Functions and Mechanisms of Brassinosteroids in Regulating Crop Agronomic Traits

Abstract

Brassinosteroids (BRs) perform crucial functions controlling plant growth and developmental processes, encompassing many agronomic traits in crops. Studies of BR-related genes involved in agronomic traits have suggested that BRs could serve as a potential target for crop breeding. Given the pleiotropic effect of BRs, a systematic understanding of their functions and molecular mechanisms is conducive for application in crop improvement. Here, we summarize the functions and underlying mechanisms by which BRs regulate the several major crop agronomic traits, including plant architecture, grain size, as well as the specific trait of symbiotic nitrogen fixation in legume crops. For plant architecture, we discuss the roles of BRs in plant height, branching number, and leaf erectness and propose how progress in these fields may contribute to designing crops with optimal agronomic traits and improved grain yield by accurately modifying BR levels and signaling pathways.

When Size Matters: New Insights on How Seed Size Can Contribute to Plant Developmental Success

“…At the molecular level, GW5 encodes for a calmodulin-containing protein localized at the plasma membrane and in the nucleus [144,145] and many pieces of evidence suggest that GW5 controls seed shape regulating the BR pathway. Besides overall plant growth, BR are also involved in the control of seed size regulating cell elongation, division and differentiation [146]. GW5 mediates BR signaling because it interacts with the GLYCOGEN SYNTHASE KINASES (GSK2, the homologous of the Arabidopsis BIN2) inhibiting its activity, which includes the phosphorylation of two transcription factors, namely BZR1 and DWARF AND LOW-TILLERING (DLT) [144].…”