MOLECULAR DIVERSITY OF ECTOMYCORRHIZAL FUNGI OF CENTRAL HIMALAYA OF INDIA: AN IMPORTANT COMPONENT OF FOREST ECOSYSTEM

Abstract

Ectomycorrhizae are symbiotic organ formed between a fungus and the roots of tree. These fungi are very important for the growth and development of higher tree species. Ectomycorrhizal diversity through effective plant growth would affect tree species composition and ecosystem functioning. In a preliminary study the comparative symbiotic efficiencies of two ectomycorrhizal fungi viz., Amanita hemibapha and Russula vesca was assessed in association with oak (Q. leucotrichophora) and pine (P. roxburghii) seedlings. Our studies indicated that the fungal species had a marked influence on competitive outcome of the seedlings, their growth and health status. Uttarakhand state (India) is very rich in tree biodiversity however; the ECM fungal diversity of Himalayan region and how they may be impacting the tree diversity is not well studied. It is essential to document this important wealth and to find out the ways to conserve it. This will essentially require a precise and authentic characterization of the fungal species and molecular approaches can meet the challenge .We have used a molecular approach using RAPD techniques on genomic DNA from different ectomycorrhizal (EM) fungal species belonging to the genus Cortinarius, Boletus, Inocybe and Xerocomus of Kumaun region. Divergence analysis using RAPD markers of different ectomycorrhizal species was done using UPGMA method (Unweighted Pair
Group Method with Arithmetic Mean). Divergence analysis of six genotypes revealed that species 1(Boletus appendiculatus) and species 5 (Boletus variegates) were found to be located on a single cluster reflecting their homology whereas species 1 (Boletus appendiculatus) and species 2 (Inocybe species) were found to be distantly related. Species 4 (Xerocomus chrysenteron) share near homology with species 1 (Boletus appendiculatus) and 5 (Boletus variegates) whereas species 3 (Cortinarious species 1) and species 6 (Cortinarious species 2) also share near homology. The study indicates that if assay conditions are carefully controlled, the RAPD methodology may provide a cheap, rapid and effective means to evaluate the genetic diversity among a large number of fungal species. When coupled to using primers specific to fungal ITS region more accurate identification can be made all the way species and strain level.