Wheat flour owes its distinctive dough properties largely to gluten proteins, whose composition influences whether flour is suitable for bread, steamed buns, noodles, biscuits, or cakes. High-molecular-weight glutenin subunits are particularly influential: although they represent a relatively small proportion of glutenin, they make a substantial contribution to variation in processing quality. Scientists have identified several transcription factors that activate or suppress the genes encoding these proteins, but the regulatory network remains incompletely understood. Earlier studies linked TaMYB44 to starch synthesis and grain development, raising questions about whether it also controls protein accumulation. Clarifying this connection could expand the genetic resources available for improving wheat quality while monitoring potential effects on grain development.
A study (DOI: 10.48130/seedbio-0026-0021) published in Seed Biology on 23 September 2026 by Yujiao Gao's & Hongxiang Ma's team, Agricultural College of Yangzhou University, identifies TaMYB44 as an endosperm-specific regulator that suppresses glutenin production.
The researchers began by examining wheat transcriptome data to identify MYB transcription factors preferentially expressed in the developing endosperm, the grain tissue that stores starch and proteins. They identified three related TaMYB44 copies on chromosomes 4A, 4B, and 4D. Quantitative gene expression measurements across tissues and developmental stages showed strong expression in the endosperm, very low expression elsewhere, and peak activity around 10–15 days after pollination. To test gene function, the team used CRISPR/Cas9 to generate two knockout lines in the wheat cultivar Fielder, introducing disruptive mutations into all three copies. They also produced plants overexpressing TaMYB44-B and compared the modified plants with unmodified controls. Measurements covered plant height, spike length, kernels per spike, grain dimensions, and thousand-grain weight. None differed significantly in the knockout lines. Near-infrared spectroscopy nevertheless revealed a 5%–10% increase in total grain protein. Protein fractionation showed that glutenin increased by 26%–33%, while gliadin remained unchanged. Gel electrophoresis further supported increased accumulation of high-molecular-weight glutenin subunits. The opposite manipulation produced the opposite protein response: overexpressing TaMYB44-B reduced these subunits by 30%–41%, again without significant changes in the measured agronomic or grain traits. To connect these outcomes to gene regulation, the researchers measured four glutenin-encoding genes during grain development and found increased expression in a knockout line. Dual-luciferase reporter assays in Nicotiana benthamiana leaves then showed that TaMYB44 suppressed activity driven by all four gene promoters. Finally, electrophoretic mobility shift assays demonstrated direct binding between purified TaMYB44 protein and a DNA fragment from the TaGlu-1Dx promoter; excess competing DNA weakened the binding signal. Together, the complementary experiments connect the regulator's activity to glutenin gene expression and protein accumulation, providing a molecular explanation for the altered grain composition observed in the edited plants. They also distinguish the protein response from detectable changes in the grain traits measured under the study's conditions.
The study extends TaMYB44's known functions from starch regulation to wheat storage protein accumulation. Removing its repressive activity offers a potential route to increasing glutenin, with no significant penalties in the traits measured here. However, improved dough performance and breadmaking quality remain applications to be tested directly. Further evaluation across wheat varieties and growing environments will help establish whether this molecular target can deliver consistent quality gains for breeders, millers, and food producers.
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References
DOI
10.48130/seedbio-0026-0021
Original Source URL
https://doi.org/10.48130/seedbio-0026-0021
Funding information
This work was funded by the National Key R&D Program of China (2023YFD1201900), the Jiangsu Key Project for the Research and Development (BE2022346), the National Natural Science Foundation of China (32201772), China Postdoctoral Science Foundation (2023M733002), and Jiangsu Association for Science & Technology Youth Science & Technology Talents Lifting Project (JSTJ-2024-327).
About Seed Biology
Seed Biology (e-ISSN 2834-5495) is published by Maximum Academic Press in partnership with Yazhou Bay Seed Laboratory. Seed Biology is an open access, online-only journal focusing on research related to all aspects of the biology of seeds, including but not limited to: evolution of seeds; developmental processes including sporogenesis and gametogenesis, pollination and fertilization; apomixis and artificial seed technologies; regulation and manipulation of seed yield; nutrition and health-related quality of the endosperm, cotyledons, and the seed coat; seed dormancy and germination; seed interactions with the biotic and abiotic environment; and roles of seeds in fruit development. Seed Biology publishes a wide range of research approaches, such as omics, genetics, biotechnology, genome editing, cellular and molecular biology, physiology, and environmental biology. Seed Biology publishes high-quality original research, reviews, perspectives, and opinions in open access mode, promoting fast submission, review, and dissemination freely to the global research community.