Researchers reveal catabolic regulation of plant hormone strigolactones

Researchers led by Prof. Hu Yuxin from the Institute of Botany of the Chinese Academy of Sciences lately reported that the Arabidopsis carboxylesterase 15 (AtCXE15) and its orthologues in seed vegetation operate as environment friendly hydrolases of plant hormone strigolactones (SLs). This discovery reveals the catalytic mechanism underlying homeostatic regulation of SLs in vegetation.

Relevant outcomes had been revealed on-line in Nature Plants.

SLs are a category of carotenoid-derived plant hormone that performs important roles in regulation of plant shoot branching, plant-fungi symbiosis, and germination of parasitic weeds. Recent research have outlined biosynthetic and signaling pathways of SLs, nonetheless, the catabolism or deactivation of endogenous SLs in planta has remained largely unclear.

In this study, the researchers confirmed that overexpression of AtCXE15 in Arabidopsis promotes shoot branching by dampening SL-inhibited axillary bud outgrowth. Meanwhile, they demonstrated that AtCXE15 might bind and effectively hydrolyze various SLs each in vitro and in planta.

Furthermore, additionally they demonstrated that the putative AtCXE15 orthologues from just a few species of dicots, monocots, and Gymnosperms, however not from bryophytes, might effectively degrade SL analogs, indicating that such CXE15-dependent catabolism of SLs is evolutionarily conserved in seed vegetation.

Interestingly, the researchers discovered that AtCXE15 is extremely conscious of SLs and various environmental stimuli. This implies that CXE15-mediated SL catabolism could be a regulatory mechanism of SL gradients and thus form plant structure below ever-changing environments.

“Since endogenous SL gradients in plants are crucial for determining the axillary bud outgrowth and shoot branches, the manipulation of endogenous SLs and signaling would be an approach to improve crop productivity and resilience,” mentioned Prof. HU, corresponding writer of the examine.

This examine additionally offers a rational method to spatial-temporally manipulating endogenous SLs and the structure of crops and decorative plants.