Evolution, family expansion, and functional diversification of plant aldehyde dehydrogenases.

Aldehyde dehydrogenases (ALDHs) act as "aldehyde scavengers" in plants, eliminating reactive aldehydes and hence performing a crucial part in response to stress. ALDH has been specified multiple activities since its identification in the mammalian system 72 years ago. But the most widely researched role in plants is their engagement in stress tolerance. Multiple ALDH families are found in both animals and plants, and many genes are substantially conserved within these two evolutionary diverse taxa, yet both have their unique members/families. A total of twenty-four ALDH protein family has been reported across organisms, where plants contain fourteen families. Surprisingly, the number of genes in the ALDH superfamily has risen in the higher plants because of genome duplication and expansion, indicating the functional versatilely. Observed expansion in the ALDH isoforms might provide high plasticity in their actions to achieve diversified roles in the plant. The physiological importance and functional diversity of ALDHs including plant development and environmental stress adaptability, and their evolution in plants has been studied extensively. Future investigations need to focus on evaluating the individual and interconnecting function of multiple ALDH isoforms across organisms in providing plants with proper development, maturation, and adaptability against harsh environmental conditions.