| As an ornamental and environmentally friendly plant with edible,medicinal and timber uses,moso bamboo(Phyllostachys heterocycla(Carr.)Mitford cv.Pubescens)is widely planted in the south of the Yangtze River in my country.Moso bamboo has a fast growth rate and strong carbon fixation ability,and it is a species with high light energy utilization efficiency.In the process of plant growth and development,light is an extremely important factor.However,there is a lack of research on the light regulation mechanism of moso bamboo,and the research on the growth regulation of moso bamboo with different light qualities is even more lacking.Since the transformation system of Phyllostachys edulis has not yet been established,this experiment mainly used transcriptome analysis to explore the regulatory mechanism of red and blue light in moso bamboo.According to previous studies,red and blue light have important regulatory mechanisms on the photomorphogenesis,flowering time and circadian clock of model plants such as Arabidopsis and rice.In this experiment,we studied the regulation mechanism of moso bamboo by red and blue light through transcriptome analysis.The physiological analysis of four-leaf moso bamboo was carried out under red light and blue light respectively,and it was found that red and blue light simultaneously regulated the plant height,bamboo length,root branch number,photosynthesis efficiency,sugar content and reactive oxygen species rate.and many other important physiological activities;and the regulation of red and blue light on maso bamboo is different from that of other monocotyledonous plants,such as rice and wheatgrass.On the basis of physiological analysis,this experiment analyzed the transcriptomic changes of maso bamboo under dark,red light and blue light treatment conditions through next-generation sequencing and bioinformatics technology,and described the expression of transcript levels under red light and blue light treatment.At the same time,a series of functional genes and key enzymes that were differentially expressed under red or blue light treatment compared with dark conditions were identified,and the important pathways in response to red and blue light treatment were explored.More importantly,at the molecular omics level,the analysis verified the physiological and biochemical regulation methods of red and blue light on moso bamboo,such as photosynthesis,sugar anabolism,reactive oxygen species metabolism,etc.,revealing the regulation mechanism of different light treatments on the growth and development of moso bamboo seedlings.This study fills the gap in the research on the growth and development of moso bamboo regulated by light,and provides guidance for the subsequent identification of functional genes of bamboo,the acquisition of transgenic bamboo,and the improvement of moso bamboo genetics and breeding.Result:1.In this experiment,we analyzed the plant height,bamboo length,root branch number(lateral root development),leaf curling degree and other indicators of moso bamboo seedlings treated with red and blue light.At the same time,it was found that Moso bamboo is different from other monocotyledonous plants(red light is higher than blue light in promoting plant height and root length,etc.),blue light and red light are similar in the regulation intensity of plant height,bamboo length and number of bamboo knots.And the total sugar content and reactive oxygen species generation rate of moso bamboo seedlings under blue light treatment were higher than those of red light.Red light was stronger than blue light and dark conditions in regulating the net photosynthesis rate and stomatal conductance of moso bamboo seedlings.These findings reveal the differences in photophysiology of Phyllostachys pubescens from other monocotyledonous plants,and also lay a physiological foundation for subsequent transcriptome studies.2.In this experiment,the transcriptomes of moso bamboo seedlings treated with red and blue light were sequenced,and bioinformatics methods were used to obtain gene expression differences and corresponding P values.Expressions of 25782,26258 and 26314 genes were identified under dark,blue and red light conditions,respectively,of which 24208 genes were co-expressed under dark,blue and red light treatment conditions.Compared with the dark conditions,2010 and 2236 genes responded to red light and blue light respectively,and there were more than 2-fold differential expression(p＿value <0.01),of which 722 genes were specifically regulated by blue light and 565 genes were specifically regulated by red light.The discovery of these specific lightregulated genes provides molecular clues for future research on the related mechanisms of light regulation in moso bamboo;at the same time,the differences in specific regulatory genes also show that red light and blue light have different regulatory mechanisms on moso bamboo.3.In this study,GO enrichment and KEGG pathway analysis were performed on genes differentially expressed under red and blue light.The results showed that compared with the dark conditions,the differentially expressed genes under red and blue light were mainly enriched in the pathways of photosynthesis,circadian rhythm,carbohydrate anabolism,cellular oxidative stress response and pigment metabolism.Through analysis,it was found that in terms of transcriptomics,moso bamboo and other monocotyledonous plants also have different regulation patterns: the genes up-regulated by red and blue light are mainly enriched in photosynthesis,carbohydrate metabolism and various stress response pathways.The genes down-regulated by red and blue light show the specificity of light wavelength: the genes down-regulated by blue light are mainly enriched in DNA damage repair,amino acid catabolism and protein kinases and other regulatory pathways,while the genes down-regulated by red light are mainly enriched in hormones Signal regulation,protease activation signaling,MAPK,and stomatal movement regulatory pathways.Among them,the regulation of red light on MAPK signaling is also different from other plants.4.In this experiment,the above GO enrichment and KEGG pathway analysis results were further confirmed by GSEA analysis,and it was found that photosynthesis,carbohydrate anabolism,cellular oxidative stress and other pathways of moso bamboo were generally up-regulated under red and blue light treatment.On the basis of previous findings that light regulates plant photomorphogenesis and photosynthesis,this experiment revealed the way that light regulates plant carbohydrate synthesis and metabolism and cellular oxidative stress at the transcriptional level of moso bamboo.At the same time,through WGCNA analysis,it was again proved that the correlation between red light-regulated MAPK-signal-related genes and reactive oxygen species regulation-related genes was significantly higher than that of dark and blue light treatments.In this experiment,through physiological experiments and transcriptomic experiments,we discovered the unique light regulation response phenomenon of moso bamboo,identified multiple light response factors and signaling pathways,and analyzed the co-regulation and specific regulation of red light and blue light on moso bamboo transcription.At the molecular level,the regulation patterns of mosobamboo under light regulation is revealed,which is different from other monocots,and provides a molecular basis for future research on the molecular mechanism of moso bamboo and the cultivation of new species of moso bamboo related to light signals. |
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