甘薯苗期耐低钾性状GWAS分析及候选基因筛选OA

Sweetpotato is a typical"potassium(K+)-loving"crop.Exploring genetic resources of low-K+-tolerance and elucidating the underlying mechanisms in sweetpotato are important strategies to address soil potassium deficiency and the shortage of potas-sium resources.This study aimed to screen candidate genes associated with low-K+tolerance in sweetpotato through ge-nome-wide association analysis(GWAS),providing a reference for breeding low-K+-tolerant varieties and mining genes for effi-cient K+utilization.A total of 213 sweetpotato varieties(lines)were subjected to hydroponic experiments under low-K+stress(0.1 mmol L-1 K+)and normal K+treatment(10.0 mmol L-1 K+).Traits including biomass,K+content,K+accumulation,K+use efficiency,and relative growth rate were collected for GWAS.Results showed that six traits—dry biomass,fresh biomass,relative growth rate,shoot K+accumulation,root K+accumulation,and whole plant K+accumulation—were significantly or extremely significantly correlated with each other.Through GWAS,seven genomic segments associated with five traits(relative growth rate,shoot K+content,root K+accumulation,plant K+accumulation,and dry biomass)were identified,containing a total of 35 SNP loci.Based on core SNP loci and gene function annotation,7 candidate genes related to low-K+-tolerance in sweetpotato were predicted.RT-qPCR verification discovered that three candidate genes,itf12g23740.t1,itf08g06140.t1,and itf08g06320.t1-encoded cation/H+exchanger 15(CHX15),auxin receptor F-box protein 5(AFB5),and vernalization-insensitivity 3-like 1(VIL1),respectively,showed expression differences among varieties with contrasting low-K+-tolerance.Overall,a total of 35 significant SNP loci associated with low-K+tolerance traits were detected in the 213 sweetpotato accessions,and seven candidate genes were predicted.Among them,itf12g23740.t1,itf05g03220.t1,and itf08g06140.t1 are important candidate genes for low-K+tolerance in sweetpotato and warrant further investigation.