Screening And Transcriptome Analysis Of Salt And Alkali Tolerance Of Maize EMS Mutagenic Materials

Due to climate change and underground saline irrigation and other factors,soil salinization is one of the ecological factors limiting crop growth,which poses a great challenge to the guarantee of food security.Understanding the physiological change mechanism of crops under saline-alkali environmental stress and related metabolic regulation genes is an important measure to mine saline-alkali tolerant germplasm resources.Corn is one of the crops with the largest planting area.With the rapid development of animal husbandry in China,the utilization of germplasm resources of corn for both food and feed.Therefor,it is of great significance to understand and explore the available saline-alkali tolerant germplasm resources of maize for ensuring food security.In this study,the inbred lines induced by EMS were selected in high concentration saline-alkali environment in the field,the materials with strong salt-alkali tolerance and good adaptability were selected for stress treatment in different concentration saline-alkali solution,through physiological and biochemical indexes and metabolite analysis of EMSinduced maize materials,salt and alkali tolerant maize germplasm materials and salt tolerant mechanism were screened.The main conclusion are as following:(1)The maize materials of 30 induced by EMS were screened in field with pH of 9.01 and salt content of 6.4g/kg.According the plant height,ear height,stem diameter,ear height and ear diameter were analyzed by principal component analysis(PCA)and cluster analysis.Form 30 maize materials induced by EMS,19M667、19M664、19Z28 and 19M902 were more sensitive to saline-alkali environment.Meanwhile,it provides reference for further research.(2)Under 5 different saline-alkali concentrations,the germination ability of maize was screened for salt-alkali tolerance,principal component analysis combined with entropy weight method and membership function was used to evaluate the maize material damage.After saline-alkali stress,the germination percentage and the average growth length of 4 EMS induced maize decreased with the increase of saline-alkali concentration.The contents of soluble protein,soluble sugar and proline in maize osmosis increased peroxide and reactive oxygen species,antioxidant enzymes,reduced ascorbic acid and reduced ascorbic acid and reduced glycidy glutamate increased first and then decreased with the increase of salinity.By principal component analysis POD、H2O2、SS、MDA and GSH were used as the criteria for the classification of injury grade.According to the entropy weight method,material M483>M699>M738>B73 was evaluated synthetically.Depend on value Z,they were divided into mild stress(0.71<Z<3.64);moderate stress(6.22<Z<9.23);severe stress(10.09<Z<11.64)and extreme stress(12.61<Z<14.97).In the pure salt solution stress treatment,the four materials showed the comprehensive performance of material M483>M699>B73>M738.(3)Mut85,a mutagenesis mutant of EMS,was sequenced in 150mmol/L salt solution at Bud stage,and wild-type B73 was used as control,there were 5637 4831 5642 and 7498 genes at 1、3、5 and 7 days after treatment,among which 2473、2797、2267 and 3698 gens were up-regulated,the number of down regulated genes was 3164、1584、3375 and 3800.The results indicated that the number of different genes responding to salt stress in Mut85 mutant at different days.According to Go function of differential genes was enriched in the BP class,with the main glutathione metabolism,followed by carbohydrate metabolism,cellular glucan metabolism and defense responses.In the CC category,membrane was the most abundant,followed by cell wall and exosome.Similarly.In the MF,the activities of hydrolases were the most abundant,followed by xylose,chitin binding,chitinase activity and transferase activity.According to KEGG function of differential genes.The result showed that it was mainly involved in plant hormone signal transduction,phenylpropaniod biosynthesis、oxidative phosphorylation reaction、carbon metabolism、MAPK signaling pathway、stress-related metabolic reactions such as starch and sucrose metabolism and glutathione metabolism,in which plant hormone signal transduction pathway and phenylpropane biosynthesis pathway were enriched at all stages of treatment.