Gene discovery sheds light on rice yield and pollen development

Jim Crocker
10th January, 2026

Gene discovery sheds light on rice yield and pollen development

Compared to the wild-type ZH11, the osg mutant of rice (Oryza sativa) exhibits significant reductions in key agronomic traits that determine yield, including decreased plant height (d), fewer tillers (e), shorter panicles (f), and a lower seed setting rate (i), as visually documented in a, b, and c.

Image adapted from: Zhao et al. / CC BY (Source)

Key Findings

  • Researchers identified a gene, OsSRS3, in rice plants that plays a key role in controlling plant height, panicle length, and grain characteristics
  • Loss of functional OsSRS3 resulted in shorter plants with reduced panicle length, shorter grains, and wider grains, but decreased overall seed weight
  • The OsSRS3 gene affects plant hormone signaling and carbohydrate metabolism pathways, impacting grain shape and pollen development
Grain yield in rice, a staple food for a large portion of the world’s population, is determined by a complex interplay of factors, with grain size and shape being particularly important. Improving these characteristics is a key goal for agricultural research. A recent study by researchers at Anhui Science and Technology University, Wuhan Technical University, and Government College University Faisalabad[1] has identified a gene, OsSRS3, that plays a crucial role in regulating these traits. The research began with an unusual rice plant – a mutant exhibiting oval-shaped grains. This mutant, created through radiation mutagenesis (exposure to radiation to induce genetic changes), displayed a distinctive combination of traits: shorter, wider, and thicker grains, but with a reduced overall weight. Alongside these changes in grain characteristics, the mutant plants were also shorter, produced fewer tillers (stems), and had lower pollen viability and seed setting rates. This suggests that the gene responsible wasn’t just affecting grain development, but also broader aspects of plant growth and reproduction. To pinpoint the gene causing these changes, the researchers used a technique called map-based cloning. This method involves identifying the location of a gene on a chromosome based on its inheritance patterns. The cloning revealed that OsSRS3 was the likely culprit. Further confirmation came from creating another mutant with a non-functional OsSRS3 gene; this mutant displayed similar characteristics to the original oval-shaped grain mutant, strengthening the link between the gene and the observed traits. Understanding how OsSRS3 affects grain shape required a deeper look at the plant’s molecular activity. The researchers performed transcriptome sequencing – a process that measures the activity of all genes in a sample – on young panicles (the flowering part of the rice plant) from both the normal rice plants and the mutant. This revealed significant differences in gene expression. In the mutant, genes involved in plant hormone signaling pathways and MAPK signaling (a communication system within cells) were more active, while genes related to starch and sucrose metabolism were less active. These changes in gene expression were further investigated by focusing on specific genes that were either up-regulated (more active) or down-regulated (less active) in the mutant. Several of these genes – OsJAZ11, OsUgp1, and OsUgp2 – had already been studied, and the characteristics of plants with mutations in these genes matched those seen in the OsSRS3 mutant. This provided further evidence that OsSRS3 regulates grain shape, at least in part, by influencing the activity of these other genes. This study builds upon earlier research demonstrating the complex genetic control of rice yield traits[2]. That work showed that grain yield is determined by multiple factors, including the number of panicles, grains per panicle, and grain weight, all of which are controlled by many genes. The identification of OsSRS3 adds to this growing list of genes involved in regulating these traits. Furthermore, the findings connect with research identifying GS3 as a major regulator of grain size[3]. GS3 functions as a negative regulator of grain size, and variations in its expression can lead to significant differences in grain length. While GS3 and OsSRS3 appear to have different roles – GS3 acting more directly on grain length and OsSRS3 influencing broader aspects of grain shape and fertility – both genes highlight the importance of cell regulation in determining grain characteristics. Similarly, the identification of GW5 as a positive regulator of BR signalling[4] and OsSPL16 as a promoter of cell proliferation[5] demonstrates the complex interplay of signalling pathways and cell division in grain development, which the current study further supports by highlighting the role of hormone signalling and MAPK pathways. The research at Anhui Science and Technology University, Wuhan Technical University, and Government College University Faisalabad provides a crucial foundation for understanding the molecular mechanisms by which SRS3 regulates grain size and fertility in rice. This knowledge could be used to develop new strategies for improving rice yield and quality through targeted genetic modifications.

AgricultureGeneticsPlant Science

References

Main Study

1) Fine mapping and transcriptomics reveal OSG function in regulation of grain size and pollen fertility in rice (Oryza sativa)

Published 8th January, 2026

https://doi.org/10.1371/journal.pone.0338401

Related Studies

2) Genetic and molecular bases of rice yield.

https://doi.org/10.1146/annurev-arplant-042809-112209

3) Linking differential domain functions of the GS3 protein to natural variation of grain size in rice.

https://doi.org/10.1073/pnas.1014419107

4) GW5 acts in the brassinosteroid signalling pathway to regulate grain width and weight in rice.

https://doi.org/10.1038/nplants.2017.43

5) Control of grain size, shape and quality by OsSPL16 in rice.

https://doi.org/10.1038/ng.2327


Related Articles

An unhandled error has occurred. Reload 🗙