Effects Of Urea Metabolism Pathway On Seed Germination And Seedling Growth Of Arabidopsis Under Salt Stress

Salt stress severely inhibits seed germination and has an irreversible effect on plant growth and development.Urease is the key enzyme of urea metabolic pathway and it plays a very important role in the germination stage of seeds.Therefore,exploring the urea metabolism pathway and salt stress has important biological significance for the physiological regulation mechanism of seed germination and seedling growth.1.The aturease and atdur3 mutants were analyzed by transcriptome sequencing technology,which gene was related to urea metabolism pathway.A total of 8 differentially expressed genes were obtained.qRT-PCR results showed that the 8 differentially expressed genes responded strongly to salt stress and there were obvious changes in the gene expression.2.Eight differentially expressed gene deletion mutants were obtained through the Arabidopsis Biological Research Center(ABRC).Seed germination and seedling growth were observed under salt stress.The results showed that high salt stress significantly inhibited seed germination and seedling growth of atgrp9 mutants.3.The atgrp9aturease homozygous double mutants were further obtained through hybridization.Under salt stress treatment,atgrp9aturease could significantly increase the inhibitory effect of salt stress on plant growth compared with atgrp9 mutants,and the accumulation of NH4+ in atgrp9aturease was significantly lower than that in atgrp9.The results showed that blocking urea metabolism and reducing the production of NH4+could alleviate the inhibitory effect of high salt stress on the atgrp9 mutant to a certain extent,and also promote the growth of plant seedlings.4.The sosl and sos3 mutants were extremely sensitive to salinity.Seeds could not germinate under 130 mM NaCl treatment.However,the tolerance of sosl and sos3 to high salt stress was significantly improved by exogenously adding urease inhibitor PPD to the salt stress medium.In addition,the sos3aturease double mutant was obtained through hybridization,and its growth under salt stress was analyzed.The results showed that compared with the sos3 mutant,the sos3aturease double mutant had obvious salt tolerance and the NH4+ content in the vivo was significantly reduced.These results indicated that the urea metabolism pathway participated in and affected the process of seed germination and seedling growth under salt stress.