Pitch canker is one of the most important diseases of pine trees worldwide, including South America. The causal agent of this disease is Fusarium circinatum, a member of the Gibberella fujikuroi ...complex (GFC). In South America, the species is reported from Colombia, Uruguay and Chile, but is considered a quarantine organism in Brazil. In this study we characterized isolates obtained from symptomatic pine seedlings intercepted in a nursery in Santa Catarina State using phylogenetic analyses, crossings and morphological markers. The Brazilian isolates grouped with reference material in an unique clade and formed fertile perithecia when crossed with reference tester strains. The detailed characterization given here and the availability of tester strains will allow for reliable identification and support monitoring of this important plant pathogen.
The taxonomy of the genus
Colletotrichum
has undergone various changes. These alterations arise from the use of modern molecular tools. Currently,
Colletotrichum
species are grouped into complexes. ...Species of
Colletotrichum
associated with diseases in lima bean have been investigated very little. In Brazil, anthracnose in lima bean has often been associated with
Colletotrichum truncatum,
but only morphological characteristics have been used for identification purposes. In this study, samples of lima bean with symptoms of spots on the leaves and pods have been collected in Piauí and Alagoas states. Comparisons of morphological characteristics revealed nine isolates with cylindrical or curved conidia. The ITS region and partial sequences of GAPDH, β-tubulin and Actin regions were amplified by PCR, sequenced and submitted to multilocus phylogenetic analysis. The isolates analyzed grouped with reference specimens from
Colletotrichum truncatum
,
C
.
cliviae
and
C
.
fructicola
. All isolates were pathogenic to 25-day-old lima bean seedlings. Therefore, this work confirms the pathogenicity of
C. truncatum
to lima bean and for the first time records the occurrence of
C. cliviae
and
C. fructicola
as pathogens of this host in Brazil.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
ABSTRACT Charcoal rot, caused by Macrophomina phaseolina, is an important disease of lima bean (Phaseolus lunatus L.) in the Northeast of Brazil. Considering that there are no reports of resistance ...to this disease in Brazil, 37 lima bean accessions were evaluated for their resistance reaction and resistance stability against isolates of M. phaseolina in two periods of the year (February-March and July-August 2016), with the aim of selecting genotypes with the potential for use in the management of this disease. Seeds were inoculated at sowing, using rice grains with husk that were colonized by the pathogen. The evaluations of genotypes were carried out at every five days, from the tenth day after sowing, using a score scale and dividing them into six reaction classes. From a population of 37 accessions of P. lunatus, no immunity reaction to M. phaseolina was seen; however, thirteen accessions presented the lowest severity levels and greatest stability in the two seasons: UFPI 892, UFPI 908 and UFPI 905, which were considered resistant to the isolate COUFPI 06. The resistance reaction of accessions considered resistant varied depending on the isolate of M. phaseolina. Accession UFPI 908 expressed the most promising results for resistance and stability of resistance against the isolates COUFPI 06, COUFPI 08 and COUFPI 10. Therefore, accession UFPI 908 constitutes a promising source of resistance to M. phaseolina, making possible its use in breeding programs and in integrated management of charcoal rot.
RESUMO A podridão cinzenta do caule, causada por Macrophomina phaseolina, é uma importante doença do feijão-fava (Phaseolus lunatus L.) no Nordeste brasileiro. Considerando que no Brasil não existem relatos de resistência a esta doença, 37 acessos de feijão-fava foram avaliados pela reação de resistência e estabilidade da resistência contra isolados de M. phaseolina em duas épocas do ano (fevereiro-março e julho-agosto de 2016), visando selecionar genótipos com potencial de utilização no manejo da doença. As sementes foram inoculadas no momento da semeadura, com grãos de arroz com casca colonizados pelo patógeno. As avaliações dos genótipos foram realizadas a cada cinco dias, a partir do décimo dia após a semeadura, com auxílio de escala de notas, discriminando-os em seis classes de reação. De uma população de 37 acessos de P. lunatus não foi observada reação de imunidade a M. phaseolina, no entanto, treze acessos apresentaram os menores níveis de severidade e maior estabilidade nas duas épocas, dentre eles UFPI 892, UFPI 908 e UFPI 905, tendo sido considerados resistentes ao isolado COUFPI 06. A reação de resistência dos acessos considerados resistentes variou conforme o isolado de M. phaseolina. O acesso UFPI 908 expressou os resultados mais promissores de resistência e estabilidade da resistência contra os isolados COUFPI 06, COUFPI 08 e COUFPI 10. Portanto, o acesso UFPI 908 constitui uma fonte promissora de resistência a M. phaseolina, sendo possível a sua utilização em programas de melhoramento e no manejo integrado da podridão cinzenta do caule.
Crown rot is an important postharvest disease of banana fruit caused by a fungal complex. The development of these microorganisms in the banana favors rot of the fruit and crown, affecting fruit ...quality and rendering the fruit unsafe to eat. Fungi that cause postharvest rot include species of the complex
Thielaviopsis paradoxa
. In March 2015, symptoms of crown rot were observed in banana grown in the state of Piauí, Northeastern Brazil. The fruits exhibited rot, usually with signs of a dark gray mycelium; fruits at an advanced stage of rot broke from the stem. Microscopic analysis revealed the presence of primary and secondary conidia as well as aleurioconidia, typical for
Thielaviopsis
spp.. The sexual phase was not observed. The ITS and TEF1-α genes were sequenced and subjected to phylogenetic analysis; consequently, the isolates were identified as
Thielaviopsis musarum
. In inoculated fruits, the fungus caused black rot, followed by a browning and softening of the pulp. This is the first record of postharvest rot in banana caused by
T. musarum
in Brazil.
The jackfruit tree (Artocarpus heterophyllus) is a tropical species of significant importance, widely distributed in various geographical regions of Brazil, where its fruits, known as jackfruit, are ...consumed fresh. Between 2019 and 2023, in three distinct geographical regions of Brazil, a 100% incidence of black rot was observed in jackfruit fruits. Additionally, symptoms of dieback were identified in jackfruit trees in these regions. Faced with this issue, the present study aims to identify the etiological agents associated with these two symptoms, employing morphological characterization, nucleotide sequencing, and inoculations in fruits and seedlings. Through sequencing of the ITS, TEF, and TUB2 regions, the isolates were grouped with references of Lasiodiplodia theobromae and L. brasiliense. The inoculated fungi were reisolated, maintaining the same morphological characteristics. This study constitutes the first report of L. theobromae and L. brasiliense as causative agents of fruit rot and dieback in jackfruit in Brazil.
•Black rot and dieback disease of jackfruit tree were very popular in three distinct geographical regions of Brazil.•Lasiodiplodia theobromae and L. brasiliense were isolated, identified by morphological and molecular methods, and finished Koch's postulates.•The first report of L. theobromae and L. brasiliense as causative agents of fruit rot and dieback in jackfruit in Brazil.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Bananas are the most widely produced fruit in the world. Crown rot, one of the main postharvest diseases of banana fruit, causes significant losses during storage, transportation, and marketing. ...Different fungi, especially species of the genus Lasiodiplodia, are associated with this disease. Lasiodiplodia isolates were obtained from asymptomatic fruits in the states of Alagoas, Ceará and Pernambuco, Brazil. On Potato Dextrose Agar (PDA), the isolates initially produced moderately dense grayish-white mycelium, then turned olive green to grayish-black, with olive-green or black reverses. The fungal isolate was classified as Lasiodiplodia hormozganensis and Lasiodiplodia laeliocattleyae based on morphological and multigene (TEF1-α, ITS and TUB2) phylogenetic analysis. Pathogenicity tests were performed by inoculating mycelial discs containing pathogen structures on banana fruits, confirming Koch's postulates. This is the first report of L. hormozganensis and L. laeliocattleyae causing crown rot disease in banana plants in the world.
•2023, crown rot disease of banana fruit occurring in three geographical areas in the northeast of Brazil.•Lasiodiplodia laelliocatleyae and L. hormozganensis were isolated, identified by morphological and molecular methods, and finished Koch's postulates.•The first report of L. laelliocatleyae and L. hormozganensis as causative agents of crown rot disease on banana fruits in the world.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Aloe vera is a plant of significant medicinal importance commonly known as “Babosa”. It is often cultivated in medicinal gardens and used to produce pharmaceuticals and cosmetics. Between 2019 and ...2022, Aloe vera plants at the Medicinal Plants Center of the Federal University of Piauí showed leaf spots and tip drying symptoms. This study aimed to determine the etiological agent responsible for the decline of Aloe vera plants. Four days post-inoculation, all symptomatic leaves exhibited necrosis, while control plants remained asymptomatic. Following initial isolations and confirmation of Koch's postulates, the causal agent was conclusively identified as Lasiodiplodia hormozganensis through a multilocus analysis involving the ITS, TEF, and TUB2 genes. It is the first known occurrence of L. hormozganensis causing leaf blight in Aloe vera in Brazil.
•Disease in medicinal plants.•Lasiodiplodia complex.•Lasiodiplodia hormozganensis aggressive pathogen on Aloe vera.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Sooty moulds are saprophytic epiphytic fungi that grow mostly on insect secretions, but they can also be associated with plant secretions. In this study, we aimed to describe de interaction of ...Capnodium alfenasii sooty mould with the extrafloral shoot nectaries of Azadirachta indica. Anatomical and histochemical studies were carried out on serial sections of extrafloral shoot nectaries of A. indica without and with C. alfenasii infestation. The total soluble sugar content of the secreted nectar was determined, and the conidial germination of the fungus in distilled water and in dextrose and nectar solutions was evaluated. The shoot nectaries of A. indica are elongated structures that occur in pairs near the base of the petiole. The exuded nectar contains an average of 534.8 µg of total soluble sugars per µL of nectar and provides ideal conditions for conidial germination and fungal growth. C. alfenasii hyphae grow on the nectary, penetrate through breaks in the cuticle, travel under the cuticle and penetrate the secretory tissue by inter- and intracellular routes. The present report is the first to describe the interaction of C. alfenasii with the A. indica nectary, including the penetration of hyphae into nectariferous tissues and the plant defence mechanisms.Sooty moulds are saprophytic epiphytic fungi that grow mostly on insect secretions, but they can also be associated with plant secretions. In this study, we aimed to describe de interaction of Capnodium alfenasii sooty mould with the extrafloral shoot nectaries of Azadirachta indica. Anatomical and histochemical studies were carried out on serial sections of extrafloral shoot nectaries of A. indica without and with C. alfenasii infestation. The total soluble sugar content of the secreted nectar was determined, and the conidial germination of the fungus in distilled water and in dextrose and nectar solutions was evaluated. The shoot nectaries of A. indica are elongated structures that occur in pairs near the base of the petiole. The exuded nectar contains an average of 534.8 µg of total soluble sugars per µL of nectar and provides ideal conditions for conidial germination and fungal growth. C. alfenasii hyphae grow on the nectary, penetrate through breaks in the cuticle, travel under the cuticle and penetrate the secretory tissue by inter- and intracellular routes. The present report is the first to describe the interaction of C. alfenasii with the A. indica nectary, including the penetration of hyphae into nectariferous tissues and the plant defence mechanisms.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Catharanthus roseus is an important plant group used for landscaping purposes and is cultivated in several locations in Brazil. However, anthracnose is compromising its development. Despite the ...importance of the disease, it is not known which Colletotrichum species is responsible for causing anthracnose. This study aimed to identify Colletotrichum isolates associated with anthracnose of vinca. It evaluated morphological markers and performed multilocus phylogenetic analysis. According to the morphological analyses and multilocus phylogeny analysis of ACT, GAPDH, ITS, and TUB gene regions, we identified the isolates as Colletotrichum truncatum. This study is the first to report C. truncatum in C. roseus worldwide.
•Anthracnose in flowers.•Colletotrichum truncatum etiological agent of anthracnose in Cataranthus roseus.•Colletotrichum truncatum aggressive pathogen on Cataranthus roseus.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The peach palm (Bactris gasipaes Kunth) is a palm of great importance to the population of the Brazilian Amazon region. Its fruits are an important food source for the local population (Alves and ...Flores, 1982). Between 2018 and 2021, peach palm fruits with black rot symptoms were collected in the state of Pará, in the municipalities of Juruti (02
09' 08'' S 56
05' 32W) and Santarém (2
26' 22''S 54
41' 55''W), Brazil. Symptomatic fruits detach easily from the bunch. When sectioned, tissues with black coloration and mycelia with white to black coloration were found (Fig. 1a-b). The incidence of the disease in orchards ranged from 5 to 50%. Then, direct isolation, was done by transferring fragments of mycelia and spores to a plate containing potato dextrose agar (PDA). Morphological markers of the asexual phase were evaluated by cultivating the isolates in malt extract agar (MEA) with fragments of Saccharum officinarum culm (Mbenoun et al., 2014). The colonies initially showed a white coloration but turned dark after eight days of cultivation. Colonies produced white mycelia with hyaline, unicellular, rectangular primary conidia (5.6-8.8 µm) (n=30) in length and 2.8-4.0 µm (n=30) in width (Fig. 1e). In the dark-colored mycelia, secondary conidia that formed exhibited three distinct shapes: cylindrical, light brown, and (6.6-11.6 µm x 3.0-3.7 µm) (n=30) (Fig 1. f-i); oblong to globose shape (5.0-10.0 x 3.0-5.3 µm) (n=30) (Fig 1. g); and ellipsoid-shaped (7.0-13.0 x 3.0-4.0 µm) (n=30) (Fig 1. h). Furthermore, unicellular aleuroconidia, produced in dark-colored colonies, exhibited cell walls (10.8-17.5 x 5.4-8.4 µm) (n=30) with a warty, dark-brown, ovoid-shaped appearance (Fig 1. j-k). Genomic DNA was isolated from 4-day-old cultures, and ITS-rDNA and TEF-1α were amplified from ITS1/ ITS2 (White et al., 1990) and EF1F/EF2R (Jacobs et al., 2004), respectively. Sequences were deposited in GenBank (ITS: OL623838, OL623839, OM643316, OL623840, and OL623841) (TEF1: OL631623, OM643318, OM643317, OL631624, and OL631625). Bayesian analysis concatenated were conducted with MrBayes v. 3.2.7 (Ronquist et al., 2011). Clustered the five isolates with the Thielaviopsis ethacetica reference isolate IMI 50560 with Bayesian posterior probability (Bpp = 0.99). (Fig. 2). The pathogenicity test, was conducted using the five isolates, that were were inoculated on six fruits early maturity. After the fruit were washed with neutral detergent and water, 0.5-cm-deep wounds were made with a sterile penknife. Next, 1 mL of primary and secondary conidia suspension at 1 x 105 spores/mL was added to each wound. Six control fruit were inoculated with distilled water. The fruits were kept in incubators at 25 °C with a 12 h photoperiod. The experiment was conducted twice (Alves and Flores, 1982). After five days of inoculation, all inoculated fruit showed characteristic symptoms (Fig 1. c), whereas the control fruit remained asymptomatic (Fig 1. d). The fungus reisolated from all inoculated fruit exhibited the same morphological markers as the inoculated fungus, thus completing Koch's postulates. Thielaviopsis ethacetica is an important pathogen in several palm species in sugarcane and pineapple crops in different parts of the world (Mbenoun et al., 2014; Borgens et al., 2019). This study is the first record of T. ethacetica causing black rot in B. gasipaes fruit in Brazil.
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