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First report of phomopis fruit rot of Eggplant in Reunion Island

Roze M., Costet L., Jourda C.. 2017. Plant Disease, 101 (7).

Fruit rot is one of the major diseases of eggplant (Solanum melongena L.) crops especially in India (Mahadevakumar and Janardhana 2016). First cases of fruit rot of eggplant were reported in 1990 in Reunion Island on the local cultivar Bringelle Rond. Typical symptoms include spots on leaves, cankers on stems (brown-to-black lesions), and fruit rots showing characteristic concentric rings and subepidermal black pycnidia. These symptoms are commonly associated with the fungus Diaporthe vexans (asexual state: Phomopsis vexans). From March to May 2016, a survey was conducted to identify the causal agent. Symptomatic fruits were collected in Piton Bloc, Petite Île, and Ligne Paradis. Fruits were surface-disinfected with 10% hypochlorite sodium solution and 70% alcohol. Fungal strains were isolated from symptoms on potato dextrose agar (PDA) medium with ampicillin (100 µg/ml). Each isolate was subcultured on PDA medium and DNA was extracted using the PowerSoil DNA isolation kit (MO BIO Laboratories). PCR amplification and DNA amplicon sequencing of the EF1-? gene and the ITS1, 5.8S, and ITS2 region were performed using respectively, EF1-? primers (Carbone and Kohn 1999) and a primer pair ITS1F/ITS4 (Gardes and Bruns 1993; White et al. 1990). Comparison of all amplicon sequences between themselves revealed that isolates share the same EF1-? sequence (KY621997¿99) and the same ITS sequence (KY007512¿14). Comparison of sequences with nucleotide D. vexans sequences available in GenBank revealed an identity of 90% for EF1-? and between 93 and 95% for ITS. Best sequence identity were obtained for ITS sequences from D. ganjae (identity, 97%), D. melonis (identity, 96%), D. endophytica (identity, 96%), D. phaseolorum (identity, 96%), and P. lactucae (identity, 96%). The best EF1-? sequence identity was 94% (Phomopsis sp. JMS-2010a). None of these species have been reported as pathogens on eggplant. These results show that the fungus isolated on eggplant fruits in Reunion Island

Mots-clés : solanum melongena; phomopsis; réunion

Thématique : Maladies des plantes

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