| The foxtail millet of the Downy mildew is an important disease that affects foxtail millet production.The screening of disease-resistant resources of Downy mildew and the research of disease resistance genes are of great significance to the disease-resistant breeding of millet and the sustainable development of the industry.In this study,resistant varieties were screened through field surveys for three consecutive years,and the F2 population obtained by crossing the high-susceptible disease Jingu 21 as the male parent and the highresistance disease Jingu 20 as the female parent were used to locate the resistant varieties through BSA analysis.Disease-related genes,and developed some molecular markers.The main findings are as follows:1.Resistance evaluations of 20 millet varieties have been conducted in the field for 3 consecutive years.There were 3 highly susceptible varieties of millet white disease,9 susceptible varieties,3 medium-resistant varieties,5 disease-resistant varieties,and 1 highly resistant variety.Among them,the average incidence rate of Jingu 20 was 4.89%,and the average incidence of Jingu 21 was 48.95%.2.Re-sequencing Jingu 21 and Jingu 20 and comparing them with the reference genome Yugu 1.The results of re-sequencing showed that the average comparison efficiency was 99.01%,the average coverage depth was 35.34 X,and the genome coverage It was 95%;Jingu 21 and Jingu 20 obtained a total of 306,511 In Del sites and 2,287,594 SNP sites;designed In Del specific molecular markers based on the difference sequence and obtained 12 effective In Del molecular markers.3.A mixed pool of extreme susceptibility and resistance was constructed for mixed separation analysis(BSA)to analyze the difference in Δ Index between the resistant and susceptible pools.The results showed that there is a region exceeding the 99% threshold on chromosomes 8 and 9 respectively,which may be the region where QTLs resistant to the disease of millet white disease are located.Among them,there are two significant differences between the resistance,sensation pool,and mixed pool on chromosome 8.The target regions are 440 kb and 990 kb;there is only one significant difference region between the resistance,sensation pool,and mixed pool on chromosome 9.The target area is 3770 kb.A total of 11 disease-resistant candidate genes(Si8g08390,Si8g03800,Si8g03890,Si8g09060,Si8g09120,Si8g09150,Si8g09160,Si8g09220,Si9g02170,Si9g03870,Si9g05680)were discovered among the anti-disease pools,the susceptible pools,and the mixed pools,and their functional annotations are anti-disease protein-RGA1.,Leucine-rich repeat protein kinase,serine/threonine protein kinase,disease-resistant protein RPM1,diseaseresistant protein RPP13,cysteine-rich receptor-like kinase,L-type lectin domain,disease resistance LOCUS class receptor protein kinase.4.The candidate genes were amplified by PCR and sequenced verification in different resistant and susceptible varieties.It was found that the three genes of Si8g09150,Si8g09160,and Si8g09220 had base differences or missing bases between resistant and susceptible varieties.The proteins translated from diseaseresistant varieties are serine,threonine,aspartic acid and other amino acids that play an important role in plant disease resistance.5.The candidate genes were correlated in the transcriptome analysis of resistance and susceptibility,and the cysteine-rich receptor kinase(CRK)gene was identified as participating in the resistance of foxtail millet disease.46 family members were identified by bioinformatics analysis. |
