Key Genes Involved in the Saline–Water Stress Tolerance of Aloe vera

Aloe vera is well known for its high tolerance to adverse environmental conditions. However, the molecular pathways governing its adaptive response mechanisms to abiotic stress remain unclear. Thus, the expression of AOG, ABA2, and GMMT genes in Aloe vera plants subjected to saline–water stress was evaluated, with the expression of key genes significantly influenced by stress response. AOG and GMMT expression levels were higher under field capacity (FC) than under water deficit (PWP), with AOG reaching ~4.3% under 40 mM salinity at FC. In contrast, ABA2 was strongly upregulated under PWP, particularly at 40 mM salinity, with expression increasing up to fivefold compared to the control. However, salinity above 40 mM led to reduced ABA2 expression. GMMT was overexpressed (~6%) under severe stress, while mannose content increased significantly with salinity but remained unaffected by soil moisture. These findings highlight gene-specific responses to combined stress.