| As a plant that can promote sustainable industrial development,moso bamboo has significant commercial and ecological value.Planting moso bamboo seedlings in pots not only saves labour but also increases the survival rate of the transplants.Light plays an important regulatory role in the growth and development of plant seedlings during the photomorphogenesis stage.In particular,red and blue light participate in the regulation of many plant light reactions.However,compared with other plants such as Arabidopsis,rice,and maize,research on moso bamboo is relatively lagging behind.It is therefore important to study the effects of the environment on young moso bamboo seedlings in pots.Although the genetic transformation system of bamboo has recently been established,it is difficult to use traditional genetics methods to study the molecular mechanism of moso bamboo photomorphogenesis after seed germination due to its low transformation efficiency and long growth cycle.With the development of technology,the proteome has become an important tool for revealing functional proteins in plant development and metabolism processes.Although previous studies have explored the effects of red and blue light on the growth and development of moso bamboo,the materials studied were bamboo seedlings that had already completed photomorphogenesis under white light.It is not clear how red and blue light affect the growth and development of bamboo during the photomorphogenesis stage.Therefore,in this experiment,moso bamboo germinated in the dark was transferred to grow under monochromatic red and blue light for 14 days,and the effects of different light treatments on moso bamboo phenotype were observed.Subsequently,DIA-MS(Data Independent Acquisition-Mass Spectrometry)technology was used to compare the proteome changes of bamboo seedlings grown under monochromatic red and blue light,and key pathways and key proteins of moso bamboo light response proteins under different light treatments were discovered.A more systematic understanding of the effects of specific wavelengths of light on the growth and development of bamboo seedlings and the expression of specific proteins during the photomorphogenesis stage can help improve the light conditions for bamboo seedling cultivation and lay the groundwork for genetic breeding,thus contributing to the future industrial production and economic development of moso bamboo.The results of this experiment can be summarized as follows:(1)The phenotype results indicated that during the photomorphogenesis of moso bamboo,red light promotes both the horizontal and vertical growth of bamboo more effectively.Moso bamboo grown under red light had longer roots and stems.In addition,red light more effectively promoted the accumulation of moso bamboo dry weight,and the stems were thicker under red light.These phenotypes were different from the phenomenon of reduced biomass in "red light syndrome".(2)Proteomic analysis was used to investigate how red and blue light regulate the growth and development of moso bamboo seedlings during photomorphogenesis.The results of the quality control analysis indicated that the proteomics data from this study were reproducible and of reliable quality for subsequent data analysis.(3)GO enrichment analysis of proteins specifically quantified under different light treatments showed that red light specifically expressed proteins involved in cell wall synthesis.Some photomorphogenesis and photosynthesis related proteins were specifically expressed in red and blue light compared to darkness(more LHCB proteins were expressed in red light and more LHCA proteins were expressed in blue light).Our study found 1867 response proteins under red light and 1508 response proteins under blue light compared to darkness.Further analysis of the function of light-responsive proteins in moso bamboo showed that both red and blue light-responsive proteins were enriched in photosynthesis,blue lightresponsive proteins were enriched in protein synthesis and degradation,and red light-responsive proteins were enriched in sugar synthesis and metabolism and cell wall macromolecular decomposition metabolism.We also investigated the expression levels of hormone-related proteins under different light treatments and found that the auxin transport protein ABCB19 may play an important role in the stem elongation and lateral root growth of bamboo under red light.(4)Further analysis of the expression patterns of photosynthesis proteins under different light conditions revealed that the expression levels of LHCA and most Psb proteins in the photosynthetic light reaction were significantly higher under blue light than under red light,while the expression levels of PsbS and proteins in the ATPF complex were significantly higher under red light than under blue light.For the photosynthetic dark reaction,only the expression level of rbcS protein was significantly higher under blue light than under red light.Further analysis of the expression patterns of sugar metabolism-responsive proteins under different light conditions revealed that red light could promote the expression of cellulose synthase(CESA)and cellulose-degrading enzymes(ATGH9A1 and BGLU11).Meanwhile,we found a high correlation between proteins related to cellulose synthesis,cell wall synthesis,and cell wall macromolecule degradation metabolism,suggesting that red light plays an important role in the cell wall formation process in moso bamboo.By detecting the differences in the expression of bamboo cell wall-related genes at the RNA level under different light treatments using qPCR,we found that the results of qPCR were not completely consistent with those of proteomics,indicating that red and blue light have some effects on moso bamboo at the post-transcriptional level.(5)In this study,by comparing and analyzing the chlorophyll content and fluorescence dynamics parameters of moso bamboo seedlings under different light conditions,it was found that the chlorophyll content of moso bamboo seedlings was higher and the utilization efficiency of PS Ⅰ and PS Ⅱ was stronger under blue light compared to red light.By comparing and analyzing the contents of soluble sugar and starch in moso bamboo under different light conditions,it was found that red light was more conducive to the accumulation of sucrose,starch,and fructose,while blue light was more conducive to the accumulation of glucose.Meanwhile,by comparing and analyzing the cellulose and hemicellulose contents of moso bamboo under different light conditions,it was found that the cellulose and hemicellulose contents of moso bamboo seedlings were highest under red light. |
