Difference Of Salt And Alkali Tolerance And Transcriptome Analysis Of Soybean Varieties At Seedling Stage

In order to provide experimental data and theoretical basis for the utilization of soybean in saline alkali land and the exploration of the mechanism of salt alkali resistance of soybean,the comprehensive evaluation of salt alkali resistance of different soybean varieties was carried out,and the relatively salt alkali resistant soybean varieties were screened out.The seedlings of 18 soybean varieties(25 d old)were treated with 60 mmol/L mixed salt(the molar ratio of NaHCO3:Na2CO3 is 9:1).After 7 d of treatment,plant height,stem diameter,leaf area,main root length,dry weight on the ground,net photosynthetic rate(Pn),intercellular CO2 concentration(Ci),transpiration rate(Tr)and stomatal conductance(Gs)were measured.Salt tolerance and alkalinity of 18 soybean varieties were evaluated by principal component analysis and fuzzy mathematics membership function,and cluster analysis was carried out.NaHCO3 and Na2CO3 were mixed The effects of mixed salt stress on physiological and biochemical characters,morphological characters,dry matter and 100 seed weight of different soybean varieties were analyzed.The mixture of NaHCO3 and Na2CO3 was used to stress the 25-day-old salt tolerant soybean variety Dongnong42 and the alkali sensitive soybean variety Jiyu256 at 0 h The transcriptome was sequenced at 3 h,12 h.The main results are as follows:1.By principal component analysis,the load of plant height,main root length and net photosynthetic rate(Pn)is the largest,which can be used as the main index to measure salt and alkali tolerance and variety selection of soybean.According to the fuzzy mathematics membership function meth od,the salt and alkali tolerance of different soybean varieties were sorted,and the salt and alkali tolerance showed obvious differences.Finally,through cluster analysis,18 soybean varieties can be divided into three categories,Dongnong 42,Hybriddou 5,Jiyu 257 and NMD2 were salt tolerant,Jiyu 611,Jiyu 299,Kaidou 18,Dongnong 69,Dongnong 60,Hefeng 35,Yabuli,Dongnong 64,NMD3,NMD1 and Tiedou 39 were middle salt tolerant,and Jiyu 256 and Dongnong63 were salt sensitive..2.Under salt and alkali stress,SPAD value,transpiration rate and qp of leaves of Dongnong42 increased first and then decreased with the increase of stress concentration,while net photosynthetic rate,stomatal conductance,Fm,Fv/Fm and ETR of leaves of Jiyu 256 decreased continuously with the increase of stress concentration,intercellular CO2 concentration and NPQ increased continuously,intercellular CO2 concentration of leaves of Dongnong42 decreased first and then increased,Fm,Fv/Fm,The SOD activity,CAT activity,starch content,relative conductivity of leaves and roots,POD activity of roots all increased first and then decreased,proline content and soluble sugar content of leaves and roots all increased continuously,MDA content decreased first and then increased,CAT activity,SOD activity,soluble sugar and soluble sugar content of leaves and roots of Jiyu 256 The content of soluble protein was lower than that of control,MDA and relative conductivity were higher than that of control.30 mmol/L salt alkali stress promoted the characters of Dongnong 42 to some extent,but did not significantly inhibit the characters of Jiyu256.Three varieties of soybean were affected by different degrees under 60 mmol/L alkali concentration.The influence of alkali resistant varieties was less than that of sensitive varieties,and all varieties of soybean were seriously affected under 90 mmol/L alkali concentration,indicating that 90 mmol/L alkali salt treatment concentration may be the salt tolerance of soybean Critical value of alkali concentration.3.In the early stage of stress(0h vs 3h),there are 2717 up-regulated genes in Jiyu 256,accounting for 71.53%of the differential expression genes,5484 up-regulated genes in Dongnong42,accounting for 77.92%of the differential expression genes,14334 up-regulated genes in Jiyu 256,accounting for 82.55%of the total differential expression genes,and 15029 up-regulated genes in Dongnong42,accounting for 85.01%of the total differential expression genes In the late stage of stress,the ability of two varieties to deal with the damage caused by stress was stronger than that in the early stage of stress,while the salt tolerant varieties showed greater advantages.4.According to the analysis of go function classification and enrichment of 4150 genes in Jiyu 256 12 vs Dongnong42 12 h group,3176 differential genes were annotated into 39 subclasses of go function classification,among which cell,cell component,linkage,catalytic process,cell process and metabolic process play a key role in the regulation of soybean salt tolerance;KEGG Functional classification showed that there were 4105 differentially expressed genes,which were enriched into 331 metabolic pathways,among which 16 pathways were significantly enriched,including phenylpropanoid biosynthesis,starch and sucrose metabolism,plant hormone signal transduction,secondary metabolite biosynthesis and flavonoids biosynthesis,peroxidase,auxin,jasmonate,β-glucosidase,trehalose-6-phosphate Acid enzyme activity is the main cause of phenylpropanoid biosynthesis,plant hormone signal transduction and changes of starch and sucrose metabolic pathways.5.After salt and alkali stress,1347 and 1096 differential genes were annotated into TFsdatabase of Dongnong 42 and Jiyu 256 respectively,covering 48 TFs families.Among them,bHLH,ERF,MYB and WRKY transcription factor families accounted for a higher proportion in the two soybean varieties.