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Assam Agricultural University, Jorhat

Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level. Genesis of AAU - The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati. Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.

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20211
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Subject: Plant Pathology × Author: Barua, Parinda × End date: 2022 × Start date: 2020 × Type: Thesis ×
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    ThesisItemOpen Access
    Diversity of bacteriophages infecting R alstonia solanacearum and their application as b io control agents
    (AAU, Jorhat, 2021-12) Barua, Parinda; Nath, P. D.
    Bacterial wilt caused by Ralstonia solanacearum is one of the most destructive plant diseases of the world that is very difficult to manage. Sustainable management of R. solanacearum using bacteriophages is one of the most promising yet unexplored areas of biological control in India. In the present study, 50 R. solanacearum isolates were collected from various bacterial wilt infected fields in 5 districts of Upper Brahmaputra Valley Zone (UBVZ) of Assam namely Golaghat, Jorhat and Sivsagar, Dibrugarh and Tinsukia from several crops like bhut jolokia, chilli, capsicum, tomato, brinjal, wild brinjal, potato and ginger. This was followed by isolation of seven lytic phages of R. solanacearum from soil from bhut jolokia fields of Jorhat, Assam. After six rounds of purification of the phages, the plaque morphology, phage titre and the multiplicity of infection (MOI) was determined where it was observed that phage RSP1 had the biggest plaque size (3.28 ± 0.40 nm) and phage RSP4 had the highest titre (1.2E+09 PFU/ml). The adsorption time, latent period, rise period as well as the burst size of the isolated phages was also determined. Physiochemical characterization of the phages revealed that the phages were stable from 4℃-50 ℃, a pH range of 4-9 and except RSP1; all other phages were stable 1% and 5% chloroform. Morphological classification using TEM revealed that all the phages had an icosahedral head with a very short non- contractile tail indicating that they may belong to either Podoviridae and/or Autographiviridae family of order Caudovirales. From the lysis dynamics curves of the individual phages, 3 phage cocktails were formed and cocktail-3 having all the seven phages gave the best results. Study on host range of the phages stated that all the phages were multi strain specific in nature and phage RSP4 had the highest host range. In vitro suppression of R. solanacearum in soil using phage cocktail-3 revealed that the cocktail was effective in managing R. solanacearum population in soil when used as a prophylactic manner. Finally, from the study on long term viability of phages at different storage temperatures it can be recommended that these seven phages could be stored in glycerol stocks at -45 ℃ or -20 ℃ and in SM buffer in +4 ℃ without losing viability for a year. Keywords: Bacteriophage, Ralstonia solanacearum, bacterial wilt, phage therapy.