Small molecules, such as peptides and miRNAs, are crucial regulators of plant growth. Here, we show the importance of cross-talk between miPEP858a (microRNA858a-encoded peptide)/miR858a and phytosulfokine (PSK4) in regulating plant growth and development in Arabidopsis (Arabidopsis thaliana). Genome-wide expression analysis suggested modulated expression of PSK4 in miR858a mutants and miR858a-overexpressing (miR858aOX) plants. The silencing of PSK4 in miR858aOX plants compromised growth, whereas overexpression of PSK4 in the miR858a mutant rescued the developmental defects. The exogenous application of synthetic PSK4 further complemented the plant development in mutant plants. Exogenous treatment of synthetic miPEP858a in the PSK4 mutant led to clathrin-mediated internalization of the peptide; however, it did not enhance growth as is the case in wild-type plants. We also demonstrated that MYB3 is an important molecular component participating in the miPEP858a/miR858a-PSK4 module. Finally, our work highlights the signaling between miR858a/miPEP858a-MYB3-PSK4 in modulating the expression of key elements involved in auxin responses, leading to the regulation of growth.
Short title: miPEP858a regulates plant growth and developmentOne sentence summary: Small peptide, miPEP858a, encoded by primary miRNA for miR858a regulates plant growth, development and flavonoid biosynthesis The authors responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors Prabodh Kumar Trivedi (prabodht@nbri.res.in).
AbstractMicroRNAs (miRNAs), small non-coding endogenous RNAs, are processed product of primary miRNAs (pri-miRNAs) and regulate target gene expression. pri-miRNAs have also been reported to encode small peptides, miRNA-Encoded Peptides (miPEPs). Though regulatory role of miPEPs has been speculated, no detailed study has been carried out to elucidate their function through developing knock-out mutants. Here, we report that pri-miR858a of Arabidopsis thaliana encodes a small peptide (miPEP858a) which regulates the expression of pri-miR858a leading to modulation in the expression of target genes involved in the plant growth and development as well as phenylpropanoid pathway. CRISPR-based miPEP858a-edited plants developed phenotypes similar to that of mature miR858-edited plants suggesting crucial role of miPEP858a in mediating miR585a function. miPEP858a-edited and miPEP858a overexpressing lines altered plant development and accumulated modulated levels of flavonoids due to changes in expression of associated genes. Exogenous treatment of synthetic-miPEP858a to the miPEP858a-edited plants complemented phenotypes and the gene function suggesting a significant role of miPEP858a in controlling the miR858 function and plant development. Keywords: CRISPR/Cas9, knock-out mutant, miPEP, miRNA, phenylpropanoid pathway, pri-miRNA responses through targeting mostly transcription factors (TFs) (Kumar et al., 2017; Tang and Chu, 2017).Recently, it has been demonstrated that the plant pri-miRNA contains short Open Reading Frames (ORFs) which encode regulatory peptides also known as miRNA-Encoded Peptides (miPEPs) (Lauressergues et al., 2015).These peptides were shown to enhance the mature miRNA levels by enhancing the transcription of their associated pri-miRNA (Couzigou et al., 2015;Couzigou et al., 2016). These miPEPs show specificity towards associated miRNAs suggesting their wide application in the regulation in gene expression and improvement of the desired agronomically important traits (Couzigou et al., 2017). Though there are only a few reports on involvement of miPEPs in the gene regulation, these provide a significant glimpse into the importance of these small peptides.
Small molecules, peptides, and miRNAs are the crucial regulators of plant growth. Here, we show the importance of cross-talk between miPEP858a/miR858a and Phytosulfokine (PSK4) in regulating plant growth and development in Arabidopsis. Genome-wide expression analysis suggested modulated expression of PSK4 in miR858 mutant and overexpression, miR858OX, plants. The silencing of PSK4 in miR858OX plants compromised the growth, whereas over-expression of PSK4 in miR858 mutant rescued the developmental defects. The exogenous application of synthetic PSK4 further complemented the plant development in mutant plants. Exogenous treatment of synthetic miPEP858a in PSK4 mutant led to clathrin-mediated internalization of the peptide however did not enhance growth as in the case of wild-type plants. We also demonstrate that the MYB3 is an important molecular component participating in miPEP858a/miR858a-PSK4 module. Finally, our work highlights the signaling between miR858/miPEP858-MYB3-PSK4 in modulating the expression of key elements involved in auxin responses leading to the regulation of growth.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.