Exogenous strigolactones modulate antioxidant metabolism via CsD27 to enhance drought tolerance in tea plants

Drought stress adversely affects the growth, yield, and quality of tea plants (<i>Camellia sinensis</i> L.). Although strigolactones (SLs) are known to mediate drought adaptation in plants, their regulatory mechanisms in tea plants remain elusive. In this study, we demonstrated that exogenous SL application alleviated drought-induced symptoms by photosynthetic adaptation and mitigating the damage of cell membrane. Moreover, exogenous SL enhanced antioxidant response through regulating catechins metabolism in drought-sensitive cv. 'Huangjinya'. Notably, we identified <i>CsD27</i> as a key SL-biosynthetic gene, whose expression level was negatively correlated with malondialdehyde (MDA), mechanistically linking its function in drought tolerance in tea plants. Overexpression of <i>CsD27</i> enhanced the drought tolerance of transgenic <i>Arabidopsis</i> with decreased MDA content and increased survival rate under drought stress. These findings elucidate a dual SL-mediated mechanism that simultaneously enhances stress tolerance and preserves tea quality, which provide a potential target for molecular breeding in perennial crops.