J Integr Plant Biol. ›› 2020, Vol. 62 ›› Issue (7): 948-966.DOI: 10.1111/jipb.12866
• Molecular Physiology •
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*
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.
Wei Wang, Xiangjin Wei, Guiai Jiao, Wenqiang Chen, Yawen Wu, Zhonghua Sheng, Shikai Hu, Lihong Xie, Jiayu Wang, Shaoqing Tang and Peisong Hu. GBSS-BINDING PROTEIN , encoding a CBM48 domain-containing protein, affects rice quality and yield[J]. J Integr Plant Biol., 2020, 62(7): 948-966.
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