Prof. Xuelu Wang’s lab had a crucial breakthrough on auxins regulating the development of plant root hair
Prof. Xuelu Wang’s lab had recently reached a breakthrough on how auxins regulate root hair development in Arabidopsis. Their latest findings had been published in eLife, a rising high-IF integrated biological journal on Apr. 25th, 2014.
As one of the most important organs for plants, root hairs help taking in water and mineral nutrition. In Arabidopsis, the development of root hair was determined by position effect. Epidermal cells between two cortical cells trichoblast cells. In molecular level, trichoblast cells and atrichoblast cells were determined by transfactor MYB-bHLH-WD40, a transcriptional complex, and were regulated by multiple endogenous and exogenous factors. brassinosteroid, as one of them, played an important role in regulating the specialization of root hairs, with its mechanism remained unknown.
By systematically analyzing the root hair phenotypes of brassinosteroid-related mutants, Wang’s lab discovered that brassinosteroid signal could suppress the formation of root hairs through GSK3-like kinase or upriver components. GL2, a cell fate marker gene for atrichoblast cells, was ectopically expressed in trichoblast cells when brassinosteroid signaling was enhanced, while its expression in atrichoblast cells was suppressed when brassinosteroid signaling was reduced. Genetic analysis demonstrated that brassinosteroid-regulated root epidermal cell patterning was dependent on the WER-GL3/EGL3-TTG1 transcriptional complex. One of the GSK3-like kinases, BIN2, interacted with and phosphorylated EGL3, and EGL3s mutated at phosphorylation sites were retained in trichoblast cell nuclei. Furthermore, BIN2 phosphorylated TTG1 to inhibit the activity of the WER-GL3/EGL3-TTG1 complex. Thus, the lab’s study provided insights into the mechanism of brassinosteroid regulation of root hair patterning.
Prof. Wang has been devoted to scientific researches on how brassinosteroid signal transduction and other auxins interact with environmental cues. In the last few years, his lab had reached multiple breakthroughs, including interactions between auxin transduction pathways, and brassinosteroid regulation on plant development. The crew has published several vital research papers on high-level integrated biological journals such as Developmental Cell, eLife and PNAS. Such findings provided important theoretical significance of auxins in regulating the fate of root epidermal cells by both cellular and molecular mechanisms. In addition, they also had great applications for plants in boosting the absorption of water and other nutritions via regulating root hair development.
Brassinosteroids control root epidermal cell fate via direct regulation of a MYB-bHLH-WD40 complex by GSK3-like kinases (Cheng et al., eLife, http://dx.doi.org/10.7554/eLife.02525.001)