Genome-wide characterization of ascorbate peroxidase (APX) gene family in Phaseolus vulgaris L. of response to multiple abiotic stresses

This study focuses on the importance of legumes, especially common beans (Phaseolus vulgaris L.) in human nutrition due to their high nutritional values such as protein, carbohydrate, fibre, vitamins and antioxidants. Additionally, the effect of abiotic stressors like drought and salinity on plant growth and development is covered, with a focus on the oxidative stress that results and the function of antioxidant defense mechanisms in reducing this harm. In particular, this study details the identification and analysis of 101 ascorbate peroxidase (APX) gene family members in the bean genome. These genes play a crucial role in plant defence against oxidative stress by scavenging hydrogen peroxide (H₂O₂). The study also includes extensive bioinformatics analyses to determine the genes’ chromosomal locations, conserved domains, genetic structures, evolutionary relationships and expression patterns. RNA-seq data and qRT-PCR techniques were used to evaluate gene expression in different tissues and under abiotic stress conditions. According to the RNA-seq data, in the different tissues of common bean, expression levels of the PvAPX-24, -30, -33, -53, -65, and -98 genes were higher while PvAPX-2, -29, and -94 had low expression levels in these tissues. Additionally, under drought and salt stresses, expression levels of 6 genes (PvAPX-30, -33, -37, -64, -78 and -100) increased under drought stress and 12 genes (PvAPX-29, -47, -52, -65, -76, -78, -84, -85, -86, -97, -100 and -101) increased under salinity stress. The results of qRT-PCR shown that the expression levels of PvAPX genes had significant changes in different varieties and tissues. This comprehensive analysis is in agreement with findings from other plant species and reinforces the importance of APX genes in enhancing plant resistance to environmental challenges. Future research focusing on the functional validation of these genes will further elucidate their role and potentially aid in the development of stress-resistant crop varieties.