Abstract
Strigolactones are a novel class of plant hormones that interact with multiple signaling molecules, including auxin, abscisic acid, ethylene, and brassinosteroid, to regulate plant growth and development. Recently, researchers have shown that sugars are involved in bud outgrowth control, suggesting a potential interaction between sugars and strigolactone signaling. To better understand the relationship between strigolactones and sugar in plant development, the sugar sensitivity of strigolactone biosynthesis and signaling mutants (max1 and max2) was evaluated in early seedling development with a low-glucose assay. Both max1 and max2 displayed obvious hyposensitivity to glucose repression, as do gin mutants, but they were hypersensitive like the wild type to the high-glucose conditions used for gin mutant screening. The strigolactones acted synergistically with glucose in repressing seedling establishment. A further comparative transcriptomic analysis indicated that the expression of stress-related genes in the max2 mutant is impaired by glucose, and a carbohydrate analysis revealed a reduced hexose content in the max mutants. Our results suggest that the roles of strigolactones in the regulation of early seedling development are probably independent of the HXK1 signaling pathway. Taken together, these findings provide evidence that strigolactones are involved in sugar signaling, thus modulating early seedling development.
