductivity of oscoi3 are lower than that of wild type under salt stress.(4)The mutation of OsCOI3 led to the reduced tolerance of rice to drought stress.The results of drought tolerance test in soil showed that the leaves of oscoi3 withered earlier than that of wild type under the same conditions.When growing in medium containing PEG,the shoot of oscoi3 was shorter than that of wild type.The results showed that MDA content and relative conductivity of oscoi3 are higher than wild type after drought treatment,and ROS accumulation in oscoi3 is more than that of wild type indicated by DAB and NBT staining.(5)The decreased sensitivity of oscoi3 to JA and ABA may mediate the signal pathway cross between JA and ABA.Sensitivity analysis showed that the inhibition rates of JA and ABA on the main root elongation of oscoi3 were lower than that of wild type.In addition,the stomatal opening and closing experiments showed that the stomatal proportion of wild type decreased more than that of oscoi3 after ABA treatment.RT-q PCR analysis showed that exogenous JA and ABA induced the expression of OsCOI3.At the same time,JA treatment could induce the expression of ABA responsive genes in wild type,and vice versa,and the expression of these genes in oscoi3 was lower than that in wild type.(6)In terms of growth and development,compared with wild type,the plant height of oscoi3 decreased,but the decreased expression of oscoi3 did not affect the agronomic traits of rice,such as seed length,width,thickness and 1000-grain weight.(7)The overexpression transgenic plants(OsCOI3-OE)were obtained.Compared with the wild type(Nip),the plant height of OsCOI3-OE decreased.JA sensitivity analysis showed that the inhibition rate of JA to the underground part of OsCOI3-OE was higher than that of Nip.When treated with Me JA in the dark,it was found that the leaves of OsCOI3-OE plants were more prone to yellowing than those of the wild type(Nip)plants.These results suggest that OsCOI3 may be involved in promoting leaf senescence.These results suggest that OsCOI3 may mediate the cross of JA and ABA pathways and participate in the response of rice to abiotic stress.In this paper,we explored the function of OsCOI3 in rice growth and abiotic stress response in theory,and provided breeding materials for breeding stress resistant rice plants in practice.