Circadian Rhythms, Such as Light Regimes Influencing in vitro Growth of Pestalotiopsis mangiferae from Mango Tree

Mariany D. Milan, Dinelí P. Souza, Paulo H.P.C. Muniz, Gustavo H.S. Peixoto, Sareer Ahmad, Gesiane R. Guimarães, Thiago A.S. Oliveira, Elizabeth A.A. Duarte, Solange X. Santos, Fabrício Rodrigues and Daniel D.C. Carvalho

Background and Objective: The fungus Pestalotiopsis mangiferae causes a gray leaf spot, which can reduce fruit production. This work aimed to carry out the pathogenic and physiological characterization of Pestalotiopsis mangiferae. Materials and Methods: For the physiological evaluation, isolates were streaked on the Petri dishes containing PDA medium and incubation in BOD chamber at 25°C under three light regimes (0, 12 and 24 h) for 6 days. Evaluations were performed daily with a digital caliper to obtain growth measures. After 6 days of incubation, a total of 10 mL of sterile distilled water was added to each Petri dish for sporulation evaluation. For the pathogenic characterization, the isolates were inoculated in leaves and kept in transparent acrylic boxes. The design was completely randomized, with 6 leaves of Mangifera indica per isolate of P. mangiferae. The lesions were measured at 2, 4, 6, 8 and 10 days of inoculation with the aid of a digital caliper. Results: The N-01-15 isolate was statistically superior to the other isolates in terms of the spotted leaf area and the area under the progress disease curve, all isolates were able to cause injuries to the mango leaves. Regarding physiological evaluation, the daily light hour regime directly influences mycelial growth and spore production of P. mangiferae. Conclusion: The amount of daily light hours directly influences mycelial growth and spore production of P. mangiferae. The isolates were capable of lesions ranging from 0.44-1.46 cm² in mango leaves.

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