Water retention capacity in association with the accumulation and composition of cuticular wax contributing to drought tolerance in centipedegrass

Centipedegrass is one of the most important warm-season turfgrasses with the advantages of strong stolons, long growing season, and low input requirements. Previous research found that the two genotypes of centipedegrass (the drought-tolerant 'CG101' and the drought-sensitive 'CG021') exhibited differential drought tolerance. The objectives of this study were to: (i) compare differences in water retention capacity between the two genotypes, and (ii) elucidate the mechanisms of the differential drought tolerance from the levels of leaf cuticular wax accumulation and composition. Plants were exposed to 24 d of drought stress and post-drought re-watered for 6 d. The findings indicated that 'CG101' exhibited superior drought tolerance, as reflected by the greater water retention capacity in comparison with 'CG021'. The enhanced water retention in 'CG101' was attributed to a lower rate of leaf water loss, which resulted from a higher cuticular wax accumulation and composition in leaves compared to 'CG021'. The increased cuticular wax content was associated with higher expression levels of genes related to wax metabolism, including <italic>EoCER1</italic>, <italic>EoKCS6</italic>, <italic>EoGL1</italic>, <italic>EoWSD1</italic>, <italic>EoABCG11</italic>, and <italic>EoPDR8</italic> in 'CG101' under drought stress. The accumulation of the cuticular wax composition in 'CG101' involved alkenes, alkanes, alcohols, and fatty acids. Our results will provide a foundation for breeding drought-resistant cultivars in centipedegrass.