Biology subjects

Raveh, D.

Publications and source records attributed to Raveh, D..

4 recordsLinked to original sources

bioRxiv2025

Ubiquitin ligase PUB41 modulates root hair development in Arabidopsis via interaction with the auxin polar transporter PIN2

Root hairs are short-lived, elongated tubular extensions of epidermal cells, that increase the surface area improving absorption of water and nutrients. Root hair development is affected by developmental, environmental, and hormonal cues, primarily Auxin. Auxin is synthesized in shoot and root apical transporters. Here, we report that mutants of the Arabidopsis PLANT U-BOX41 (AtPUB41) gene encoding a ubiquitin ligase (E3) develop fewer and shorter root hairs than wild-type (WT) plants. pub41 mutants are not impaired in sensing and responding to exogenous auxin, suggesting that the root hair phenotype may result from a change in auxin levels and/or distribution. Indeed, Auxin enhances the steady-state levels of PUB41 transcript and protein in the roots. A catalytically inactive decoy protein lacking the U-box, PUB41({Delta}U), complements the sparse root hair phenotype of pub41 mutants to the same extent as full-length PUB41. Plants expressing PUB41({Delta}U) are hyperresponsive to auxin-induced root hair development and PUB41({Delta}U) accumulates in the root elongation and differentiation zones, preferentially in trichoblast cells and their root hairs. Furthermore, in these cells, PUB41-eGFP and PUB41({Delta}U)-eGFP are primarily located on the anticlinal faces, as is the auxin PIN2 exporter. We show colocalization of PUB41({Delta}U)-eGFP and PIN2-mCherry, and binding in vitro of PUB41 to the cytoplasmic hydrophilic loop of PIN2. Moreover, PUB41({Delta}U) protein stabilizes PIN2 and enhances its abundance in the roots. Our results indicate that PUB41 modulates root hair development via interaction with PIN2. Significance StatementRoot hairs are extensions of the root epidermal cells, which are crucial for the uptake of water and nutrients from the soil. Root hair development is highly regulated and affected by developmental, environmental, and hormonal cues. In this study, we demonstrate that the auxin-induced ubiquitin ligase, PLANT U-BOX 41 (PUB41), regulates root-hair development by interacting with the auxin polar transporter PIN2 responsible for determining auxin levels.

plant biology↗

bioRxiv2024

Arabidopsis ubiquitin ligase PUB41 is a positive regulator of the ABA response

Seed germination is a highly controlled developmental process. Prevention of early germination is essential to avoid germination at a time that is not likely to allow the completion of the plant life cycle before entering unfavorable seasons. The plant hormone ABA is the key regulator of seed dormancy and inhibition of germination. ABA is also involved in the plant response to drought. Here we report on the involvement of AtPUB41, a U-BOX E3 ubiquitin ligase from Arabidopsis thaliana, in regulating ABA signaling, seed dormancy, germination, and drought resilience. AtPUB41 is expressed in most plant vegetative and reproductive tissues. AtPUB41 protein is localized in the cytosol and nucleus. pub41 T-DNA insertion mutants display reduced seed dormancy, and their germination is less inhibited by exogenous ABA than seeds of wild-type plants. pub41 mutant plants are also hypersensitive to drought. ABA induces AtPUB41 promoter activity and steady-state mRNA levels in the roots. Our data suggest that AtPUB41 is a positive regulator of ABA signaling. Main ConclusionArabidopsis ubiquitin ligase PUB41 is induced by ABA and acts as a positive regulator of ABA signaling by modulating seed dormancy, germination, and drought resilience.

plant biology↗

bioRxiv2021

The Activity of the Stress Modulated Arabidopsis Ubiquitin Ligases PUB46 and PUB48 is Partially Redundant

The Arabidopsis ubiquitin ligases PUB46, PUB47 and PUB48 are encoded by paralogus genes; pub46 and pub48 mutants display increased drought sensitivity compared to wild type (WT). Although the phenotype displayed in the single gene mutants, suggest that each has specific biological activity, PUB46 and PUB48 activity may be also redundant. To test functional redundancy between two gene products requires a double mutant. Unfortunately, the close proximity of the PUB46 and PUB48 gene loci precludes obtaining a double mutant by crossing the available single mutants. We thus applied microRNA technology to reduce the activity of all three gene products of the PUB46-48 subfamily by constructing an artificial microRNA (aMIR) targeted to this subfamily. Expressing aMIR46-48 in WT plants resulted in increased drought-sensitivity, a phenotype resembling that of the single pub46 and pub48 mutants, and enhanced sensitivity to methyl viologen, similar to that observed for the pub46 mutant. Furthermore, the WT plants expressing aMIR46-48 also revealed reduced inhibition by ABA at seed germination, a phenotype not evident in the single mutants. Expressing aMIR46-48 in pub46 and pub48 mutants further enhanced the drought sensitivity of each parental single mutant and of WT expressing aMIR46-48. Thus, whereas the gene-specific activity of the PUB46 and PUB48 E3s is partially redundant in that absence of either E3 leads to drought sensitivity, our ability to eliminate the activity of both PUB46 and PUB48 in the same plant reveals additional gene specific facets of their activity in the reaction to abiotic stress.

plant biology↗

bioRxiv2018

Overexpression of Arabidopsis ubiquitin ligase AtPUB46 enhances tolerance to drought and oxidative stress

The U-Box E3 ubiquitin ligase, AtPUB46, functions in the drought response: T-DNA insertion mutants of this single paralogous gene are hypersensitive to water- and oxidative stress (Adler et al. BMC Plant Biology 17:8, 2017). Here we analyze the phenotype of AtPUB46 overexpressing (OE) plants. AtPUB46-OE show increased tolerance to water stress and have smaller leaf blades and reduced stomatal pore area and stomatal index compared with wild type (WT). Despite this, the rate of water loss from detached rosettes is similar in AtPUB46-OE and WT plants. Germination of AtPUB46-OE seeds was less sensitive to salt than WT whereas seedling greening was more sensitive. We observed a complex response to oxidative stress applied by different agents: AtPUB46-OE plants were hypersensitive to H2O2 but hyposensitive to methyl viologen. AtPUB46-GFP fusion protein is cytoplasmic, however, in response to H2O2 a considerable proportion translocates to the nucleus. We conclude that the differential stress phenotype of the AtPUB46-OE does not result from its smaller leaf size but from a change in the activity of a stress pathway(s) regulated by a degradation substrate of the AtPUB46 E3 and also from a reduction in stomatal pore size and index.\n\nAccession NumbersSequence data for this article can be found in: The Arabidopsis Information Resource database (http://www.arabidopsis.org) under accession numbers At5G18320 (PUB46).

plant biology↗