Colletotrichum plurivorum causes anthracnose on okra in Brazil
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Colletotrichum plurivorum causes anthracnose on okra in Brazil Izabel Cristina Alves Batista 1
&
Alessandra de Jesus Boari 2 & Caterynne Melo Kauffmann 3 & Katia de Lima Nechet 4
Received: 5 February 2020 / Accepted: 14 July 2020 # Società Italiana di Patologia Vegetale (S.I.Pa.V.) 2020
Keywords Ascomycetes . Fungal pathogen . Vegetable . Abelmoschus esculentus
Okra (Abelmoschus esculentus) is a tropical vegetable cultivated widely in the Amazon region. In August 2016, typical anthracnose symptoms were observed on the leaves of okra in Altamira, Pará, Brazil with 60% disease incidence. Symptomatic leaf tissue were surface sterilized, rinsed with sterile water, and plated on potato dextrose agar. Colonies had greyish white aerial mycelium in 7-day-old cultures at 25 ± 2 °C. Conidiophores were smoothwalled, septate. Conidiogenous cells were hyaline, straight, and 19 × 4 μm. Appressoria were single, elliptical, and 8.5 × 6.5 μm. The conidia were aseptate, cylindrical, with round apex and base, and 13 × 5 μm. The isolated fungus was identified as Colletotrichum sp. The isolate was deposited in Culture Collection of Microorganisms (CMAA), Jaguariúna, Brazil (CMAA 1735). The isolate was further identified by sequencing the actin (ACT), chitin synthase (CHS1), beta-tubulin (TUB) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes (Damm et al. 2019). The sequences were deposited in GenBank (accession Nos. MK495949, MK495952, MK495951 and MK495950) and revealed over 98% identity with Colletotrichum plurivorum (MG747766, MG600847, MG600984 and MK862223). Reference sequences of C. orchidearum and C. magnum species complexes were used for the alignment and the phylogenetic analyses conducted using Bayesian method clustered the isolate in the clade corresponding to Colletotrichum plurivorum. The pathogenicity of the isolate was confirmed by spraying a suspension of conidia (1 × 106 mL−1) on okra cv. Santa Cruz 47 with 4–6 leaves and the control
* Izabel Cristina Alves Batista [email protected] 1
Universidade Federal de Viçosa, Viçosa, MG, Brazil
2
Embrapa Amazônia Oriental, Belém, PA, Brazil
3
Universidade Federal Rural da Amazônia, Belém, PA, Brazil
4
Embrapa Meio Ambiente, Jaguariúna, SP, Brazil
plants were sprayed with distilled water. The plants were maintained in a dew chamber for 24 h under greenhouse at 27 °C with a 12-h-light/dark photoperiod. After 5 days, dark brown necrotic lesions were observed on the leaves of okra plants whereas control plants were all symptomless. The fungus was re-isolated, and showed the same morphological characteristics as the inoculated strain, fulfilling Koch’s postulates. C. plurivorum has been reported to infect papaya (Sun et al. 2019) and cassava (Liu et al. 2019). To our knowledge, this is the first report of Colletotrichum plurivorum causing anthracnose on okra in Brazil. Data availability Not applicable. Code availability Not applicable.
Compliance with ethical standards Conflict of interest The authors declare that they have no conflict of int
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