| The global soil salinization has become more and more serious because of all kinds of factors of the cultivation, such as unreasonable irrigation, fertilization,natural disasters .Soybean is the main oil crops in China, but cultivated soybean genetic diversity has become increasingly narrow in the process of the breeding. Wild soybean is wild relatives of cultivated soybean, a lot of excellent genes were stored in the wild species of the soybean, including resistance to salt,drought,cold,insect ,more pod etc, especially, the wild soybean has a good performance in resistance to salt. In this study,we screened and established the wild soybean population with high genetic diversity by analyzing the phenotypic traits and SSR markers of 327germplasm resources of wild soybean. The comparative analysis of physiological and biochemical characters of the salt resistant wild soybean ST-335 and salt sensitive one SS-736 were carried out in this study. we also did a research on expression of salt-tolerant related genes and the salt tolerance mechanism of wild soybean. The effects of SOS1, SKOR and NSCC on soybean salt tolerance were analyzed by gene overexpressing and mutation in soybean hairy roots. The results of this study provided the theoretically basis for deciphering the salt tolerance mechanism and selecting salt tolerant germplasm of wild soybean. The main results were as follows:1.The agronomic traits of 327 wild soybean germplasm resources were investigated, including main stem, leaf shape, leaf length, leaf width, petiole length,pod length, pod width, flower color etc. It was found that the diversity of the wild soybean resources is very high, but similarity also presented in some of them. A group was established which contained 101 wild soybeans and has a rich diversity by combined agronomic traits and SSR analysis which used 10 of SSR primers. The wild soybean which was chosen to consist the group has high polymorphism of SSR and phenotype. The SSR primers were present high diversity.2.It was found that the wild soybean population had a rich diversity of agronomic traits and other aspects t including main stem type, leaf length, leaf width, petiole length, leaf area, pod length, pod width, grain weight per plant, plant height, dry weight, salt tolerance in seedling stage, etc. The variation coefficients range from 0.18 to 0.79 and the diversity index range from 1.73 to 2.05.3.The comparative physiological and biochemical analysis were carried out in ST-335 and SS-736 after 48 hours by 0.9% NaCl treated. The result of this study showed that the relative water and soluble sugar content, the activity of SOD, POD and CAT, the gene expression of SKOR and SOS1 of ST-335 ( salt-tolerant material)were higher than that of SS-736( salt sensitive material ),but Na + / K +and the gene expression of KOR, NHX ,NSCC of ST-335 is lower than that of SS-736. The tolerances to ion poisoning,osmotic stress and oxidative stress may be higher in ST-335 than that of SS-736, and the exchange of Na +, K + in roots may be controlled by the synergy effect of some ion transport genes. It may be the reasons that ST-335 has higher tolerance to salt stress.4.Overexpression of SKOR and SOS1gene in the soybean hairy roots enhanced the salt tolerance ability of soybean complex Overexpression of NSCC gene made the soybean complex became more sensitive to salt stress. Gene mutations were successfully induced by using CRISPR/Cas9 system in wild soybean hairy roots. We found that Na + / K + ratio of NSCC mutations of hairy roots is significantly lower than that of wild type. It was suggested that the salt tolerance ability of wild soybean could be affected by the expression level of ion channel genes. The method used in this study also provide important theoretical basis for searching salt tolerance genes in the wild soybean. |
PDF Full Text Request