The Biosynthesis Of Polyphenols And The Differential Expression Of Relative Genes In Tea Plant [Camellia Sinensis (L.) O. Kuntze]

The biosynthesis and metabolic regulation of polyphenols in tea plant are complicatednetwork. The contents of tea polyphenols are influenced by many inner and externalfactors, so the accumulation of polyphenols showed specificity in development, differentorgans and tissues, and the induction of environment factor. This research analysed therelationship between the changes of tea polyphenols and the expression differences ofrelative genes by taking different organs and different developmental leaves under varioustreatments as experimental materials.1. The biosynthesis and accumulation of polyphenols in tea plant had thedevelopmental specificity. The results showed that the catechins contents in tea leaveswere reduced gradually with the maturation of tea leaves. Six kinds of catechins weredetectable, in which epigallocatechin gallate (EGCG) accounted for the largest proportionwhile catechin (C) took the least. The change trend and the kind of catechins in tea stemwere similar to those in tea leaf. The catechins content in tea root was very low and thekinds of catechins were few. The changes of F3’5’H and DFR in tea leaves were consistentwith that of catechins. CHI and F3’5’H were reduced rapidly, while the Ester-typecatechins could not be find in tea roots. PAL and C4H did not have an evidence relationshipin catechins accumulate and genes expression.2. The study for organ specificity on the biosynthesis and accumulation ofpolyphenols in tea showed that in tea seedlings, the leaves has the highest content ofcatechins, in which6kinds of catechins could be found. The content of catechins in stemwas lower, while all kinds of catechins could be found. Only a little nonester catechinswere found in roots. The content of total proanthocyanins in stems was the highest, whilein leaves it was least. The relative genes expression showed a significant different trend indifferent organs, but the changes trend of CHS、CHI、 F3’5’H were consistent with that ofcatechins. The contents of catechins in tea leaves, stems and roots were1604.41,143.98,6.03folds of those in tea callus, respectively, while the content ofproanthocyanins in tea leaves, stems and roots were0.31、1.38、0.98folds of those in teacallus. The gene expression in tea callus was higher than that in leaves.3. The study of light and shading treatment on the biosynthesis and accumulation ofpolyphenols in tea showed that flavonol and proanthocyanidin biosyntheses wereinfluenced significantly in tea leaves cultured in shading. The contents of flavonol and proanthocyanidin in shading tea leaves decreased61.5%and53.3%, respectively,compared to the control. However, light and shading treatment showed less influence oncatechins and lignins in tea leaves. The contents of flavonol and proanthocyanidin inshading tea leaves decreased16.7%and9.3%respectively, compared to the control. Theexpressions of PAL,CHS, CHI, F3H, F3’H, DFR, LAR, ANS, ANR and UFGT weresuppressed in the shading leaves, especially to CHI、F3H、UFGT and F3’H, while lest inF3’5’H.The contents of catechins, proanthocyanidins and lignins in light-exposed tea calluswere2.50、1.74and3.46folds of those in shading tea callus. The expressions of PAL、C4H、CHS、CHI、F3H、F3’H、F3’5’H、DFR、LAR、ANS、ANR、UFGT in light-exposedtea callus were0.81,0.28,0.78,1.01,1.05,1.22,1.54,1.19,0.64,1.39,0.81and3.45foldsof those in shading tea callus.4. The fragment of PAL109363choosed from transcription analysis was cloned. A2300bp sequence was obtained, which differed from PAL (AY694188.1, in NCBI) basedon the sequence alignment.