ZmABA2 Modulates Drought-Stress Response in Maize

Abscisic acid (ABA) is crucial for plant growth and abiotic stress responses. We screened a dwarf, drought-sensitive maize mutant and found that a non-synonymous mutation in ZmABA2, encoding a short-chain alcohol dehydrogenase involved in the conversion of xanthoxin to ABA-aldehyde, was responsible for the altered phenotype. The mutant’s significantly reduced ABA levels led to drought sensitivity, which was partially restored by exogenous ABA application. Our study demonstrates ZmABA2’s role in ABA biosynthesis and provides a valuable ABA-deficient mutant for further maize research.