Genome-wide Analysis Of NBS-LRR Disease Resistance Genes In Gossypium Hirsutum And Revealing Its Roles In Resistance To Verticillium Wilt

Nucleotide binding site-leucine-rich repeats(NBS-LRR)disease resistance gennes are the main class of disease resistance genes.In order to fully understand the structure characteristic and composition of G.hirsutum disease resistance genes family,and further reveal the functional roles of G.hirsutum disease resistance genes in disease resistance responses,we collected amino acid sequences of NBS-LRR disease resistance genes in genome sequences of Gossypium hirsutum,then its physical located distribution on chromosomes and architecture of the NBS domain was analyzed,and further its homologous comparison compared with Arabidopsis thaliana NBS-LRR genes were conducted.The results showed that 437 NBS-LRR genes can be divided into two subfamilies of group CC-NBS-LRR(315 genes)and TIR-NBS-LRR(122 genes).The CC-NBS-LRR subtype can be further classified into five groups,A,B,C,D,and NL-A.The TIR-NBS-LRR subtype contain seven groups of B,C,D,E,G,TN-A,and putative genes.The starting positions of 380 NBS-LRR genes were obtained.These genes are distributed singly or in clusters on the chromosome,but the distribution does not show specific regularity.Among them,27 % of the disease resistantance genes(103)were distributed on chromosomes in the form of a single gene,which is similar to the proportion of individual disease resistantance genes in Arabidopsis thaliana.The main motifs(p-loop,kinase2,GLPL,MHD)in the NBS region of NBS-LRR were present in the CC-NBS-LRR and TIR-NBS-LRR class,and were highly similar to their corresponding motifs in Arabidopsis thaliana.Some cotton NBS-LRR genes have homologous gene with those of Arabidopsis thaliana,but,most NBS-LRR resistance genes were not homologous with Arabidopsis thaliana NBS-LRR disease resistance genesWe selected some genes from CC-NBS-LRR-B of NBS-LRR disease resistance genes,including 76 genes.Using the virus induced gene silencing(VIGS)technology to study the role of these genes in cotton Verticillium wilt.The results showed that 49 disease resistance genes silencing,the resistance of cotton to Verticillium wilt was not significantly affected.Gh A04G0309,Gh D05G3345,Gh D10G2091,Gh A06G1627,Gh A01G0542,Gh D11G3108,Gh D11G3112,Gh A11G2358,Gh D11G2670,Gh A04G0315,Gh D05G3335,Gh A04G1309,Gh D05G3459,Gh D05G3336,Gh D05G3338,Gh D10G2278,Gh D10G2263,Gh D10G2271,Gh D10G2281,Gh Sca027192G01,Gh D10G2422 and Gh A10G2174 gene silencing,the resistance of cotton to Verticillium wilt was weakened and even disappeared.It showed that these disease resistantance genes are involved in the molecular recognition and resistance of the cotton to Verticillium wilt,which plays an important role in the treatment of Verticillium wilt.This study provides the basis of the data,which is beneficial to further study on disease resistance genes in the biological function and role of G.hirsutum,especially deep understanding disease resistance genes in the role of cotton resistance to all kinds of adversity stress.