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Your search keyword '"Lakshman, Dilip"' showing total 127 results
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127 results on '"Lakshman, Dilip"'

11. Assessment of Genetic Diversity and the Population Structure of Species from the Fusarium fujikuroi Species Complex Causing Fusarium Stalk Rot of Maize.

Author

Jambhulkar, Prashant P., Bajpai, Ruchira, Reddy, Harish Jayarama, Tripathy, Partha Sarathi, Varun, Priyanka, Rout, Ajaya Kumar, Behera, Bijay Kumar, Lakshman, Dilip K., and Nanjundappa, Mallikarjuna

Subjects
GENETIC drift, GENETIC variation, GIBBERELLA fujikuroi, GENETIC polymorphisms, HAPLOTYPES
Abstract

Fusarium stalk rot (FSR), caused by the Fusarium species complex, is an economic threat to maize cultivation all over the world. We investigated the population structure and genetic diversity of Fusarium species obtained from five major maize-growing regions in India. The Tef-1α locus was used for phylogenetic analysis of geographically distinct isolates of Fusarium verticillioides, F. andiyazi, F. proliferatum, F. nygamai, and F. acutatum causing FSR. A phylogenetic tree showed monophyletic, polyphyletic, and paraphyletic groupings reflecting the complex evolutionary history and genetic diversity within the genus. Monophyletic groupings depicting strong bootstrap support were shown to have a single common ancestor and genetic coherence with limited genetic divergence among sequences. Polyphyletic groupings also presented significant genetic differentiation within the F. verticillioides sequences from diverse ecological niches. Nucleotide diversity of moderate level 0.02471 reflected genetic variations within populations that were attributed to factors such as mutation, genetic drift, or varying selection pressures. The Fst value of 0.98205 is particularly indicative of high genetic differentiation, implying that most of the genetic variance is due to differences between populations rather than within them. F. verticillioides, with 57 sequences, showed low genetic diversity with three segregating sites and a low haplotype diversity of 0.19486, suggesting the founder effect, where a reduced population expands from a limited genetic pool. The total data estimates across all populations for haplotype analysis showed 72 sequences, 44 segregating sites, and 9 haplotypes with a haplotype diversity of 0.48513. The evolutionary dynamics showed genetic differentiations among Fusarium species causing FSR. AMOVA indicated high within-population variations, depicting a substantial genetic diversity within individual populations. The results offer a comprehensive framework for discussing the implications of genetic diversity in pathogen management and the evolutionary dynamics of the Fusarium species causing FSR in maize in the Indian subcontinent. [ABSTRACT FROM AUTHOR]

Published
2024
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22. Assessment of Immune Responses to Rabies Vaccination in Free-Ranging Dogs in Bengaluru, India

Author

Prakash Rao, Vinay Chavan, primary, Ramakrishnaiah, Sharada, additional, Isloor, Shrikrishna, additional, Doddamane, Rathnamma, additional, Lakshman, Dilip, additional, Maralavadi, Manjunath Shinde Sundar Rao, additional, Bhat, Avinash, additional, Chandrashekar, Balaji, additional, Natesan, Krithiga, additional, Kondabattula, Ganesh, additional, and Hegde, Nagendra R., additional

Published
2023
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23. Comparative Evaluation of Intradermal vis-à-vis Intramuscular Pre-Exposure Prophylactic Vaccination against Rabies in Cattle

Author

Gopalaiah, Swathi, primary, Appaiah, Kshama M., additional, Isloor, Shrikrishna, additional, Lakshman, Dilip, additional, Thimmaiah, Ramesh P., additional, Rao, Suguna, additional, Gouri, Mahadevappa, additional, Kumar, Naveen, additional, Govindaiah, Kavitha, additional, Bhat, Avinash, additional, and Tiwari, Simmi, additional

Published
2023
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29. Efficacy of different inoculum forms of Rhizoctonia solaniAG 2-2IIIB for resistance screening of sugar beet varieties

Author

Bhuiyan, M. Z. R., del Río Mendoza, Luis E., Lakshman, Dilip K., Qi, Aiming, and Khan, M. F. R.

Abstract

Sugar beet (Beta vulgarisL.) is one of the major sugar sources in the world. Rhizoctonia solanicauses damping-off and crown and root rot that can result in significant yield and economic losses. R. solaniAG 2–2 IIIB is the most damaging anastomosis group in sugar beet production. In this study, we evaluated three different types of inoculums, namely barley grains colonized by fungal mycelium (CBG), agar plugs containing fungal mycelia (MAP), and sclerotia (SCL) for their ease of production and efficacy in inducing disease in sugar beet. First, the fungal growth rate and sclerotia production were compared on six types of media, clarified V8 [CV8], potato dextrose agar [PDA], metalaxyl benomyl vancomycin agar [MBV], yeast malt agar [YMA], corn meal agar [CMA], and oatmeal agar [OMA]. The fungus grew faster and produced more sclerotia in CV8 medium than in other media (P < 0.05). The rate of fungal growth from CBG, MAP, and SCL was evaluated. The in vitro rate of growth of R. solaniwas faster when originated from MAP than from SCL (P < 0.05) but equal to that from CBG. The different inoculum forms were then used to inoculate seeds at planting and 4-leaf stage sugar beet plants to evaluate the disease incidence and severity. R. solanion CBG caused greater severity. Overall, CBG was the best form of inoculum due to its ease of inoculum production, low cost, and ability to consistently cause severe disease symptoms on sugar beet plants.

Published
2023
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34. Evaluation of fungicides and bacterial antagonists for management of Corynespora leaf spot on mungbean (Vigna radiata L. Wilczek)

Author

Bairwa, Narendra K., primary, Jambhulkar, Prashant P., additional, Sushmitha, V., additional, Arya, Meenakshi, additional, Manjunatha, N., additional, Bajpai, Ruchira, additional, Singh, Dinesh, additional, Mani, Chandra, additional, Kumar, Shailendra, additional, Chaturvedi, Sushil. K., additional, and Lakshman, Dilip, additional

Published
2022
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41. Sclerotinia sclerotiorum (Lib) deBary causes root rot and necrosis in sugar beet in Moorhead, MN, USA.

Author

Bhuiyan, Md. Ziaur Rahman, Lakshman, Dilip K., Del Rio Mendoza, Luis E., Mosher, Presley, and Khan, Mohamed F. R.

Subjects
SCLEROTINIA sclerotiorum, ROOT rots, SUGAR crops, SUGAR beets, STUNTED growth, BEETS, NECROSIS
Abstract

Sugar beet is a major sugar yielding crop in the states of Minnesota (MN) and North Dakota (USA). Sugar beet root samples collected from Moorhead, MN in September 2020 had typical rot symptoms along with whitish mycelia growth and blackish sclerotia on the external surface of the root. Pure, sterile cultures were obtained from infected roots. Sclerotinia sclerotiorum was identified based on morphological features and further confirmed molecularly by sequencing of the Internal Transcribed Spacers (ITS) region and matching homology with reported ITS of the fungus. Pathogenicity of S. sclerotiorum was confirmed through mycelial inoculation of seeds and roots under laboratory and greenhouse conditions. Inoculated seeds showed a range of symptoms that included pre- and post-emergence damping off, wilting, black discoloration of roots, constricted collar regions and stunted seedling growth. Under laboratory conditions, roots were artificially wounded using a cork borer and inoculated by mycelial plug. This resulted in noticeable root decay and growth of whitish, cottony mycelia and sclerotia externally. Transverse sections of the diseased root showed brown to black discoloration and rotting of internal tissue. Root inoculation of 4-week old sugar beet plants was achieved by depositing pathogen colonized barley grains near roots in the greenhouse, resulting in brown to black lesions and necrosis of root tissue when evaluated at 28 days post inoculation. The S. sclerotiorum was re-isolated from inoculated roots showing infection and identical pure isolates of the pathogen were recovered from field samples. These findings could be useful for sugar beet growers in Minnesota, allowing better management of this pathogen under field and storage conditions before its widespread future occurrence. [ABSTRACT FROM AUTHOR]

Published
2021
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42. Symptom Development in Response to Combined Infection of In Vitro-grown Lilium longiflorum with Pratylenchus penetrans and Soilborne Fungi Collected from Diseased Roots of Field-grown Lilies

Author

Lakshman, Dilip, Vieira, Paulo, Pandey, Ruchi, Slovin, Janet, Kamo, Kathryn, and School of Plant and Environmental Sciences

Subjects
food and beverages
Abstract

Eight fungal isolates (ELRF 1 to 8) were recovered from necrotic roots of Easter lilies, Lilium longiflorum cv. Nellie White, grown in a field in the U.S. Pacific Northwest. The eight fungal isolates were identified by sequencing and molecular phylogenetic analyses based on their ITS rDNA region. Five isolates were identified as Fusarium oxysporum, two as F. tricinctum, and one as Rhizoctonia sp. AG-I. This constitutes the first report of Rhizoctonia sp. AG-I infecting lilies worldwide and the first report of F. tricinctum infecting lilies in the United States. To study and validate their pathogenicity, pure cultures of each isolate were used to infect the roots of Easter lily plants growing in vitro. In addition, Easter lily plants growing in vitro were infected either with or without Pratylenchus penetrans, the root lesion nematode, prior to placing a culture plug of fungus 1 cm from a lily root. Pratylenchus penetrans is a nematode species commonly found in the sampled fields. The presence of both nematode and Rhizoctonia sp. AG-I isolate ELRF 3 in infected lilies was evaluated by molecular analyses, confirming the infection of roots 3 days after inoculation, prior to development of disease symptoms. Necrosis and root rot developed more rapidly with all eight fungal isolates when there had been prior infection with P. penetrans, the major nematode parasitizing Easter lily roots in the field in Oregon. Public domain – authored by a U.S. government employee

Published
2017

43. Additional file 4: Figure S2. of Characterization of mechanisms underlying degradation of sclerotia of Sclerotinia sclerotiorum by Aspergillus aculeatus Asp-4 using a combined qRT-PCR and proteomic approach

Author

Xiaojia Hu, Qin, Lu, Roberts, Daniel, Lakshman, Dilip, Yangmin Gong, Maul, Jude, Lihua Xie, Changbing Yu, Yinshui Li, Hu, Lei, Xiangsheng Liao, and Liao, Xing

Abstract

KEGG classification of unigenes. KEGG classification of unigenes of Aspergillus aculeatus Asp-4 grown on sclerotia of Sclerotinia sclerotiorum. KEGG pathway grouping: A, cellular processes; B, environmental information processing; C, kinetic information processing; D, metabolism; E, organismal systems. (PPTX 369Â kb)

Published
2017
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44. Additional file 3: Figure S1. of Characterization of mechanisms underlying degradation of sclerotia of Sclerotinia sclerotiorum by Aspergillus aculeatus Asp-4 using a combined qRT-PCR and proteomic approach

Author

Xiaojia Hu, Qin, Lu, Roberts, Daniel, Lakshman, Dilip, Yangmin Gong, Maul, Jude, Lihua Xie, Changbing Yu, Yinshui Li, Hu, Lei, Xiangsheng Liao, and Liao, Xing

Subjects
animal structures
Abstract

Length distribution of unigenes and transcripts, and functional classification of unigenes. A. Length distribution of unigenes and transcripts of Aspergillus aculeatus Asp-4 grown on sclerotia of Sclerotinia sclerotiorum. B. Functional classification of unigenes of Aspergillus aculeatus Asp-4 grown on sclerotia of Sclerotinia sclerotiorum for biological process, cellular component, and molecular function. (PPTX 249Â kb)

Published
2017
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47. Symptom Development in Response to Combined Infection of In Vitro-grown Lilium longiflorum with Pratylenchus penetrans and Soilborne Fungi Collected from Diseased Roots of Field-grown Lilies

Author

School of Plant and Environmental Sciences, Lakshman, Dilip, Vieira, Paulo, Pandey, Ruchi, Slovin, Janet, Kamo, Kathryn, School of Plant and Environmental Sciences, Lakshman, Dilip, Vieira, Paulo, Pandey, Ruchi, Slovin, Janet, and Kamo, Kathryn

Abstract

Eight fungal isolates (ELRF 1 to 8) were recovered from necrotic roots of Easter lilies, Lilium longiflorum cv. Nellie White, grown in a field in the U.S. Pacific Northwest. The eight fungal isolates were identified by sequencing and molecular phylogenetic analyses based on their ITS rDNA region. Five isolates were identified as Fusarium oxysporum, two as F. tricinctum, and one as Rhizoctonia sp. AG-I. This constitutes the first report of Rhizoctonia sp. AG-I infecting lilies worldwide and the first report of F. tricinctum infecting lilies in the United States. To study and validate their pathogenicity, pure cultures of each isolate were used to infect the roots of Easter lily plants growing in vitro. In addition, Easter lily plants growing in vitro were infected either with or without Pratylenchus penetrans, the root lesion nematode, prior to placing a culture plug of fungus 1 cm from a lily root. Pratylenchus penetrans is a nematode species commonly found in the sampled fields. The presence of both nematode and Rhizoctonia sp. AG-I isolate ELRF 3 in infected lilies was evaluated by molecular analyses, confirming the infection of roots 3 days after inoculation, prior to development of disease symptoms. Necrosis and root rot developed more rapidly with all eight fungal isolates when there had been prior infection with P. penetrans, the major nematode parasitizing Easter lily roots in the field in Oregon.

Published
2017

48. Identification of Rhizopus arrhizus(Fisher) causing root rot in sugar beet in North Dakota and Minnesota, USA

Author

Bhuiyan, Md Ziaur Rahman, Lakshman, Dilip K., Mosher, Presley, and Khan, Mohamed F. R.

Abstract

North Dakota (ND) and Minnesota (MN) are two leading sugar beet producing states in the US jointly contributing 57% of domestic production, which results in over $5 billion in total economic activities. Sugar beet plant samples that had typical wilting and root rot symptoms were collected from Hickson, ND and Foxhome, MN in 2020. A fungus was isolated from diseased roots in potato dextrose agar media and was identified as Rhizopus arrhizus(synonym: R. oryzae) based on morphological features, microscopic visualizations, and the ribosomal Internal Transcribed Spacer DNA sequence identity. The pathogenicity of the R. arrhizusisolates was checked by seed and root inoculation in the laboratory and greenhouse. In vitro inoculation of sugar beet seeds with mycelial agar plugs in PDA plates showed reduced seedling growth and emergence. In the greenhouse, seeds inoculated with young growing mycelial agar plugs showed seedling rot, wilting and abnormal growth of cotyledons when evaluated at 10 days post inoculation (dpi). Sugar beet plants at four weeks old were inoculated with fungal spore suspension by the dipping method. At 21-dpi, inoculated roots showed characteristics root rot and wilting symptoms. Re-isolated fungus from inoculated seedlings with root rot symptom was found to be identical to pure culture of the isolates retrieved from the field samples. These findings added a new insight on and better understanding of the fungus causing seedlings and root rot of sugar beet; the information generated will direct further plan of action for its management to prevent crop loss.

Published
2021
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49. Characterization of mechanisms underlying degradation of sclerotia of Sclerotinia sclerotiorum by Aspergillus aculeatus Asp-4 using a combined qRT-PCR and proteomic approach

Author

Hu, Xiaojia, primary, Qin, Lu, additional, Roberts, Daniel P., additional, Lakshman, Dilip K., additional, Gong, Yangmin, additional, Maul, Jude E., additional, Xie, Lihua, additional, Yu, Changbing, additional, Li, Yinshui, additional, Hu, Lei, additional, Liao, Xiangsheng, additional, and Liao, Xing, additional

Published
2017
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