QTL Mapping And Transcriptome Analysis Of Aluminum Tolerance Traits In Sweet Corn Seedlings

Aluminum toxicity is a key factor limiting the growth and development of crops in acidic soil,if the harm of aluminum toxicity to crops in acidic soil can be solved,the yield and quality of crops in acidic soil can be improved.In this study,sweet corn aluminum resistant inbred line T56 and aluminum sensitive inbred line T49 were used as experimental materials to perform QTL mapping and transcriptome analysis for aluminum resistant traits at seedling stage.The main results are as follows:Aluminum resistant inbred line T56 and aluminum sensitive inbred line T49 were used as parent,the F₂ isolates were used as the mapping population,which was 208.826 pairs of SSR primer sequences were selected from the maize genome database,and 187 pairs of polymorphic primers were screened out,among which 153 pairs of SSR primers were linked to the linkage group.The linkage map was 1199.10cm in length with an average spacing of 7.83 cm and a range of spacing from 6.05 cm to 11.61 cm.The genetic linkage map met the requirements of QTL localization.The F₂ populations of T56 and T49 were used to locate QTLs for the trait coefficients of plant height,shoot weight,root length,root weight and total fresh weight of the whole plant,a total of 17 QTLs were detected.Three plant height coefficient?PH?QTLs were detected on chromosomes 2,3 and 9 respectively.The explained phenotypic variation ranged from 1.26%to 18.93%.Four QTLs of shoot weight coefficient?SW?were detected,which were located on chromosomes 1 and 9 respectively.The explained phenotypic variation ranged from 7.96%to 25.37%.Four root length coefficient?RL?QTLs were detected on chromosomes 3,9 and 10.The explained phenotypic variation ranged from5.63%to 23.56%.Three root weight coefficient?RW?QTLs were detected,which were located on chromosomes 5 and 9 respectively.The explained phenotypic variation ranged from 13.14%to 23.77%.Three total fresh weight coefficient?FW?QTLs were detected on chromosomes 6 and 9 respectively.The explainable phenotypic variations ranged from6.46%to 18.70%.One of the five QTLs detected in this study was located on chromosome9,with the marker interval of phi065-umc1271,and the explainable phenotypic variation was between 18.67%and 25.37%.Therefore,it is speculated that there are stable main effect genes of aluminum tolerance in this range,which can provide certain reference significance and theoretical guidance for the location,screening and breeding of aluminum tolerance genes of sweet corn and the selection of new varieties of aluminum tolerance.Through the analysis of transcriptome results,there were 3532 differentially expressed genes between T56 and T49 at 0h after aluminum treatment.There were 2185 differentially expressed genes between the two parents after 1 hour of treatment.After 4 hours of treatment,there were 2625 differentially expressed genes between the two parents.After 24hours of treatment,there were 4517 differentially expressed genes between the two parents.After GO enrichment analysis,a total of 9 GO terms with significantly enriched differentially expressed genes were correlated with plant aluminum tolerance.Through KEGG enrichment analysis,the biosynthesis of phenylpropion in the pathway with significantly enriched differentially expressed genes was correlated with plant aluminum tolerance.Further analysis showed that 320 genes related to aluminum response were differentially expressed at 1h,4h and 24h after aluminum treatment.On chromosome 9,there were 25 identical differentially expressed genes within the interval of phi065-umc1271 and 24 hours after the aluminum treatment of both parents.The25 genes were compared with 320 differentially expressed genes that were all expressed after 1 h,4 h and 24 h of aluminum treatment,and there was one identical differentially expressed gene Zm00001d046262.This differentially expressed gene may be the key gene for sweet corn to be resistant to aluminum toxicity,which can improve the ability of sweet corn to be resistant to aluminum toxicity and provide a certain research basis for the breeding of sweet corn varieties with strong resistance to aluminum toxicity.