Open Access

ARTICLE

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

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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