Computational study of the plastid rRNA methyl transferase (CMAL) gene in higher plants and its role in drought and salt stresses

Abstract This study uses a bioinformatic approach to investigate plastid rRNA methyltransferase ( CMAL ) genes in four plant species ( Arabidopsis thaliana , Oryza sativa , Glycine max , Zea mays ). Furthermore, the gene expression levels of the CMAL gene of maize and soybean plants under drought and salt stress were investigated using RT-qPCR. We found differences between monocot and dicot CMALs, observed structural variations among species, and revealed a close evolutionary relationship between dicots and bacteria. CMAL genes show dynamic regulation in response to heat and drought stress, with maize showing tissue-specific variability. Specifically, the ZmCMAL gene in maize has a potential role in nutrient uptake and soil-related challenges, whereas AtCMAL in A. thaliana is involved in several cellular processes based on protein interactions. In a wet-lab study, ZmCMAL exhibited a fluctuating expression pattern under salt stress, with its ability to cope decreasing at higher salt concentrations. Meanwhile, GmCMAL was sensitive to both drought and salt, displaying an adaptive increase in expression as salt stress intensified. The promoter regions of CMAL genes predominantly contain cis-elements linked to abiotic stress and hormone responses, indicating their potential involvement in auxin-related pathways in cellular metabolism. These findings shed light on the regulatory role of CMAL genes in plants and their responses to stresses.