Magnesium transporter Gene Family: Genome-Wide Identification and Characterization in Theobroma cacao, Corchorus capsularis, and Gossypium hirsutum of Family Malvaceae

Magnesium (Mg) is an element involved in various key cellular processes in plants. Mg transporter (MGT) genes play an important role in magnesium distribution and ionic balance maintenance. Here, MGT family members were identified and characterized in three species of the plant family Malvaceae, Theobroma cacao, Corchorus capsularis, and Gossypium hirsutum, to improve our understanding of their structure, regulatory systems, functions, and possible interactions. We identified 18, 41, and 16 putative non-redundant MGT genes from the genome of T. cacao, G. hirsutum, and C. capsularis, respectively, which clustered into three groups the maximum likelihood tree. Several segmental/tandem duplication events were determined between MGT genes. MGTs appear to have evolved slowly under a purifying selection. Analysis of gene promoter regions showed that MGTs have a high potential to respond to biotic/abiotic stresses and hormones. The expression patterns of MGT genes revealed a possible role in response to P. megakarya fungi in T. cacao, whereas MGT genes showed differential expression in various tissues and response to several abiotic stresses, including cold, salt, drought, and heat stress in G. hirsutum. The co-expression network of MGTs indicated that genes involved in auxin-responsive lipid metabolism, cell wall organization, and photoprotection can interact with MGTs.