A glutathione-dependent control of the indole butyric acid pathway supports Arabidopsis root system adaptation to phosphate deprivation

Abstract

Root system architecture results from a highly plastic developmental process to adapt to environmental conditions. In particular, the development of lateral roots and root hair growth are constantly optimized to the rhizosphere properties, including biotic and abiotic constraints. The development of the root system is tightly controlled by auxin, the driving morphogenic hormone in plants. Glutathione, a major thiol redox regulator, is also critical for root development but its interplay with auxin is scarcely understood. Previous work showed that glutathione deficiency does not alter root responses to indole acetic acid (IAA), the main active auxin in plants. Because indole butyric acid (IBA), another endogenous auxinic compound, is an important source of IAA for the control of root development, we investigated the crosstalk between glutathione and IBA during root development. We show that glutathione deficiency alters lateral roots and root hair responses to exogenous IBA but not IAA. Detailed genetic analyses suggest that glutathione regulates IBA homeostasis or conversion to IAA in the root cap. Finally, we show that both glutathione and IBA are required to trigger the root hair response to phosphate deprivation, suggesting an important role for this glutathione-dependent regulation of the auxin pathway in plant developmental adaptation to its environment.

Glutathione-mediated plant response to high-temperature

“…While our RNAseq analysis fail to identify clear GO categories of thermomorphogenesis genes among the differentially expressed genes in the cad2 mutant, we do observe some differences in individual genes like PIF4 or some auxin metabolism genes ( Supplemental Figure 6 ). Moreover, connections between glutathione and auxin metabolism have been previously described in other plant development aspects (Bashandy et al, 2010) (Schnaubelt et al, 2015) (Trujillo-Hernandez et al, 2020). Also, glutathione-dependent glutaredoxins are suggested to regulate brassinosteroids pathway (Bender et al, 2015).…”

Regulation of root architecture by Pseudomonas oryzihabitans is mediated by strigolactones and redox processes.

“…This result is perhaps not surprising given that mutants lacking glutathione peroxidases (GPX) have an altered root phenotype (Passaia et al2014) and glutaredoxins such as GRXS8 are considered to be major regulators of RSA (Ehrary et al 2020). Moreover, GSH is required for indole butyric acid (IBA) conversion to indole acetic acid (IAA), suggesting an important role for GSH-dependent regulation of the auxin pathway in root development (Trujillo-Hernandez et al 2020).…”

Fluorescence Probes for Reactive Sulfur Species in Agricultural Chemistry

“…Among them, GSH is a stable small-molecule tripeptide, which is abundantly present in plants as a major antioxidant thiol. It is indispensable in the process of plant development, resistance to biotic and abiotic stresses, heavy metal detoxification, and maintenance of redox homeostasis. − Genetic analyses have shown that GSH can regulate the homeostasis of the endogenous auxin indole butyric acid in the root cap of Arabidopsis, which is beneficial to the growth and development of the plant . The interaction between GSH and pathogens prompts plants to resist biological stresses (e.g., bacteria, fungi, and nematodes) effectively as well .…”

“…44−48 Genetic analyses have shown that GSH can regulate the homeostasis of the endogenous auxin indole butyric acid in the root cap of Arabidopsis, which is beneficial to the growth and development of the plant. 49 The interaction between GSH and pathogens prompts plants to resist biological stresses (e.g., bacteria, fungi, and nematodes) effectively as well. 50 As an antioxidant thiol, GSH can be not only coupled with the pesticide chlorothalonil to control redox homeostasis to regulate chlorothalonil metabolism but also closely related to the expression of stress defense genes involved in many physiological processes.…”