Symbiosis最新文献

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.

Information regarding the relationship between fertilization, mycorrhizas, and plant growth is scattered for non-conventional productive plant species. We evaluated the effect of different substrates and fertilization treatments on growth and colonization by arbuscular mycorrhizas of young Berberis microphylla plants, a native Patagonian shrub with edible fruits. We conducted a greenhouse experiment based on two factors: substrate (conventional or native soil) and fertilization (no fertilization, organic fertilization, or inorganic fertilization). When plants were grown in conventional substrate, both fertilizers promoted growth, having the inorganic fertilizer a greater effect. The effect of both fertilizers was similar when plants were cultivated in native soil, and lesser than in conventional substrate. Plants grown in native soil were larger than those in conventional substrate when organic fertilizer or no fertilizer was applied, but this was reversed when inorganic fertilizer was applied. There was no mycorrhization on plants grown in conventional substrate. In native soil, mycorrhization was highest for non-fertilized plants (60.1%), followed by those with organic fertilization (40.4%), and lowest when inorganic fertilizer was applied (29.9%). The relative abundances of both vesicles and arbuscules showed the opposite tendency, having both their highest values in treatments with inorganic fertilizer. Mycorrhization was positively correlated with plant size, but only when fertilizers were applied. Based on our results, we hypothesized that fertilization reduce mycorrhization but select more beneficial mycorrhizal fungi. We concluded that organic fertilizers have a comparable effect to inorganic fertilizers in terms of promoting plant growth, accompanied by a lesser reduction of mycorrhization.

Acacia longifolia is an aggressive invader in Mediterranean-type ecosystems severely impacting biodiversity and ecosystem functions. The species’ invasiveness has been linked to its ability to thrive in nutrient poor soils, high seed production, and quick establishment after fire. In this study, we identify and compare the bacterial endophytes of A. longifolia seeds collected from populations in the species’ native (Australia) and invasive (Portugal) ranges. For this, we characterised the morphology (length, width, and weight) of seeds from two sites in each range and isolated and cultivated bacteria from seeds. DNA fingerprinting and cluster analyses revealed slightly higher, and distinct, bacterial diversity associated with seeds collected from native range populations in comparison to those collected from invasive populations. Sequencing of the 16S rDNA gene identified 119 bacterial isolates from 15 genera, with Curtobacterium strains being common in both ranges. Several differences in bacterial genera were found among ranges and sites: Dermacoccus, Frigoribacterium, Kocuria, Pantoea and Phyllobacterium taxa were each unique to seeds from the native populations, while Brevundimonas, Microbacterium, Rhizobium and Sphingomonas taxa were only found in the invasive seeds. The genus Paraburkholderia occurred in all invasive-range seeds but was not isolated from the native-range. Bacillus and Paenibacillus co-occurred in seeds collected from all invaded sites, but the simultaneous presence of both taxa was not found in native-range seeds. We propose that the bacterial endophytes present in invasive-range seeds may be important players for the invasiveness of A. longifolia, due to their role as plant growth promoters, providing extra capabilities helping acacia expansion.

In this work, we analyzed the effect of water stress and acid pH on the growth of the endemic fodder legume Chamaecytisus albidus, inoculated with four strains of Bradyrhizobium, from three different symbiovars previously isolated from the plant grown in different eco-geographical areas of Morocco. We also assessed the competitiveness of the three symbiovars for plant nodulation under water stress and acidity. We analyzed the strain’s nodulation ability, rates of nodules occupancy, shoot, and root dry weights of plants grown at -100, -80, and − 60 MPa water potential, and 6.0 and 7.0 pH values. The strains CM64 and CJ2 belong to the symbiovar genistearum and strains CA20 and CB10 to the symbiovars retamae and lupini, respectively. The strains CB10 and CJ2 were the most infective regardless of the pH and water potential at which the plants were grown. The strain CB10 was also the most abundant in nodules from plants grown at any conditions examined. Reductions in the water potential altered the nodulation ability, the strains CB10 and CJ2 still being the more infective. These strains were also the most infective at pH 6.0 and 7.0. The highest values of shoot and root dry weights were recorded in plants inoculated with strain CA20 under all the irrigation regimes used. The reduction from 100% to 80 and 60% field capacity decreased the shoot dry weight of the plants by 31.23 and 67.06%, respectively. Moreover, there was a 37.95 and 61.74% decrease in plant root dry weight when grown at 80 and 60% of field capacity, respectively. Despite variations in the efficiency of each strain, overall, the pH did not affect either the SDW or the RDW of the plants. The inoculation of C. albidus with a mix of the four strains did not result in further improvement of nodulation or symbiotic efficiency. These results show that water deficiency drastically affects the growth of C. albidus and that the retamae symbiovar was the most effective under the conditions examined. This is the first report on the competitiveness of symbiovars for the nodulation of a legume under stress.

Symbiosis can benefit hosts in numerous ways, but less is known about whether interactions with hosts benefit symbionts—the smaller species in the relationship. To determine the fitness impact of host association on symbionts in likely mutualisms, we conducted a meta-analysis across 91 unique host-symbiont pairings under a range of spatial and temporal contexts. Specifically, we assess the consequences to symbiont fitness when in and out of symbiosis, as well as when the symbiosis is under suboptimal or varying environments and biological conditions (e.g., host age). We find that some intracellular symbionts associated with protists tend to have greater fitness when the symbiosis is under stressful conditions. Symbionts of plants and animals did not exhibit this trend, suggesting that symbionts of multicellular hosts are more robust to perturbations. Symbiont fitness also generally increased with host age. Lastly, we show that symbionts able to proliferate in- and outside host cells exhibit greater fitness than those found exclusively inside or outside cells. The ability to grow in multiple locations may thus help symbionts thrive. We discuss these fitness patterns in light of host-driven factors, whereby hosts exert influence over symbionts to suit their own needs.