Analysis of Growth,Development and Carbon Metabolism of Rice BR Receptor Mutant Fn189 at Jointing Stage
Rice brassinosteroids(BR)receptor BRI1 coding gene(OsBRI1)mutant Fn189 and its wild type Tz65 were used as test materials.Under field conditions,a randomized block design was used to study the effects of BR on growth and development and carbon metabolism-related physiological indexes of rice at jointing stage.The results showed that compared with the wild-type Tz65,the growth of Fn189 was inhibited at jointing stage,and the plant height and tiller number of Fn189 were decreased by 25.07%and 15.82%,respectively.In addition,the Rubisco activity of Fn189 leaves decreased at jointing stage,and the ability of leaves to fix CO2 decreased.Compared with the wild-type,the activities of sucrose phosphate synthetase,sucrose synthase,ADP-glucose pyrophosphorylase,soluble starch synthase and granule-bound starch synthase of Fn189 leaves decreased at jointing stage,and the activity of acid invertase increased,indicating that the synthesis of sucrose and starch in the mesophyll cells of Fn189 decreased,while the decomposition of sucrose accelerated.The results showed that the contents of sucrose,soluble sugar,starch and non-structural carbohydrates in Fn189 leaves were significantly decreased by 23.76%,13.46%,9.02%and 10.40%,respectively,compared with the wild-type.Finally,the yield of Fn189 was 71.04%lower than that of wild-type.Therefore,BR signal transduction not only affected the growth and development of rice at jointing stage,it also affected the photosynthesis of rice leaves and the metabolism of sucrose and starch,and ultimately affected the yield of rice.
RiceBrassinosteroidsMutant Fn189Jointing stageGrowth and developmentCarbon metabolism