Symbiosis最新文献

Microbiome insect research has grown rapidly over the last years thanks to advances in next-generation sequencing. The bacterial microbiome inhabiting insects often involves mutualistic associations between the insect hosts and maternally transmitted symbiotic bacteria. Among insect groups, aphids are the most studied regarding insect symbiosis, but with a strong bias toward a few well studied species. Increased resistance to parasitic wasps, entomopathogenic fungi and tolerance to thermal stresses are the most common facultative endosymbiont-mediated effects in aphid biology. Here, we studied the microbiome of the woolly apple aphid Eriosoma lanigerum, a severe pest of apple orchards, which has been poorly studied concerning facultative symbionts. Our 16S rRNA gene Illumina sequencing-based taxonomic assignment, showed a high representation of reads assigned (99% similarity) to a recently recognized bacterial taxon, not previously described in aphids, identified as Symbiopectobacterium purcellii. This bacterial endosymbiont has been recognized as a new clade of Enterobacteriaceae, vertically transmitted and mutualistic in various invertebrate hosts, including one nematode species and four insect species from the order Hemiptera. This finding emphasizes the need to extend the study of symbionts from entire microbiomes of insect hosts, to understand the diversity of endosymbionts across host species and their role in insect ecology.

The gut microbiome of wild birds contributes to host fitness by supporting nutrient absorption, toxin processing, and immune function. It also fights bacterial pathogens through competitive exclusion and the production of antimicrobial metabolites. This study analyzed the in vitro antagonistic activity of bacteria isolated from the feces of the violet-crowned hummingbird (Ramsomyia violiceps) against strains of Bacillus spp., Escherichia coli, Salmonella enterica, and Acinetobacter baumannii. Mist nets were placed in three parks within the Guadalajara Metropolitan Area. Fecal samples were collected from captured R. violiceps and inoculated into culture media. Bacteria exhibiting antagonist activity were identified using molecular techniques that targeted the V1-V9 region of the 16S rRNA gene. The gut strains Bacillus sp. 1, Bacillus sp. 2, B. altitudinis, B. thuringiensis, and B. subtilis exhibited antagonistic activity against Bacillus cereus, B. tequilensis, and A. baumannii. Pseudomonas putida M5 antagonized Bacillus spp., E. coli, S. enterica, and A. baumannii. This result indicates that some Bacillus spp. and Pseudomonas spp. in the cultivable bacterial assembly of the gut of R. violiceps produce secondary metabolites that can inhibit the growth of both Gram-positive and Gram-negative strains. Since diet plays a determining role in the gut bacterial assemblage of birds, our results suggest that the strains that showed antagonistic activity in vitro could be related to the nectar consumed by the hummingbird. This may help promote the synthesis of antimicrobial compounds as a resistance mechanism.

Aphids (Hemiptera: Aphididae) are small, phloem-feeding insects that exhibit remarkable adaptability and resilience to various environmental conditions, including heat stress. Recent research has shed light on the role of bacterial symbionts in influencing the heat tolerance of aphids. Additionally, an intriguing avenue of investigation has explored how aphids can acquire bacterial symbionts through a unique mechanism involving soil nematodes. In this paper, we provide an in-depth overview of the interplay between heat stress, bacterial symbionts, and soil nematodes in the context of aphid biology. In reviewing the existing literature and collating available knowledge, we highlight the mechanisms by which bacterial symbionts contribute to aphid heat stress tolerance and examine the symbiont acquisition process facilitated by soil nematodes. Furthermore, we discuss the implications of these symbiotic associations in relation to the ecology, evolution, and agricultural management of a major globally expanding pest aphid, the corn leaf aphid, Rhopalosiphum maidis (Fitch). Overall, it may be concluded that both primary and secondary bacterial endosymbionts play a significant role in aphid biology with evolutionary consequences. These include adaptations through bacterial symbionts in terms of longevity and fecundity, heat shock tolerance, and resistance to fungal pathogens and primary hymenopterous wasp parasitoids.

The effect of plant growth regulators and Methylobacterium oryzae CBMB20 treatment on the growth and stress responses of red pepper was evaluated under in vitro and green house conditions. The highest increase (50%) in wet weight of 1279.2 mg explant^− 1 and dry weight of 37.9 mg explant^− 1 was observed with the combination of 6-Benzylaminopurine (BAP) and Indole-3-butyric acid (IBA) treatment. Among the different combinations tested, BAP + 2,4-Dichlorophenoxyacetic acid (2,4-D) treatment showed the highest number of shoots per explant, shoot length, and rooting response. The combination of CBMB20 (M. oryzae CBMB20) and IBA recorded the highest rooting response in red pepper plants. Colonization in xylem vessels by CBMB20 in red pepper plants can be observed based on the electron microscopic photographs. CBMB20-treated red pepper plants recorded less Malondialdehyde (MDA) content (30–43%), less proline content (52 − 43%), and less electrolyte leakage (38–72%), when compared to plants devoid of CBMB20 treatment. CBMB20 inoculated plants recorded less ethylene emission of 27–57%, 1-aminocyclopropane-1-carboxylic acid (ACC) content of 43–47%, and 1-Aminocyclopropane-1-carboxylic acid oxidase (ACO) activity of 23–25% were recorded in micropropagated plants inoculated with CBMB20 compared to the plants without inoculation. CBMB20-treated red pepper plants recorded a higher survivability of 11–18%, when compared to plants without CBMB20 inoculation. CBMB20 treated micropropagated-red-pepper plants showed a 28–30% increase in plant dry weight compared to micropropagated plants with CBMB20 inoculation.

In the era where food security is one of the challenges caused by global food demand, understanding the strategies needed is a must. Chemical fertilizers and synthetic pesticides have been used over decades to increase crop production. This practise however causes detrimental effects to human and environment in the long run. To replace the dependency on chemical fertilizer, usage of a sustainable microbe-based fertilizer has become a recent focus. Trichoderma, a plant growth-promoting fungi have been reported to promote plant growth and development in wide variety of crops. This fungus is able to enhance plant growth performance and indirectly protecting plants from phytopathogens and abiotic stresses through the induction of plant defence systems. The ability of this genus to confer beneficial effects lie in the complex fungal-plant interactions. Multi-omics, a molecular technology offers great potential to be used in providing detailed understanding on how Trichoderma interacts with the host plants vice versa. Although the knowledge of the actual mechanisms is still lacking, many studies have been conducted following the current multi-omics biotechnological advancements. This article reviews current findings on the biochemical and molecular mechanisms involved during Trichoderma and host plant interaction using multi-omics approaches. This will act as a reference for future studies that focus on the integration of different omics technologies.

Arbuscular mycorrhizal fungi (AMF) are beneficial soil organisms that can form symbiotic associations with the host plant roots. Mycorrhizal symbiosis between plant root and fungi can influence plant diversity and ecosystem productivity. However, the impacts of AMF frequently documented in the loamy to sandy soil, whereas it has no precise mechanism of influencing plant productivity, macronutrient uptake, and aggregation in a clay soil. A pot experiment was carried out to investigate the impact of AMF on plant growth, nutrient uptake and soil aggregation in a clay soil of Bangladesh. Okra (Abelmoschus esculentus L.) was cultivated over 105 days with AMF and without AMF (NAMF) with 5 replications. Plant productivity, nutrient uptake, soil organic carbon (SOC), microbial biomass carbon (MBC), aggregate stability (MWD), and glomalin-related soil protein (GRSP) were measured after 105 days. Results showed that the plant productivity and nutrient availability in soil and their subsequent uptake in AMF were significantly higher compared to the NAMF treatment (p < 0.01). We observed 17% increase in aggregate stability (measured as mean weight diameter) and 28% increase in organic carbon in AMF inoculated soil compared to NAMF. The microbial biomass carbon and GRSP were significantly higher in the AMF than NAMF treatment (p < 0.01). The findings highlight that AMF introduction can be a promising tool for improving plant production and soil condition in the clay soil instead of conventional farming system.

The hermit crab-sea anemone (HCA) partnership is a common facultative mutualism. The anemone protects its host from predators such as cephalopods and shell crushing crabs by its stinging cells. The crab provides the anemone with a hard substrate and increased access to oxygenated water and food and in some cases with protection from predators. These partnerships are extremely diverse and complex. This overview addresses issues related to formation of the associations, the early history of these partnerships, placement of anemones on the hermit crab shell, intra and interspecific competition amongst hermit crabs over sea anemones, costs and benefits for crab and anemone from being associated and the evolution of these partnerships based on molecular phylogenies using nuclear and mitochondrial markers.