Alexandre Reis Machado

This study evaluated the sensitivity of Colletotrichum musae isolates to demethylation inhibitor (DMI) fungicides flutriafol and tebuconazole, as well as fitness and competitive ability of isolates with reduced sensitivity. A positive correlation was observed between the sensitivity of C. musae isolates to different concentrations of both fungicides; however, the isolates were generally more susceptible to tebuconazole. The effective concentration required to inhibit mycelial growth by 50% (EC₅₀) was determined and used to select four isolates with the lowest and highest EC₅₀ values for each fungicide, classified as sensitive (S) and less sensitive (LS), respectively. Isolates sensitivity profile remained stable after ten successive transfers on fungicide-free medium. Both fungicides effectively controlled anthracnose caused by S and LS isolates on banana fruit when applied at recommended doses. Fitness analyses included mycelial growth, sporulation, conidial germination, and disease severity. No significant differences were detected between the fitness parameters of the S and LS isolates those classified by their sensitivity to flutriafol and tebuconazole; however, the occurrence of adaptive cost for LS isolates to these fungicides could be observed through competition tests. These results provide new insights into the sensitivity and fitness of C. musae isolates from Brazil and underscore the importance of continuous monitoring of LS isolates to guide more effective chemical management strategies for banana anthracnose.

Species in the Asteraceae , either cultivated or wild, are strongly affected by downy mildews. Despite its importance, the broad species concept used for decades and the lack of molecular data for the genera Plasmopara and Bremia have obscured the true diversity and distribution of downy mildew-causing species in Asteraceae . Given the great relevance of downy mildew-causing oomycetes in Asteraceae , the objective of this study was to investigate the phylogenetic relationships of downy mildew-causing oomycetes in lettuce and other Asteraceae in Brazil. Based on molecular and morphological data, we describe a new species, Plasmopara pernambucoensis sp. nov., and present the first record of Plasmopara sphagneticolae in Brazil and South America, as well as the first record of Bremia sonchicola in Brazil.

This study investigated whether the genus Luffa could act as a sporulation inducer for Macrophomina euphorbiicola , with the aim of providing a morphological description and proposing a taxonomic amendment for the species. In a greenhouse, Luffa cylindrica was inoculated with M. euphorbiicola to induce the formation of pycnidia and conidia. Previously, M. euphorbiicola had been described only using molecular methods. Eighty days after inoculation, symptoms of stem rot disease were observed, such as collar lesions, leaf necrosis, and pycnidia on the hypocotyl and roots. Molecular identification of the isolate used was confirmed through amplification of the TEF1-α gene using specific primers (MeTefF/MeTefR). Morphological characterization revealed structures (pycnidia and conidia) smaller than those reported in other species of the genus. These findings reinforce the importance of an integrated approach combining morphological and molecular data for the identification of M. euphorbiicola and highlight L. cylindrica as an effective host for inducing sporulation.

RESUMO Objetivou-se avaliar o efeito in vitro e in vivo de diferentes concentrações de eugenol, extrato de própolis, óleo essencial de citronela e óleo essencial de capim-limão sobre isolados de Aspergillus associados a grãos de feijão-caupi. Foram utilizados, quatros isolados de Aspergillus sendo: LPPC 104 e LPPC 122 (Aspergillus niger), LPPC 113 (Aspergillus tamarii) e LPPC 130 (Aspergillus sp.). No ensaio in vitro foram testadas as concentrações de 0,0, 15,62, 31,25, 62,50, 125 µL/L para o eugenol e 0, 25, 50, 75, e 125 µL/L para extrato de própolis, OE de citronela e OE de capim-limão. Foram preparadas suspensões de conídios na concentração de 105 conídios/mL para cada isolado de Aspergillus. Foram mensuradas as quantidades de unidades formadoras de colônias e porcentagem de germinação de esporos a cada 24 h. O controle correspondeu a deposição de suspensão fúngica em meio BDA sem a presença dos compostos utilizados. No teste in vivo 200 grãos de feijão-caupi foram imersos por 3 minutos em soluções de eugenol, extrato de própolis, OE de citronela, OE de capim-limão e a testemunha (água) e incubadas de acordo com metodologia do papel de filtro. Após oito dias de incubação avaliou-se a frequencia de fungos associados aos grãos. Os resultados indicam que todos os compostos testados apresentam atividade fungitóxica e que o OE de capim-limão foi mais eficiente tanto nos teste in vitro como in vivo para isolados de Aspergillus e pode ser uma alternativa para o tratamentos de fungos associados aos grãos de feijão-caupi.

Several specific primers based on the internal transcribed spacer (ITS) region of rDNA have been used to discriminate anastomosis groups (AGs) and subgroups in Rhizoctonia solani , but the efficacy of these primers was not evaluated considering several known AGs. This study aimed to evaluate the efficacy of seven PCR‐specific primers for the detection of four AGs and subgroups of R. solani (AG‐1 IA, AG‐1 IB, AG‐2‐1, AG‐3 PT, AG‐3 TB, AG‐4 HGI, and AG‐4 HGII). Thirteen isolates of R. solani and seven isolates of binucleate Rhizoctonia belonging to different AGs and subgroups were used in the detection assays and were amplified and sequenced using ITS1 and ITS4 universal primers to confirm the previous identification of AGs and the viability of the DNA samples. In addition, three isolates of unrelated fungal species ( Fusarium oxysporum, Macrophomina phaseolina , and Sclerotium rolfsii ) were tested simultaneously with each primer set above as a negative control. All primers tested nonspecifically amplified other AGs, and most of the primers produced bands for unrelated fungal species. Therefore, the exclusive use of these primers under the PCR conditions should be avoided due to the lack of accuracy in the results.

Knowledge of the factors structuring populations of pathogenic fungi is fundamental to disease management efforts and basic biology. However, this crucial information is missing for many important pathogens, including broad-host-range and drought-associated pathogens from the globally distributed Macrophomina genus. The objectives of this work were to evaluate the evidence for host specialization, geographic adaptation, and recombination using a global survey of Macrophomina isolates from diverse geographic, temporal, and host sources. We obtained high-quality short-read sequence data for 463 Macrophomina spp. isolates, representing four putative species, collected from 91 host plant species and soil in 23 countries. Analysis of bi-allelic, single-nucleotide polymorphisms revealed high diversity, admixture, and equal mating type ratios, suggesting ongoing recombination. Although most tested isolates asymptomatically colonized strawberry, only strawberry-derived isolates caused disease on this host. These isolates were all in a single lineage, suggesting that the ability to cause disease on strawberry is not widespread among M. phaseolina. Significant associations were also found between isolations from soybean plants and specific population clusters, suggesting that specialization for virulence or reproduction has also occurred for soybean. Geography × isolate genotype associations were weak, suggesting that Macrophomina spp. were frequently trafficked between regions. Reference-free whole-genome comparisons support current boundaries among four Macrophomina species, and new molecular markers were designed to specifically identify each species. Contrary to expectations, M. phaseolina should be considered a single species with both specialist and generalist populations in which meiosis can maintain genetic diversity. [ ] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Allophoma brasiliensis J.L.V.R. Carvalho, J.D.P. Bezerra & Souza-Motta is reported for the first time as endophyte from leaves of Capsicum annuum L. (Solanaceae) isolated in an agricultural site from Brazilian Atlantic Forest. For species determination, morphological characters were analysed along with a multigene analysis performed using the ITS region of the rDNA, the partial large subunit nuclear ribosomal RNA gene (LSU rRNA), the partial second largest subunit of the RNA polymerase II gene subunit (rpb2), and the partial β–tubulin gene (tub2). A key to Allophoma Qian Chen & L. Cai species is provided. This new record contributes to the global fungal diversity, indicating a new geographical distribution, and a new lifestyle.

Cucumbers have great economic and social importance. Annual worldwide production is approximately 80 million tons (FAOSTAT, 2019), 184 thousand tons of which are produced in Brazil (IBGE, 2020). Leaves with symptoms of anthracnose (necrotic brown or angular spots) were observed on cucumber plants grown in organic systems in September 2021, Pernambuco, Brazil (8°7'45''S, 35°16'167''W). About 40% of the plants fields were infected. Samples were collected and fragments were cut from the margins of the symptomatic tissue. The fragments were superficially disinfected with 70% ethanol (30 s) and 2% sodium hypochlorite (2 min), then washed three times with sterile distilled H2O and dried on sterile filter paper. The fragments were placed on potato dextrose agar (PDA) containing chloramphenicol (50 mg/L) and incubated at 28 ± 2 °C for 3 days. From the fungal isolates obtained, a representative specimen of Colletotrichum spp. was isolated, purified by subculturing from emergent hyphae tips and used for morphological characterization, phylogenetic analysis, and pathogenicity testing. The fungus isolated on PDA formed gray to grayish-black colonies with white aerial mycelia after 7 days. Ascomata were globose to subglobose, 120-200 × 100-150 μm in size (n = 10). Setae formed directly on the hyphae. Asci were 50-70 × 10-12 μm in size, 8-spored, unitunicate, thin-walled, and clavate. Ascospores were 14-22 × 4-5 μm in size (n = 30), hyaline, slightly curved to curved with obtuse to slightly rounded ends. Conidia were hyaline, smooth-walled, aseptate, straight, cylindrical, the apex and base rounded, and 12-15 × 5 μm in size, (n = 30). For molecular identification, the nuclear ribosomal internal transcribed spacers (nrITS), actin (ACT), beta-tubulin (TUB), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were sequenced (Damm et al. 2019). The sequences obtained were deposited in GenBank (nrITS: OP720945, ACT: OP723523, TUB: OP723525, and GAPDH: OP723524). The sequences from the nrITS region, ACT, TUB2, and GAPDH were highly similar to those from C. plurivorum: nrITS - CBS 125474 (539/539 - 100%; NR_160828); ACT - CBS 125474 (270/271 - 99%; MG600925), TUB2 - CBS 125474 (517/518 - 99%; MG600985); and GAPDH - CBS 125474 (197/197 - 100%; MG600781), respectively. Multilocus phylogenetic analysis was performed using Bayesian inference, which showed that the isolate C. plurivorum FPO04 clustered in the same clade as the ex-type of C. plurivorum (CBS 125474). In the pathogenicity test, leaves of five healthy cucumber plants, previously injured in the middle region with sterile needles, were inoculated with 50 µl of a conidial suspension (1 × 106 spores mL -1) prepared from 7-day-old of colonies of C. plurivorum. Sterile distilled water was used as negative controls. The inoculated plants were maintained in a humid greenhouse chamber for 24 hours. After 7 days, the same anthracnose symptoms seen in the field were observed on the inoculated plants. Control plants remained healthy. Colletotrichum plurivorum was reisolated from symptomatic leaves, fulfilling Koch's postulates. This species has been reported from several crops, including Abelmoschus esculentus (okra) (Damm et al. 2019) and Glycine max (soybeans) (Zaw et al. 2019). To our knowledge, this is the first report of C. plurivorum causing anthracnose on cucumber leaves in Brazil. This report lays the groundwork for future studies to determine management practices for control of this disease in C. sativus.

The sweet potato is of great socioeconomic importance in Brazil and throughout the world. Among the fungal pathogens associated with root diseases of this crop, Fusarium is of particular importance due to the diversity of species, the pathogenic potential in their various hosts and their ability to survive inside plants as endophytes without apparently causing damage. The objective of this work was to identify fusarioid genera from stems and roots of symptomatic and asymptomatic plants. The identification of fungal species was based on multilocus phylogenetic analysis and morphology. A total of 51 isolates, distributed in the Fusarium incarnatum‐equiseti species complex (FIESC), Fusarium fujikuroi species complex (FFSC), Fusarium oxysporum species complex (FOSC)—with a taxonomic novelty—and Neocosmospora were identified. The pathogenicity test on roots showed that 13 of the 14 tested isolates obtained from symptomatic roots and stems and from asymptomatic stems were capable of reproducing the rot symptoms observed in the field. The confirmation of the pathogenicity of isolates from asymptomatic stems corroborates the hypothesis that these fungi can live endophytically in asymptomatic tissue and are capable of causing damage to their hosts in stress situations. This is the first report of Fusarium agrestense , Fusarium annulatum , Fusarium caatingaense , Fusarium elaeidis , Fusarium pernambucanum , Fusarium pseudocircinatum , Neocosmospora falciformis and Neocosmospora suttoniana associated with root and stem rot of sweet potato.