Morphological and molecular diversity of endophytic Colletotrichum gloeosporioides from tea plant, Camellia sinensis (L.) O. Kuntze of Assam, India.

Thirty isolates of endophytic fungi were isolated from healthy asymptomatic leaves of tea plant (Camellia sinensis) and identified morphologically based on colony morphology, spore shape and size, growth and sporulation rate. Internal transcribed spacer r-DNA sequence analysis supported for molecular identification of all the isolates. Based on morphological and molecular characteristics the isolates were identified as Colletotrichum gloeosporioides. Variations on colony morphology which included the production of conidial masses, led to divide the isolates into different groups. Variations on spore size, growth rate and sporulation rate were exhibited by all the isolates. With RAPD molecular markers, genetic variations among the thirty isolates were observed. Genetic variations and relatedness among the thirty isolates were analyzed with UPGMA phylogram using NTSYS program. Two major groups were obtained among the thirty isolates. Group I comprised of 16 isolates which included three sub groups (Ia, Ib and Ic) and Group II constituted fourteen isolates and it also had three sub groups (IIa, IIb and IIc). A partial co-relationship among the isolates was established on the basis of morphological and molecular based clustering.

In Vitro Evaluation of Antagonism of Endophytic Colletotrichum gloeosporioides Against Potent Fungal Pathogens of Camellia sinensis.

An endophytic fungus isolated from Camellia sinensis, Assam, Northeastern India was identified as Colletotrichum gloeosporioides on the basis of morphological characteristics and rDNA ITS analysis. This endophytic fungus was evaluated for growth inhibition against tea pathogens Pestalotiopsis theae and Colletotrichum camelliae. One isolate of C. gloeosporioides showed strong antagonistic activity against Pestalotiopsis theae (64 %) and moderate activity against C. camelliae (37 %). Fifty percent cell-free culture filtrate from 5-day-old cultures showed highest antagonistic activity against both the pathogens although the inhibition percent was less as compared to dual culture. In the experiment of volatile compounds none of the isolates of C. gloeosporioides strains showed visible inhibition against P. theae and C. camelliae. The activity of extracellular hydrolytic enzymes chitinase and protease was also high in this culture fluid and measured 10 and 4.3 IU/µl, respectively.