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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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ThesisItem Open Access Molecular cloning and in silico characterization of linalool synthase gene from Cymbopogon winterianus(AAU, Jorhat, 2018-07) Saha, Oliva; Sen, PriyabrataCitronella (Cymbopogon winterianus), an aromatic and medicinal grass from Poaceae family, is grown for the commercial and industrial purpose. It has the large repository of isoprenoid compounds known for its anti-tumoral, anti-bacterial, anti-fungal, anti-viral, anticancerous, detoxifying and natural insect repellent properties. Out of the different components of citronella oil, linalool (3,7-Dimethylocta-1,6-dien-3-ol) is one of the significant aromatic ingredient. Formation of linalool is catalysed by linalool synthase (LIS) which is encoded by linalool synthase gene. This gene has been widely studied in many medicinal plants along with sorghum, rice, maize, setaria, etc.However, till date, no studies on molecular cloning, characterization and tissue-specific expression profiling of LIS gene from C. winterianus (CwLIS) has been reported.Therefore, the present study aims at cloning and characterization of full-length cDNA of LIS gene from C. winterianus. The full-length sequence of CwLIS was obtained by primer walking using several pairs of degenerate primers and the sequence fragments were aligned to acquire full length sequence. Cloning of the desired gene (1758bp) was performed using TOPO TA vector (3.9kb), and the transformation was done in E. coli DH5α competent cells. The sequence analysis revealed 1758 bps cDNA, which has a Coding Sequence (CDS) of 1422 bps that encodes a protein of 473 amino acids. The domain analysis revealed that CwLIS is a single domain protein under terpene synthase superfamily. The multiple sequence alignment (MSA) based on PSI-BLAST search against RefSeq with 62% sequence identity revealed the presence of two aspartate-rich regions, which are supposed to coordinate 3 Mg2+ ions. The phylogenetic analysis revealed that the CwLIS is closely related to Sorghum bicolor linalool synthase. To understand the molecular mechanism behind Mg2+ and linalool binding, first, the 3D model of CwLIS was generated and validated with their stereo chemical parameters. Further, to find out the expression profile of CwLIS in different tissues, Reverse Transcriptase-PCR was performed and the results revealed a higher expression in leaf sheath followed by leaf, root and flower and further conformed by qRTPCR analysis. The result from the present study provide basic information for further research about linalool synthase and comprehensive sequence resource for study, such as gene expression, genomics and functional genomics in Cymbopogon winterianus.ThesisItem Open Access Assessment of Genetic Diversity For Ideal Plant Architecture in Rice Cultivars of Assam With Special Importance to Aromatic Group(AAU, Jorhat, 2018-08) Debnath, Neelakshi; Baruah, A.R.The development of super rice to break the yield plateau is one of the goals for rice breeding in recent years. Ideal plant architecture (IPA), which is under polygenic control, has been proposed as means to enhance rice yield potential. A study directed towards assessing the presence of desired alleles for IPA related genes/quantitative trait loci (QTL) in rice cultivars grown in diverse agroecological situations, specifically the aromatic rice of Assam (joha rice) that usually bears weaker plant type should be of prime importance. The present study was conducted to detect allelic variation for IPA in traditional, high yielding and joha rice cultivars of Assam and to compare nucleotide sequence variation for aroma gene in cultivars possessing IPA. A total of 80 cultivars comprising sali, ahu, boro and joha rice of Assam were assessed for markers linked to five IPA related QTLs (Sol1, PAY1, IPA1, Gn1 and LAZY1). Although a total of 15 markers (M3, M6, M8, M10 for Sol1; RM339, RM223, SP5, SP7 for PAY1; RM149, RM1345, M4, M5 for IPA1; PD56, M265 for LAZY1; 16BPDEL for Gn1) were employed to check for polymorphism, only five markers (GN1, M10, M265, RM 1345, SP5) showed reproducible and polymorphic results. The Gn1 and Sol1 were most abundant in cultivars as evident from the observation that 46 numbers of cultivars harboured desired alleles for Gn1 and Sol1 followed by PAY1( 31 cultivars), LAZY1 (12 cultivars) and IPA1(12 cultivars). Among HYVs, the varieties such as Ranjit, Mahsuri and Bahadur were found to possess four numbers of desired alleles, however, IPA1 allele was other than the expected. Among Joha cultivars, Bengoli joha, Goalporia joha, Kartica joha were with the maximum of four numbers of positive alleles. As Ranjit missed the expected size of the IPA1 allele, differential expression for the gene in Ranjit and one cultivar possessing the desired IPA1 allele (Chakaw Poireton) was conducted. It revealed that although Ranjit did not possess the desired IPA1, however, the expression pattern revealed that 25-30 fold more accumulation of transcripts for the gene in Ranjit than Chakaw Poireton, suggesting the functional differences in the coding regions. The allele specific analysis for aroma gene, badh2 revealed that the markers could efficiently group 53.66% of the cultivars corresponding to the existing phenotype, indicating the power of the marker to be utilized in a large germplasm screening for aroma. The sequencing for badh2.hapG9 detected a non-synonymous substitution (AG) which was not being reported elsewhere; however, novelty of which needed to be confirmed and validated. The study will enhance our knowledge to formulate breeding strategies for combing IPA with aroma.ThesisItem Open Access HOST RANGE, INCIDENCE AND GENETIC VARIABILITY OF watermelon mosaic virus IN CENTRAL SPAIN(AAU, Jorhat, 2018-01) Paswan, Ricky Raj; Acharjee, SumitaWatermelon mosaic virus (WMV, Potyvirus) is an economically important pathogen common in cucurbits of temperate and Mediterranean regions worldwide. The presence of WMV in cucurbits in the Mediterranean basin has been known for decades. More recently, an emergent strain that causes more severe symptoms compared to classic strains has been recognized in France. The cultivation of melon is threatened by the spread of emergent strains of WMV. Diagnostic methods for detecting the host range, incidence and evolution of these emergent types are critical for developing control strategies to optimize agricultural production. In this study, next generation sequencing and RT-PCR approaches are combined to investigate the epidemiology of WMV in an agro-ecosystem of Central Spain. Four vegetation types, or habitats, including cultivated and adjacent land-use types were surveyed in the summer and autumn of 2015. Forty-three plant species were screened for WMV, 15 of which were WMV-positive across two habitats other than crops. The results indicated an increase in the extent of the WMVs known host range. The incidence of WMV ranged from 64% in Cucumis melo to 5% in a weed species, Datura Stramonium. Genetic analyses of the coat protein gene of 30 isolates from melon and 3 other ‘weed’ species sampled in crops showed population variation in nucleotide diversity, but pairwise fixation indices indicated negligible distinctions between them. Phylogenetic inferences showed both negligible and large branch length differences between isolates from different host species. When sequences of a number of different strains were added to the isolates from the melon crops, one clad clustered with an emergent group previously identified from elsewhere in Europe and Asia. This study reports the first instance of an emerging (EM) strain in Central Spain.ThesisItem Open Access MOLECULAR CHARACTERIZATION OF NBS-LRR RESISTANT GENE ANALOGUES (RGAs) FROM INDIGENOUS AND WILD BANANA (MUSA SPP.) GERMPLASM(AAU, Jorhat, 2018-01) Hazarika, Geetimollika; Bhorali, PriyadarshiniCommercial banana varieties are highly susceptible to fungal and bacterial pathogens, nematodes, viruses and insect pests. The largest known family of plant disease resistance (R) genes encodes proteins with nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domains. Conserved motifs in such genes in diverse plant species offer a means for the isolation of candidate genes in banana that may be involved in plant defense. In the present study, an attempt was made to isolate and characterize the conserved region NBS of the NBS-LRR resistance gene analogues (RGAs) from locally cultivated indigenous and wild banana germplasms of Assam. The investigation was started with the isolation of genomic DNA from ten cultivated indigenous germplasms viz. Kach kol, Cheni champa, Ukho jahaji, Malbhog, Manuhor, Athiya kol, Bhim kol, Ketekihunda, Phesa manuhor and Ximolu manuhor and, five wild germplasms (designated as W1, W2, W3, W4 and W5). To target the NBS region of the banana germplasms, four pairs of PCR primers out of which two were degenerate primers, were designed from existing NBS-LRR sequences available in the GenBank. After successful isolation and sequencing of the PCR amplified NBS fragments from all the fifteen samples, confirmation about the identity of the sequences was done by homology search using BLASTn and BLASTp algorithms which revealed the sequences to be significantly similar to the NBS-LRR class disease resistance proteins available in NCBI. The sequence identity was further confirmed by checking for the Pfam NB-ARC domain, which is a protein domain characteristic of the plant resistance NBS-LRR protein. The NB-ARC domain was obtained in all the isolated NBS sequences. Finally, the presence of the consensus sequence for Kinase-2 motif (LLDDVW) and phylogenetic analysis of the isolated NBS sequences further provided evidence that the sequences belong to the typical non-Toll/interleukin-1 receptor- like domain NBS-LRR gene family, as expected. As a future prospect, upon cloning of the full length NBS-LRR sequences from these germplasms would open up possibilities for development of disease resistant cultivars through genetic engineering approaches.ThesisItem Open Access Cloning of viral genome associated with leaf curl disease of Bhut Jolokia (Capsicum chinense Jacq.)(AAU, Jorhat, 2018-01) Rajkhowa, Sushmita; Borah, B.K.Bhut Jolokia (CapsicumchinenseJacq.) is known as one of the hottest chilli in the world. It is cultivated as a major cash crop in Assam and other northeastern states, mostly Manipur and Nagaland. In the international market Bhut Jolokia has high value due to its high Capsicin content which has various important properties like anti-inflamatory, anti-diabetic, anticancerous, pain relief, gastro intestinal disorder etc. The fruit has got multiple uses in medicines, biological warfare,elephant repelling, pickles and culinary purposes. Around 1400- 1500 tonnes of the fruits are exported annually from Assam. However,the productivity of the crop is hindered due to attack ofvarious diseases and pests. Viruses have been reported to be one of the major factors that affect Bhut Jolokia plants. Both RNA viruses (Potyvirus, Cucumovirus, Tospovirus) and DNA viruses (Geminivirus) incidence have been reported that infect Bhut Jolokia in Assam. Among the DNA viruses chilli leaf curl virus (ChLCV) and tomato leaf curl virus (ToLCV) have been reported to infect Bhut Jolokia which produces symptoms of leaf curling, mosaic symptoms, stunting growth and vein clearing. Some geminivirus also contains a satellite genome which functions as silencing suppressors and in symptom determinant. As such, to determine the genome sequence of the DNA virus(es) infecting the Bhut Jolokia plants with leaf curl disease, both universal and specific primers were used to detect the virus(es) associated with leaf curl disease. Partial sequences were obtained from ChLCV-specific primers designed from available sequences. The sequences were obtained from samples collected of AAU experimental farm, Lichubari and Teok, Jorhat. Multiple sequence alignment followed by phylogenetic analysis of the four sequences showed 98% identity with the chilli leaf curl isolate of Oman (Accession No.JN604500.1). The phylogeny could not establish a geographical grouping, possibly because of short length of the sequences. Meanwhile, the nucleotide similarity search for the sequences obtained from the universal primer and ToLCV specific primers did not amplify any viral sequence. Satellite-specific primers were used for detection of satellite genomes (both alpha-satellite and beta-satellite) possibly associated with the leaf curl disease of Bhut Jolokia. However, presence of any associated satellite could not be determined. Therefore, further works will be needed in these regards.ThesisItem Open Access IDENTIFICATION OF LOCI INVOLVED IN SALT TOLERANCE BY ASSOCIATION ANALYSIS ON japonica RICE(AAU, Jorhat, 2018-01) Hazarika, Mousumi; Baruah, AiswaryaSoil salinity is one of the environmental constraints that affect crop cultivation worldwide. More than 800 Mha of land throughout the world and about 20% of the irrigated areas suffer from salinization problems (FAO, 2008). Among cereals, rice (Oryza sativa L.) is one of the most salt-sensitive although cultivars can differ in their response to salt stress (Horie et al., 2012; Munns and Tester, 2008). In European coastal rice areas, salty raining and the salt water intrusion phenomenon caused by the rise in the sea levels due to climate changes are provoking a tendency toward salinization in the adjacent paddy fields where rice is grown (Yáñez, 2010.) Moreover, the island apple snail (Pomacea maculata) is becoming one of the major pest problems for rice throughout the world, including the European areas. Till date its only effective control measure is to flood the field with sea water, which even though kill the pest but leads to residual salinization problem. In India too, soil salinity is a problem in the coastal rice growing area. It has been estimated that an approximate area of 6.3 million hectares of land is covered by saline soil in India (Patel et al., 2011). Taking into account the above statements, it is clear that the identification of elite rice varieties tolerant to salt stress is necessary. Salinity tolerance in rice is a very complex trait. Genome-wide association study (GWAS) is proving to be an effective approach for identifying loci controlling complex traits in plants (Ingvarsson and Street, 2011; Korte and Farlow, 2013; Huang and Han, 2014). In the present work, a phenotyping activity for mid-salt stress has been performed on a subset of rice panel of 281 japonica rice accessions. Then, a GWAS was carried out in order to identify possible loci involved in salt tolerance in japonica rice. The measurement of phenotypic data highlighted variability among the genotypes in response to the treatment. This suggests that the panel might be a good resource for the discovery of traits related to salt stress response. The genome-wide association study identified significant associations between SNPs and the analyzed salt stress-related traits. A preliminary functional analysis of the identified loci by the GWAS has revealed many possible candidate genes involved in salt tolerance in japonica rice.ThesisItem Open Access A study on the role of exopolysaccharide in conferring acid tolerance in Bacillus sp.(AAU, Jorhat, 2018-01) Deka, Priyadarshini; Barooah, MadhumitaSoil bacteria have evolved various mechanisms to adapt to stress environmental conditions such as temperature, salinity, drought and low pH condition of soil. Among the several environmental stress conditions, soil acidity an important factor influencing physicochemical and biological properties of soil along with microbial diversity and crop production is an emerging issue of immense concern due to its wide spread distribution across the globe. Although low soil pH restricts the number and diversity of bacteria, it is known that some soil bacteria are able to thrive in such conditions having evolved various mechanisms including production of biofilm to circumvent acid stress. Bacterial exopolysaccharide (EPS) are high-molecular-weight complex polymers composed of sugar moieties that form the main component of the biofilm which aid the bacteria to colonize substrata. In the present study, a total of 28 isolates were identified and characterized as acid tolerant EPS producing bacteria among which, B. amyloliquefaciens p16 produce the highest EPS (219.96 μg/ml). A culture medium containing sucrose (3.5%) as carbon source with pH 5.0 and incubated for 24 hrs was optimal for maximum production of EPS. The HPLC analysis of monomeric units of EPS produced by B. amyloliquefaciens p16 revealed the abundance of galactose at pH 7.0 which however, changed to arabinose when shifted to acidic condition (pH to 5.0 and 4.5). The isolate B. amyloliquefaciens p16, significantly improved soil physical properties in terms of greater soil aggregation (80.59 mm diameter aggregates) and water holding capacity (53.90%) when inoculated into soil over the control (31 mm diameter aggregates and 18.21%, respectively). The differential expression of epsA and epsB, the first two genes of the eps operon showed a 7 and 9 fold increased expression in pH 5.0 compared to pH 7.0 respectively. Disruption of the epsB gene in B. amyloliquefaciens p16 using integration vector pMUTIN4 generated mutants that produced significantly lesser EPS (33.23 μg/ml) when compared to the WT (223.87 μg/ml). The generated mutant of B. amyloliquefaciens p16 lacking the wrinkled morphology had an extended lag phase of 24 hrs and was barely able to survive in acidic medium (pH 4.5) unlike that of the WT type. Soil inoculated with generated mutants formed smaller soil aggregates (42.41±1.70 mm) and had decreased water holding capacity (27.67±1.94%) compared to the WT (80.59± 0.22 mm and 53.90± 1.66%, respectively). This study indicates that EPS secreted by acid tolerant bacteria (B. amyloliquefaciens p16) imparts acid tolerance and also aids in improving the soil physical structure through increased soil aggregation and water holding capacity.ThesisItem Open Access KNOWLEDGE AND PRACTICES OF HOMEMAKERS OF DHEMAJI DISTRICT OF ASSAM REGARDING FOOD HYGIENE(AAU, Jorhat, 2018-07) Konch, Kalyani; Sarmah, JulianaThe present research study entitled ‘Knowledge and practices of homemakers of Dhemaji district of Assam regarding Food hygiene’ was conducted in Dhemaji Sub-division of Assam.. The objective of the study were i) to study the profile of the respondents, ii) to assess the existing knowledge and practices of homemakers regarding food hygiene and iii) to find out the relationship between independent variables and respondent’s knowledge and practices on food hygiene. Blocks and municipality area of Dhemaji sub-division were considered for the study. Form each of the block one gaon panchayat was selected randomly. From each of the gaon panchayat five villages were selected randomly from each of the village, three respondents were selected who belonged to well to do family and possessing at least a refrigerator in her household. And from municipality area all the wards were considered for the present study. From each of the wards, six respondents were selected randomly who belonged to well to do family and possessing at least a refrigerator in her household. Thus, total 120 numbers were the respondents of the present study. The study revealed that more than 43per cent of the total respondents belonged to the age group 47-above years. Majority of total respondents (71.67per cent) belonged to nuclear family and 60 per cent were from small family. More than half of the total respondents that is 50.83 per cent had educational qualification up to college level and not a single respondent was found illiterate. Majority of the total respondents that is 62.50 had membership in one organization. Only 5 per cent of the total respondents had training related to personal hygiene and food hygiene. Majority of the total respondents that is 55.33 per cent had medium level of mass media exposure. The percentage of respondents belonging to medium level of mass media exposure was more in urban area than the rural area. Nearly 62 per cent of the respondents had medium level of knowledge on food hygiene. A higher percentage of respondents that is nearly 23 per cent respondents had high knowledge on food hygiene. In rural area, more than 47 per cent respondent had medium level of knowledge on food hygiene in all the stages. Not a single respondent had high knowledge on food hygiene in any stage except storage and pre-preparation. In urban area, more than 47 per cent respondent had medium level of knowledge on food hygiene in all the stages. Nearly 30 per cent and above urban respondents had high knowledge on food hygiene only in two stages such as storage and pre-preparation. A higher percentage of respondents that is 62.50 per cent belonged to moderate category on overall food hygiene practices followed by 26.67 per cent in poor and 10.83 per cent respondents belonged to good category on following food hygiene practices. In rural area, half of the respondents and more had moderate level of practice on food hygiene in all the stages. Nearly 7 per cent and 15 per cent respondents of rural area had good practice on food hygiene only in two stages such as storage and pre-preparation respectively. In urban area, nearly half of the respondents and more had moderate level of practice on food hygiene in all the stages. Nearly 22 per cent and 30 per cent respondents of urban area had good practice on food hygiene only in two stages such as storage and pre-preparation respectively. There was highly significant relationship between the knowledge of urban area respondents and with their practice on food hygiene. There was highly positive significant relationship between knowledge of respondents and their independent variable such as educational qualification and mass media exposure. There was negatively significant relationship between knowledge of the respondents with independent variable such as age and family size. There was highly positive significant relationship between practice of respondents and their independent variable such as educational qualification and mass media exposure. There was negatively significant relationship between practice of the respondents with independent variable such as age, and family size.ThesisItem Open Access Optimization of cellulose – andhemicellulose- saccharification from sugarcane bagasse for alcohol fermentation(AAU, Jorhat, 2018-01) Dilip A, Rajput; Nath, T.Lignocellulosic alcohol production from agricultural residues has the great potential to produce transport fuel as the substitute of petroleum or diesel, as it is renewable in nature, no competition with food as well as less emission problems. Sugarcane bagasse is one of the largest agricultural wastes in many countries including India. The country produces ~40 million metric ton (MMT) of bagasse annually, most of which is burnt and contributes to air pollution. So, it can be considered as one of the lignocellulosic sources for alcohol production, but it needs proper characterization as a feed for alcohol production. In this present research, sugarcane bagasse from Assam (Buraliksion, RARS, AAU, Jorhat) has been tried to be characterized considering its sugar components (cellulose and hemicellulose) which ultimately contributes to ethanol production. Cellulose and hemicellulose composition were found 37.6% and 29.2%, respectively.The process complexity, mainly pretreatment (prior to saccharification) and enzymatic saccharification (conversion to complex carbohydrates to fermentable monomers) has been studied. Among the different pretreatment methods available, the most commonly practiced one, i.e. Acid-Alkali treated method was studied and subsequent enzymatic hydrolysis was done with known commercial enzymes. Hemicellulose was hydrolyzed by hemicellulase enzyme procured from Sigma-Aldrich and found the maximum efficiency of releasing reducing pentose monomers along with acid pretreatment (H2SO4) about 65% of total hemicellulose content. Cellulose was hydrolyzed by cellulase enzyme procured from HiMedia and found the maximum efficiency of releasing reducing hexose sugars (glucose) about 74% of total cellulose content.Not having complete conversion or having less conversion of hemicellulose/cellulose to its monomeric units may be associated with less efficiency of the enzyme or complexity of the cellulose or both.
