TaWUS2D regulates the number of grains per spikelet by enhancing the number of fertile ovaries in Multi-Ovary Wheat

Authors: SCHOEN, ADAM - University Of Maryland; KUMAR SHARMA, PARVA - University Of Maryland; MAHLANDT, ALEX - Max Planck Institute For Plant Breeding Research; CHEN, ANDY - University Of Guelph; SHENG, HUAJIN - University Of Saskatchewan; DATLA, RAJU - University Of Saskatchewan; KOCHIAN, LEON - University Of Saskatchewan; GAO, PENG - Agriculture And Agri-Food Canada; XIANG, DAOQUAN - National Research Council - Canada; QUILICHINI, TEAGEN - National Research Council - Canada; VENGLAT, PRAKASH - University Of Saskatchewan; SINGH YADAV, INDERJIT - Punjab Agricultural University; Gu, Yong; RODRIGUEA-LEAL, DANIEL - University Of Maryland; LUO, WEIFENG - University Of Maryland; QI, YIPING - University Of Maryland; MEIER, NATHAN - University Of California, Davis; KAJLA, ANMOL - University Of Maryland; WILLMAN, MATTHEW - North Carolina State University; Brown Guedira, Gina; YOUNGBLOOD, CAL - Mississippi State University; Hulse-Kemp, Amanda; MURPHY, ANGUS - University Of Maryland; UAUV, CRISTOBAL - John Innes Center; GILL, BIKRAM - Kansas State University; RAWAT, NIDHI - University Of Maryland; TIWARI, VIJAY - University Of Maryland

Submitted to: Proceedings of the National Academy of Sciences (PNAS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2025
Publication Date: 10/14/2025
Citation: Schoen, A., Kumar Sharma, P., Mahlandt, A., Chen, A., Sheng, H., Datla, R., Kochian, L., Gao, P., Xiang, D., Quilichini, T., Venglat, P., Singh Yadav, I., Gu, Y.Q., Rodriguea-Leal, D., Luo, W., Qi, Y., Meier, N., Kajla, A., Willman, M., Brown Guedira, G.L., Youngblood, C., Hulse-Kemp, A.M., Murphy, A., Uauv, C., Gill, B., Rawat, N., Tiwari, V. 2025. TaWUS2D regulates the number of grains per spikelet by enhancing the number of fertile ovaries in Multi-Ovary Wheat. Proceedings of the National Academy of Sciences (PNAS). https://doi.org/10.1073/pnas.2510889122.
DOI: https://doi.org/10.1073/pnas.2510889122

Interpretive Summary: As wheat yields have plateaued over the past 30 years across all major growing regions, novel genetic approaches to yield improvement are required. Here, we report the map-based cloning of a gene responsible for a multi-ovary phenotype in wheat, characterized by the development of three fertile ovaries per floret that results in three grains, as opposed to single ovary wheat. We used a variety of tools, including whole genome sequencing and analyses of mutants, to demonstrate that mis-expression of a gene referred as TaWUS2D underlies the multi-ovary trait. Insights gained from this research lay the groundwork for new approaches to improve wheat production potential.

Technical Abstract: Innovative genetic improvements in food crops are urgently needed to address global food security. Here, we report the map-based cloning of TaWUS2D, the gene responsible for dominant multi-ovary phenotype in wheat, characterized by the development of three fertile ovaries per floret that results in three grains, as opposed to single ovary wheat. We generated HiFi long-reads assembly for a 14.48 Gbp genome scaffold of the multi-ovary wheat line “MOV" and used high-resolution genetic mapping to place the Mov-1 locus within a 135 Kbp region containing two genes. Using five independent deletion mutants and eight TILLING mutants, we demonstrate that the WUSCHEL homolog TaWUS2D, is required for the multi-ovary phenotype. Expression analyses reveal that TaWUS2D is upregulated in later stages of ovary development in the MOV, suggesting a developmental delay in floral meristem termination. Insights gained from this research lay the groundwork for new approaches to improve wheat production potential.