Drought stress is one of the most destructive environmental factors that
affect tomato plants. Mitogen-activated protein kinases (MAPKs) are
important signaling molecules that respond to drought stress in plants. Liu
Wang from the American Chemical Society studied the gene SlMAPK3, which is
induced by drought stress. The team also used the CRISPR-Cas9 system to
generate loss-of-function slmapk3 mutants.

Two independent T1 lines and wild type tomato plants were used to analyze
drought tolerance. Compared with WT plants, slmapk3 mutants exhibited severe
wilting, higher hydrogen peroxide content, lower antioxidant enzymes
activities, and suffered more membrane damage under drought stress.
Furthermore, knockout of SlMAPK3 affected the expressions of drought
stress-responsive genes.

These results suggest that SlMAPK3 is involved in drought response in tomato
plants by protecting cell membranes from oxidative damage and modulating
transcription of stress-related genes.

[pubs.acs.org]