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Antibiotic resistance (AR) is a global healthcare threat that requires a comprehensive assessment. Poorly regulated antibiotic stewardship in clinical and non-clinical settings has led to a horizontal dissemination of AR. A variety of often neglected elements facilitate the circulation of AR from antibiotic sinks like concentrated animal feeding operations and healthcare settings to other environments that include healthy human communities. Insects are one of those elements that have received underwhelming attention as vectors of AR, despite their well-known role in transmitting clinically relevant pathogens. We here make an exhaustive attempt to highlight the role of insects as zoonotic reservoirs of AR by discussing the available literature and deriving realistic inferences. We review the AR associated with insects housing various human-relevant environments, namely, animal farm industry, edible-insects enterprise, healthcare institutes, human settlements, agriculture settings and the wild. We also provide evidence-based accounts of the events of the transmission of AR from insects to humans. We evaluate the clinical threats associated with insect-derived AR and propose the adoption of more sophisticated strategies to understand and mitigate future AR concerns facilitated by insects. Future works include a pan-region assessment of insects for AR in the form of AR bacteria (ARB) and AR determinants (ARDs) and the introduction of modern techniques like whole-genome sequencing, metagenomics, and in-silico modelling.

The effect of Groundnut bud necrosis virus (GBNV) infection on the life history traits of its vector, Thrips palmi, and its feeding preference on GBNV-infected plants were studied. A significant difference was observed in the developmental period (first instar to adult) between the GBNV-infected and healthy thrips, wherein the developmental period of GBNV-infected thrips was decreased. However, there was no effect on the other parameters such as preadult mortality, adult longevity, and fecundity. Further investigation on a settling and feeding choice assay of T. palmi to GBNV-infected and healthy plants showed that T. palmi preferred GBNV-infected cowpea plants more than the healthy cowpea plants. This preference was also noticed for leaf disks from GBNV-infected cowpea, groundnut, and tomato plants.

Begomoviruses are the largest group of plant viruses transmitted exclusively by the whitefly

Begomoviruses are a major group of plant viruses, transmitted exclusively by Bemisia tabaci (Gennadius) in a persistent circulative non-propagative manner. The information regarding molecular and cellular basis underlying Begomovirus - whitefly interaction is very scarce. Evidences have suggested that the insect gut possesses some crucial protein receptors that allow specific entry of virus into the insect haemolymph. We have performed yeast two hybrid gut cDNA expression library screening against coat protein of Tomato leaf curl New Delhi virus (ToLCV) and Cotton leaf curl Rajasthan virus (CLCuV) as bait. Midgut protein (MGP) was the common protein found interacting with both ToLCV and CLCuV. MGP was localized in whole mount B. tabaci as well as in dissected guts through confocal microscopy. Pull down and dot blot assays confirmed in vitro interaction between ToLCV/CLCuV coat protein and MGP. Immunolocalization analysis also showed colocalization of ToLCV/CLCuV particles and MGP within insect's gut. Finally, anti-MGP antibody fed B. tabaci, exhibited 70% reduction in ToLCV transmission, suggesting a supportive role for MGP in virus transmission.

Bacterial endosymbionts are present in majority of the agricultural pests and provide various physiological and ecological traits to its host. The beneficial traits are responsible for the success of these host insects in utilization of their plant hosts, in developing resistance to insecticides and in transmitting viruses as vectors. This study reveals the identification and localization of various bacterial endosymbionts, both primary (Portiera) and secondary (Wolbachia, Rickettsia and Arsenophonus) in the life stages of Asia II genetic group of whitefly Bemisia tabaci (Gennadius) deploying diagnostic polymerase chain reaction and technique of fluorescence in situ hybridization (FISH). The observation on the localization of bacterial endosymbionts was prominent in specialized cells called bacteriocytes in all the life stages of whitefly among the nymphs and adults.

Bemisia tabaci is a polyphagous agricultural pest and it has varied genetic groups harboring different bacterial endosymbionts. Many studies had revealed the reproductive potential of B. tabaci with different endosymbionts. But a comparative study showing the effects of endosymbionts on parthenogenetically reproducing (without mating) whiteflies resulting in only male progenies have not been conducted. This study evaluates the role of a secondary endosymbionts Arsenophonus on the life parameters of parthenogenetically reproducing Asia II genetic group with and without Arsenophonus (A+ and A). The results revealed that A females had increased fecundity and nymphal developmental time and longevity. Thus, it is demonstrated that parthenogenetically reproducing A+ whiteflies have lesser fitness as compared to Awhiteflies.

Begomoviruses are a major group of plant viruses, transmitted exclusively by Bemisia tabaci (Gennadius) in a persistent circulative non-propagative manner. The information regarding molecular and cellular basis underlying Begomovirus - whitefly interaction is very scarce. Evidences have suggested that the insect gut possesses some crucial protein receptors that allow specific entry of virus into the insect haemolymph. We have performed yeast two hybrid gut cDNA expression library screening against coat protein of Tomato leaf curl New Delhi virus (ToLCV) and Cotton leaf curl Rajasthan virus (CLCuV) as bait. Midgut protein (MGP) was the common protein found interacting with both ToLCV and CLCuV. MGP was localized in whole mount B. tabaci as well as in dissected guts through confocal microscopy. Pull down and dot blot assays confirmed in vitro interaction between ToLCV/CLCuV coat protein and MGP. Immunolocalization analysis also showed colocalization of ToLCV/CLCuV particles and MGP within insect's gut. Finally, anti-MGP antibody fed B. tabaci, exhibited 70% reduction in ToLCV transmission, suggesting a supportive role for MGP in virus transmission.

Bemisia tabaci is an invasive agricultural pest with more than 24 genetic groups harboring different bacterial endosymbionts categorized into obligatory and facultative endosymbionts. Arsenophonus is one of the facultative endosymbionts prevalent in B. tabaci of Indian sub-continent. Not much is known about the functional role of this endosymbiont in its host. Some studies have revealed its involvement in virus transmission by B. tabaci, but how it effects the biology of B. tabaci is unknown. In this study, tetracycline was used to eliminate Arsenophonus from B. tabaci to study its effects with regard to development and other fitness parameters. Bacteria specific 16S Polymerase chain reaction (PCR) was used to ascertain Arsenophonus absence with differential effects on other secondary endosymbionts present in B. tabaci. Our results revealed that Arsenophonus negative (A(-)) whiteflies had more fecundity, increased juvenile developmental time, increased nymphal survival and increased adult life span as compared to control (A(+)) whiteflies. Thus, our results demonstrate that A(+) whiteflies have lesser fitness as compared to A(-) whiteflies. These observations give a new insight about the probable role of Arsenophonus in B. tabaci, that need to be explored further.

The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a phloem-feeding, economically important pest of crops worldwide. In addition to direct damage, it also vectors a number of plant viruses belonging to the family Geminiviridae. Its populations differ biologically with respect to insecticide resistance, virus transmission and host range. Therefore, understanding genetic variation among populations is important for management. We sequenced 850 bp of the mitochondrial COI (mtCOI) gene from B. tabaci populations surveyed across India. BLAST analysis of the mtCOI sequences generated in this study with sequences from the mtCOI dataset showed the presence of one invasive group, MEAM1, and eight other groups of B. tabaci in India. mtCOI sequence analyses showed the presence of Asia I, Asia I-India, Asia II-1, Asia II-5, Asia II-7, Asia II-8, and Asia II-11 genetic groups. We also found China-3 in a field in Birbhum district, West Bengal, India, suggesting a role of anthropogenic activities in the distribution of B. tabaci. Interestingly, more than one genetic group was found coexisting in the same field.

Bacterial endosymbionts have been associated with arthropods and large number of the insect species show interaction with such bacteria. Different approaches have been used to understand such symbiont- host interactions. The whitefly, Bemisia tabaci, a highly invasive agricultural pest, harbors as many as seven different bacterial endosymbionts. These bacterial endosymbionts are known to provide various nutritional, physiological, environmental and evolutionary benefits to its insect host. In this study, we have tried to compare two techniques, Polymerase chain reaction (PCR) and Flourescence in situ Hybridisation (FISH) commonly used for identification and localization of bacterial endosymbionts in B. tabaci as it harbors one of the highest numbers of endosymbionts which have helped it in becoming a successful global invasive agricultural pest. The amplified PCR products were observed as bands on agarose gel by electrophoresis while the FISH samples were mounted on slides and observed under confocal microscope. Analysis of results obtained by these two techniques revealed the advantages of FISH over PCR. On a short note, performing FISH, using LNA probes proved to be more sensitive and informative for identification as well as localization of bacterial endosymbionts in B. tabaci than relying on PCR. This study would help in designing more efficient experiments based on much reliable detection procedure and studying the role of endosymbionts in insects.