J Integr Plant Biol ›› 2020, Vol. 62 ›› Issue (7): 948-966.DOI: 10.1111/jipb.12866

所属专题： Crop yield

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  • 收稿日期:2019-06-25 接受日期:2019-08-20 出版日期:2020-07-01 发布日期:2019-08-26

GBSS-BINDING PROTEIN , encoding a CBM48 domain-containing protein, affects rice quality and yield

Wei Wang1,2†, Xiangjin Wei2†*, Guiai Jiao2, Wenqiang Chen2, Yawen Wu2, Zhonghua Sheng2, Shikai Hu2, Lihong Xie2, Jiayu Wang1, Shaoqing Tang2* and Peisong Hu1,2*   

  1. 1Rice Research Institute, Shenyang Agricultural University, Shenyang 110866, China
    2State Key Laboratory of Rice Biology, China National Center for Rice Improvement, China National Rice Research Institute, Hangzhou 310006, China

    †These authors contributed equally to this work.
    *Correspondences:
    Email: Xiangjin Wei (weixiangjin@caas.cn); Shaoqing Tang (tangshaoqing@caas.cn); Peisong Hu (peisonghu@126.com, hupeisong@caas.cn , Dr. Hu is fully responsible for the distribution of all materials associated with this article)
  • Received:2019-06-25 Accepted:2019-08-20 Online:2020-07-01 Published:2019-08-26

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GBSS-BINDING PROTEIN (OsGBP), a CBM48 domain-containing protein, interacts with GBSSs to affect the biosynthesis of amylose in rice leaf and grain. Osgbp mutants show a chalky endosperm, resulting in reduced qualityand grain weigh. Our data show that the CBM48 domain is crucial for OsGBP binding to starch.

Abstract:

The percentage of amylose in the endosperm of rice (Oryza sativa ) largely determines grain cooking and eating qualities. Granule‐bound starch synthase I (GBSSI) and GBSSII are responsible for amylose biosynthesis in the endosperm and leaf, respectively. Here, we identified OsGBP , a rice GBSS‐binding protein that interacted with GBSSI and GBSSII in vitro and in vivo . The total starch and amylose contents in osgbp mutants were significantly lower than those of wild type in leaves and grains, resulting in reduced grain weight and quality. The carbohydrate‐binding module 48 (CBM48) domain present in the C‐terminus of OsGBP is crucial for OsGBP binding to starch. In the osgbp mutant, the extent of GBSSI and GBSSII binding to starch in the leaf and endosperm was significantly lower than wild type. Our data suggest that OsGBP plays an important role in leaf and endosperm starch biosynthesis by mediating the binding of GBSS proteins to developing starch granules. This elucidation of the function of OsGBP enhances our understanding of the molecular basis of starch biosynthesis in rice and contributes information that can be potentially used for the genetic improvement of yield and grain quality.

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