bioRxiv Science⌕ Search

Biology subjects

Ariel, F. D.

Publications and source records attributed to Ariel, F. D..

2 recordsLinked to original sources

The transcription factor NF-YA10 determines the area explored by Arabidopsis thaliana roots through direct regulation of LAZY and TAC genes

Root developmental plasticity relies on transcriptional reprogramming, which largely depends on the activity of transcription factors (TFs). NF-YA2 and NF-YA10 (Nuclear Factor A2 and A10) are down-regulated by the specific miRNA isoform miR169defg, in contrast to miR169a. Here, we analyzed the role of the Arabidopsis thaliana TF NF-YA10 in the regulation of lateral root development. Plants expressing a version of NF-YA10 resistant to miR169 cleavage showed a perturbation in the lateral root gravitropic response. By extracting novel features of root architecture using the ChronoRoot deep-learning-based phenotyping system, we uncovered a differential emergence angle of lateral roots over time when compared to Col-0. Detailed phenotyping of root growth dynamics revealed that NF-YA10 activity modulates the area explored by Arabidopsis roots. Furthermore, we found that NF-YA10 directly regulates TAC1 and LAZY genes by targeting their promoter regions, genes previously linked to gravitropism. Hence, the TF NF-YA10 is a new element in the control of LR gravitropism and root system architecture.

plant biology↗

NAC1 directs CEP1-CEP3 peptidase expression and decreases cell wall extensins linked to root hair growth in Arabidopsis

Plant genomes encode a unique group of papain-type Cysteine EndoPeptidases (CysEPs) containing a KDEL endoplasmic reticulum (ER) retention signal (KDEL-CysEPs or CEPs). CEPs process the cell-wall scaffolding EXTENSIN proteins (EXTs), which regulate de novo cell wall formation and cell expansion. Since CEPs are able to cleave EXTs and EXT-related proteins, acting as cell wall-weakening agents, they may play a role in cell elongation. Arabidopsis thaliana genome encodes three CEPs (AtCPE1-AtCEP3). Here we report that the three Arabidopsis CEPs, AtCEP1-AtCEP3, are highly expressed in root-hair cell files. Single mutants have no evident abnormal root-hair phenotype, but atcep1-3 atcep3-2 and atcep1-3 atcep2-2 double mutants have longer root hairs (RHs) than wild type (Wt) plants, suggesting that expression of AtCEPs in root trichoblasts restrains polar elongation of the RH. We provide evidence that the transcription factor NAC1 activates AtCEPs expression in roots to limit RH growth. Chromatin immunoprecipitation indicates that NAC1 binds the promoter of AtCEP1, AtCEP2, and to a lower extent to AtCEP3 and may directly regulate their expression. Indeed, inducible NAC1 overexpression increases AtCEP1 and AtCEP2 transcript levels in roots and leads to reduced RH growth while the loss of function nac1-2 mutation reduces AtCEP1-AtCEP3 gene expression and enhances RH growth. Likewise, expression of a dominant chimeric NAC1-SRDX repressor construct leads to increased RH length. Finally, we show that RH cell walls in the atcep1-1 atcep3-2 double mutant have reduced levels of EXT deposition, suggesting that the defects in RH elongation are linked to alterations in EXT processing and accumulation. Taken together, our results support the involvement of AtCEPs in controlling RH polar growth through EXT-processing and insolubilization at the cell wall.

plant biology↗