Species composition of root-associated mycobiome of ruderal invasive Anthemis cotula L. varies with elevation in Kashmir Himalaya / La composición de especies del micobioma asociado a las raíces de la invasora ruderal Anthemis cotula L. varía con la elevación en Cachemira Himalaya

Investigating the microbial communities associated with invasive plant species can provide insights into how these species establish and thrive in new environments. Here, we explored the fungal species associated with the roots of the invasive species Anthemis cotula L. at 12 sites with varying elevations in the Kashmir Himalaya. Illumina MiSeq platform was used to identify the species composition, diversity, and guild structure of these root-associated fungi. The study found a total of 706 fungal operational taxonomic units (OTUs) belonging to 8 phyla, 20 classes, 53 orders, 109 families, and 160 genera associated with roots of A. cotula, with the most common genus being Funneliformis. Arbuscular mycorrhizal fungi (AMF) constituted the largest guild at higher elevations. The study also revealed that out of the 12 OTUs comprising the core mycobiome, 4 OTUs constituted the stable component while the remaining 8 OTUs comprised the dynamic component. While α-diversity did not vary across sites, significant variation was noted in β-diversity. The study confirmed the facilitative role of the microbiome through a greenhouse trial in which a significant effect of soil microbiome on height, shoot biomass, root biomass, number of flower heads, and internal CO2 concentration of the host plant was observed. The study indicates that diverse fungal mutualists get associated with this invasive alien species even in nutrient-rich ruderal habitats and may be contributing to its spread into higher elevations. This study highlights the importance of understanding the role of root-associated fungi in invasion dynamics and the potential use of mycobiome management strategies to control invasive species.(AU)

Bacterial communities associated with mushrooms in the Qinghai-Tibet Plateau are shaped by soil parameters / Las comunidades bacterianas asociadas con los hongos en la meseta de Qinghai-Tíbet están formadas por parámetros del suelo

Fungi capable of producing fruit bodies are essential food and medicine resources. Despite recent advances in the study of microbial communities in mycorrhizospheres, little is known about the bacterial communities contained in fruit bodies. Using high-throughput sequencing, we investigated the bacterial communities in four species of mushrooms located on the alpine meadow and saline-alkali soil of the Qinghai-Tibet Plateau (QTP). Proteobacteria (51.7% on average) and Actinobacteria (28.2% on average) were the dominant phyla in all of the sampled fairy ring fruit bodies, and Acidobacteria (27.5% on average) and Proteobacteria (25.7% on average) dominated their adjacent soils. For the Agria. Bitorquis, Actinobacteria was the dominant phylum in its fruit body (67.5% on average) and adjacent soils (65.9% on average). The alpha diversity (i.e., Chao1, Shannon, Richness, and Simpson indexes) of the bacterial communities in the fruit bodies were significantly lower than those in the soil samples. All of the fungi shared more than half of their bacterial phyla and 16.2% of their total operational taxonomic units (OTUs) with their adjacent soil. Moreover, NH4+ and pH were the key factors associated with bacterial communities in the fruit bodies and soils, respectively. These results indicate that the fungi tend to create a unique niche that selects for specific members of the bacterial community. Using culture-dependent methods, we also isolated 27 bacterial species belonging to three phyla and five classes from fruit bodies and soils. The strains isolated will be useful for future research on interactions between mushroom-forming fungi and their bacterial endosymbionts.(AU)

Role of acetosyringone in the accumulation of a set of RNAs in the arbuscular mycorrhiza fungus Glomus intraradices

Plant root exudates contain a range of low molecular weight metabolites that trigger many of the structural and physiological changes associated with the progression and establishment of mycorrhizal symbiosis. Here, the physiological response triggered by acetosyringone (AS) was studied in Glomus intraradices. Incubation of G. intraradices spores with AS resulted in an overall increase in hyphal respiration. A G. intraradices cDNA library was then screened with a total cDNA probe obtained from the AS-treated spores and mycelium. cDNAs from genes induced in AS-treated G. intraradices were assigned to different functional categories, such as protein synthesis, membrane transport, signal transduction, and general metabolism, but without further information regarding their function or identity. A cDNA coding a fragment of a histidine kinase was also induced by AS, suggesting a two-component mediated response to the metabolite. In addition, the differential accumulation of a cruciform DNA-binding protein mRNA, termed as GiBP1, was also observed. Time-course experiments demonstrated the rapid accumulation of GiBP1 within 2 h of AS induction. These results indicate the presence of a set of fungal genes that are induced by AS. These findings are discussed in terms of the possible molecular events that follow the exchange of signals between mycorrhizal symbionts (AU)

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Microscopic and transcriptome analyses of early colonization of tomato roots by Trichoderma harzianum

The capacity of the fungus Trichoderma harzianum CECT 2413 to colonize roots and stimulate plant growth was analyzed. Tobacco seedlings (Nicotiana benthamiana) transferred to Petri dishes inoculated with T. harzianum conidia showed increased plant fresh weight (140%) and foliar area (300%), as well as the proliferation of secondary roots (300%) and true leaves (140%). The interaction between strain CECT 2413 and the tomato-root system was also studied during the early stages of root colonization by the fungus. When T. harzianum conidia were inoculated into the liquid medium of hydroponically grown tomato plants (Lycopersicum esculentum), profuse adhesion of hyphae to the plant roots as well as colonization of the root epidermis and cortex were observed. Confocal microscopy of a T. harzianum transformant that expressed the green fluorescent protein (GFP) revealed intercellular hyphal growth and the formation of plant-induced papilla-like hyphal tips. Analysis of the T. harzianum-tomato interaction in soil indicated that the contact between T. harzianum and the roots persisted over a long period of time. This interaction was characterized by the presence of yeast-like cells, a novel and previously undescribed developmental change. To study the molecular mechanism underlying fungal ability to colonize the tomato-root system, the T. harzianum transcriptome was analyzed during the early stages of the plant-fungus interaction. The expression of fungal genes related to redox reactions, lipid metabolism, detoxification, and sugar or amino-acid transport increased when T. harzianum colonized tomato roots. These observations are similar to those regarding the interactions of mycorrhiza and pathogenic fungi with plants (AU)

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Interacciones microorganismos-suelo-planta en la preservación del medio ambiente y la salud / Plant-soil-microorganisms interactions on the protection of the environment and health

Se pone de relieve la importancia de los microorganismos del suelo, que establecen simbiosis con las plantas como biofertilizantes y su aplicación en el control biológico de patógenos. Las interacciones beneficiosas: bacteria-planta y hongo-planta tienen gran interés por su impacto en la Agricultura, Silvicultura y Medioambiente y constituyen una alternativa a la aplicación de fertilizantes químicos que actúan como contaminantes de suelos y aguas con gran perjuicio para la salud. Las bacterias fijadoras de nitrógeno y los hongos micorrizógenos se encuentran entre los simbiontes de plantas más extendidos y ecológicamente más importantes. El potencial de los microorganismos del suelo parece ilimitado. Corresponde a la ciencia realizar el estudio profundo de las interacciones de organismos autóctonos del suelo con las plantas, con el fin de que éstas puedan autoabastescerse y autodefenderse en condiciones ambientales adversas, y además se cumpla con el deber de mantener nuestro planeta en óptimas condiciones de salud ambiental para las generaciones futuras (AU)