Clinical and Anatomopathological Evaluation of BALB/c Murine Models Infected with Isolates of Seven Pathogenic Sporothrix Species

Background: Sporotrichosis is a subcutaneous mycosis with worldwide distribution and caused by seven pathogenic species of Sporothrix genus: S. schenckii sensu stricto, S. brasiliensis, S. globosa and S. luriei (clinical clade), and the species S. mexicana, S. pallida and S. chilensis (environmental clade). Isolates of the same species of Sporothrix may have different pathogenicities; however, few isolates of this fungus have been studied. Thus, the aim of this work was to analyze the clinical and anatomopathological changes in immunocompetent and immunosuppressed BALB/c mice infected with clinical and environmental isolates of seven different species of Sporothrix, from both clades. One human clinical isolate of S. schenckii sensu stricto, S. brasiliensis, S. globosa, S. luriei, S. mexicana and S. chilensis species and one environmental isolate of S. pallida were inoculated subcutaneously in immunocompetent mice and the same isolates of S. brasiliensis and S.schenckii sensu stricto were inoculated in immunossupressed mice. Clinical manifestations as external lesions, apathy, and alopecia were observed. At 21, 35, and 49 days after fungal inoculation, four mice from each group were weighed, euthanized and necropsied for evaluation of splenic index, recovery of fungal cells, macroscopic and histopathological analysis of livers, lungs, kidneys, and hearts. The survival assessment was observed for 50 days following inoculation. Our results demonstrated that, clinical S. schenckii isolate, followed by clinical S. mexicana, and environmental S. pallida isolates, the last two, species grouped in the environmental clade, were capable of inducing greater anatomopathological changes in mice, which was reflected in the severity of the clinical signs of these animals. Thus, we reinforce the hypothesis that the pathogenicity of Sporothrix is not only related to the species of this fungus, but also shows variation between different isolates of the same species.

Trichoderma hamatum Increases Productivity, Glucosinolate Content and Antioxidant Potential of Different Leafy Brassica Vegetables

Brassica crops include important vegetables known as “superfoods” due to the content of phytochemicals of great interest to human health, such as glucosinolates (GSLs) and antioxidant compounds. On the other hand, Trichoderma is a genus of filamentous fungi that includes several species described as biostimulants and/or biological control agents in agriculture. In a previous work, an endophytic strain of Trichoderma hamatum was isolated from kale roots (Brassica oleracea var. acephala), describing its ability to induce systemic resistance in its host plant. In the present work, some of the main leafy Brassica crops (kale, cabbage, leaf rape and turnip greens) have been root-inoculated with T. hamatum, having the aim to verify the possible capacity of the fungus as a biostimulant in productivity as well as the foliar content of GSLs and its antioxidant potential, in order to improve these “superfoods”. The results reported, for the first time, an increase in the productivity of kale (55%), cabbage (36%) and turnip greens (46%) by T. hamatum root inoculation. Furthermore, fungal inoculation reported a significant increase in the content of total GSLs in cabbage and turnip greens, mainly of the GSLs sinigrin and gluconapin, respectively, along with an increase in their antioxidant capacity. Therefore, T. hamatum could be a good agricultural biostimulant in leafy Brassica crops, increasing the content of GSLs and antioxidant potential of great food and health interest.

Evaluation of thermo-mechanical and microbial-facilitated processing on the chemical composition of soybean meal

A laboratory experiment was conducted to examine the effects of microbial fermentation using Bacillus subtilis and Aspergillus oryzae on the chemical composition of a commercial soybean meal (SBM). Five quadruplicate samples of SBM were subjected to four treatments with one batch serves as a control. The treatments were steam conditioning treatment (P1) where the other three groups were further fermented with B. subtilis (P2), A. oryzae (P3), and the combination of B. subtilis + A. oryzae (P4). The results showed that bacterial and fungal inoculation increased crude protein (CP) content when compared to control (p<0.05). In addition, fiber fractions including neutral detergent fiber (NDF) and acid detergent fiber (ADF) were concomitantly decreased with fermentation (p<0.05). In this study, no significant difference was observed on CP and NDF content with heating treatment (P1, p>0.05). However, this treatment decreased ADF content (p<0.05). Ether extract (EE), ash, non-fibrous carbohydrates (NFC), and total phosphorus contents were not affected by the treatments. To conclude, fermentation either with bacterial or fungal inoculants was effective to improve the chemical composition of SBM as indicated by increasing CP and decreasing fiber contents of SBM.

Effects of fungal inoculation on the growth of Salicornia (Amaranthaceae) under different salinity conditions

Endophytic fungi are known to be present in roots of salt marsh plants, but their ecological role in this symbiosis is still largely unknown. Generally considered parasitic or saprophytic, they may still be mutualistic, at least under certain circumstances. Among salt marsh plants, Salicornia spp. are recognized as particularly salt-tolerant and their frequent colonization by root endophytes has also been reported. This study aimed to investigate whether the inoculation of Salicornia with different root endophytes isolated from field-collected Salicornia affects biomass production, nutrient uptake and photosynthesis (assessed via chlorophyll fluorescence). In addition, we investigated whether fungal inoculation confers tolerance to salt stress given that endophytes are suggested to increase salt tolerance and improve plant fitness in other less salt-tolerant plants. The inoculation of Salicornia with an isolate of the genus Stemphylium positively influenced total biomass production and nitrogen concentration in roots at optimum salinity condition (150 mM NaCl). However, under salt stress (650 mM NaCl), no significant effects of fungal inoculation on biomass production and photosynthesis were observed. Further, positive and negative effects of fungal inoculation on nutrient concentrations were observed in roots and shoots, respectively. Our results indicate that different endophytic fungi and their interaction result in distinct fungal species-specific plant growth responses of Salicornia under different growth conditions.

Novel genome characteristics contribute to the invasiveness of Phragmites australis (common reed)

The rapid invasion of the non-native Phragmites australis (Poaceae, subfamily Arundinoideae) is a major threat to native ecosystems in North America. We describe a 1.14 Gbp reference genome for P. australis and compare invasive (ssp. australis) and native (ssp. americanus) genotypes collected across the Laurentian Great Lakes to deduce genomic bases driving its invasive success. We report novel genomic features including a lineage-specific whole genome duplication, followed by gene loss and preferential retention of genes associated with transcription factors and regulatory functions in the remaining duplicates. The comparative transcriptomic analyses revealed that genes associated with biotic stress and defense responses were expressed at a higher basal level in invasive genotypes, but the native genotypes showed a stronger induction of defense responses following fungal inoculation. The reference genome and transcriptomes, combined with previous ecological and environmental data, support the development of novel, genomics-assisted management approaches for invasive Phragmites.

Effect of Arbuscular Mycorrhiza Fungal Inoculation on Growth of Tropical Tree Species under Nursery and Post-Opencast Bauxite Mining Field in Bintan Island, Indonesia

The purpose of this investigation was to examine the effects of native AM fungal inoculation on the growth of Gmelina arborea, Samanea saman, Falcataria moluccana, and Enterolobium cyclocarpum under nursery and post-opencast bauxite mining field conditions. Two native AM fungi, Rhizophagus clarus and Gigaspora decipiens, were inoculated into seeds of G. arborea, S. saman, F. moluccana, and E. cyclocarpum. The seeds were sown in post-bauxite mining soil and grown in the nursery for three months. Seeds without AM inoculation were used as the control treatment. The seedlings were transplanted into a post-opencast bauxite mining field and grown for 12 months. Arbuscular mycorrhizal fungal colonization and shoot and root dry weights were measured. Under nursery conditions, G. arborea inoculated with G. decipiens increased shoot and root dry weights by 1,431 and 359 %, respectively, while shoot dry weight of E. cyclorapum inoculated with R. clarus and G. decipiens increased by 510 and 220%, respectively, in comparison with control seedlings. Root dry weight of E. cyclorapum inoculated with R. clarus increased by 224%, in comparison with control seedlings. Shoot dry weight of E. cyclorapum inoculated with R. clarus increased by 90%, in comparison with seedlings inoculated by G. decipiens. Twelve months after transplanting into post-opencast field conditions, the shoot dry weight of F. moluccana inoculated with G. decipiens was higher than that of the control seedlings by 188%. Shoot dry weight of E. cyclorapum inoculated with R. clarus and G. decipiens increased by 198% and 149%, respectively, in comparison with control seedlings. Shoot dry weight of E. cyclorapum seedlings inoculated with R. clarus was higher by 20% than that of seedlings inoculated with G. decipiens. These results show that AM fungal inoculation promotes the growth of tropical tree species on post-opencast bauxite mining land.

Ectopic expression of LhMYC2 increases susceptibility to Botrytis cinerea in Arabidopsis thaliana

Gray mold disease, mainly caused by Botrytis elliptica and B. cinerea, leads to severe losses in lily cut flower and bulb production. MYC2 is a critical regulator of the activation of jasmonate (JA)-mediated defense responses in plants. However, information about the lily MYC2 gene is limited. Therefore, functional characterization of MYC2 in lily, especially its role in plant immune responses, should be performed. Here, significant differences between the Botrytis-resistant Lilium hybrid ‘Sorbonne’ and the Botrytis-susceptible ‘Tresor’ were found following B. cinerea inoculation, as indicated by jasmonic acid (JA) and JA-isoleucine (JA-Ile) accumulation and related gene expression. More JA and JA-Ile were detected in ‘Sorbonne’ than in ‘Tresor’ following fungal inoculation, and higher transcript levels of JA biosynthesis genes (LhAOS, LhAOC, and LhOPR3) and a signaling gene (LhCOI1) were detected in ‘Sorbonne’ than in ‘Tresor’. In contrast, expression of the critical signaling regulator LhMYC2 was higher in ‘Tresor’ than in ‘Sorbonne’. LhMYC2 was then isolated from ‘Sorbonne’ and found to be similar to several plant MYC2 homologs that have pivotal roles in JA signaling. The expression of LhMYC2 increased significantly in response to JA and salicylic acid (SA) in ‘Sorbonne’. Ectopic expression of LhMYC2 in Arabidopsis resulted in greater susceptibility to B. cinerea than that observed in wild-type plants. This susceptibility was coupled with the transcriptional changes in SA- and JA-responsive genes. Overall, our findings indicate that LhMYC2 plays a negative role in Arabidopsis resistance to B. cinerea.