A wheat-specific proline-rich protein regulates grain weight through a ubiquitin-mediated delay of endosperm cellularization.

Authors

Li Guo, Yang Yuan, Shuanglin Du, Duoduo Hou, Zongyuan Guo, Shirong Liu, Li Ma, Quan Xie, Zhengqiang Ma, Haiyan Jia

Published in

The Plant journal : for cell and molecular biology. Volume 128. Issue 1. Pages e71148.

Abstract

Grain weight is a key determinant of wheat yield, yet the developmental mechanisms that define this trait remain poorly understood. Here, we identify TaPGW1-A1, a wheat-specific proline-rich gene that regulates grain weight. TaPGW1-A1 is a recently evolved gene found only in wheat. It is highly expressed in early developing grains, and its overexpression delays endosperm cellularization and prolongs the syncytial phase, resulting in an 8% increase in field-based grain weight. TaPGW1-A1 protein directly interacts with the ubiquitin receptor TaDSK2a (Dominant Suppressor of KAR2 homolog) via its N-terminal signal peptide, and the protein-protein complex localizes to the cell periphery. Biochemical assays show that TaDSK2a binds both K48- and K63-linked polyubiquitin chains. Loss-of-function of TaDSK2a leads to reduced grain size, confirming its essential role in grain development. The E3 ligase TaRGLG2 inhibits the binding of TaPGW1-A1 to TaDSK2a. Together, these findings define a TaPGW1-A1-TaDSK2a-TaRGLG2 regulatory module that links developmental timing with ubiquitin-mediated protein turnover, revealing a previously unrecognized mechanism controlling endosperm cellularization and grain yield in wheat.

PMID:
42856000
Bibliographic data and abstract were imported from PubMed on 10 Oct 2026.

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