Fruit firmness is an important trait in sweet cherry breeding because it directly positivelyinfluences fruit transportability, storage and shelf life. However, the underlying genesresponsible and the molecular mechanisms that control fruit firmness remain unknown. In thisstudy, we identified a candidate gene, PavSCPL, encoding a serine carboxypeptidase-likeprotein with natural allelic variation, that controls fruit firmness in sweet cherry using map-based cloning and functionally characterized PavSCPL during sweet cherry fruit softening.Genetic analysis revealed that fruit firmness in the ‘Rainier’ 9 ‘Summit’ F 1 population wascontrolled by a single dominant gene. Bulked segregant analysis combined with fine mappingnarrowed the candidate gene to a 473-kb region (7418778–7891914 bp) on chromosome 6which included 72 genes. The candidate gene PavSCPL, and a null allele harbouring a 5244-bpinsertion in the second exon that completely inactivated PavSCPL expression and resulted in theextra-hard-flesh phenotype, were identified by RNA-sequencing analysis and gene cloning.Quantitative RT-PCR analysis revealed that the PavSCPL expression level was increased withfruit softening. Virus-induced gene silencing of PavSCPL enhanced fruit firmness andsuppressed the activities of certain pectin-degrading enzymes in the fruit. In addition, wedeveloped functional molecular markers for PavSCPL and the Pavscpl5.2-k allele that co-segregated with the fruit firmness trait. Overall, this research identified a crucial functionalgene for fruit firmness. The results provide insights into the genetic control and molecularmechanism of the fruit firmness trait and present useful molecular markers for molecular-assisted breeding for fruit firmness in sweet cherry.
Plant Communications. 2024 Jun 10;5(6):100977, IF=10.5.
DOI:https://doi.org/10.1016/j.xplc.2024.100977