A VIN3-like Protein OsVIL1 Is Involved in Grain Yield and Biomass in Rice

Abstract

In chromatin remodeling, the post-translational modification of histone proteins is mediated by multimeric protein complexes. VERNALIZATION INSENSITIVE3 (VIN3) forms a complex with Polycomb Repressive Complex 2 (PRC2), which mediates the trimethylation of H3K27 to repress target gene expression. In rice, four genes (OsVIL1-OsVIL4) encoding the VIN3-like proteins are expressed ubiquitously in various tissues. Null mutants of osvil2 display pleiotropic phenotypes such as altered flowering time, floral organ defects, and reduced tiller size. In contrast, osvil1 mutants did not show significant phenotypes except in fertilization compared with the wild type. However, transgenic plants overexpressing OsVIL1 showed phenotypes of increased biomass and grain yield. Cross-sections of the basal region of elongating stems revealed that the increased biomass was mediated by inducing cell proliferation in the meristem. Chromatin immunoprecipitation assay indicated that OsVIL1 repressed expression of cytokinin oxidase/dehydrogenase gene (OsCKX2) by binding to the promoter and genic regions of OsCKX2. We also observed that OsVIL1 modified the levels of H3K27me3 in the OsCKX2 chromatin. Because OsCKX2 encodes an enzyme that degrades active cytokinin, we conclude that OsVIL1 functions in the regulation of endogenous active cytokinin levels, thereby increasing plant height and productivity.

Sucrose preferentially promotes expression of OsWRKY7 and OsPR10a to enhance defense response to blast fungus in rice

“…Rice Actin1 (OsActin1) was used as an endogenous control to normalize the expression level of the respective genes. All experiments were repeated at least three times, and the relative transcript levels were calculated using the DDCt method (Schmittgen and Livak, 2008;Yoon et al, 2022). The primers used in this study are listed in Supplementary Table 1.…”

“…The chromatin immunoprecipitation (ChIP) assay was performed using the protocols described in Haring et al (2007) and Yoon et al (2022) with some modifications. Firstly, the fresh leaves from the OsWRKY7-HA transgenic plants were collected and the proteins and chromatin were cross-linked using 3% formaldehyde.…”

“…The enriched chromatin was analyzed by qRT-PCR using the primers listed in Supplementary Table 1. The obtained data were normalized using the fold enrichment method (Haring et al, 2007;Yoon et al, 2022).…”

Harnessing Knowledge from Plant Functional Genomics and Multi-Omics for Genetic Improvement

“…Overexpression of a new starch biosynthetic gene of maize ( ZmCBM48-1 ), which contains a carbohydrate-binding module 48 (CBM48) domain, altered grain size and thousand grain weight, and increased the starch content in rice [ 16 ]. Yoon et al found that VERNALIZATION INSENSITIVE 3-LIKE 1 (OsVIL1), a homolog of the flowering regulator OsVIL2 in rice, increased grain yield and biomass by directly regulating OsCKX2 expression [ 17 ].…”

Genetic and molecular pathways controlling rice inflorescence architecture

“…The loss of function of LP leads to an increase in branch number and grain number, which is most likely attributed to up-regulation of CK levels ( Li et al., 2011 ). The chromatin interacting factor VIN3-LIKE1 (OsVIL1) and OsVIL2 directly binds to the promoter of OsCKX2 and regulates H3K27 methylation, resulting in decreased OsCKX2 expression, increased CK levels and an increase in the number of branches and grains ( Yang et al., 2019 ; Yoon et al., 2021 ).…”