Both Gibberellin And Brassinolide Are Involved In Regulating Cellulose Synthesis

Cell elongation is an important basis for the growth and morphology of higher plants.Previous studies have found that the plant hormones gibberellin(GA)and brassinolide(BR)play important regulatory roles in cell elongation.Molecular cellulose is essential for the formation of new cell walls during cell elongation.However,little is known about the cell wall events of these two hormones in regulating cell growth.In this study,RT-qPCR amplification technology,spectrophotometry technology,microscopy technology,and chromatin immunoprecipitation technology were used to model the hypocotyl elongation of the model plant Arabidopsis thaliana as a model.Observation of mustard phenotype,number of hypocotyl cells,cell length,cellulose content,RT-qPCR detection of primary wall cellulose synthesis-related gene expression,etc.to study the cell wall events produced by GA and BR hormones in regulating cell growth Effects,expound the role of two hormones in cellulose synthesis.The results show:(1)Effect of GA on cellulose synthesisUnder white and dark conditions,GA promoted the increase in hypocotyl length,hypocotyl cell length,and hypocotyl cellulose content,and increased the transcription level of genes related to cellulose synthesis.In rga / gai mutants,the hypocotyl length,hypocotyl cell length,hypocotyl cellulose content,and transcription levels of genes related to cellulose synthesis were higher in the treated samples than in the blank-treated ecotypes.(2)Effect of BR on cellulose synthesisIn the dark or light environment,BR all promoted the increase of hypocotyl length,hypocotyl cell length,hypocotyl cellulose content and transcription levels of genes related to cellulose synthesis in Arabidopsis thaliana.Under white light and dark conditions,the length of hypocotyl cells,the content of hypocotyl cellulose,and the transcription level of cellulose-synthesis-related genes of the bri1-5 mutants after exogenous application of BL were almost no compared with the bri1-5 mutants of the blank group.The change still showed a phenotype with suppressed elongation.The data of det2-1 mutant that was significantly lower than Col ecotype after exogenous application of BL were restored to the same level;the hypocotyl length,hypocotyl cell length,hypocotyl of BZR1-1D mutant The level of transcription of axillary cellulose and genes related to cellulose synthesis was significantly higher than that of the Col ecotype.And BZR1 transcription factor binds to the promoter region of genes related to cellulose synthesis.This study revealed that both GA and BR are involved in regulating cellulose synthesis in plant cells.In this process,GA is involved in regulating cellulose synthesis through DELLA protein;BR is involved in regulating cellulose synthesis through BZR1 transcription factor.This study clarifies the molecular mechanisms by which GA and BR are involved in regulating cellulose synthesis,and analyzes their underlying mechanisms.It provides theoretical basis for further understanding of the important biological process of cell elongation.