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University of Agricultural Sciences, Bengaluru
University of Agricultural Sciences Bangalore, a premier institution of agricultural education and research in the country, began as a small agricultural research farm in 1899 on 30 acres of land donated by Her Excellency Maharani Kempa Nanjammanni Vani Vilasa Sannidhiyavaru, the Regent of Mysore and appointed Dr. Lehmann, German Scientist to initiate research on soil crop response with a Laboratory in the Directorate of Agriculture. Later under the initiative of the Dewan of Mysore Sir M. Vishweshwaraiah, the Mysore Agriculture Residential School was established in 1913 at Hebbal which offered Licentiate in Agriculture and later offered a diploma programme in agriculture during 1920. The School was upgraded to Agriculture Collegein 1946 which offered four year degree programs in Agriculture. The Government of Mysore headed by Sri. S. Nijalingappa, the then Chief Minister, established the University of Agricultural Sciences on the pattern of Land Grant College system of USA and the University of Agricultural Sciences Act No. 22 was passed in Legislative Assembly in 1963. Dr. Zakir Hussain, the Vice President of India inaugurated the University on 21st August 1964.
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ThesisItem Embargo IDENTIFYING THE MOLECULAR MECHANISMS OF BACTERIAL EFFECTOR PROTEINS FROM Xanthomonas oryzae pv. oryzae CAUSING LEAF BLIGHT DISEASE IN RICE AND USE OF SMALL MOLECULES IN DISEASE RESISTANCE(University of Agricultural Sciences, Bangalore, 2023-05-05) SWATHI, S. PATIL; M. K. PrasannakumarRice (Oryza sativa L.) is the most important staple commodity, providing food for nearly half the global population. The bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most destructive diseases afflicting rice fields. The morphological, biochemical and pathogenicity characteristics of ten Xoo isolates from various rice-growing regions in India were used to differentiate them. The pathogenicity assay determined that all isolates were virulent on the susceptible variety TN-1, with the KA isolate producing significantly more lesion length, in planta bacterial count, xanthomonadin, and exopolysaccharide. Through dual transcriptome analysis of contrasting rice cultivars (TN-1 and RP-Bio226), disease resistance genes such as ARK1AS, mla1, RPM1, RPS2 and RPP-13 protein 1 were found to be upregulated in RP-Bio226 in response to Xoo infection. In the susceptible variety, the production of the susceptibility gene OsSWEET11 was upregulated, whereas it was downregulated in the resistant cultivar RP-Bio226. Many type 3 secretion system proteins, including PthXo1, XopN, XopW, HrpB2, SctJ, and SctN were identified in Xoo infecting the susceptible variety, but none in the resistant variety. RP-Bio226 produced higher levels of hydrogen peroxide and superoxide anion than the susceptible variety TN-1. Using plants expressing OsSWEET11- gRNA, the OsSWEET11 gene was characterised using the CRISPR Cas9 gene editing technology. Gene editing was confirmed in the transgenic plant S21 with change in amino acid from isoleucine to leucine at position 263 and leucine to isoleucine at position 266. S21 also displayed a resistant reaction to Xoo. In addition, a novel small molecule 6-[(3- oxido-2,1,3-benzoxadiazol-3-ium-5-yl)oxy]2,1,3-benzoxadiazol-1-ium-1-olate was identified through a chemical genomics approach, targeting the effector protein PthXo1 to confer resistance against Xoo in the TN-1 variety. The plants sprayed with the small molecule immediately following Xoo inoculation exhibited a significant decrease in lesion length and in planta bacterial count compared to the control.ThesisItem Open Access DECIPHERING SUPPRESSORS OF PLANT CELL DEATH (SPD) EFFECTORS DURING MAGNAPORTHE ORYZAE: RICE INTERACTION AND DEVELOPMENT OF BLAST DISEASE FORECASTING MODEL(University of Agricultural Sciences, Bangalore, 2023-02-13) JAYASHREE A; A. NAGARAJARice blast disease caused by Magnaporthe oryzae (Hebert) Barr is one of the leading constraints to global rice production and a serious threat to food security. The present study aims to decipher the role of suppressors of plant cell death (SPD) effectors during host pathogen interaction and develop a weather driven forecasting model for rice blast disease by employing machine learning algorithms and understanding the rice defence response to high temperature upon challenge inoculation with the pathogen. In-silico identification, modelling and functional analysis of SPD effectors in M. oryzae revealed that eleven SPD effectors under study were predicted to fulfil the criteria to fit in the definition of candidate secreted effector proteins. The SPD effectors were composed of a signal peptide, ≥ 3 per cent of cysteine residues, no transmembrane domains, ≤ 250 amino acids and a low molecular weight of below 50 KDa. The majority of homologs, orthologs and paralogs identified belonged to ascomycetes. The SPD effector MG01_03488 was expressed using a pET32a (+) expression vector and the protein was purified using Ni- NTA affinity chromatography. Priming rice plants with prokaryotic expression product of MG01_03488 resulted in the suppression of reactive oxygen species and other defence related enzymes, consequently facilitating pathogen virulence. Of the six machine learning techniques employed in rice blast prediction, the artificial neural network was more efficient, with 98.84 per cent accuracy. Temperature and relative humidity were significant weather contributors in predicting rice blast through machine learning approaches. Magnaporthe oryzae inoculation and induced high temperature stress increased rice blast disease severity and resulted in a substantial reduction in the photosynthetic pigments, carotenoids and anthocyanin content and increased membrane injury index, malondialdehyde, reactive oxygen species, lipoxygenase activity, antioxidant activities and higher relative expression of Pi2 and Pi54 resistance genes as compared to non-stress rice seedlings.ThesisItem Open Access DIVERSITY, MOLECULAR CHARACTERIZATION AND INTEGRATED MANAGEMENT OF MUNGBEAN YELLOW MOSAIC VIRUS DISEASE(2021-10-18) CHIRAG GAUTAM; RAMAPPA, H K.Mungbean Yellow Mosaic Virus (MYMV) disease of mungbean causes severe losses to crop yield worldwide. Disease incidence ranged between 27.06-87.80 and 29.67-95.58 per cent during Rabi summer 2016-17 and 2017-18 respectively. The highest per cent disease incidence and whitefly population was recorded in Chamarajanagar district. Molecular confirmation of diseased samples was done by using CP specific set of primers. Maximum transmission efficiency (80 %) was observed when ten or more whiteflies per plant were used. Maximum (90%) per cent transmission was observed at an AAP and IAP of 24 h. MYMV isolate of Chamarajanagar, Mandya, GKVK and Tumakuru produced various symptoms when inoculated on susceptible mungbean genotype (BGS-9). Host plants viz., mungbean, urdbean, soybean, cowpea and horsegram noculated with MYMV recorded 30 to 70 per cent disease incidence. However, pigeonpea and dolichos did not develop any symptoms. Cross infectivity of YMV from horsegram and urdbean showed chlorotic and leaf deformation symptoms on mungbean genotype BGS-9. AC1, AC2, AC3, AC4 and AV1 of DNA A and BC1 of DNA-B of Chamarajanagar, GKVK and Mandya isolates were amplified by using gene specific set of primers. BLAST results and phylogenetic analysis revealed that all the genes from different isolates had some variability within but showed similarity with MYMV. Out of 150 mungbean genotypes screened, 10 genotypes found moderately resistant against MYMV. Seed treatment with imidacloprid 48 FS @ 5.0 ml/kg seed+ one spray with imidacloprid 17.8 SL @ 0.24 ml/l (T8) was highly effective in reducing whitefly population by 60.82 and 56.48 per cent, and disease incidence by 56.37 and 50.38 percent, resulted in highest yield (1095.00 and 1132.23 Kg/ha) during 2016-17 and 2017-18, respectively.ThesisItem Embargo CHARACTERIZATION OF VOLATILE ORGANIC COMPOUNDS (VOCs) PRODUCED BY BIOAGENTS AND POSTHARVEST MANAGEMENT OF FRUIT ROT IN GRAPES(University of Agricultural Sciences, Bangalore, 2022-12-06) POOJA S, PATEL; SRIRAM, SGrapes (Vitis vinifera L.) is an important fruit crop belonging to the family Vitaceae. Even though grapes fruits are prone to a number of diseases, fungal pathogens inflict greater losses. Grapes fruits are extremely susceptible to postharvest spoilage because of its perishable nature. The causal agent of the important postharvest pathogens of grapes were isolated and identified as Alternariaalternata,Colletotrichumgloeosporioides and Penicilliumcitrinum. Their identity was confirmed at molecular level. Twenty-nine bacterial and two yeast epiphytes were isolated from the phylloplane and fructoplane of grapes and screened them for their antagonistic effect against postharvest pathogens of grapes. Among them fifteen bacterial and two yeast isolates were found effective and they were identified at molecular level and characterized biochemically. After excluding three opportunistic bacterial pathogen isolates, remaining fourteen isolates were tested for the production of VOCs and among them threebacterial (Bacillus spp.) and two yeast isolates (Hanseniosporaopuntiae) were effective in the production of anti-fungal volatiles suitable for the postharvest disease management. The VOCs viz., styrene, aceticacid 2-phenylether ester, azulene, n-hexadecanoic acid, beta- cubebene, trans- beta bergamotene, beta- phyllandrene and benzene propyl were identified from effective antagonists in pure culture and during their interaction with pathogen using solid phase microextraction -gas chromatography and mass spectrometry (SPMEGCMS). Based on the commercial availability of the VOCs, n- hexadecanoic acid (palmitic acid) was selected for further work and at higher concentration (20%), and inhibited the radial growth of target pathogens significantly. Exposure of grapes fruits (cv. Dilkush) to the volatiles of IIHR_MIFY01 and IIHR_GSPB02 and fruits of cv. Sonaka to 20 per cent of palmitic acid was found effective in reducing the postharvest diseases and maintaining the shelf life and quality of grapes fruits.ThesisItem Open Access STUDIES ON FUNGAL ENDOPHYTES AGAINST SOIL-BORNE FUNGAL PATHOGENS OF TOMATO(University of Agricultural Sciences, Bangalore, 2021-03-31) NANDAN, M; LAKSHMINARAYANA REDDY), C. N.Studies on fungal endophytes against soil-borne fungal pathogens of tomato was conducted in-vitro and in-vivo. Thirty-five fungal endophytic OTUs were isolated from leaf, stem and root tissues of Tridax procumbens, Cassia tora and Parthenium hysterophorus and one potential fungal endophyte from previous studies, i.e.,Trichoderma asperellum isolate 1 (TA1) were evaluated against targeted pathogens, Sclerotium, Fusarium and Rhizoctonia infecting tomato by dual culture technique.OTU’s showing more than 50 per cent inhibition against targeted pathogens and three pathogens mentioned above were taken for further characterization through ITS region sequencing and analysis. To decipher the mechanism involved by potential endophyte Trichoderma asperellum isolates against selected pathogens, disc diffusion assay and double Petri dish assay was conducted. Further, endophytes showing positive inhibition of pathogen in these assays were processed for LC-ESI-MS/MS and GC-MS analysis and diffusible and volatile compounds involved in interaction were identified, respectively, which showed the presence of antimicrobial diffusible and volatile compounds produced by isolates of T. asperellum. To confirm the antimicrobial nature of diffusible compounds in-silico docking analysis was performed, which revealed the potentiality of diffusible compounds in binding to β-tubulin and inhibiting the targeted pathogens. Scanning electron microscopic studies showed the parasitizing behaviour of T. asperellum against Rhizoctonia and Fusarium pathogens. Tomato seed primed with endophyte, T. asperellum showed delayed in the onset of Sclerotium wilt in comparison with control plants. The gene expression studies using qRT-PCR analysis for seven genes involved in resistance pathways showed increase in their expression indicated the role of T. asperellum in inducing the plant systemic resistance.ThesisItem Embargo STUDIES ON GRAIN DISCOLOURATION OF RICE (Oryza sativa L.)(University of Agricultural Sciences, Bangalore, 2022-12-31) POMPANA GOUDA, BAPURADA; NARENDRAPPA, TThe ‘Rice is life’, a slogan most appropriate for our country as this crop plays a vital role in our national food security. Globally, India stands first in area (42.41 Mha) and second in rice production (166.5 Mt). This crop is associated with various diseases and among them the grain discolouration found to be a serious disease in India resulting huge yield loss and deteriorating quality of the seed. A roving survey conducted during Kharif 2017 and 2018 across three rice growing ecosystems of Karnataka, the highest mean per cent incidence of disease (15.21%) and severity (13.79%) was recorded in Hilly ecosystem followed by Coastal ecosystem (14.66%) and (13.35%); Tungabhadra & Upper Krishna Project (12.42% and 11.85%); Kabini & Kaveri (12.19% and 11.43%) and Thunga & Bhadra (11.54% and 10.62%). Mycoflora associated with discoloured grain samples were species of Helminthosporium, Curvularia, Alternaria, Aspergillus, Fusarium, Cladosporium, Phoma, Trichoderma, Rhizopus and Magnaporthe oryzae. They were isolated and identified based on morphology/spore characters. Among 38 rice genotypes screened during Kharif 2017 and 2018 under natural condition, none of them exhibited immune and resistance to grain discolouration. However, five genotypes viz., Jaya, BR-2655, Rajamudi, KCP-1 and Ratnachudi were found moderately resistant and twenty-one genotypes exhibited moderate susceptibility and remaining twelve genotypes showed susceptible réaction against grain discolouration. Biochemical studies revealed that phenol content in discoloured grains was significantly more that varied from 44.86 to 76.87 mg/g than in healthy grains (39.74 to 64.10mg/g) of all tested genotypes. Similarly reducing, non-reducing and total sugars recorded significantly high in diseased grains as compared to healthy grains. The spray of tebuconazole 50%+trifloxystrobin 25% 75WG @ 0.04% at panicle emergence was significantly superior in management of rice grain colouration with disease severity of 4.65%, grain yield of 53.09 q ha-1 with incremental benefit cost ratio of 1: 11.47.ThesisItem Open Access IDENTIFICATION AND CHARACTERIZATION OF Alternaria alternata (Fr.) KEISSLER INCITING LEAF BLIGHT IN LITTLE MILLET(University of Agricultural Sciences, Bangalore, 2021-02-25) BODA PRAVEEN; A., NagarajaLittle millet is one of the hardiest minor millet indigenous to the Indian subcontinent and is mainly grown for food, fodder and feed. However, leaf blight caused by Alternaria alternata is one of the emerging malady in the successful cultivation of little millet. Intensive roving survey unravelled that the severity of leaf blight ranged from 19.49 to 67.33 per cent. The leaf blight pathogen was identified as Alternaria alternata based on morpho-cultural characteristics and molecular profiling with ITS, SSU, Histione-H3, GAPDH, RPB2, Alt a1, endoPG, OPA10-2 and KOG1058 gene/genomic regions. Whole genome sequencing of A. alternata UASB1 isolate using Illumina and Oxford Nanopore ensued genome size of 33. 13 Mb, 12, 388 predicted genes, 10, 266 proteins in which 762 were annotated and 9504 hypothetical proteins and 635 Simple Sequence Repeats (SSRs). Effect of fungal culture filtrate on Vigour Index (V. I) showed drastic reduction compared to water control. Seedling growth was also affected with culture filtrate and the crop leaves exhibited chlorosis, necrosis, drooping with loss of turgidity. Toxin characterization through LCMS revealed that the pathogen produces various toxic compounds like Tenuazonic acid (TeA), Alternariol Monomethyl Ether (AME), Alternariol (AOH), Altenuene (ALT), Altertoxin II, Alterperylenol and Stemphylotoxin III. Host range studies indicated that the pathogen is not host specific and can infect other plant species like kodo millet, wheat and oat. Among the 142 genotypes screened under natural field conditions 46, 38 were found resistant to leaf blight disease at Mandya and Bangalore respectively. Eucalyptus leaf extract recorded highest mean per cent inhibition of mycelial growth (84.82 %) in vitro. Among the bio-agents, highest mycelial radial growth inhibition was noticed with Trichoderma harzianum ThB5 (75.18%) and Bacillus velezensis strain P42 (84.75%) in vitro. Highest mean mycelial growth inhibition of Alternaria alternata was observed in mancozeb 75% WP (78.43%) among the contact fungicides, tebuconazole 50 % WG + trifloxystrobin 25 % WG (95.74 %) combi-product and hexaconazole (100.0%) systemic fungicide in vitro.ThesisItem Embargo CHARACTERIZATION AND MANAGEMENT OF EARLY BLIGHT OF TOMATO(University of Agricultural Sciences GKVK, Bangalore, 2022-12-16) SUDARSHAN, G.K; Nagaraj, M.SEarly blight caused by Alternaria solani is a predominantly occurring disease of Tomato. Roving survey results of Rabi 2018-19 and 2019-20 in major tomato rowing areas of southern Karnataka revealed that the maximum mean disease severity was recorded in Kolar district (38.63%) followed by Chikkaballapur 38.36%) district during fruiting stage. Among the 23 isolates, isolates AMaNaL and AMaNaS recorded maximum radial growth on six solid media out of the ine media. The isolate AHaBeL showed highest number of horizontal septation (5-7) on oatmeal agar medium and the highest number of vertical septation of -3 were observed in AKoMaL (host leaf extract) and AMyNjL (oatmeal agar). Sporulation was observed only in five isolates viz., AHaBel, AHaCrl, AHaHaL, KoMaL and AMyNjL. The PCR amplification of 23 isolates using universal primer pair revealed that, ITS region of the isolates showed highest nucleotide dentity varying from 91.2 to 94.2 per cent to the Alternaria solani infecting Tomato. The epidemiological studies revealed that per cent disease index (PDI) progressed in linear rate as the age of the plant advances and weather parameters like minimum temperature, evening relative humidity, morning relative umidity rainfall, number of rainy days were found significant and in negative correlation with disease development. Among the three contact fungicides valuated, the highest per cent inhibition (78.61) was recorded in mancozeb 75% WP. Among the different antagonists evaluated maximum mycelial inhibition was noticed in Trichoderma asperellum (69.69%). Hexaconazole 5% EC @0.1% was found effective both under laboratory and field condition against A. solani. Among the 50 commercial varieties/hybrids evaluated, three varieties/ hybrids viz., (ArkaSurabh, Arka Samrat and Arka Vikas) showed moderately resistant (MR) reactionThesisItem Open Access CHARACTERIZATION, EPIDEMIOLOGY, HOST PLANT RESISTANCE AND MANAGEMENT OF URDBEAN LEAF CRINKLE VIRUS (ULCV) IN BLACKGRAM (Vigna mungo L. Hepper)(University of Agricultural Sciences, Bangalore, 2022-02-17) AISHWARYA, P.; Ramappa, H. K.Urdbean Leaf Crinkle Virus (ULCV) is a major threatening disease in blackgram. The biological characterisation of ULCV revealed the sap transmission between 92-100 per cent, seed transmission between 55-95 per cent and Aphis craccivora C.L. Koch transmission upto 100 per cent with 10 minute of Acquisition Feeding Period, 12 and 24 hours of Inoculation Feeding Period with 10 aphids per plant. The host range studies revealed that soybean, field bean, horsegram, cowpea, greengram and weed Euphorbia geniculata to be hosts for ULCV disease. The rate of infection was severe at younger stages upto 35 DAS and reduced at later growth stages upon sap inoculation. Transmission Electron Microscopic observations of ULCV infected blackgram indicated isometric particles with size of 25-30 nm. The ULCV samples of blackgram showed no amplification for any of the primers of potyvirus, geminivirus and viroids. Metagenomic sequencing of ULCV samples showed nucleotide and amino acid identity of 76.44 and 90.66 per cent with Cotesia glomerata bracovirus (putative histone 4 gene) respectively which can be validated further. None of the 124 blackgram genotypes screened under controlled conditions showed resistant reaction for ULCV disease. The minimum (16- 180C) and maximum (32-340 C) temperature range co-related negatively and positively during late Kharif and Summer for ULCV disease incidence respectively. Seed treatment of thiamethoxam 30 % FS @ 10 ml-kg of seeds with neem (oil based) spray 10,000ppm @ 2 ml-L of water at 30, 45 and 60 DAS reduced the ULCV disease incidence compared to control.
