Nitrate induction of root hair density is mediated by TGA1/TGA4 and CPC transcription factors in Arabidopsis thaliana

Abstract

Root hairs are specialized cells that are important for nutrient uptake. It is well established that nutrients such as phosphate have a great influence on root hair development in many plant species. Here we investigated the role of nitrate on root hair development at a physiological and molecular level. We showed that nitrate increases root hair density in Arabidopsis thaliana. We found that two different root hair defective mutants have significantly less nitrate than wild-type plants, suggesting that in A. thaliana root hairs have an important role in the capacity to acquire nitrate. Nitrate reductase-null mutants exhibited nitrate-dependent root hair phenotypes comparable with wild-type plants, indicating that nitrate is the signal that leads to increased formation of root hairs. We examined the role of two key regulators of root hair cell fate, CPC and WER, in response to nitrate treatments. Phenotypic analyses of these mutants showed that CPC is essential for nitrate-induced responses of root hair development. Moreover, we showed that NRT1.1 and TGA1/TGA4 are required for pathways that induce root hair development by suppression of longitudinal elongation of trichoblast cells in response to nitrate treatments. Our results prompted a model where nitrate signaling via TGA1/TGA4 directly regulates the CPC root hair cell fate specification gene to increase formation of root hairs in A. thaliana.

Integration of A Nitrate-Related Signaling Pathway in Rhizobia-Induced Responses During Interactions with Non-Legume Host Arabidopsis thaliana

“…Furthermore, a meta-analysis indicates nitrate regulation of root hair growth by bZIP and G2-transcription factors coordinated auxin signaling response (Canales et al, 2014). Interestingly, the NRT1.1-TGA1/4 nitrate signaling complex additionally controls root hair density and trichoblast cell length (Canales et al, 2017). This is in agreement with our data, showing that NRT1.1 also controls rhizobia-induced differences in trichoblast patterning (Fig.6).…”

“…The importance of nitrate-regulated transcription factors during plant root development has been extensively described. For example, the bZIP transcription factors TGA1 and TGA4 control nitrateinduced lateral root formation (Alvarez et al, 2014) and root hair cell fate, latter by regulating the root hair cell-specific gene CAPRICE (CPC) (Canales et al, 2017). Furthermore, a meta-analysis indicates nitrate regulation of root hair growth by bZIP and G2-transcription factors coordinated auxin signaling response (Canales et al, 2014).…”

Clade I TGACG-Motif Binding Basic Leucine Zipper Transcription Factors Mediate BLADE-ON-PETIOLE-Dependent Regulation of Development

“…Clade I TGAs are also reported to have developmental roles. tga1 tga4 double mutants have altered root architecture under low nitrate conditions (Alvarez et al, 2014;Canales et al, 2017) and curved petioles (Shearer et al, 2012). Biochemical experiments show that TGA4 interacts with CONSTANS and binds to the FLOWERING LOCUS T promoter, suggesting formation of a complex that regulates flowering (Song et al, 2008).…”

Mapping the Salt Stress-Induced Changes in the Root miRNome in Pokkali Rice

“…It has been shown to be differentially regulated under salt stress in the roots of various plants [26]. osa-miR1864 regulates the expression of its target mRNA that encodes the ternary complex factor MIP1 leucine-zipper protein, which plays an important role in root hair development [63,64]. The osa-miR162 family regulates DCL1 [65], indicating that miR biogenesis was tightly regulated in PK roots in this study.…”