番茄抗青枯病资源的鉴定与分析OA

Bacterial wilt is a devastating soil-borne disease caused by Ralstonia solanacearum,causing severe damage in the main tomato-producing areas of southern China.Traditional breeding methods for bacterial wilt resistance suffer from drawbacks such as long breeding cycles and low efficiency,making molecular marker-assisted breeding a key technology to address this issue.In this study,25 representative tomato accessions were used for field resistance evaluation and competitive allele-specific PCR(KASP)genotyping.By integrating these approaches,the effectiveness of novel single nucleotide polymorphism(SNP)markers targeting three bacterial wilt resistance genes,Bwr12,Bwr6-4,and Bwr6-6,was systematically validated,and the association between genotypes and field resistance was analyzed.The results showed that the three molecular markers had strong specificity and produced stable and reliable genotyping results,enabling efficient discrimination among resistant homozygous,susceptible homozygous,and heterozygous genotypes.The two gene combinations,'Bwr12+Bwr6-4'and'Bwr12+Bwr6-6',were strongly correlated with high bacterial wilt resistance in tomato,and in a single-gene background the resistance effects of Bwr6-4 and Bwr6-6 were superior to that of Bwr12.Resistance level and genotype did not exhibit a simple additive relationship,being modulated by factors such as gene expression levels,genetic background,and environmental interactions.Tomato line LT255 and LT131,which did not carry any of the three target resistance genes,still displayed moderate resistance,confirming the existence of as-yet-unidentified bacterial wilt resistance genes or a'cryptic resistance'system in tomato.This study provides reliable technical support for molecular marker-assisted breeding of bacterial wilt resistance in tomato and lays a foundation for the discovery of novel resistance genes and the elucidation of resistance mechanisms.