The Study On The Response Of Endogenous Hormones To Ecological Factors And Influence Of Biosynthesis Of Main Flavor Components In Tea Plant

Endogenous hormones affect growth and development,secondary metabolism and resistance of tea plant.The biosynthesis of endogenous hormones in tea plants is regulated by ecological factors such as light intensity,environment temperature and air relative humidity.So far,the response of endogenous hormones（auxin,gibberellin,cytokinin,abscisic acid,jasmonic acid and salicylic acid,etc.）to ecological factors such as light intensity,environment temperature and air relative humidity has not been clarified.Using one-year-old cuttings Camellia sinensis cv.“Huangdan”as the experimental material.This study investigated the response of 34 kinds of endogenous hormones in five categories to the single factor changes of light intensity,environment temperature and air relative humidity and their potential molecular mechanisms by accurately controlling the ecological factors of light,temperature and humidity parameters in the artificial climate chamber and combined with multi-dimensional correlation analysis.Using whole genome analysis and multi-factor comprehensive experimental verification,this study revealed a mechanism of synergistic regulation of endogenous hormone biosynthesis and a mechanism of endogenous hormone regulation of EGCG,theanine and caffeine biosynthesis in tea plant by three ecological factors.This study provides a new perspective for tea plant biosynthesis of main endogenous hormones in response to light,temperature and humidity,provides a reference for ecological tea garden construction and tea plant factory cultivation,and provides a new idea for increasing the content of main taste components in fresh tea leaves.The main results are as follows:（1）Response regularity and potential mechanism of endogenous hormone content in tea plant to single factor changes of ecological factorsThe ecological factor single factor parameters were set:The light intensity is 150,250,350,450,550μmol·m^-2·s^-1,the environment temperature is 15,20,25,30℃,and the air relative humidity is 40,50,70,90%.The experimental results showed that under the single factor condition,the total contents of 3 auxin and 2 free auxin were the highest when the light intensity was 250μmol·m^-2·s^-1,the environment temperature was 25℃and the relative humidity of air was 90%.The content of 1 bound auxin was the highest when the light intensity was350μmol·m^-2·s^-1,environment temperature was 25℃and air relative humidity was 90%.The total contents of 16 kinds of gibberellin were higher at light intensity of 150μmol·m^-2·s^-1,environment temperature of30℃and air relative humidity of 90%.The total contents of 3 kinds of active gibberellin were the highest at light intensity of 150μmol·m^-2·s^-1,environment temperature of 30℃and air relative humidity of 70%,respectively.The total contents of 14 inactive gibberellins were the highest when the light intensity was 350μmol·m^-2·s^-1,the environment temperature was 30℃and the air relative humidity was 90%.The total contents of four kinds of cytokinins were the highest when the light intensity was 350μmol·m^-2·s^-1,the environment temperature was 30℃,and the air relative humidity was 40%.The content of abscisic acid was the highest when the light intensity was 350μmol·m^-2·s^-1,the environment temperature was 15℃,and the air relative humidity was 40%.The total amount of salicylic acid,methyl salicylic acid and salicylic acid was the highest when the light intensity was 350μmol·m^-2·s^-1,the environment temperature was 20℃and the air relative humidity was 40%,respectively.Multi-dimensional association analysis showed that light intensity mainly regulated the expression of structural genes Cs UGT74B1,Cs ALDH and Cs YUCCA through transcription factors Cs GRF,Cs RAV Cs WRKY,Cs SBP and Cs AP2 to affected auxin biosynthesis.Light intensity affected gibberellin biosynthesis by regulating the expression of Cs GA2ox through transcription factor Cs ERF,and regulating the expression of structural genes Cs GA2ox and Cs GA20ox.Light intensity regulated the expression of structural gene Cs UGT73C through transcription factors Cs WRKY,Cs ERF,Cs AP2,Cs TCP,Cs GRF and Cs SBP,and directly regulates the expression of structural genes Cs ZOX1,Cs YP735A and Cs CKX,which affected the biosynthesis of cytokinin.Light intensity regulated the expression of structural genes Cs NCED,Cs CYP707A and Cs AOG through transcription factors Cs MYB＿related,Cs ERF and Cs AP2,and then affected the biosynthesis of ABA.Light intensity affected the biosynthesis of salicylic acid by regulating the expression of structural genes Cs PAL,Csphe A2 and Cs TAT.Environment temperature mainly regulated the expression of structural genes Cs UGT74B1,Cs ALDH,Csami E and Cs YUCCA through transcription factors Cs SBP,Cs WRKY,Cs C2H2,Cs MYB＿related,Cs Dof,Cs ERF and Csb ZIP,which affected auxin biosynthesis.Environment temperature affected the gibberellin biosynthesis by regulating the expression of structural genes Cs GA20ox and Cs CYP701 through transcription factors Cs WRKY and Cs SBP.Environment temperature regulated the expression of structural gene Cs CKX through transcription factor Cs SBP,which influenced the biosynthesis of cytokinin.Environment temperature affected ABA biosynthesis by regulating the expression of structural genes Cs NCED and Cs CYP707A.Environment temperature regulated the expression of structural genes Cs PAL and Cs GOT1 through transcription factors Cs WRKY and Cs SBP,and directly affected the biosynthesis of salicylic acid by regulating the expression of Cs TAT.Air relative humidity mainly regulated the expression of 3 Cs UGT74B1and 1 Csami E in structural genes through transcription factors Cs WRKY,Cs Dof,Cs TCP,Cs MYB＿related,Cs ERF and Cs SBP,which affected auxin synthesis.Air relative humidity regulated the expression of structural gene Cs GA3ox through transcription factors Cs WRKY,Cs ERF,Cs Dof,Cs SBP and Cs GATA,and directly regulated the expression of Cs KAO,which affected gibberellin biosynthesis.Air relative humidity regulated 5 Cs UGT73C and 1 Cs ZOX1 in structural genes by transcription factors Cs MYB＿related,Cs WRKY,Cs ERF,Cs AP2,Cs TCP,Cs GRF,Cs SBP,Cs HD-ZIP,Cs GATA,Cs C2H2,Cs Dof,Cs MYB,and Cs G2-like,to affect the synthesis of cytokinin.The expression of structural gene Cs CYP707A was regulated by transcription factors Cs Dof,Cs G2-like,Cs HD-ZIP and Cs ERF,which affected ABA synthesis.Air relative humidity regulated the expression of structural genes Csaro K,Cs PAL,Csphe A2,Cs GOT1,Cs TAT and Cs CHM through transcription factors Cs WRKY,Cs HD-ZIP,Cs Dof,Cs C2H2,Cs ERF,Cs GATA,Cs MYB,Cs G2-like,Cs MYB＿related,Cs SBP and Cs TCP,to affect the synthesis of salicylic acid.（2）The molecular mechanism of the synergistic regulation of endogenous hormone biosynthesis by three ecological factors:light,temperature and humidityAccording to the experimental results of single-factor ecological factors,six hormones（IAA,GA19,t ZR,ABA,JA,SA）were selected to be synergistically regulated by light intensity,environment temperature and air relative humidity.Based on the whole-genome analysis,the multi-factor comprehensive experimental verification was carried out.The results showed that the three ecological factors,light intensity,environment temperature and air relative humidity,co-regulated the expression of 5 Cs ALDH,5 Cs UGT74B1,2 Csami E and 1 Cs DDC in structural genes,and regulated the biosynthesis of IAA.Three ecological factors synergistically regulated the expression of 2 Cs GA20ox,2Cs GA2ox,1 Cs KAO and 1 Cs KO in structural genes,affecting the synthesis of GA19;Three ecological factors synergistically regulated the expression of 4 Cs UGT73C and 2 Cs CKX in structural genes,and regulated the synthesis of t ZR;Three ecological factors synergistically regulate the expression of 2 Cs NCED and 1 Cs ZEP in structural genes,and affected the synthesis of ABA;Three ecological factors synergistically regulate the expression of 3 Cs ACX,4 Cs LOX2S,2 Cs JMT,1 Cs AOC,1 Cs PLA2G16,1 Cs OPCL1,1 Cs OPR in structural genes,and regulate the synthesis of JA;Light and air relative humidity co-regulated the expression of structural gene Csaro K to affect the SA biosynthesis.（3）The three ecological factors of light,temperature and humidity synergistically regulated the mechanism of EGCG,theanine and caffeine biosynthesis in tea plant mediated by endogenous hormonesAccording to the results of three single factor experiments,comprehensive experiments of light,temperature and humidity were conducted based on whole-genome analysis.The results showed that the three ecological factors of light,temperature and humidity synergically regulated IAA and its signal transduction factors（Cs ARF,Cs GH3,Cs IAA）mediated the expression of Cs4CL,Cs CHS,Csaro D,and promoted EGCG biosynthesis.The three ecological factors synergistically regulated ABA and its signal transduction factors（Cs PYL,Cs Sn RK2,Cs PP2C）mediated the expression of Cs PAL,Cs C4H,Cs CHS,Cs ANS,Cs ANR,Csaro D,and inhibit the synthesis of EGCG.Exogenous application of IAA and ABA inhibitors in tea plant also further verified that ecological factors mediated the expression of EGCG synthetic genes through endogenous hormones IAA and ABA,respectively,and thus regulated EGCG biosynthesis.Light,temperature and humidity synergistically regulated SA and its signal transduction factor（Cs NPR1）to mediate the expression of Csndk and Csadk,and promote the synthesis of caffeine.Light,temperature and humidity synergically regulate IAM and its signal transduction factors（Cs AUX1,Cs GH3,Cs IAA）to mediate the expression of Csndk and inhibit the synthesis of caffeine.According to the whole-genome analysis,the results showed that the three ecological factors of light,temperature and humidity might synergistically regulate Me SA and its signal transduction factors（Cs NPR1,Cs PR1,Cs TGA）to mediate the expression of structural genes Cs CA,Cs GST,Cs GLT1,Cs PK,Cs GS,and thus affect the biosynthesis of theanine.