title: Differential expression of genes in purple-shoot tea tender leaves and mature leaves during leaf growth.
abstract: BACKGROUND
  Tea (Camellia sinensis L.), contains high levels of secondary metabolic products with both commercial and medicinal value. At present, most cultivated tea plant have green leaves; although tea plants with purple leaves exist, their supply is inadequate. During leaf growth and maturation, the content of secondary metabolic compounds decreases, resulting in higher content in tender purple leaves (TPL), and lower content in mature green leaves (MGL). The aim of this study was to analyze the differential expression of genes in these two tissues, with a cDNA-AFLP (amplified fragment length polymorphism) approach and biochemical analysis.
  
  
  RESULTS
  Compared to MGL samples, TPL samples had higher content of anthocyanin, total polyphenols and total catechins, a higher carotenoid-to-chlorophyll ratio and lower content of soluble sugars (glucose, fructose and sucrose). TPL samples showed a lower photosynthetic ability, demonstrated by a lower CO2 assimilation and carbohydrate accumulation rate. Using cDNA-AFLP with 256 primer combinations, differential transcript profiling generated 148 matched transcript-derived fragments (TDFs). Among these TDFs, 77 genes were upregulated and 71 were downregulated. These were grouped into 11 functional categories which are important for final tea quality parameters.
  
  
  CONCLUSIONS
  Our data presented the first effort to elucidate the molecular basis of differential accumulation of key metabolites during tea leaf maturation. Our findings also provided a theoretical molecular explanation for the color change during leaf growth.
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
authors.forename: Qiongqiong
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.|Anxi College of Tea Science, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
authors.forename: Weijiang
authors.initials: W
authors.lastname: Sun
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
authors.forename: Zhongxiong
authors.initials: Z
authors.lastname: Lai
mesh_terms: D002110:Caffeine / Q000378:metabolism; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry; D002245:Carbon Dioxide / Q000378:metabolism; D002396:Catechols / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D008315:Malondialdehyde; D018515:Plant Leaves / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D059808:Polyphenols / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013662:Tea / Q000235:genetics / Q000378:metabolism*
chemical_list: D002241:Carbohydrates; D002396:Catechols; D059808:Polyphenols; D018749:RNA, Plant; D013662:Tea; D002245:Carbon Dioxide; D002110:Caffeine; D008315:Malondialdehyde; C034221:catechol
keywords: Camellia sinensis; anthocyanins; cDNA-AFLP; leaf; transcript-derived fragment