Symbiosis最新文献

Known as the Roscoff worm or mint-sauce worm, Symsagittifera roscoffensis is an Acoel distinguishable due to the presence of symbiotic alga Tetraselmis convolutae, held beneath the epidermis. Isolated populations of S. roscoffensis span a broad geographical range along the north-eastern Atlantic coast, from Wales to Portugal. The only known population of the worm in the United Kingdom was discovered in Wales decades ago, but very little research has been conducted since. For 13 months, we measured how environmental conditions such as temperature, salinity and light intensity coincided with population size at the Welsh field site. To establish phylogenetic relationships among the different populations and their algal symbionts, we designed new polymerase chain reaction (PCR) oligonucleotides to assess the nucleotide diversity of the mitochondrial cytochrome c oxidase I subunit (COI) gene in gDNA extracted from representative worms across their known range (Wales, France, Portugal, Spain, and Guernsey). We also targeted the 18S rRNA gene of their algal symbiont, Tetraselmis convolutae. We observed temporal shifts in environmental factors coinciding with fluctuating worm colony size, notably temperature. Based on the molecular data, the worm exhibited different ecotypes across locations, while the algal symbiont showed little genetic variation.

The rhizobial and the arbuscular mycorrhizal symbioses are present on legume roots and lead to local and systemic transcriptional changes of common and specific plant genes. Among them, some small GTPase proteins called ROPs (Rho of plants) have been shown to be involved in the establishment of the legume-rhizobia interaction. In this study, we aimed to characterise the effects of LjROP3 knockdown in Lotus japonicus on plant physiology and expression of symbiosis-related genes after single and dual inoculation with rhizobia and arbuscular mycorrhizal fungus. In wild-type (Gifu) plants, the dual inoculation increased the shoot and root dry weight, nitrogen (derived from symbiosis) and phosphate content, and the number of arbuscules or nodules compared with single inoculation treatments. In addition, we observed a decrease in the expression of genes encoding the mycorrhizal transcription factors LjRAM1 and LjRAM2, and the downstream genes involved in ammonium (LjAMT2.2) and phosphate (LjPT4 and LjPT8) uptake by the plant at the arbuscule level when the dual inoculation was compared with fungal inoculation. An alteration in the expression of the Nod factor receptor LjNFR1, but not of LjNFR5, was measured in wild-type (Gifu) L. japonicus plants compared to rop3 plants under dual inoculation. We have also measured a reduction in the expression of genes encoding rhizobial and mycorrhizal transcription factors (LjNIN and LjRAM1), and of the downstream mycorrhizal genes involved in ammonium (LjAMT2.2) and phosphate (LjPT4 and LjPT8) uptake by the plant at the arbuscule level. In addition, the expression of AM fungal genes encoding nutrient transporters (known to be expressed at the arbuscule level) was also altered. In conclusion, despite altered expression of plant genes involved in the functioning of the symbioses, and associated with a reduction in the number of nodules and arbuscules, knockdown of LjROP3 did not alter plant growth and nutrition under dual inoculation, suggesting that the beneficial effects of the dual symbiosis were maintained.

The use of biological inoculants in replacement of the application of chemical fertilizers is a desirable strategy taking into account it is more sustainable and economically less costly. Considering that agricultural practices can produce effects on soil microbial communities associated to the plant crops, the objective of this study was to analyze and compare the effect of these two practices on the structure of the rhizobacterial community of peanut and maize plants. For this purpose, microcosm assays were performed in which peanut and maize plants were inoculated individually with native peanut phosphate solubilizing strains or chemical fertilized with phosphorus, nitrogen, zinc and sulphur. At the beginning and at the end of the assays, samples of rhizospheric soil DNA were obtained and the structure of the rhizospheric bacterial community was analyzed by high-throughput sequencing of the 16S rRNA gene by using Illumina MiSeq platform. The results obtained indicated that the structures of the rhizospheric bacterial communities were different depending on plant type. It was possible to observe changes with respect to the initial bacterial structure in all taxonomic levels analyzed of all treatments. The more notorious structural changes of bacterial community were observed in those rhizospheres exposed to chemical fertilizers, mainly in soil samples associated to maize plants. The rhizospheric bacterial community of peanut showed to change mainly with plant growth. In conclusion, the rhizobacterial community structure is highly dynamic and influenced by different factors such as type of plant, the fertilizer input and bio-inoculant applied.

Plants are exposed to various abiotic stresses, which lead to crop losses and become a significant threat to agriculture worldwide. To survive, they have developed a range of mechanisms throughout their life cycle. While they develop immunity against stressors through their metabolic and hormonal pathways, as another strategy, they can also modify their environment by interacting with symbiotic microorganisms involved in the critical pathways for plant health. Several beneficial microorganisms can be used as plant stimulants to augment plant health and growth. Therefore, elucidating the cause-effect relationship and possible roles of critical players during plant–microbe interaction may help us better understand the usage of microorganisms for plant benefits. The presented review discusses the molecular mechanisms regulating the responses of plants and their environment during plant–microbe interactions. We focus on the potential roles of plant heterotrimeric G-proteins and small RNAs as inside players and the possible roles, connections, and effects of microalgae and pollinators as outside players/elements during plant–microbe interactions under abiotic stress. Utilizing microbial inoculants with a better combination of endophytes based on various plant species/populations under different environmental conditions is critical for successful field applications. The current knowledge in this review may provide a detailed assessment to gain insight into unraveling different parameters for efficient use of the endophytes on plants/crops to address food security challenges and mitigate the impact of climate change on agriculture.

The knowledge of the interactions between endophytic entomopathogenic fungi and forage plants and their influence on Spodoptera frugiperda, an emerging pest of pastoral systems, is important to elucidate the multifunctionality of these microorganisms and their benefits to agroecosystems. This study investigated the influence of endophytic colonization with different isolates of Metarhizium anisopliae on Cynodon dactylon (L.) Pers (Poaceae) cv. Tifton 85 on biological and behavioral aspects of S. frugiperda. The application of a suspension of isolates (1 × 10⁸ conidia ml⁻¹) to the base (soil drench) of C. dactylon seedlings was effective to promote endophytic colonization. Spodoptera frugiperda caterpillars fed throughout their larval stage with leaves of plants colonized endophytically by the three isolates studied (CEPAF_ENT 25, CEPAF_ENT 27, and IBCB 425) of M. anisopliae showed considerable reduction in their biological performance, especially in parameters of their fertility life table. However, the tested isolates did not show pronounced effects on feeding and oviposition preference, although there was a trend of preference of caterpillars and moths for colonized plants, especially in no-choice tests. Thus, applications of mycoinsecticides based on M. anisopliae for the management of the spittlebug complex (its main use currently) may lead to the endophytic colonization of C. dactylon cv. Tifton 85 and influence S. frugiperda population density as well as the impact this pest causes to pastures. The isolates used in this study exhibit multiple spectrums of action and potential to produce new biological products for the market.

Bioinoculants are beneficial microorganisms that are used in agriculture to enhance plant growth and productivity, improve soil health, and reduce the use of chemical fertilizers and pesticides. They include bacteria, fungi, protozoa, and endophytes that interact with plants in various ways to promote growth, nutrient uptake, and stress tolerance. The interactions between bioinoculants and their host plants are complex, and different strains of bacteria, fungi, and protozoa have specific interactions with different plants. Understanding these interactions is critical in selecting the appropriate bioinoculant for a particular crop and soil type. This paper reviews the interaction of different types of bioinoculants with plants, and their potential to improve the sustainability of agriculture and their applications. Techniques for applying bioinoculants include seed treatment, soil application, and foliar application. Bioinoculant application has been shown to improve crop yield, quality, and nutrient content. In addition, they help to reduce environmental pollution and protect soil biodiversity. Some of the challenges associated with the application of bioinoculants include the need for optimized formulations, storage, and transportation. To maximize the potential of bioinoculants in sustainable agriculture, it is necessary to continue research into their interactions and develop effective application techniques that can be used on a large scale.

Actinorhizal symbiosis naturally harbours beneficial categories of diverse plant growth promoting microorganisms (PGPMs), including the Frankia species. The beneficial microorganisms can be used as efficient, non-chemical and sustainable alternatives for adopting effective soil restoration programmes and revegetation schedules in chemical and industrial-contaminated sites, including treating degraded lands contaminated with toxic chemicals and pesticides. It has been proposed that the interactions between the microbial gene pool are of immense agricultural significance that would facilitate an improvement in the health, hygiene and nutrient acquisition pathway of native soil. The present review is focused on exploiting the hitherto-unexplored Frankia-actinorhizal symbiosis with due interest for their application in soil restoration programmes, including the reclamation of degraded lands. This opens up new insights for the development of sustainability in forestry and plantation research. Additionally, it would promise an improvement in plant growth and vigour, hygiene, and other parameters related to crop yield, such as plant biomass, root/shoot ratio, crop yield, and so on. Novel and putative microorganisms isolated from the actinorhizal may be used for bio-transformation of allelochemicals and toxic heavy metals into compounds with modified biological properties, opening up novel avenues for mediating microbial degradation of putative allelochemicals that would otherwise accumulate at phytotoxic levels in soil. Endophyte-host specificities, the phylogeny of Frankia, and the conservation of unique endemic plant genetic resources like actinorhizal plants, are of paramount significance in the advancement of genomics, metabolomics and phenomics.