Study on the mechanism of CpPLLs genes influencing fruit storage performance in Chinese cherry ‘Manaohong’

To investigate the impact of fruit quality characteristics and pectin metabolism-related gene expression on low-temperature storage performance among different germplasms of Guizhou's distinctive Chinese cherry. This study conducted identification and analysis of gene family members encoding pectin lyase ( Pectate lyase-like, PLLs ). We examined physiological indices, cellular structure characteristics, and CpPLLs gene expression patterns in cherry germplasms under 4°C storage conditions. The results showed that the total pectin content in mature fruits of different germplasms ranged from 5.52 to 7.96 mg/g, with protopectin accounting for 41.5% to 77.1% of total pectin. The total pectin and protopectin contents in all germplasms exhibited a decreasing trend during storage. Among them, the storage-tolerant germplasms maintained protopectin levels at 3.44 mg/g and 3.31 mg/g respectively, with the lowest decay rates of 6.7% and 5.5%. A total of 33 full-length CpPLLs with complete structural domains were identified in ‘Mnaohong’ cherry. The expression levels of genes such as CpPLL5-3 , CpPLL7-3 , CpPLL11 , and CpPLL14-1 were significantly downregulated during low-temperature storage in storage-tolerant germplasm. qRT-PCR validation results also indicated that the expression levels of CpPLL11 and CpPLL5-3 in storage-tolerant germplasm were significantly suppressed by low-temperature exposure. This study confirms that differences in fruit storage tolerance among Chinese cherry germplasms are primarily associated with the degree of protopectin degradation. Among these, the CpPLL5-3 and CpPLL11 genes rapidly respond to low-temperature changes, significantly reducing their expression levels. This effectively inhibits the hydrolysis rate of protopectin and markedly enhances fruit storage efficacy under low-temperature conditions.