Genetic Mechanism On Drought-resistance Of Broomcorn Millet At Germination Stage And Seedling Stage Based On GWAS And RNA-seq

Understanding the drought resistance characteristics of broomcorn millet resources and analyzing its molecular genetic mechanism are the premise of mining excellent genes and rational utilization of broomcorn millet crops.This study took broomcorn millet microcore germplasm constructed earlier as the research object,and carried out PEG6000 simulation of drought stress.GWAS analysis was used to explore drought-related QTL sites,and transcriptome sequencing was used to analyze the genetic mechanism of drought resistance of broomcorn millet.The test results are as follows:(1)A total of 256 broomcorn millet microcore germplasm were used as materials.Through comprehensive evaluation of 2 methods of drought resistance identification,3 super-strong drought resistance materials and 7 strong drought resistance materials at germination stage,26 super-strong drought resistance varieties and 14 strong drought resistance varieties at seedling stage were identified.Among them,the Zijingan(00003289),Ukraine shu(00006438)and Baimeizi(00000101)in germination stage and seedling stage have a strong drought resistance.(2)The genome-wide association analysis of drought resistance of broomcorn millet was carried out by using the second-generation resequencing technology combined with drought resistance identification indexes at the germination and seedling stage.Through PCA analysis,linkage disequilibrium analysis and population structure analysis of the sequencing population,we detected that the experimental materials were divided into two populations.A total of 10,911,343 SNP markers and 1,312,430 In Del markers were obtained.Many genes related to drought resistance were selected,such as zinc finger family and E3 ubiquitin ligase.(3)A total of 24,838 SSR markers,5,488 new gene loci,48,248 new transcripts,24,497 complete ORF sequences and 930 lnc RNAs were predicted by transcriptome sequencing analysis,and 43,677 new transcripts were functional annotated and 9,604 transcription factors were predicted.Under drought stress,the differential expression genes of broomcorn millet regulate biosynthesis,photosynthesis,and arginine and proline metabolism.The results showed that broomcorn millet with different drought resistance had different coping mechanisms under drought stress.