Genome-wide identification and expression analysis of the ALDH gene family and functional analysis of PaALDH17 in Prunus avium

Abstract

ALDH (Aldehyde dehydrogenase), as an enzyme that encodes the dehydroxidization of aldehydes into corresponding carboxylic acids, played an important role inregulating gene expression in response to many kinds of biotic and abiotic stress, including saline–alkali stress. Saline–alkali stress was a common stress that seriously affected plant growth and productivity. Saline–alkali soil contained the characteristics of high salinity and high pH value, which could cause comprehensive damage such as osmotic stress, ion toxicity, high pH, and HCO³⁻/CO₃²⁻ stress. In our study, 18 PaALDH genes were identified in sweet cherry genome, and their gene structures, phylogenetic analysis, chromosome localization, and promoter cis-acting elements were analyzed. Quantitative real-time PCR confirmed that PaALDH17 exhibited the highest expression compared to other members under saline–alkali stress. Subsequently, it was isolated from Prunus avium, and transgenic A. thaliana was successfully obtained. Compared with wild type, transgenic PaALDH17 plants grew better under saline–alkali stress and showed higher chlorophyll content, Superoxide dismutase (SOD), Peroxidase (POD) and Catalase (CAT) enzyme activities, which indicated that they had strong resistance to stress. These results indicated that PaALDH17 improved the resistance of sweet cherries to saline–alkali stress, which in turn improved quality and yields.