Most of the world's poorest smallholders depend on tropical roots and tuber crops as their princi... more Most of the world's poorest smallholders depend on tropical roots and tuber crops as their principal source of food and nutrition. Sucking pests like whiteflies are major limiting factors in their production. Although whiteflies are important pests of tuber crops, their taxonomic diversity is poorly understood in these crops. As DNA barcoding is an effective tool for resolving species complexes and analyzing species distributions, the approach was used to analyze genetic diversity in the whitefly species infesting tuber crops such as cassava (Manihot esculenta), sweetpotato (Ipomoea batatas) and arrowroot (Maranta arundinacea). Among the whiteflies characterized, a 'distinct' genetic variant/ biotype was identified as a pest in sweetpotato and is found to be quite different when compared with all available 44 whitefly genetic variants of Bayesian phylogenetic tree inferred from mtCOI data using the GTR+G model.
Silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most noto... more Silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most notorious invasive insect pests, infesting more than 900 species of plants and spreading more than 200 viral diseases. This polyphagous agricultural pest harbours diverse bacterial communities in its gut, which perform multiple functions in whiteflies, including nutrient provisioning, amino acid biosynthesis, and virus transmission. The present exploratory study compares the bacterial communities associated with silverleaf whitefly infesting cassava, also known as cassava whitefly, collected from two different zones (zone P: plains; zone H: high ranges), from Kerala, India, using next-generation sequencing of 16S rDNA. The data sets for these two regions consisted of 1 321 906 and 690 661 high-quality paired-end sequences with mean length of 150 bp. Highly diverse bacterial communities were present in the sample, containing approximately 3513 operational taxonomic units (OTUs). Sequence anal...
Detection of specific endosymbionts of mealybugs infesting cassava (Manihot esculenta Crantz) using diagnostic PCR and Sanger sequencing, 2022
Cassava is one of the most produced food materials and constitutes the major energy source for ab... more Cassava is one of the most produced food materials and constitutes the major energy source for about 800 million people worldwide. Mealybugs have been reported to be the main concern in cassava production for the past few years in all the major tuber cultivated ecosystems of India. Endosymbiotic bacteria found in mealybugs have been observed to interact and provide specific advantages to the host and they can be one of the reasons for the pests' insecticidal resistance. In the present study, endosymbiotic bacteria were isolated from cassava mealybugs, allowed to grow in media after insecticidal treatments, and after observing colony morphology, distinct bacterial colonies were sub-cultured and selected for further molecular identification procedures. PCR analysis was carried out for bacteria using 16S rRNA primer, with an annealing temperature of 49 o C, and yielded fragments at 1500 bp. Based on the sequencing report, the observations were that the culturable endosymbionts Pseudomonas oryzihabitans, Staphylococcus sp. which are resistant to the insecticide thiamethoxam are present in Paracoccus marginatus, and malathion resistant Paenibacillus alvei, Ralstonia sp., and thiamethoxam resistant Clostridium lundense are present in Ferrisia virgata. The sequences were submitted to NCBI, and the accession numbers obtained were OP572218, OP572193, OP572215, OP572194, and OP572097, respectively. Also, through diagnostic PCR using specific bacterial primers, the presence of Wolbachia is confirmed in mealybug F. virgata at a fragment length of 650 bp.
Cassava (Manihot esculenta Crantz), the perennial crop belonging to the family Euphorbiaceae, tog... more Cassava (Manihot esculenta Crantz), the perennial crop belonging to the family Euphorbiaceae, together with maize and rice constitutes the major source of energy and carbohydrates for the people in tropics and subtropics (Ceballos et al., 2012). In Africa, the Indian sub-continent, Latin America, and several Southeast Asian countries, cassava is one of the major root crops and acts as a tropical food crop (Karthikeyan et al., 2016). Various biotic factors (Abaca et al., 2014) considerably reduce the crops yield potential; among them, mealybugs are
Genetic and multivariate analysis of processing and yield traits in sweet potato for varied end-uses, 2023
The present study aims to assess the genetic and multivariate component analysis of processing tr... more The present study aims to assess the genetic and multivariate component analysis of processing traits, yield traits, weevil resistance and other tuber traits in sweet potatoes based on the evaluation of 12 genotypes, including checks for yield and processing. Significant variability for tuber physical, processing and vine traits was observed. Nearly 75% of the genotypes had dry matter content (>30%), 50% had starch content (>20%), and none was resistant to sweet potato weevils. High genotypic and phenotypic variation, heritability and genetic advance were observed for tuber yield, tuber girth, total sugar and weight. Among the 13 phenotypic traits used in the present study, multivariate analysis identified only eight, contributing to 83.67% of the variation. UPGMA clustering yielded two major clusters and five sub-clusters. S27,
Bacterial communities associated with the gut of tomato fruit borer, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) based on Illumina Next-Generation Sequencing, 2016
Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), a polyphagous agricultural pest of global... more Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), a polyphagous agricultural pest of global importance, harbour diverse bacterial communities in its gut. We analysed the composition and diversity of gut bacteria using Illumina Next-Generation Sequencing of 16S ribosomal RNA amplicons. The data set consisted of 864,813 high-quality paired end sequences with mean length of 150 base pairs. Highly diverse bacterial communities were present in the sample containing approximately 2303 operational taxonomic units (OTUs). A total of 17 bacterial phyla, 34 classes, 84 orders, 173 families, 334 genera, and 707 species were identified from the sequence analysis. Actinobacteria was the most dominant groups, followed by Proteobacteria and Firmicutes. The search on function of different gut inhabiting bacteria of H. armigera revealed their role in nutrition, detoxification of lethal insecticide molecules, and defensive action against pathogens. Insecticidal toxin producing bacterial species were also found associated with the H. armigera gut.
International Journal of Bio-resource and Stress Management
The study was conducted during March–December 2021 in Thiruvananthapuram, Kerala for the identif... more The study was conducted during March–December 2021 in Thiruvananthapuram, Kerala for the identification of distinct endosymbionts of cassava whiteflies (Bemisia tabaci (Gennadius) and Aleurodicus dispersus (Russell). Endosymbiotic bacteria found in whiteflies have been reported to interact and provide specific advantages to the hosts and they can be one of the reasons for whiteflies’ insecticidal resistance. In the present study, endosymbiotic bacteria were isolated from the insects, allowed to grow in media after insecticidal treatments and after observing colony morphology, distinct bacterial colonies were sub-cultured and selected for further molecular identification procedures. PCR analysis was carried out for bacteria using 16S rRNA primer, with an annealing temperature of 49°C and yielded fragments at 1500 bp. Based on the sequencing report the observations were that the culturable endosymbionts Providencia present in B. tabaci is resistant to chlorpyrifos and Paenibacillus a...
Aphids are one of the important sucking pests of many agriculturally important crops, associated ... more Aphids are one of the important sucking pests of many agriculturally important crops, associated with a wide variety of bacterial endosymbionts that confer many ecologically relevant traits to the host insect. Endosymbiotic bacteria (ESB) play a vital role even in the physiology of the host, hence identification of ESB associated with the aphids will help to develop important strategies for the management of this noxious pest. In the present study molecular characterization of ESB associated with the aphid, Aphis gossypii infesting taro was done. Morphological characters of the four strains revealed that each isolate has different colony characters. Further, the genomic DNA was isolated from each of the EPB isolates and PCR amplification of 16S rRNA gene was carried out using universal primers. The 16S rDNA gene sequences of endosymbiotic bacterial isolates were generated by sequencing the PCR product and were aligned with each other by using BioEDIT software. The nucleotide sequenc...
A field experiment was conducted at Sunhemp Research Station, Pratapgarh, Uttar Pradesh, India lo... more A field experiment was conducted at Sunhemp Research Station, Pratapgarh, Uttar Pradesh, India lo find out the effect of varieties, irrigation and nitrogen management on the fibre yield of sunhemp. T11e results showed no significant varietal difference on fibre y ield but irrigation at 18 days interval and nitrogen @ 20 kg ha·1 was found lo increase the fibre yield significantly.
The silverleaf whitefly, Bemisia tabaci, is the main limiting factor in the production of one of ... more The silverleaf whitefly, Bemisia tabaci, is the main limiting factor in the production of one of the most important tuber crops in the world, cassava. The cassava mosaic virus transmitted by the insect causes cassava mosaic disease and it accounts for about 40% reduction in the tuber yield. The present study evaluates the presence of different genetic groups, using morphometric variations among whitefly populations collected from all agro-ecological zones of Kerala, India. Studying fourteen different pupal characters and nine different adult characters could not establish significant variations in most of the characters studied, between these agro-ecological zones. But, the principal component analysis revealed the presence of more variations in populations collected from Sulthan Bathery compared to others. Further molecular studies using the populations could provide a clear cut idea about the presence of different genetic groups/ biotypes in these regions.
The study was conducted to isolate potential bacteria and fungi from soil, cow dung and to study ... more The study was conducted to isolate potential bacteria and fungi from soil, cow dung and to study their pathogenicity on the most important pest of cassava, cassava whitefly (Bemisia tabaci). Entomopathogenic microbes were isolated from rhizosphere soil and cowdung, and their pathogenicity was tested against Bemisia tabaci. Microbes showing promising results were subjected to DNA extraction and PCR study; subsequently sequenced for isolate identification. The Basic Local Alignment Search Tool (BLAST) analysis of sequences identified the bacterial isolates as Bacillus cereus and B. pumilus, and fungus as Beauveria bassiana, Metarhizium anisopliae and Penicillium citrinum.
Abstract Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), a polyphagous agricultural pest ... more Abstract Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), a polyphagous agricultural pest of global importance, harbour diverse bacterial communities in its gut. We analysed the composition and diversity of gut bacteria using Illumina Next-Generation Sequencing of 16S ribosomal RNA amplicons. The data set consisted of 864,813 high-quality paired end sequences with mean length of 150 base pairs. Highly diverse bacterial communities were present in the sample containing approximately 2303 operational taxonomic units (OTUs). A total of 17 bacterial phyla, 34 classes, 84 orders, 173 families, 334 genera, and 707 species were identified from the sequence analysis. Actinobacteria was the most dominant groups, followed by Proteobacteria and Firmicutes . The search on function of different gut inhabiting bacteria of H. armigera revealed their role in nutrition, detoxification of lethal insecticide molecules, and defensive action against pathogens. Insecticidal toxin producing bacterial species were also found associated with the H. armigera gut .
Identification of Distinct Endosymbionts of Whiteflies-infesting Cassava (Manihot esculenta Crantz), using Diagnostic PCR and Sanger Sequencing, 2022
Legal restrictions are imposed on the public sharing of raw data. However, authors have full righ... more Legal restrictions are imposed on the public sharing of raw data. However, authors have full right to transfer or share the data in raw form upon request subject to either meeting the conditions of the original consents and the original research study. Further, access of data needs to meet whether the user complies with the ethical and legal obligations as data controllers to allow for secondary use of the data outside of the original study.
Most of the world's poorest smallholders depend on tropical roots and tuber crops as their princi... more Most of the world's poorest smallholders depend on tropical roots and tuber crops as their principal source of food and nutrition. Sucking pests like whiteflies are major limiting factors in their production. Although whiteflies are important pests of tuber crops, their taxonomic diversity is poorly understood in these crops. As DNA barcoding is an effective tool for resolving species complexes and analyzing species distributions, the approach was used to analyze genetic diversity in the whitefly species infesting tuber crops such as cassava (Manihot esculenta), sweetpotato (Ipomoea batatas) and arrowroot (Maranta arundinacea). Among the whiteflies characterized, a 'distinct' genetic variant/ biotype was identified as a pest in sweetpotato and is found to be quite different when compared with all available 44 whitefly genetic variants of Bayesian phylogenetic tree inferred from mtCOI data using the GTR+G model.
Silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most noto... more Silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most notorious invasive insect pests, infesting more than 900 species of plants and spreading more than 200 viral diseases. This polyphagous agricultural pest harbours diverse bacterial communities in its gut, which perform multiple functions in whiteflies, including nutrient provisioning, amino acid biosynthesis, and virus transmission. The present exploratory study compares the bacterial communities associated with silverleaf whitefly infesting cassava, also known as cassava whitefly, collected from two different zones (zone P: plains; zone H: high ranges), from Kerala, India, using next-generation sequencing of 16S rDNA. The data sets for these two regions consisted of 1 321 906 and 690 661 high-quality paired-end sequences with mean length of 150 bp. Highly diverse bacterial communities were present in the sample, containing approximately 3513 operational taxonomic units (OTUs). Sequence anal...
Detection of specific endosymbionts of mealybugs infesting cassava (Manihot esculenta Crantz) using diagnostic PCR and Sanger sequencing, 2022
Cassava is one of the most produced food materials and constitutes the major energy source for ab... more Cassava is one of the most produced food materials and constitutes the major energy source for about 800 million people worldwide. Mealybugs have been reported to be the main concern in cassava production for the past few years in all the major tuber cultivated ecosystems of India. Endosymbiotic bacteria found in mealybugs have been observed to interact and provide specific advantages to the host and they can be one of the reasons for the pests' insecticidal resistance. In the present study, endosymbiotic bacteria were isolated from cassava mealybugs, allowed to grow in media after insecticidal treatments, and after observing colony morphology, distinct bacterial colonies were sub-cultured and selected for further molecular identification procedures. PCR analysis was carried out for bacteria using 16S rRNA primer, with an annealing temperature of 49 o C, and yielded fragments at 1500 bp. Based on the sequencing report, the observations were that the culturable endosymbionts Pseudomonas oryzihabitans, Staphylococcus sp. which are resistant to the insecticide thiamethoxam are present in Paracoccus marginatus, and malathion resistant Paenibacillus alvei, Ralstonia sp., and thiamethoxam resistant Clostridium lundense are present in Ferrisia virgata. The sequences were submitted to NCBI, and the accession numbers obtained were OP572218, OP572193, OP572215, OP572194, and OP572097, respectively. Also, through diagnostic PCR using specific bacterial primers, the presence of Wolbachia is confirmed in mealybug F. virgata at a fragment length of 650 bp.
Cassava (Manihot esculenta Crantz), the perennial crop belonging to the family Euphorbiaceae, tog... more Cassava (Manihot esculenta Crantz), the perennial crop belonging to the family Euphorbiaceae, together with maize and rice constitutes the major source of energy and carbohydrates for the people in tropics and subtropics (Ceballos et al., 2012). In Africa, the Indian sub-continent, Latin America, and several Southeast Asian countries, cassava is one of the major root crops and acts as a tropical food crop (Karthikeyan et al., 2016). Various biotic factors (Abaca et al., 2014) considerably reduce the crops yield potential; among them, mealybugs are
Genetic and multivariate analysis of processing and yield traits in sweet potato for varied end-uses, 2023
The present study aims to assess the genetic and multivariate component analysis of processing tr... more The present study aims to assess the genetic and multivariate component analysis of processing traits, yield traits, weevil resistance and other tuber traits in sweet potatoes based on the evaluation of 12 genotypes, including checks for yield and processing. Significant variability for tuber physical, processing and vine traits was observed. Nearly 75% of the genotypes had dry matter content (>30%), 50% had starch content (>20%), and none was resistant to sweet potato weevils. High genotypic and phenotypic variation, heritability and genetic advance were observed for tuber yield, tuber girth, total sugar and weight. Among the 13 phenotypic traits used in the present study, multivariate analysis identified only eight, contributing to 83.67% of the variation. UPGMA clustering yielded two major clusters and five sub-clusters. S27,
Bacterial communities associated with the gut of tomato fruit borer, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) based on Illumina Next-Generation Sequencing, 2016
Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), a polyphagous agricultural pest of global... more Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), a polyphagous agricultural pest of global importance, harbour diverse bacterial communities in its gut. We analysed the composition and diversity of gut bacteria using Illumina Next-Generation Sequencing of 16S ribosomal RNA amplicons. The data set consisted of 864,813 high-quality paired end sequences with mean length of 150 base pairs. Highly diverse bacterial communities were present in the sample containing approximately 2303 operational taxonomic units (OTUs). A total of 17 bacterial phyla, 34 classes, 84 orders, 173 families, 334 genera, and 707 species were identified from the sequence analysis. Actinobacteria was the most dominant groups, followed by Proteobacteria and Firmicutes. The search on function of different gut inhabiting bacteria of H. armigera revealed their role in nutrition, detoxification of lethal insecticide molecules, and defensive action against pathogens. Insecticidal toxin producing bacterial species were also found associated with the H. armigera gut.
International Journal of Bio-resource and Stress Management
The study was conducted during March–December 2021 in Thiruvananthapuram, Kerala for the identif... more The study was conducted during March–December 2021 in Thiruvananthapuram, Kerala for the identification of distinct endosymbionts of cassava whiteflies (Bemisia tabaci (Gennadius) and Aleurodicus dispersus (Russell). Endosymbiotic bacteria found in whiteflies have been reported to interact and provide specific advantages to the hosts and they can be one of the reasons for whiteflies’ insecticidal resistance. In the present study, endosymbiotic bacteria were isolated from the insects, allowed to grow in media after insecticidal treatments and after observing colony morphology, distinct bacterial colonies were sub-cultured and selected for further molecular identification procedures. PCR analysis was carried out for bacteria using 16S rRNA primer, with an annealing temperature of 49°C and yielded fragments at 1500 bp. Based on the sequencing report the observations were that the culturable endosymbionts Providencia present in B. tabaci is resistant to chlorpyrifos and Paenibacillus a...
Aphids are one of the important sucking pests of many agriculturally important crops, associated ... more Aphids are one of the important sucking pests of many agriculturally important crops, associated with a wide variety of bacterial endosymbionts that confer many ecologically relevant traits to the host insect. Endosymbiotic bacteria (ESB) play a vital role even in the physiology of the host, hence identification of ESB associated with the aphids will help to develop important strategies for the management of this noxious pest. In the present study molecular characterization of ESB associated with the aphid, Aphis gossypii infesting taro was done. Morphological characters of the four strains revealed that each isolate has different colony characters. Further, the genomic DNA was isolated from each of the EPB isolates and PCR amplification of 16S rRNA gene was carried out using universal primers. The 16S rDNA gene sequences of endosymbiotic bacterial isolates were generated by sequencing the PCR product and were aligned with each other by using BioEDIT software. The nucleotide sequenc...
A field experiment was conducted at Sunhemp Research Station, Pratapgarh, Uttar Pradesh, India lo... more A field experiment was conducted at Sunhemp Research Station, Pratapgarh, Uttar Pradesh, India lo find out the effect of varieties, irrigation and nitrogen management on the fibre yield of sunhemp. T11e results showed no significant varietal difference on fibre y ield but irrigation at 18 days interval and nitrogen @ 20 kg ha·1 was found lo increase the fibre yield significantly.
The silverleaf whitefly, Bemisia tabaci, is the main limiting factor in the production of one of ... more The silverleaf whitefly, Bemisia tabaci, is the main limiting factor in the production of one of the most important tuber crops in the world, cassava. The cassava mosaic virus transmitted by the insect causes cassava mosaic disease and it accounts for about 40% reduction in the tuber yield. The present study evaluates the presence of different genetic groups, using morphometric variations among whitefly populations collected from all agro-ecological zones of Kerala, India. Studying fourteen different pupal characters and nine different adult characters could not establish significant variations in most of the characters studied, between these agro-ecological zones. But, the principal component analysis revealed the presence of more variations in populations collected from Sulthan Bathery compared to others. Further molecular studies using the populations could provide a clear cut idea about the presence of different genetic groups/ biotypes in these regions.
The study was conducted to isolate potential bacteria and fungi from soil, cow dung and to study ... more The study was conducted to isolate potential bacteria and fungi from soil, cow dung and to study their pathogenicity on the most important pest of cassava, cassava whitefly (Bemisia tabaci). Entomopathogenic microbes were isolated from rhizosphere soil and cowdung, and their pathogenicity was tested against Bemisia tabaci. Microbes showing promising results were subjected to DNA extraction and PCR study; subsequently sequenced for isolate identification. The Basic Local Alignment Search Tool (BLAST) analysis of sequences identified the bacterial isolates as Bacillus cereus and B. pumilus, and fungus as Beauveria bassiana, Metarhizium anisopliae and Penicillium citrinum.
Abstract Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), a polyphagous agricultural pest ... more Abstract Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), a polyphagous agricultural pest of global importance, harbour diverse bacterial communities in its gut. We analysed the composition and diversity of gut bacteria using Illumina Next-Generation Sequencing of 16S ribosomal RNA amplicons. The data set consisted of 864,813 high-quality paired end sequences with mean length of 150 base pairs. Highly diverse bacterial communities were present in the sample containing approximately 2303 operational taxonomic units (OTUs). A total of 17 bacterial phyla, 34 classes, 84 orders, 173 families, 334 genera, and 707 species were identified from the sequence analysis. Actinobacteria was the most dominant groups, followed by Proteobacteria and Firmicutes . The search on function of different gut inhabiting bacteria of H. armigera revealed their role in nutrition, detoxification of lethal insecticide molecules, and defensive action against pathogens. Insecticidal toxin producing bacterial species were also found associated with the H. armigera gut .
Identification of Distinct Endosymbionts of Whiteflies-infesting Cassava (Manihot esculenta Crantz), using Diagnostic PCR and Sanger Sequencing, 2022
Legal restrictions are imposed on the public sharing of raw data. However, authors have full righ... more Legal restrictions are imposed on the public sharing of raw data. However, authors have full right to transfer or share the data in raw form upon request subject to either meeting the conditions of the original consents and the original research study. Further, access of data needs to meet whether the user complies with the ethical and legal obligations as data controllers to allow for secondary use of the data outside of the original study.
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