Genome-wide analysis of the annexin gene family in alfalfa (Medicago sativa L.) and functional characterization of MsANN22 under drought stress

MsANN22 is a strongly drought-responsive annexin in alfalfa, and its overexpression enhances drought tolerance, including 1.38-fold higher superoxide dismutase and 1.70-fold higher peroxidase activity.

• Why it matters: Annexin-mediated drought tolerance in Medicago sativa remains largely unexplored, limiting candidate gene discovery and mechanistic understanding for improving drought resilience.
• What they did: The study identified 73 MsANN genes and analyzed phylogeny, synteny, conserved motifs, gene structures, and promoter cis-elements, then used expression profiling to select MsANN22 for functional tests. MsANN22 overexpression was evaluated in Arabidopsis thaliana and alfalfa, with antioxidant assays, DAB/NBT staining, and yeast two-hybrid plus luciferase complementation for interactions with MsIAA and MsPR-10.
• The result: In alfalfa, MsANN22-overexpressing plants accumulated ~20% less malondialdehyde and showed reduced H2O2 and O2*- accumulation, supporting a role in drought tolerance and providing a candidate for alfalfa improvement.