Genome-wide analysis of drought-related genes of 'Alphonso'and 'Tommy Atkins' mango (Mangifera indica L.) cultivars

Mango (Mangifera indica L.) is one of the most popular fruit crops grown and traded globally. Mango can withstand seasonal drought periods, especially during flowering. However, prolonged drought stress can cause the weakening of the plant and may encourage injuries and diseases caused by abiotic and biotic factors. With the availability of the mango genome, genomic studies related to drought adaptation of mango can now be extensively explored. In this study, genome-wide drought-related genes (DRGs) of mango were analyzed using the whole genome sequences (WGS) of 'Alphonso' and 'Tommy Atkins' cultivars (PRJNA487154 and PRJNA450143, respectively). A total of 261 and 257 DRGs were identified in the genome of 'Alphonso' and 'Tommy Atkins,' respectively, using BLASTP. Approximately 50% of these genes are involved in both molecular and physiological adaptations of mango to drought. Among the drought stress genes, the ABC transporter gene ABCG40 had the highest number of homologs in mango, followed by calcium-dependent protein kinase genes ZmCPK4, CPK21, and CDPK7, as well as the plasma membrane proton ATPase OST2. Gene ontology (GO) analysis of the DRGs revealed that protein binding, ATP binding, and mRNA binding are the most common molecular functions, whereas the predominant biological process of these DRGs is related to their response to water deprivation. Phylogenetic analysis showed that the drought-related proteins in 'Alphonso' and 'Tommy Atkins' are broadly clustered into seven and six major clades, respectively. This study, to date, offers the most comprehensive information on the genome-wide DRGs of the mango, which can strengthen marker-assisted breeding programs for drought tolerance in mango and other related fruit trees, as well as the future incorporation of favorable alleles toward improving the overall agronomic characteristics of this Philippine important fruit crop.