Open Access

ARTICLE

Phytosulfokine-α Promotes Root Growth by Repressing Expression of Pectin Methylesterase Inhibitor (PMEI) Genes in Medicago truncatula

by Liangliang Yu, Wenjun Zhou, Danping Zhang, Junhui Yan, Li Luo

Shanghai Key Lab of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, 200444, China

* Corresponding Author: Liangliang Yu. Email:

Phyton-International Journal of Experimental Botany 2020, 89(4), 873-881. https://doi.org/10.32604/phyton.2020.011882

Received 03 June 2020; Accepted 14 June 2020; Issue published 09 November 2020

Abstract

Phytosulfokine-α (PSK-α), a sulfated pentapeptide with the sequence YIYTQ, is encoded by a small precursor gene family in Arabidopsis. PSK-α regulates multiple growth and developmental processes as a novel peptide hormone. Despite its importance, functions of PSK-α in M. truncatula growth remains unknown. In this study, we identified five genes to encode PSK-α precursors in M. truncatula. All of these precursors possess conserved PSK-α signature motif. Expression pattern analysis of these MtPSK genes revealed that each gene was expressed in a tissue-specific or ubiquitous pattern and three of them were remarkably expressed in root. Treatment of M. truncatula seedlings with synthetic PSK- α peptide significantly promoted root elongation. In addition, expression analysis of downstream genes by RNA-seq and qRT-PCR assays suggested that PSK-α signaling might regulate cell wall structure via PMEI-PME module to promote root cell growth. Taken together, our results shed light on the mechanism by which PSK-α promotes root growth in M. truncatula, providing a new resource for improvement of root growth in agriculture.

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