Brassinosteroids promote photosynthesis and growth by enhancing activation of Rubisco and expression of photosynthetic genes in XXXX .

@entity24634 @entity4375 @entity515 @entity9688 @entity24315 @entity9578 @entity16044
Brassinosteroids ( @entity4375 ) are a new group of plant growth substances that promote plant growth and productivity. We showed in this study that improved growth of @entity9688 ( @entity9688 ) plants after treatment with @entity16044 (EBR), an active BR, was associated with increased @entity515 assimilation and quantum yield of PSII (Phi(PSII)). Treatment of @entity24315 ( @entity24634 ), a specific inhibitor for BR biosynthesis, reduced plant growth and at the same time decreased @entity515 assimilation and Phi(PSII). Thus, the growth-promoting activity of @entity4375 can be, at least partly, attributed to enhanced plant photosynthesis. To understand how @entity4375 enhance photosynthesis, we have analyzed the effects of EBR and Brz on a number of photosynthetic parameters and their affecting factors, including the contents and activity of @entity9578 carboxylase/oxygenase (Rubisco). Northern and Western blotting demonstrated that EBR upregulated, while Brz downregulated, the expressions of rbcL, rbcS and other photosynthetic genes. In addition, EBR had a positive effect on the activation of Rubisco based on increased maximum Rubisco carboxylation rates (V (c,max)), total Rubisco activity and, to a greater extent, initial Rubisco activity. The accumulation patterns of Rubisco activase (RCA) based on immunogold-labeling experiments suggested a role of RCA in BR-regulated activation state of Rubisco. Enhanced expression of genes encoding other Calvin cycle genes after EBR treatment may also play a positive role in RuBP regeneration (J (max)), thereby increasing maximum carboxylation rate of Rubisco (V (c,max)). Thus, @entity4375 promote photosynthesis and growth by positively regulating synthesis and activation of a variety of photosynthetic enzymes including Rubisco in @entity9688 .
