AM fungi are widespread and are found from arctic to tropics in most agricultural and natural ecosystems. They play an important role in plant growth, health and productivity. They increase seedling tolerance to drought, high temperatures, toxic heavy metals, high or low pH and even extreme soil acidity. The cultivation of medicinal and herbal plants has assumed greater importance in recent years due to their tremendous potential in modern and traditional medicine. They are also used as raw materials for pharmaceutical, cosmetic and fragrance industries. Indian system of medicine (ISM) uses 25,000 species belonging to more than 1000 genera. About 25% species are used by the industries. The Barak Valley is the southernmost part of the Assam and consists of three districts namely Cachar, Karimganj and Hailakandi. Different tribes staying here are directly using of medicinal plants for the treatments of different ailments. Comparatively very less attention has been given for the conservation of some of these rare and endangered medicinal plants which are extensively used by the tribes of Assam. So, AM fungi can play an effective role in the conservation of some valuable medicinal plants where Glomus sp. was found to be widely used for the increase yield of important medicinal plants. This review summarizes the data from recent studies to elucidate the potential use of AM fungi for promoting growth and disease resistance in medicinal plants found in southern part of Assam, which in turn provide a natural enhancer for the commercial production of traditional drugs from various important plants.

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Tea plantation is covered by 434,000 hectares of land, which is further divided into two distinct regions - the North Indian tea belt and the South Indian tea belt. North-East India produces 75% of the total Indian tea. Present study is carried out to understand the various agro-climatic conditions of Barak valley like temperature, humidity, rainfall etc which are responsible for occurrence of various diseases in tea plant. Six genera of fungi were isolated and identified as Aspergillus niger, Trichoderma sp., Penicillium sp., Cladosporium sp., Helminthosporium sp. and Fusarium sp. Percentage of relative abundance of all the isolated fungi also estimated and it is found that Aspergillus niger shows high percentage of relative abundance (30%), followed by Trichoderma sp. (22%), Penicillium sp. (12%), Cladosporium sp.(18%), Helminthosporium sp. (8%) and Fusarium sp.(10%). The isolated bacterial strain (Bacillus sp) screened for their antagonistic potential against the pathogen Marasmius equicrinis by dual culture technique. The study indicated that biocontrol agents (Bacillus sp.) are very effective to control the horse hair blight disease in tea plant under in vitro conditions. Our preliminary investigations provided a key concept to use the inoculums of Bacillus sp as biocontrol equipment in the tea gardens of N.E. region to get control over horse hair blight disease of tea.

The present investigation was carried out to estimate the colony forming units of indigenous fungi and to study the diversity and Arbuscular mycorrhizal (AM) of some medicinal plants. The study was also aimed to estimate and isolate the Arbuscular mycorrhizal (AM) spore population from the rhizospheric soil of some important medicinal plants from the Botanical garden of College campus. All the selected medicinal plants i.e., Mentha sp. Ocimum sanctum, Bryophyllum sp. Adhatoda vasica, and Andrographis paniculata showed a very good diversity of rhizospheric soil fungi. The highest number of Colony forming unit (c.f.u) was estimated in Mentha sp (162/10-1) followed by Bryophyllum sp. (156/10-1), Andrographis paniculata (91/10-1), Adhatoda vasica (72/10-1) and Ocimum sanctum (68/10-1). Arbuscular mycorrhizal (AM) spore population was also estimated in all the medicinal plants. The higest number of AM spores was estimated in Andrographis paniculata (121/50gm-1) followed by Ocimum sanctum (112/50gm-1), Adhatoda vasica (94/50gm-1), Bryophyllum sp.(89/50gm-1) and Mentha sp (75/ 50gm-1). The rhizospheric soil fungal diversity including mycorrhizal fungi (Glomus sp.) also was found to be beneficial for increasing the photosynthetic activity and uptake of phosphorus in medicinal plants. Thus, the use of AM inoculum can increase the yield of medicinal plants along with their secondary metabolites to utilize on a sustainable basis as a traditional and herbal medicine for the human welfare.

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