A role for the F-box protein HAWAIIAN SKIRT in plant miRNA function

Abstract

Summary statementHAWAIIAN SKIRT is a regulator of Arabidopsis thaliana microRNA biogenesis and acts in an Fbox-dependent manner. AbstractAs regulators of gene expression in multicellular organisms, microRNAs (miRNAs) are crucial for growth and development. While a plethora of factors involved in their biogenesis and action in Arabidopsis thaliana have been described, these processes and their fine-tuning are not fully understood in plants. Here, we used plants expressing an artificial miRNA target mimic (MIM) to screen for negative regulators of miR156 activity. We identified a new mutant allele of the F-box protein HAWAIIAN SKIRT (HWS; At3G61590), hws-5, as a suppressor of the MIM156-induced developmental and molecular phenotypes. In hws plants, levels of endogenous miRNAs are increased and their mRNA targets decreased. Plants constitutively expressing full-length HWSbut not a truncated version lacking the F-box domain -display morphological and molecular phenotypes resembling those of mutants defective in miRNA biogenesis and activity. In combination with such mutants, hws loses its delayed floral organ abscission ('skirt') phenotype, suggesting epistasis. Also, the overall hws transcriptome profile partially resembles well-known miRNA mutants hyl1-2 and se-3, indicating action in a common pathway. We thus propose HWS as a novel, F-box dependent regulator of miRNA biogenesis.

HAWAIIAN SKIRT controls size and floral organ number by modulating CUC1 and CUC2 expression

“…The sepal fusion phenotype observed in the hws-1 mutant, which phenocopies the sepal fusion of a MIR164B overexpression line [ 21 , 22 ], is likely due to an increase of MIR164B and MIR164B C levels. Overexpressing HWS results in a decreased transcript level of MIR164 , suggesting that the target of HWS play an important role in regulating MIR164 , either in their production, function or degradation; indeed, our own work and that of [ 42 ] propose a role for HWS in the microRNA pathway.…”

SpPKE1, a Multiple Stress-Responsive Gene Confers Salt Tolerance in Tomato and Tobacco

“…F-box proteins are involved in post-transcriptional regulation by targeted protein ubiquitination [36]. F-box protein gene plays an important role in abiotic stress [37,38,39,40] and plant miRNA function in plant [41]. For example, an F-box protein DOR inhibits the ABA-induced stomatal closure under drought stress in Arabidopsis [39], and another F-box protein MAX plays an important role in the regulation of plant growth and development and in response to abiotic stress conditions [38].…”