Responses To Drought Stress And Analysis Of Differentially Expressed Genes In Sunflower Seedlings

Sunflower is an important oil crop in the world and our country.It is drought-resistant and barren-resistant.In Inner Mongolia and other major sunflower cultivation areas of China,the lack of rainfall or uneven distribution of rainfall,such as perennial spring drought,leads to a significant decrease in the yield and quality of sunflower.In this study,drought-resistant inbred line(K58)and water-sensitive inbred line(K55)were used as materials,the growth,development and physiological and biochemical characteristics related to drought resistance of sunflower seedlings were measured,and the response of sunflower to drought stress was discussed based on the transcriptome analysis of drought-resistant inbred line(K58)under different stress,the differential expression of sunflower genes under drought stress was studied.The main results are as follows:(1)The plant height,leaf area,root length,root surface area,root volume,and the ratio of root to shoot,dry weight and root to shoot of sunflower seedlings decreased under14 d and 21 d persistent drought stress,the plant height and root-shoot ratio of drought-resistant inbred lines K58 were significantly lower than those of water-sensitive inbred lines K55.(2)Drought stress has significant effects on the four indicators of catalase activity,proline content,electrical conductivity,and leaf water content.Among them,the reduction in leaf water content and the increase in electrical conductivity of the drought-resistant inbred line K58 are significantly less than that of water sensitivity Inbred line K55 and drought-resistant inbred line K58 have better recovery ability of physiological characteristics after rewatering than water sensitive inbred line K55.(3)In the three comparison groups CK-vs-T7 d,CK-vs-T14 d,and CK-vs-T21 d,the number of differentially expressed genes in sunflower seedling leaves was 6512(4015up-regulated genes,2496 down-regulated genes)and 10553(5952 up-regulated genes,4601 down-regulated genes),1280(866 up-regulated genes,414 down-regulated genes),there are 488 differentially expressed genes shared by the three comparison groups.This indicated that drought stress significantly affected the gene expression of sunflower seedling leaves.(4)Based on the results of differentially expressed gene annotation,3 abscisic acid receptor genes,LOC110869013,LOC110884474,and LOC110879398 were screened out,Four serine protein kinase genes,LOC110895591,LOC110865680,LOC110868435,and LOC110912424,it can be used as key candidate genes for subsequent gene cloning and functional studies.