The Role of Exobasidium vexans Massee in Flavanoid Synthesis by Cammelia assamica Shneider

Blister blight caused by the fungus Exobasidium vexans Massee is a major problem in tea plantations. The new flush - two leaf and a bud, produced by bushes after pruning are the worst affected. Since the tender leaves are used for tea manufacture, it is difficult to segregate the diseased leaves from the healthy ones. Tea prepared from blistered leaves has been reported to be weak, lacks character and is of poor quality. Certain enzymes involved in secondary metabolism get activated in response to infection and it is the same set of enzymes that are associated with flavour development during processing. Pathogenesis is also accompanied by metabolic changes that lead to alterations in the levels of biochemical constituents such as pigments, free amino acids, free fatty acids and carbohydrates. The leaves, which are oriented towards defense in response to infection, are able to offer an endophytic niche for the fungus and upto 25% infection is tolerated by the tea plant. This leads to an improvement in the quality of finished tea.