Identification And Application Potential Of Resistant Receptor Protein Of Tomato Bacterial Wilt

Tomato bacterial wilt caused by Ralstonia solanacearum is one of the most serious diseases in the tomato growth cycle,and once it occurs,it will cause huge economic losses.At present,the exploration of resistance genes for tomato bacterial wilt is still very limited,and identifying the main resistance genes for tomato bacterial wilt is of great significance for the prevention and control of tomato bacterial wilt.Previous studies have found that tomato bacterial wilt resistance genes are located on chromosomes 6 and 12,and there are multiple genes on chromosome 12 that have potential resistance functions such as RLP(receptor like protein).By analyzing the transcriptome data of tomato roots infected by R.solanacearum.Screening out 6 candidate RLP genes that are specifically upregulated in disease resistant varieties.The resistance genes of these RLP genes were validated using methods such as tomato hairy root transient expression system,virus mediated gene silencing system,and transgenic tomato disease resistance detection.The main results are as follows:Through virus mediated gene silencing experiments,it has been demonstrated that key node proteins in tomato PTI and ETI signaling pathways are involved in the resistance of Hawaii 7996 to bacterial wilt.Hawaii 7996 mediated bacterial wilt resistance in tomato relies on co-receptors BAK1 and SOBIR1,as well as downstream key genes EDS1,PAD4,SAG101,ADR1,and NDR1 of TNL.Previous studies have found that the PTI response mediated by RLP relies on the ETI key node protein EDS1/PAD4/ADR1.This study also found that Hawaii 7996 silenced plants with multiple RLP genes(SlRLP2,SlRLP4,and SlRLP5)have reduced resistance to bacterial wilt GMI1000 and significantly reduced survival compared to control plants,suggesting that these genes play an important role in tomato resistance to bacterial wilt infection.In order to explore the functions of the six selected RLP Genes,overexpression vectors were constructed separately.In the susceptible variety Moneymaker,these proteins were overexpressed instantaneously using Agrobacterium mediated hairy root transformation technology.It was found that the expression of SlRLP1 and SlRLP5 proteins increased Moneymaker’s resistance to R.solanacearum GMI1000 and significantly reduced bacterial growth compared to the control plant.Using Agrobacterium-mediated tomato genetic transformation technology,constitutive expression of OXSlRLP2 and OXSlRLP4 transgenic tomatoes were constructed.OXSlRLP2 and OXSlRLP4 transgenic tomatoes showed delayed disease onset,decreased disease index,and increased survival rate compared to wild-type tomatoes.In summary,the RLP protein is involved in the resistance of tomato to bacterial wilt,multiple RLP proteins have demonstrated resistance potential to bacterial wilt,and two transgenic plants with RLP protein were created.The experimental results of this study provide some clues for further exploring tomato bacterial wilt resistance genes.