Transcriptompe Analysis Of Leaf Morphology And Function Of Pinot Noir Grape At Different Leaf Stages

Pinot Noir is a Eurasian grape native to Europe and is a high-quality wine grape.Mature grape leaves are the main place for photosynthesis and important source organs,which are closely related to fruit growth and quality formation.From immature leaves to mature leaves,the structure and function of leaves will change,and the metabolic molecular mechanisms related to function will also change at different leaf ages.At present,there are many studies on the response of grape leaf age to environmental stress,but few studies on the structural and functional changes and molecular mechanisms related to metabolism during leaf development of different leaf ages.In this paper,through the study of the structure of different leaf age leaf function of observation and analysis,and then from the Angle of the transcriptome analysis of related metabolic mechanism,help to understand the laws of different leaf age of leaf growth and transformation of carbon flow and accumulation,in order to improve the blade growth conditions,explore leaf photosynthate distribution regularity and provide theoretical basis to improve fruit quality.In this paper,grape ’Pinot Noir’ was used as experimental material to explore the changes of leaf structure and function and transcriptome analysis at different leaf ages.The main results are as follows:1.The thickness of undeveloped leaves is 74.98 μm,which needs to be protected by superficial fur.The stomatal density and stomatal opening are small,mesophyll cell gap is small,and gas exchange ability is weak.The stomata are concentrated in the tip of the tooth,and the formation of large stomata is earlier than the leaf development,and the plastid in the leaf is less.With the growth of leaves,the leaf thickens gradually,the surface fur falls off gradually,stomatal density and stomatal opening increase,mesophyll cell gap increases,stomatal group in the middle of leaves increases,gas exchange ability increases,internal plastid increases,starch accumulation increases.The stomatal density of mature leaves decreased slightly due to the increase of leaf area.The leaf thickness of mature leaves was 165.3 μm,and the stomatal opening rate was 81.08%.The thickness of senescent leaves decreased,stomatal density and stomatal opening rate decreased,gas exchange was in dynamic balance by increasing stomatal opening,and stomatal opening reached 148.62μm2.2.Pn,Gs and Tr of grape leaves were diurnal variation curves with bimodal peaks,and the maximum peak appeared at around 11 am,and " midday depression of photosynthesis"appeared at around 13 PM,with stomatal restriction as the main limiting factor.The chlorophyll content in undeveloped leaves was only 0.71 mg/g,with weak light capture ability,low photosynthetic product output and soluble sugar accumulation.The sucrose content was only 0.68 mg/g,and the lowest C/N ratio was only 13.14.The carbon and nitrogen metabolism in leaves was active,and the demand for assimilates was high.After the leaves began to grow,the chlorophyll content increased,the ability to transform light energy was enhanced,the net photosynthetic rate increased,the accumulation of photosynthate increased,and the soluble sugar content increased.The maximum Pn of mature leaves was 22.05 μmolCO2m-2s-1 at 11a.m,and the maximum chlorophyll content was 1.96 mg/g.When leaves entered senescence stage,the net photosynthetic rate decreased,chlorophyll content decreased,the C/N ratio increased significantly,reaching 26.14,the C/N metabolism was not active in leaves,and a large amount of sucrose was accumulated.3.A total of 58.57GB clean date was obtained by transcriptomic analysis of undeveloped leaves,middle growing leaves and mature leaves.A total of 10,856 differentially expressed genes in the three comparison combinations were found to be mainly enriched in the synthesis of thylakoid and chloroplast in photosynthesis polysaccharide metabolism KEGG enrichment analysis of chlorophyll binding protein and other processes revealed that the differentially expressed genes were mainly enriched in the metabolic pathways of photosynthetic plant hormone signal transduction starch and sucrose metabolism.RT-qPCR was used to analyze the expression levels,functions and regulatory pathways of major differentially expressed genes in key pathways.PSB28、PSAK、PetC are key genes in photosynthesis,SBPase、FBPAplay an important role in the process of carbon fixation,HEMA1 is conducive to the synthesis of ALA,CHLH,CHLI,CRD1,PORA can promote the synthesis of Chl a,CAO is involved in Chl In the process of transformation from a to Chl b,sucrose metabolism is accompanied by the expression of CWINV,PGM and other genes,and the accumulation of starch is regulated by AGPase,SS,SBE and other genes.AMY and BAM participate in the hydrolysis process of starch.