Analysis On Resistance Function Of WAK And DUF642 Gene Families To Verticillium Wilt In Gossypium Hirsutum

Verticillium wilt,a vascular fungal disease,is transmitted through soil and seeds and one of the most important diseases affecting cotton yield and fiber quality in China.Verticillium wilt is mainly caused by Verticillium dahliae.In this study,two gene families,wall associated kinase(WAK)and domain of unknown function 642(DUF642),were identified from the genome of G.hirsutum TM-1.These two gene families were characterized with bioinformatics analysis,including chromosome location,physicochemical properties,gene structures and genetic relationship.Through transcriptome data and real-time quantitative detection technology,the expressiones of these genes under various stresses were analyzed.In addition,three genes including GhWAK26,GhWAK77 and GhDUF642-10 were further studied on their resistance to V.dahliae.The main results were as follows:1.81 WAKs genes(GhWAKs)were identified from the upland cotton genome.GhWAKs distribute on 18 chromosomes and mostly localized on the plasma membrane.Most of GhWAKs have similar genetic structures.According to the protein domain,GhWAKs could be divided into 7 subgroups.2.12 GhWAKs could be induced at the transcriptional level by V.dahliae.GhWAK77 was located on plasma membrane.After spraying with MeJA and SA,GhWAK26 and Gh WAK77 were significantly up-regulated.3.VIGS technology was used to silence GhWAK26 and GhWAK77.At 20 dpi(days post inoculation),the disease index of silencing group was significantly higher than that of the control,indicating that the resistance of cotton plants to V.dahliae was significantly reduced because of GhWAK26 and GhWAK77 silencing.The results of isolation and culture for V.dahliae showed that the silencing of GhWAK26 and GhWAK77 accelerated the expansion of Verticillium wilt in cotton.The results of PCR detection showed that the silencing of Gh WAK26 and GhWAK77 significantly increased the quantity of V.dahliae in cotton stems.Additionally,the silencing of Gh WAK26 and GhWAK77 significantly reduced the content of H2O2 and NO,increased the activity of POD,and decreased the content of lignin.4.Upland cotton genome contains 23 DUF642 genes,which are distributed on 14 chromosomes and 1 scaffold.Each coding protein of DUF642 contains 1-2 conserved DUF642 domains.DUF642 are mostly located on the plasma membrane.DUF642 genes could be divided into four subgroups,which are relatively conservative in evolution.DUF642 genes are expressed in various tissues,especially in roots and leaves.5.By qRT-PCR technology,six DUF642 genes induced by V.dahliae were screened out.Using VIGS technology to silence GhDUF642-10,as a result,the silenced plants were more chlorosis and wilt comparing to the control with higher disease index,suggesting that GhDUF642-10 play an important role in cotton resistance to V.dahliae.In conclusion,81 GhWAKs and 23 GhDUF642s were identified from the upland cotton genome,which have a variety of potential biological functions in cotton.GhWAK26,GhWAK77 and GhDUF642-10 are important disease-resistant genes,which can participate in cotton resistance to Verticillium wilt by affecting H2O2,NO content,POD activity and lignin content.