The Positive Regulation of AsMYB44 on Shade Tolerance in Creeping Bentgrass

Shade stress is a primary abiotic factor that limits plant growth and development. Its impact is exerted chiefly through photosynthetic pathways, and this effect is especially pronounced in turfgrass species growing under the shade of large trees and buildings. MYB transcription factors play a key role in plant photosynthesis, and several MYB members are involved in plant shade responses. However, the function of MYB44 in shade responses has not yet been reported in plants. In this study, overexpression of AsMYB44 in creeping bentgrass under shade stress increased the plant’s chlorophyll a, chlorophyll b, and carotenoid content, net photosynthetic rate, and antioxidant enzyme activities in creeping bentgrass. Transcriptome analysis revealed that AsMYB44 overexpression significantly upregulated the expression of genes associated with photosynthesis, photosynthesis antenna proteins, and chlorophyll metabolism pathways. Collectively, these results demonstrated that overexpressing AsMYB44 improved shade tolerance in creeping bentgrass. Our findings provides important candidate genes for shade tolerance breeding in plants.