SLG2 specifically regulates grain width through WOX11‐mediated cell expansion control in rice

Abstract

SummaryGrain size is specified by three dimensions of length, width and thickness, and slender grain is a desirable quality trait in rice. Up to now, many grain size regulators have been identified. However, most of these molecules show influence on multi‐dimensions of grain development, and only a few of them function specifically in grain width, a key factor determining grain yield and appearance quality. In this study, we identify the SLG2 (SLENDER GUY2) gene that specifically regulates grain width by affecting cell expansion in the spikelet hulls. SLG2 encodes a WD40 domain containing protein, and our biochemical analyses show that SLG2 acts as a transcription activator of its interacting WOX family protein WOX11. We demonstrate that the SLG2‐associated WOX11 binds directly to the promoter of OsEXPB7, one of the downstream cell expansion genes. We show that knockout of WOX11 results in plants with a slender grain phenotype similar to the slg2 mutant. We also present that finer grains with different widths could be produced by combining SLG2 with the grain width regulator GW8. Collectively, we uncover the crucial role of SLG2 in grain width control, and provide a promising route to design rice plants with better grain shape and quality.

The WOX Genes from the Intermediate Clade: Influence on the Somatic Embryogenesis in Medicago truncatula

“…Transcriptomic analysis of A. thaliana seeds revealed the participation of WOX11 in the regulation of seed dormancy and germination [ 14 ]. In rice, WOX11 interacts with SLENDER GUY2 and regulates grain width [ 15 ].…”

Genome-Wide Identification and Co-Expression Networks of WOX Gene Family in Nelumbo nucifera

“…Several AtWOX genes are essential for multiple processes of tissue formation, including AtWUS and PRS1/AtWOX3 in the shoot apical meristem (STM) [13,14], AtWOX2 in the egg cell and zygote [15], AtWOX6 in the ovule development [16], STIP/AtWOX9 in STM, the root and other aerial organs [17], and At-WOX13 in floral transition [18]. In a model rice plant, the interaction of OsWOX11 and SLG2 determined grain width and affected quality traits [19]. Variation in the gene expression level of OsWUS negatively affects the phenotypic traits in rice [20].…”

Identification of cis-Acting Elements Recognized by Transcription Factor LlWOX11 in Lilium lancifolium

“…PgWOX11 binds to the PgCLE45 promoter to regulate adventitious root branching (Liu et al, 2020). A new study shows that OsWOX11 works together with OsSLG2 regulate grain width by affecting the expansion of cells within the spikelet shell in rice (Xiong et al, 2023). Liao et al(2023) found that WOX11 regulates seed dormancy through mediating phytochrome B (PHYB) signaling during the induction stage.…”