Artificial inoculation on plants and banana leaf pieces withMycosphaerellaspp., responsible for Sigatoka leaf spot diseases

Abstract

Artificial inoculation on plants and banana leaf pieces with Mycosphaerella spp., responsible for Sigatoka leaf spot diseases. Abstract-Introduction. This protocol aims at (i) analysing the nature of host-parasite interactions (resistance or susceptibility), and (ii) studying the variability of the pathogenicity of different pathogen populations (intra/inter-specific) with regard to both virulence and aggressiveness using artificial inoculation with Mycosphaerella fijiensis or Mycosphaerella musicola on plants and banana leaf pieces. The principle, key advantages, starting plant material and time required for the method are presented. Materials and methods. Laboratory materials required and details of the sixteen steps of the protocol (conidial inoculum preparation, artificial inoculation on banana plants and artificial inoculation on banana leaf pieces) are described. Possible troubleshooting is discussed. Results. Typical symptoms of the different diseases are obtained after artificial inoculation. France / Musa sp. / Mycosphaerella fijiensis / Mycosphaerella musicola / disease resistance / methods Inoculation artificielle sur plants et tissus de feuille de bananier avec Mycosphaerella spp., responsables de la maladie de Sigatoka. Résumé-Introduction. Ce protocole vise (i) à analyser la nature des interactions hôtesparasites (résistance ou sensibilité), (ii) à étudier la variabilité de la pathogénicité de différentes populations pathogènes (intra/interspécifiques) quant à leur virulence et leur agressivité mesurées à partir d''inoculation artificielle avec Mycosphaerella fijiensis ou Mycosphaerella musicola sur des plants et des morceaux de feuille de bananier. Le principe, les principaux avantages, le matériel végétal de départ et le temps nécessaire de la méthode sont présentés. Matériel et méthodes. Le matériel de laboratoire nécessaire et le détail des seize étapes de réalisation du protocole (préparation de l'inoculum conidial, inoculation artificielle sur des plants de bananier, et inoculation artificielle sur des morceaux de feuille de bananier) sont décrits. Des problèmes potentiels sont évoqués. Résultats. Des symptômes-types de la maladie sont obtenus après inoculation artificielle. France / Musa sp. / Mycosphaerella fijiensis / Mycosphaerella musicola / résistance aux maladies / méthode

Phenylphenalenones protect banana plants from infection by Mycosphaerella fijiensis and are deactivated by metabolic conversion

“…The standard protocol reported by Abadie et al . () was used with slight modifications. Briefly, M. fijiensis strain E22 kept in glycerol (15%) at −80 °C was placed in PDA medium and incubated at 25 °C under dark conditions for 20 d. Afterwards, the fungal mycelium was cut off from the agar medium and transferred to Petri dishes with sterile V8 juice agar (containing 300 mL of vegetable juice V8, 3 g CaCO 3 , 20 g of agar and 700 mL water) and incubated for 15 d under 12 h photoperiod.…”

Comparative analysis of the in vitro and in planta secretomes from Mycosphaerella fijiensis isolates

“…To obtain the in planta secretome of M. fijiensis, an in vitro inoculation of leaves of 'Yangambi Km 5' plants grown in vitro was performed, using a modified procedure originally described by Abadie et al (2008), with conidia of the avirulent and virulent fungal isolates. The conidia inocula from both M. fijiensis isolates were prepared as mentioned above.…”

A novel bioassay to monitor fungicide sensitivity in Mycosphaerella fijiensis

“…Isolates of the collection maintained at −80 °C were first cultured on V8 300 solid medium containing V8 juice (300 mL), CaCO 3 (3 g), agar (20 g L −1 ) and H 2 O (700 mL) at 25 °C for 10 days. Conidial sporulation was induced in V8 100 solid medium containing V8 juice (100 mL), CaCO 3 (0.2 g), agar (10 g L −1 ) and H 2 O (900 mL) at pH 6 and 20 °C under continuous fluorescent light for 8–10 days . A conidial suspension was then obtained by stirring a fragment of the colony in sterile distilled water (0.5 mL), and 10 µL of this suspension was deposited on different solid media (agar 20 g L −1 ), supplemented or not supplemented with fungicide.…”