Draft Genome Sequence of Calonectria pteridis, the Causal Agent of Calonectria Leaf Blight on Eucalyptus.

Here, we report the draft genome sequence of Calonectria pteridis, the causal agent of Calonectria leaf blight in eucalyptus plantations in Brazil. The 58,373,473-bp genome assembly consists of 1,167 scaffolds, with a GC content of 50.21%. These genomic data can contribute to future studies involving the biology, adaptability, and pathogenicity of C. pteridis.

First report on the enzymatic profile of Kretzschmaria zonata.

Enzymes from phytopathogenic fungi are desirable for biotechnological applications and a highly virulent phytopathogen shows great appeal for enzymes production. To assess the biotechnological potential of Kretzschmaria zonata, a plant pathogenic fungus, we analyzed its enzymatic profile after growth on six different types of lignocellulosic biomasses. The fungus was able to produce a wide variety of enzymes with superior xylanase activity. The corn cob induced the highest specific activity of xylanase, 56.30 U/mg of protein, as well as other important enzymatic activities such as endoglucanase, 11.20 U/mg of protein; pectinase, 4.52 U/mg of protein; and ß-glucosidase, 2.77 U/mg of protein. The highest release of xylose, 0.88 g/L, was observed after saccharification of 10% of alkaline pretreated sugarcane bagasse by a commercial cocktail supplemented with the crude extract from K. zonata after growth on corn cob. The fungus extract is rich in hemicellulases and accessory enzymes and the result showed synergism between the enzymes present in the commercial mixture and in the K. zonata extract. This is the first report concerning the biotechnological potential of the fungus K. zonata, especially regarding to its ability to produce plant biomass degrading enzymes related to second generation ethanol production.

Arbuscular Mycorrhizal Fungi (Rhizophagus clarus) and Rhizobacteria (Bacillus subtilis) Can Improve the Clonal Propagation and Development of Teak for Commercial Plantings.

The Tectona grandis L.f. (teak) is an important forest species with high economy value in Asia, Africa, and Latin America. In Latin America, Brazil is one of the countries with the most cultivated areas. The cultivation of teak turns out to be challenging because of its high nutritional demand and the need for seedling production by clonal propagation that includes about 90 days in the nursery phase. The optimization of seedling production is necessary for better results in the nursery and to enhance growth in the field. In this way, the well-known advantage of using microorganisms that promote plant development appears as a potential biotechnological approach to be explored and for the implantation of new areas of wood production. In this study, the inoculation of Bacillus subtilis as plant growth-promoting rhizobacteria (PGPR) was evaluated, and Rhizophagus clarus, an arbuscular mycorrhizal fungus (AMF), and the co-inoculation of these microorganisms in the teak seedling production phase can improve the development of commercial plantations under field conditions. Experiments were carried out under greenhouse and field conditions to evaluate four treatments based on the substrate inoculation of the seedlings. Treatments consisted of a non-inoculated control, PGPR inoculation, AMF inoculation, and PGPR + AMF inoculation. The results of the biometric evaluation of seedlings in the greenhouse showed that there was a significant difference in AMF inoculation and PGPR + AMF inoculation in terms of the specific root length and root density treatments, there was also a positive correlation between these two treatments and the absorption of some nutrients, such as P, N, K, Mg, Cu, Mn, and Zn. This response led to an increase between 4.75 and 11.04% in the field growth rate.

Root collar rot, a new lethal disease on Tectona grandis caused by Kretzschmaria zonata in Brazil.

Tectona grandis L.f., known as teak, is one of the most valuable tropical hardwood species that has been extensively planted in tropical zones, covering about 6,8 million hectares (Kollert and Kleine 2017). Recent advances in silvicultural management and use of improved clones have enhanced productivity and wood quality of teak plantations in Brazil. However, the incidence of diseases has increased over time being a threat to sustainability of commercial teak plantations. Therefore, forest pathology studies have been conducted in Brazil to minimize the risks of losses caused by the diseases on teak, ensuring the expected economic profitability. In a recent disease survey conducted in Midwest of Brazil, almost one thousand teak trees showing typical die-back symptoms with root collar rot were found. The diseased trees showed undersize leaves displaying yellowish to pale brown color, followed by wilt, defoliation and death. At the base of the trunk, root collar rot was observed, with sloughing and deterioration of the bark exhibiting flattened and encrusted fungi fruiting bodies of gray to bright white color. Over the time, the wood of infected trees develops black zone lines and soft tissue due to both lignin and cellulose decay. The disease begins in the root and spreads to the collar of the tree, causing a collapse in sap flow leading to mortality. To discover the disease cause, samples of infected trees were collected to perform an accurate pathogen identification by polyphasic approach, as well as pathogenicity test. From isolation in Malt Extract Agar (MEA), one fungus showing white progressing to gray mycelial growth was consistently isolated. Two isolates named as GFP131 and GFP132 were characterized. Microscopic examination showed conidia aseptate, hyaline, ovoid to fusiform-ellipsoid shaped, measuring 6-8 x 2-4 µm; stromata with surface brown to dark brown; perithecia with variable shapes and ostioles papillate; and ascospores aseptate, dark brown, fusiform to ellipsoid, measuring 20-37 × 8-15 µm, displaying a straight germinal line slightly less than ascospore length. These morphological characteristics were similar to descriptions for genus Kretzschmaria (Rogers and Ju 1998; Stadler et al. 2013). Genomic DNA was extracted from mycelium, and the internal transcribed spacer (ITS) region of rDNA with primer pair ITS1/ITS4 was sequenced and then deposited under Genbank codes MH481853 and MH481854. A BLASTn search showed >99% identity with K. zonata sequence (KY660541). Phylogenetic inference by Maximum Likelihood method using Kimura 2-parameter model confirms that the isolates belong to Kretzschmaria zonata (Lév.) P.M.D. Martin. A pathogenicity test was established in a greenhouse with controlled conditions of temperature (28-30 °C) and humidity (80-90 %). Five plants were inoculated with GFP132 at the collar region with one mycelium disk of approximately 5 mm in diameter each, and the inoculated area was wrapped in plastic film. Disks of MEA culture media were placed on five additional plants as controls. Forty days after inoculation, all of the previously mentioned symptoms were observed for all inoculated plants, while control plants showed only scars at the inoculation point. The pathogen was reisolated from all five of the inoculated plants. Kretschmaria zonata has been reported on teak in Nigeria (West 1938) and in Mexico (Cibrian Tovar et al. 2014). However, this is the first report of K. zonata on T. grandis for Brazil and the first report anywhere to include Koch's postulates, proving the etiology of the disease.

Effects of Sublabeled Rates of Dazomet and Metam-Sodium Applied Under Low-Permeability Films on Calonectria Microsclerotia Survival.

Infested soil is the primary inoculum source for Calonectria spp. for initiating disease in ornamental and forestry crops. The effects of dazomet and metam-sodium on survival of microsclerotia of 28 isolates belonging to 19 Calonectria spp. were evaluated in this study under nursery conditions. Two experiments with exotic Calonectria spp. in plastic containers in a greenhouse and three trials with endemic species in field plots were performed during different seasons. The containers and plots were artificially infested with Calonectria microsclerotia differentiated on carnation leaf tissues. Basamid (dazomet) was applied at 100, 160, 200, 400, and 500 kg/ha, while Divapan (metam-sodium) was applied at 250, 350, 400, 700, and 1,000 liters/ha in both the containers and plots. The fumigants were applied under virtually and totally impermeable films. Fungal survival was evaluated after 21 days using leaf tissues collected from treated soil and plated on potato dextrose agar, and the ability of microsclerotia to cause infection was tested on red clover. The survival of Calonectria inocula and microsclerotia decreased with increasing fumigant rates. In the greenhouse trials, where Basamid was applied at 200, 400, and 500 kg/ha and Divapan at 400, 700, and 1,000 liters/ha, no viable microsclerotia were recovered for 14 exotic Calonectria spp., whereas viable inocula of Calonectria hongkongensis, C. naviculata, and C. sulawesiensis were retrieved from the fumigated plots. Low rates of Basamid (100 and 160 kg/ha) and Divapan (250 and 350 liters/ha) were less effective at reducing Calonectria viability and, for these treatments, the rate of microsclerotia survival was highly variable among the different isolates and species. Furthermore, totally impermeable film significantly enhanced fumigant performance. Relative to endemic Calonectria spp., all of the treatments killed microsclerotia of C. polizzii and C. pauciramosa independent from fumigant, rate, and film. This research demonstrated the possibility of reducing the application rates by up to 160 kg/ha for Basamid and 400 liters/ha for Divapan under low-permeability films (virtually impermeable film or totally impermeable film) for eradicating or reducing the primary inoculum of Calonectria spp. in soil.

The influence of pretreatment methods on saccharification of sugarcane bagasse by an enzyme extract from Chrysoporthe cubensis and commercial cocktails: A comparative study.

Biomass enzymatic hydrolysis depends on the pretreatment methods employed, the composition of initial feedstock and the enzyme cocktail used to release sugars for subsequent fermentation into ethanol. In this study, sugarcane bagasse was pretreated with 1% H2SO4 and 1% NaOH and the biomass saccharification was performed with 8% solids loading using 10 FPase units/g of bagasse of the enzymatic extract from Chrysoporthe cubensis and three commercial cocktails for a comparative study. Overall, the best glucose and xylose release was obtained from alkaline pretreated sugarcane bagasse. The C. cubensis extract promoted higher release of glucose (5.32 g/L) and xylose (9.00 g/L) than the commercial mixtures. Moreover, the C. cubensis extract presented high specific enzyme activities when compared to commercial cocktails mainly concerning to endoglucanase (331.84 U/mg of protein), ß-glucosidase (29.48 U/mg of protein), ß-xylosidase (2.95 U/mg of protein), pectinase (127.46 U/mg of protein) and laccase (2.49 U/mg of protein).

Optimization of endoglucanase and xylanase activities from Fusarium verticillioides for simultaneous saccharification and fermentation of sugarcane bagasse.

Enzymatic hydrolysis is an important but expensive step in the production of ethanol from biomass. Thus, the production of efficient enzymatic cocktails is of great interest for this biotechnological application. The production of endoglucanase and xylanase activites from F. verticillioides were optimized in a factorial design (2(5)) followed by a CCDR design. Endoglucanase and xylanase activities increased from 2.8 to 8.0 U/mL and from 13.4 to 114 U/mL, respectively. The optimal pH and temperature were determined for endoglucanase (5.6, 80 °C), cellobiase (5.6, 60 °C), FPase (6.0, 55 °C) and xylanase (7.0, 50 °C). The optimized crude extract was applied in saccharification and fermentation of sugarcane bagasse from which 9.7 g/L of ethanol was produced at an ethanol/biomass yield of 0.19.

What is Scirrhia?

The ascomycetous genus Scirrhia is presently treated as a member of Dothideomycetidae, though uncertainty remains as to which family it belongs in Capnodiales, Ascomycota. Recent collections on stems of a fern, Pteridium aquilinum (Dennstaedtiaceae) in Brazil, led to the discovery of a new species of Scirrhia, described here as S.brasiliensis. Based on DNA sequence data of the nuclear ribosomal DNA (LSU), Scirrhia is revealed to represent a member of Dothideomycetes, Capnodiales, Mycosphaerellaceae. Scirrhia is the first confirmed genus in Mycosphaerellaceae to have well developed pseudoparaphyses and a prominent hypostroma in which ascomata are arranged in parallel rows. Given the extremely slow growth rate and difficulty in obtaining cultures of S. brasiliensis on various growth media, it appears that Scirrhia represents a genus of potentially obligate plant pathogens within Mycosphaerellaceae.

What is Johansonia?

The bitunicate ascomycete genus Johansonia is presently treated as a member of Saccardiaceae, a family regarded as incertae sedis within the Ascomycota. Recent collections on leaves of a leguminous host, Dimorphandramollis, in Mato Grosso, Brazil, led to the discovery of a new species of Johansonia, described here as J.chapadiensis. Based on DNA sequence data of the nuclear ribosomal DNA (LSU), Johansonia is revealed to represent a member of Dothideomycetes, Capnodiales. Although its family could not be resolved, it clustered basal to Schizothyriaceae and Mycosphaerellaceae, and could well represent a species of Saccardiaceae. DNA sequence data of other members of Saccardiaceae would be required, however, to confirm this classification.