Molecular cloning and expression analysis of root-knot nematode resistance related gene in watermelon

【Objective】To screen watermelon(Citrullus lanatus) root-knot nematode resistance genes,toanalyze its relationship with the root-knot nematode resistance,and to make a foundation for breeding re-sistant varieties of watermelon and root stock.【Methods】With wild resistant watermelon‘09005'and cul-tivated susceptible watermelon‘ZDPI0006'as materials,the related gene cla006580 was screened byblasting in Cu Gen DB according to the known plant resistance proteins,and it had 65% similarities tosugar beet nematode resistance gene Hs1^pro-1and was named Cla Hs1^pro-1. The CDS of Cla Hs1^pro-1was clonedin resistant and susceptible materials respectively and was analyzed with bioinformatics and the expres-sion pattern was detected with q RT-PCR. Multiple sequence alignment and phylogenetic analysis wereperformed using sequence from cloned nematode resistance protein and Cla Hs1^pro-1protein.【Results】Twoconserved functional domains of Hs1pro-1_N and Hs1pro-1_C and four SNPs were detected in coding se-quence which had 1 434 bp coding 478 aa. The analysis of RT- PCR indicated that the transcript of Cla Hs1pro- 1in resistant material decreased first and then increased after nematode infection,while thetrend in CK was opposite. The transcript of Cla Hs1^pro-1in susceptible material showed a trend of“increasing-decreasing-increasing”,and the same variation trends was observed in CK.【Conclusion】The ex-pression level of Cla Hs1^pro-1in resistant watermelon is closely related to root-knot nematode inoculation,but the correlation does not exist in susceptible watermelon. Cla Hs1pro- 1might be the possible candidateroot-knot nematode resistance gene in watermelon.