The PGS1 basic helix‐loop‐helix protein regulates Fl3 to impact seed growth and grain yield in cereals

• DOI: 10.1111/pbi.13809
• Publication Date: 2022-03-22T07:44:56Z
• Authors: Xiaojiang Guo; Yuxin Fu; Yuh‐Ru Julie Lee; Mawsheng Chern; Maolian Li; Mengping Cheng; Huixue Dong; Zhongwei Yuan; Lixuan Gui; Junjie Yin; Hai Qing; Chengbi Zhang; Zhien Pu; Yujiao Liu; Weitao Li; Wei Li; Pengfei Qi; Guoyue Chen; Qiantao Jiang; Jian Ma; Xuewei Chen; Yuming Wei; Youliang Zheng; Yongrui Wu; Bo Liu; Jirui Wang
• Keywords: Crop and Pasture Production; 0301 basic medicine; 570; and promotion of well-being; Technology; Agricultural biotechnology; Veterinary and Food Sciences; Medical and Health Sciences; 630; endosperm; 03 medical and health sciences; Gene Expression Regulation, Plant; Basic Helix-Loop-Helix Transcription Factors; 3.3 Nutrition and chemoprevention; transcription factor; Research Articles; Triticum; Plant Proteins; grain size; Plant biology; 2. Zero hunger; Agricultural; 0303 health sciences; grain weight; Oryza; Plant; Biological Sciences; Prevention of disease and conditions; Gene Expression Regulation; Seeds; Edible Grain; Biotechnology

SummaryPlant transcription factors (TFs), such as basic helix‐loop‐helix (bHLH) and AT‐rich zinc‐binding proteins (PLATZ), play critical roles in regulating the expression of developmental genes in cereals. We identified the bHLH protein TaPGS1 (T. aestivum Positive Regulator of Grain Size 1) specifically expressed in the seeds at 5–20 days post‐anthesis in wheat. TaPGS1 was ectopically overexpressed (OE) in wheat and rice, leading to increased grain weight (up to 13.81% in wheat and 18.55% in rice lines) and grain size. Carbohydrate and total protein levels also increased. Scanning electron microscopy results indicated that the starch granules in the endosperm of TaPGS1 OE wheat and rice lines were smaller and tightly embedded in a proteinaceous matrix. Furthermore, TaPGS1 was bound directly to the E‐box motif at the promoter of the PLATZ TF genes TaFl3 and OsFl3 and positively regulated their expression in wheat and rice. In rice, the OsFl3 CRISPR/Cas9 knockout lines showed reduced average thousand‐grain weight, grain width, and grain length in rice. Our results reveal that TaPGS1 functions as a valuable trait‐associated gene for improving cereal grain yield.