Namgay Om

An estimated 69% of the population of Bhutan is engaged in agriculture. Farmers are exposed to a wide variety of pesticides during the preparation, transport, storage, mixing and application of pesticides posing a significant health risk. A controlled cross-sectional study of farmers in selected sites of Bhutan was conducted to characterize the level of exposure to pesticides and assess their knowledge attitude and practice on the safe handling of pesticides. A total of 399 participants were enrolled in the study comprising of 295 exposed farmers and 104 healthy and unexposed controls. A structured investigator administered questionaries was used to assess their Knowledge, Attitude and practice, and their blood samples were taken for measuring Acetyl Cholinesterase enzyme activity level. There was a significant difference between the Acetyl Cholinesterase enzyme inhibition of exposed and non-exposed control groups observed in the study (P < 0.001). Of the total of 295 farmers, 62...

Additional file 2: Figure S2. Phylogenetic analysis of 16S rRNA gene sequences of Rickettsiella-like bacteria found within two of the species of Bhutanese psyllids (emboldened). The evolutionary history was inferred using maximum likelihood based on the Kimura 2-parameter model [54]. The tree with the highest log likelihood (− 1263.03) is shown. A discrete Gamma distribution was used to model evolutionary rate differences among sites (5 categories (+G, parameter = 0.3116)). The rate variation model allowed for some sites to be evolutionarily invariable ([+I], 55.45% sites). The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. (NB OTU numbers are reference sequences in the Greengenes database; see Supplementary Table 3 and [30]).

Five separate experiments were conducted to test the susceptibility of different cut flowers and bedding plants to root-knot nematodes, Meloidogyne incognita (Kofoid & White) Chitwood race 2, M. javanica (Treub) Chitwood, and M. arenaria (Neal) Chitwood. The first set of experiments involving two separate tests was conducted in Oct. 2007. The first two tests consisted of seven cultivars of cut flowers and bedding plants grown under greenhouse conditions to test their susceptibility to root-knot nematodes, Meloidogyne incognita race 2 and M. javanica. Cultivars examined included ‘Thumbelina’ and ‘Envy’ zinnia (Zinnia elegans L.); ‘Petite’ and ‘Jaguar’ marigold (Tagetes patula L.), and ‘Snowdrift’ marigold (T. erecta L.); ‘Dwarf Jewel Blend’ nasturtium (Tropaeolum minus L.); and ‘Potomac Pink’ snapdragon (Antirrhinum majus L.). In a separate experiment, ‘Potomac Pink’ snapdragon plants were tested to determine their response to M. arenaria and varying concentrations of M. incognita ra...

Citrus in Bhutan is cultivated on steep hillsides up to ~ 1550 m above sea level (ASL). Since 2000, the Asiatic form of huanglongbing caused by ‘ Candidatus Liberibacter asiaticus’ ( C Las) has led to dramatic losses of trees below 1200 m ASL. Surveys prior to this study indicated a low incidence of the disease and the psyllid Diaphorina citri (the principal vector of the pathogen), above 1200 m ASL, the presence of Diaphorina communis below 1200 m ASL and Cacopsylla heterogena above 1200 m ASL. This study was conducted in the Tsirang Dzongkhag (a southern administrative district) to determine relationships between ambient air and leaf temperatures, relative humidity, rainfall, plant growth and altitude on the incidence of psyllids and huanglongbing. In May 2013, C Las free seedling mandarin trees were planted at eight altitudes from 783 to 1473 m ASL to determine presence of the psyllids and development of C Las. Root and trunk tissues from these seedlings and mature trees in the d...

The draft genome sequence of a novel “Candidatus Liberibacter” species detected in an unidentified species of Zanthoxylum (Rutaceae) collected in Bhutan is reported. The total length is 1,408,989 bp with 1,169 coding sequences in 96 contigs, a GC content of 37.3%, and 76 to 77% average nucleotide identity with several other “Ca. Liberibacter” species. ABSTRACT The draft genome sequence of a novel “Candidatus Liberibacter” species detected in an unidentified species of Zanthoxylum (Rutaceae) collected in Bhutan is reported. The total length is 1,408,989 bp with 1,169 coding sequences in 96 contigs, a GC content of 37.3%, and 76 to 77% average nucleotide identity with several other “Ca. Liberibacter” species.

In insects, little is known about the coevolution between their primary endosymbionts and hosts at the intraspecific level, and this study has examined codiversification between the notorious agricultural pest Diaphorina citri and its P-endosymbiont, 'Candidatus Carsonella ruddii' at the population level. Maximum likelihood, haplotype network, principal components and Bayesian clustering identified three lineages for D. citri and its P-endosymbiont: a Western clade containing individuals from Pakistan, Bhutan (Phuentsholing), Vietnam (Son La), USA, Myanmar and China (Ruili, Yunnan); a Central clade, with accessions originating from Southwest China, Bhutan (Tsirang) and Bangladesh; and an Eastern clade containing individuals from Southeast Asian countries, and East and South China. A more diverse genetic structure was apparent in the host mtDNA compared to their P-endosymbionts; however, the two sets of data were strongly congruent. This study provides evidence for the codive...

Background Several plant-pathogenic bacteria are transmitted by insect vector species that often also act as hosts. In this interface, these bacteria encounter plant endophytic, insect endosymbiotic and other microbes. Here, we used high throughput sequencing to examine the bacterial communities of five different psyllids associated with citrus and related plants of Rutaceae in Bhutan: Diaphorina citri, Diaphorina communis, Cornopsylla rotundiconis, Cacopsylla heterogena and an unidentified Cacopsylla sp. Results The microbiomes of the psyllids largely comprised their obligate P-endosymbiont ‘Candidatus Carsonella ruddii’, and one or two S-endosymbionts that are fixed and specific to each lineage. In addition, all contained Wolbachia strains; the Bhutanese accessions of D. citri were dominated by a Wolbachia strain first found in American isolates of D. citri, while D. communis accessions were dominated by the Wolbachia strain, wDi, first detected in D. citri from China. The S-endos...