Cloning and functional determination of PpyASR1 during fruit development in Pyrus pyrifolia

Abscisic acid, stress and ripening-induced genes (ASRs) play crucial roles in fruit maturation, and the isolation, identification, and functional characterization of these genes have been extensively studied in plants. 'Guanyang' snow pear is a high-quality pear cultivar with distinct regional characteristics in Guangxi. However, the gene responsible for ASR1 and its specific functional attributes remain unidentified.

In this study, PpyASR1 was successfully isolated from 'Guanyang' snow pear fruits. This gene was found to exhibit specific expression during fruit development, with its expression level following an initial increase followed by a subsequent decrease. Subcellular localization analysis revealed that the protein product of the PpyASR1 gene predominantly localizes within the nucleus, supporting its role as a transcription factor regulating maturation and senescence in fruit tissues. Virus-induced gene silencing experiments demonstrated that suppressing of PpyASR1 gene expression in 'Guanyang' snow pear fruit significantly delayed senescence-associated deterioration. Compared to the control group, the treated fruits exhibited higher firmness, lower ABA content, reduced ethylene production, lower soluble solid content, and higher titratable acidity. Transient overexpression of PpyASR1 in 'Guanyang' snow pear resulted in markedly accelerated fruit senescence and postharvest deterioration. Compared to controls, these fruits showed reduced firmness, increased ABA content and ethylene production, and lower titratable acidity, whereas no significant difference in soluble solids content was detected.

The current findings provide valuable insights into the storage characteristics of 'Guanyang' snow pear and establish a theoretical foundation for understanding the potential role of PpyASR1 in regulating fruit senescence and postharvest deterioration.