Bacterial communities of the psyllid pest Bactericera cockerelli (Hemiptera: Triozidae) Central haplotype of tomato crops cultivated at different locations of Mexico.

Background: The psyllid, Bactericera cockerelli, is an insect vector of 'Candidatus Liberibacter' causing "Zebra chip" disease that affects potato and other Solanaceae crops worldwide. In the present study, we analyzed the bacterial communities associated with the insect vector Bactericera cockerelli central haplotype of tomato crop fields in four regions from Mexico. Methods: PCR was used to amplify the mitochondrial cytochrome oxidase I gene (mtCOI) and then analyze the single nucleotide polymorphisms (SNP) and phylogenetic analysis for haplotype identification of the isolated B. cockerelli. Moreover, we carried out the microbial diversity analysis of several B. cockerelli collected from four regions of Mexico through the NGS sequencing of 16S rRNA V3 region. Finally, Wolbachia was detected by the wsp gene PCR amplification, which is the B. cockerelli facultative symbiont. Also we were able to confirm the relationship with several Wolbachia strains by phylogenetic analysis. Results: Our results pointed that B. cockerelli collected in the four locations from Mexico (Central Mexico: Queretaro, and Northern Mexico: Sinaloa, Coahuila, and Nuevo Leon) were identified, such as the central haplotype. Analyses of the parameters of the composition, relative abundance, and diversity (Shannon index: 1.328 ± 0.472; Simpson index 0.582 ± 0.167), showing a notably relatively few microbial species in B. cockerelli. Analyses identified various facultative symbionts, particularly the Wolbachia (Rickettsiales: Anaplasmataceae) with a relative abundance higher. In contrast, the genera of Sodalis and 'Candidatus Carsonella' (Gammaproteobacteria: Oceanospirillales: Halomonadaceae) were identified with a relatively low abundance. On the other hand, the relative abundance for the genus 'Candidatus Liberibacter' was higher only for some of the locations analyzed. PCR amplification of a fragment of the gene encoding a surface protein (wsp) of Wolbachia and phylogenetic analysis corroborated the presence of this bacterium in the central haplotype. Beta-diversity analysis revealed that the presence of the genus 'Candidatus Liberibacter' influences the microbiota structure of this psyllid species. Conclusions: Our data support that the members with the highest representation in microbial community of B. cockerelli central haplotype, comprise their obligate symbiont, Carsonella, and facultative symbionts. We also found evidence that among the factors analyzed, the presence of the plant pathogen affects the structure and composition of the bacterial community associated with B. cockerelli.

Characterization of microbial communities from rumen and large intestine of lactating creole goats grazing in arid plant communities.

Arid plant communities provide variable diets that can affect digestive microbial communities of free-foraging ruminants. Thus, we used next-generation sequencing of 16S and 18S rDNA to characterize microbial communities in the rumen (regurgitated digesta) and large intestine (faeces) and diet composition of lactating creole goats from five flocks grazing in native plant communities in the Sonoran Desert in the rainy season. The bacterial communities in the rumen and large intestine of the five flocks had similar alpha diversity (Chao1, Shannon, and Simpson indices). However, bacterial community compositions were different: a bacterial community dominated by Proteobacteria in the rumen transitioned to a community dominated by Firmicutes in the large intestine. Bacterial communities of rumen were similar across flocks; similarly occurred with large-intestine communities. Archaea had a minimum presence in the goat digestive tract. We detected phylum Basidiomycota, Ascomycota, and Apicomplexa as the main fungi and protozoa. Analyses suggested different diet compositions; forbs and grasses composed the bulk of plants in the rumen and forbs and shrubs in faeces. Therefore, lactating goats consuming different diets in the Sonoran Desert in the rainy season share a similar core bacterial community in the rumen and another in the large intestine and present low archaeal communities.

Milk production and quality patterns of double-purpose goats grazing in arid rangelands.

Lactation curves are a valuable tool for improving flock production efficiency, adjusting flock sizes, and improving farmers' income in grazing-based livestock production. Therefore, we used natural cubic splines to estimate (a) a general flock production pattern throughout a year, (b) an average lactation curve, and (c) patterns of milk chemical components in dual-purpose goats grazing in arid plant communities in the Sierra de San Francisco, Baja California Peninsula, during years of abundant precipitation. Also, milk chemical composition was compared between flocks. Annual flock milk production showed a wiggly pattern with two greater waves in summer and spring. The average individual lactation curve (kg/doe/day) and production curves of fat, protein, lactose, and ashes (g/doe/day) showed a decreasing and wiggly pattern across 35-week lactation; the greatest average daily production was in week 2. Milk, protein, lactose, and ash production curves had similar persistency values that were greater than those of the fat production curve. Milk production had a high-positive correlation with fat production and very high-positive correlations with protein, lactose, and ash production. Density (g/ml) and fat, protein, lactose, and ash contents (%) showed a ditch-shaped pattern across lactation, with greater values at the end. Goat flocks grazing across plant communities produced different quality milk. Thus, native plant communities are a valuable resource that favors a great fat content and moderate protein content in local goat milk. Also, breeding programs must pay attention that an increment in individual milk production could decrease fat and protein production, which are valuable for cheesemaking.