Dark septate endophytic fungi associated with sugarcane plants cultivated in São Paulo, Brazil.

Dark septate endophytes (DSEs) constitute a polyphyletic group within the Ascomycota, with global distribution and a wide range of host plant species. The present study evaluated the diversity of DSE in sugarcane roots of the varieties RB867515, RB966928, and RB92579, and four varieties of not commercialized energy cane. A total of 16 DSE strains were isolated, mostly from the varieties RB966928 and RB867515, with six and five isolates, respectively. Just one of the four energy cane varieties had fungi with DSE appearance. The analyses of the DNA sequences from the internal transcribed spacer (ITS) and the large subunit (LSU), in association with the micromorphology of the isolates, allowed the differentiation of the 16 isolates in at least five species, within the families Periconiaceae, Pleosporaceae, Lentitheciaceae, Vibrisseaceae, and Apiosporaceae and the orders Pleosporales, Helotiales, and Xylariales. The order Pleosporales represented 80% of the isolates, and the species Periconia macrospinosa, with six isolates, accounted for the highest isolation frequency. The results confirm the natural occurrence of the DSE symbiosis in sugarcane varieties and the generalist character of these fungi as some of the detected species have already been reported associated with other host plants, ecosystems, and regions of the world

Characterization of fungal soil communities by F-RISA and arbuscular mycorrhizal fungi from Araucaria angustifolia forest soils after replanting and wildfire disturbances

The Fungal Ribosomal Intergenic Spacer Analysis (F-RISA) was used to characterize soil fungal communities from three ecosystems of Araucaria angustifolia from Brazil: a native forest and two replanted forest ecosystems, one of them with a past history of wildfire. The arbuscular mycorrhizal fungi (AMF) infection was evaluated in Araucaria roots of 18-month-old axenic plants previously inoculated with soils collected from those areas in a greenhouse experiment. The principal component analysis of F-RISA profiles showed different soil fungal community between the three studied areas. Sixty three percent of F-RISA fragments amplified in the soil and the substrate samples presented lengths between 500 and 700 bp. The number of Operational Taxonomic Units (OTUs) was 34 for soil and 38 for substrate, however, more fragments were detected in soil (214) than in substrate (163). An in silico F-RISA analysis to compare our data with ITS1-5.8S-ITS2 sequences from NCBI database showed the presence of Ascomycota, Basidiomycota and Glomeromycota among the soil and substrate fungal communities. AMF infection was higher in plants inoculated with soil from the native forest and the replanted forest with wildfire, both presenting similar chemical characteristics but with different disturbance levels. These results indicate that soil chemical composition may influence the soil fungal community structures rather than the anthropogenic or fire disturbances

Contrasting coastal ecosystems in Cabo Frio, Brazil alter the correlations between plant Species and arbuscular mycorrhizal fungi community.

Contrasting coastal ecosystems, dune and restinga, in Peró Beach, Cabo Frio, State of Rio de Janeiro altered the correlations between the spatial patterns of the Arbuscular mycorrhizal fungal (AMF) and the diversity of plants. We recorded, during rainy and dry seasons in 2014, a total of 35 plant species. Ipomoea imperati, Stenotaphrum secundatum, Hydrocotyle bonariensis and Remirea maritima were the most common. Higher plant species richness was found in restinga over dune in both seasons. Considering that coastal environments occupy large areas around the world, we consider that the AMF-plant relationships evidenced here may contribute to conservation of these environments

Photosynthetic and metabolic acclimation to repeated drought events play key roles in drought tolerance in coffee

Over the last decades, most information on the mechanisms underlying tolerance to drought has been gained by considering this stress as a single event that happens just once in the life of a plant, in contrast to what occurs under natural conditions where recurrent drought episodes are the rule. Here we explored mechanisms of drought toler- ance in coffee (Coffea canephora) plants from a broader perspective, integrating key aspects of plant physiology and biochemistry. We show that plants exposed to multiple drought events displayed higher photosynthetic rates, which were largely accounted for by biochemical rather than diffusive or hydraulic factors, than those submitted to drought for the first time. Indeed, these plants displayed higher activities of RuBisCO and other enzymes associated with car- bon and antioxidant metabolism. Acclimation to multiple drought events involved the expression of trainable genes related to drought tolerance and was also associated with a deep metabolite reprogramming with concordant altera- tions in central metabolic processes such as respiration and photorespiration. Our results demonstrate that plants exposed to multiple drought cycles can develop a differential acclimation that potentiates their defence mechanisms, allowing them to be kept in an ‘alert state’ to successfully cope with further drought events

Overview of the Mycorrhizal Fungi in South America

The advances in plant cataloging and the increase of studies on mycorrhiza in South America (SA) have led to the compilation of information to better understand the native ecosystems and their constraints. Selected environments ranging from natural to anthropized ecosystems were analyzed according to their fungal-endophyte-associations and fungal-symbionts occurrence in relation to relevant physical-chemical properties of soils of the principal biomes in SA. Considering conservation units, no National Park is under continuous research in SA and few ones have been investigated for mycorrhizal symbioses. Ectomycorrhizas, with scant host-tree species in SA, are also investigated in Argentina and Chile forestry and mostly in exotic trees in Brazil. The study of the mycorrhizas and mycorrhizal fungi ecology and their response to global change, which is urgently recommended, is still incipient. Further, the publication revisions showed that Brazil, Argentina, Chile, Venezuela, and Ecuador are the countries with more published reports. Studies on mycorrhizas have developed largely; however, most of them were concerned with diversity and morphology, while the applications of mycorrhizas in environmental issues are still limited. The cooperative work between researchers from the Northern Hemisphere and SA could lead to greater advances on the quick and improved knowledge of the wonderful SA ecosystems and their mycorrhizas. This chapter revises and discusses the advances in mycorrhizal fungi understanding drawing on recent research.Fil: Lugo, Mónica Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; ArgentinaFil: Pagano, Marcela Claudia. Universidade Federal de Minas Gerais; Brasi