Int.J.Curr.Microbiol.App.Sci (2017) 6(9): 2953-2968 2953 Original Research Article https://doi.org/10.20546/ijcmas.2017.609.363 Assessment of Culturable Microbial Diversity Associated with Arnebia euchroma: A Critically Endangered Plant Growing in Trans-Himalayas of Himachal Pradesh, India Sunita Devi * and Kirti Kaundal Department of Basic Sciences, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni- Solan (H.P) -173230, India *Corresponding author ABSTRACT Introduction India, particularly the Trans-Himalayan region, is a varietal emporium of medicinal plants species and has been a major part of India‟s rich medicinal plant heritage (Alluri et al., 2005; Bhadrecha et al., 2017). This vast wealth is widely distributed in different parts of the country having specific phyto geographical entities. Medicinal plants are considered as the backbone of the traditional medicines being used worldwide. Owing to variations in altitude and topography, Himachal Pradesh, located in the lap of the Himalayas, has varied climatic conditions, which make this state ideal for the thriving of a wide diversity of medicinal plant species (Sharma and Mishra, 2009; Singh and Thakur, 2014). Consequently, the state is a bucket of large variety of medicinal herbs. More than 50% medicinal plants traditionally used in India come from the Himalayan region (Uniyal et al., 2002; Verma and Tiwari, 2016). This biodiversity of medicinal plants and its sustainable utilization by the local people for various activities (traditional healthcare, cultural and religious) help in International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 9 (2017) pp. 2953-2968 Journal homepage: http://www.ijcmas.com This paper presents a pioneer study on the microbial diversity associated with the rhizosphere of Arnebia euchroma, considering the medicinal importance and critically endangered status of this taxon. Rhizospheric soil samples of Arnebia euchroma were collected from two villages namely Nako and Chango in Kinnaur and one i.e. Gue in Lahaul & Spiti district of Himachal Pradesh. Chemical profile of soils revealed pH value in alkaline range of 7.97 to 8.43. The organic carbon content varied from 0.60 to 1.20 %. The available P and N contents were very high and low, respectively. The available K content was high in Nako and Chango and medium in Gue. Zn and Mn contents were found to be low whereas, Cu and Fe contents were comparatively high. A total of 105 microbial isolates were obtained from all the samples. The bacterial and actinomycetes loads were found to be significantly higher at Gue followed by Nako and Chango. High value of Shannon - Wiener index (H‟) was found at Gue as compared to Chango and Nako. However, evenness (E1) values were comparatively low at Gue than Chango and Nako, which implies that Gue has a greater diversity of microbial species, which however was not evenly distributed. Keywords Arnebia euchroma, Microbial diversity, Shannon - Wiener index, Microbial load, Medicinal plants, Trans – Himalaya. Accepted: 28 August 2017 Available Online: 10 September 2017 Article Info