A quantitative trait locus GW6 controls rice grain size and yield through the gibberellin pathway. (28th May 2020)

• Record Type: Journal Article
• Authors: Shi, Chuan‐Lin; Dong, Nai‐Qian; Guo, Tao; Ye, Wang‐Wei; Shan, Jun‐Xiang; Lin, Hong‐Xuan
• Is Part Of: Plant journal. Volume 103:Number 3(2020)
• Page Start: 1174
• Page End: 1188
• Publication Date: 2020-05-28
• Subjects: cell expansion -- domestication -- gibberellin biosynthesis -- grain size -- Oryza sativa -- quantitative trait locus -- rice yield; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.14793
• Languages: English
• ISSNs: 0960-7412

Abstract

SUMMARY: Grain size is one of the essential components determining rice yield and is a target for both domestication and artificial breeding. Gibberellins (GAs) are diterpenoid phytohormones that influence diverse aspects of plant growth and development. Several quantitative trait loci (QTLs) have been identified that control grain size through phytohormone regulation. However, little is known about the role of GAs in the control of grain size. Here we report the cloning and characterization of a QTL, GW6 ( GRAIN WIDTH 6 ), which encodes a GA‐regulated GAST family protein and positively regulates grain width and weight. GW6 is highly expressed in the young panicle and increases grain width by promoting cell expansion in the spikelet hull. Knockout of GW6 exhibits reduced grain size and weight, whereas overexpression of GW6 results in increased grain size and weight. GW6 is induced by GA and its knockout downregulates the expression of GA biosynthesis genes and decreases GA content in the young panicle. We found that a natural variation in the cis element CAAT‐box in the promoter of GW6 is associated with its expression level and grain width and weight. Furthermore, introduction of GW6 to Oryza indica variety HJX74 can lead to a 10.44% increase in rice grain yield, indicating that GW6 has great potential to improve grain yield in rice. Significance Statement: GW6 participates in the regulation of gibberellin biosynthesis in the rice panicle, by which it can positively regulate grain size and weight by promoting cell expansion in the spikelet hull and accelerating the grain filling rate, leading to a significant increase in grain yield. Therefore, GW6 has great potential to improve grain yield in rice breeding.