SCANNING ELECTRON MICROSCOPY (SEM) OF INTERACTION BETWEEN Penicillium digitatum AND ANTAGONISTIC YEAST Candida famata ON FRUITS OF ORANGE

Wounds made by sterilized scalpel on oranges (ten) were inoculated with C. famata yeast ( 5x 106 cells/ml) for 12 h and followed by inoculation with the fungal pathogen, P. digitatum. Another treatment was interchanged in which wounds were inoculated with the pathogen for 12 h followed by the yeast (5x 106 cells/ml). Both sets were incubated at 25°C temperature at humid chamber for 24 h and 48h. Then inoculated wounded tissues (5 mm2) of five orange of each set were excised from the treated fruits, immediately and subjected to preparation for SEM study. Remaining inoculated wounded tissues of oranges were excised from the treated fruits, immediately and subjected to analysis for cfu/g estimation. SEM showed that in both cases, yeast (C. famata) grows, competes for nutrition and space with the pathogen and within 24h quickly multiplied and colonized on the infected zone and intermingled with the hyphae of P. digitatum. The cells of C. famata adhered on the cell wall of the pathogen. After 48 h, C. famata highly multiplied, colonized and over dominated the zone and hyphae of P. digitatum are not present. It revealed that at 0 time i,e. inoculum of yeast was 5x106/ml in the wound which increases after 24 hs and after 48 h; the cfu/g estimated were 10x106±0.75b /g and 30x106±1.25c/g respectively. It indicated that C. famata multiplied, colonized and dominated in the wound of Citrus fruits. This experiment supports the finding of our SEM’s study. Both experiments (SEM and cfu /g analysis) revealed that C. famata in presence of P. digitatum can multiply, and colonize very quickly and over dominant or control the fungal pathogen.