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The gut microbiome plays an important role in a host’s development and adaption to its dietary niche. In this study, a group of bamboo-feeding insects are used to explore the potential role of the gut microbiota in the convergent adaptation to extreme diet specialization. Specifically, using a 16S rRNA marker and an Illumina sequencing platform, we profiled the microbial communities of 76 gut samples collected from nine bamboo-feeding insects, including both hemimetabolous (Orthoptera and Hemiptera) and holometabolous (Coleoptera and Lepidoptera) species, which are specialized in three distinct dietary niches: bamboo leaf, shoot, and sap. The gut microbiota of these insects were dominated by Proteobacteria, Firmicutes, and Bacteroidetes and were clustered into solid (leaf and shoot) and liquid (sap) dietary niches. The gut bacterial communities of insects feeding on solid diet overlapped significantly, even though these insects belong to phylogenetically distant lineages representing different orders. In addition, the presence of cellulolytic bacterial communities within the gut microbiota allows bamboo-feeding insects to adapt to a highly specialized, fiber-rich diet. Although both phylogeny and diet can impact the structure and composition of gut microbiomes, phylogeny is the primary driving force underlying the convergent adaptation to a highly specialized diet, especially when the related insect species harbor similar gut microbiomes and share the same dietary niche over evolutionary timescales. These combined findings lay the foundation for future research on how convergent feeding strategies impact the interplays between hosts and their gut microbiomes and how the gut microbiota may facilitate convergent evolution in phylogenetically distant species in adaptation to the shared diet.

Social corbiculate bees such as honey bees and bumble bees maintain a specific beneficial core microbiome which is absent in wild bees. It has been suggested that maintaining this microbiome can prevent disease and keep bees healthy. The main aim of our study was to identify if there are any core bacterial groups in the non-corbiculate bees Ceratina and Megalopta that have been previously overlooked. We additionally test for associations between the core bee microbes and pollen provisions to look for potential transmission between the two. We identify three enterotypes in Ceratina samples, with thirteen core bacterial phylotypes in Ceratina females: Rosenbergiella, Pseudomonas, Gilliamella, Lactobacillus, Caulobacter, Snodgrassella, Acinetobacter, Corynebacterium, Sphingomonas, Commensalibacter, Methylobacterium, Massilia, and Stenotrophomonas, plus 19 in pollen (6 of which are shared by bees). Unlike Apis bees, whose gut microbial community differs compared to their pollen, Ceratina adults and pollen largely share a similar microbial composition and enterotype difference was largely explained by pollen age. Megalopta displays a highly diverse composition of microbes throughout all adults, yet Lactobacillus and Saccharibacter were prevalent in 90% of adults as core bacteria. Only Lactobacillus was both a core bee and pollen provision microbe in all three species. The consequences of such diversity in core microbiota between bee genera and their associations with pollen are discussed in relation to identifying potentially beneficial microbial taxa in wild bees to aid the conservation of wild, understudied, non-model bee species.

In this study, we show that introduction of human N-acetylglucosaminyltransferase (GnT)-III gene into tobacco plants leads to highly efficient synthesis of bisected N-glycans. Enzymatically released N-glycans from leaf glycoproteins of wild-type and transgenic GnT-III plants were profiled by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in native form. After labeling with 2-aminobenzamide, profiling was performed using normal-phase high-performance liquid chromatography with fluorescence detection, and glycans were structurally characterized by MALDI-TOF/TOF-MS and reverse-phase nano-liquid chromatography-MS/MS. These analyses revealed that most of the complex-type N-glycans in the plants expressing GnT-III were bisected and carried at least two terminal N-acetylglucosamine (GlcNAc) residues in contrast to wild-type plants, where a considerable proportion of N-glycans did not contain GlcNAc residues at the nonreducing end. Moreover, we have shown that the majority of N-glycans of an antibody produced in a plant expressing GnT-III is also bisected. This might improve the efficacy of therapeutic antibodies produced in this type of transgenic plant.

Dehydrins belong to a protein family whose expression may be induced or enhanced by developmental process and environmental stresses that lead to cell dehydration. A dehydrin gene named OesDHN was isolated and characterized from oleaster (Olea europaea L. subsp. europaea, var. sylvestris), the wild form of olive. To elucidate the contribution of OesDHN in the development of drought tolerance, its expression levels were investigated in oleaster plants during development and under drought stress condition. The involvement of OesDHN in plant stress response was also evaluated in Arabidopsis transgenic lines, engineered to overexpress this gene, and exposed to a controlled mild osmotic stress. OesDHN expression was found to be modulated during development and induced under mild drought stress in oleaster plants. In addition, the Arabidopsis transgenic plants showed a better tolerance to osmotic stress than wild-type plants. The results demonstrated that OesDHN expression is induced by drought stress and is able to confer osmotic stress tolerance. We suggest a role for OesDHN, as a putative functional marker of plant stress tolerance.

N-glycosylation of a mAb may have a major impact on its therapeutic merits. Here, we demonstrate that expression of a hybrid enzyme (called xylGalT), consisting of the N-terminal domain of Arabidopsis thaliana xylosyltransferase and the catalytic domain of human β-1,4-galactosyltransferase I (GalT), in tobacco causes a sharp reduction of N-glycans with potentially immunogenic core-bound xylose (Xyl) and fucose (Fuc) residues as shown by Western blot and MALDI-TOF MS analysis. A radioallergosorbent test inhibition assay with proteins purified from leaves of WT and these transgenic tobacco plants using sera from allergic patients suggests a significant reduction of potential immunogenicity of xylGalT proteins. A mAb purified from leaves of plants expressing xylGalT displayed an N-glycan profile that featured high levels of galactose, undetectable xylose, and a trace of fucose. Hence, a transgenic plant expressing the hybrid GalT might yield more effective and safer monoclonals for therapeutic purposes than WT plants and even transgenic plants expressing the unchanged GalT.