摘要
Grain size is an important determinant of yield potential in crops. We previously demonstrated that natural mutations in the regulatory sequences of qSW5/GW5 confer grain width diversity in rice. However, the biological function of a GW5 homolog, named GW5-Like(GW5 L), remains unknown. In this study, we report on GW5 L knockout mutants in Kitaake, a japonica cultivar(cv.)considered to have a weak gw5 variant allele that confers shorter and wider grains. GW5 L is evenly expressed in various tissues, and its protein product is localized to the plasma membrane. Biochemical assays verified that GW5 L functions in a similar fashion to GW5. It positively regulates brassinosteroid(BR) signaling through repression of the phosphorylation activity of GSK2. Genetic data show that GW5 L overexpression in either Kitaake or a GW5 knockout line, Kasaorf3(indica cv. Kasalath background), causes more slender, longer grains relative to the wild-type. We also show that GW5 L could confer salt stress resistance through an association with calmodulin protein OsCa M1-1. These findings identify GW5 L as a negative regulator of both grain size and salt stress tolerance, and provide a potential target for breeders to improve grain yield and salt stress resistance in rice.
Grain size is an important determinant of yield potential in crops. We previously demonstrated that natural mutations in the regulatory sequences of qSW5/GW5 confer grain width diversity in rice. However, the biological function of a GW5 homolog, named GW5-Like(GW5 L), remains unknown. In this study, we report on GW5 L knockout mutants in Kitaake, a japonica cultivar(cv.)considered to have a weak gw5 variant allele that confers shorter and wider grains. GW5 L is evenly expressed in various tissues, and its protein product is localized to the plasma membrane. Biochemical assays verified that GW5 L functions in a similar fashion to GW5. It positively regulates brassinosteroid(BR) signaling through repression of the phosphorylation activity of GSK2. Genetic data show that GW5 L overexpression in either Kitaake or a GW5 knockout line, Kasaorf3(indica cv. Kasalath background), causes more slender, longer grains relative to the wild-type. We also show that GW5 L could confer salt stress resistance through an association with calmodulin protein OsCa M1-1. These findings identify GW5 L as a negative regulator of both grain size and salt stress tolerance, and provide a potential target for breeders to improve grain yield and salt stress resistance in rice.
基金
supported by the Major Research Project of Natural Science Foundation of China (91735304)
the Major Science and Technology Project to Create New Crop Cultivars using Gene Transfer Technology (2016ZX08001006)
the National Key Research and Development Program of China (2016YFD0100301)
