Abstract
An isolate of Pseudornonas cepacia (ID 2131) inhibited germination of Penicillium digitatum and showed strong ability to protect wounded oranges from infection by P. digitatum. The protective ability of this bacterial strain was closely related to cell concentration within the range of 1.8 × 105 to 109 cfu/mL (r=0.867). The mode of action in biocontrol provided by this antagonist is possibly due to the production of an antibiotic and to spatial separation of the fungal spores from the damaged fruit tissue. Brown pigmentation appeared around some wound sites when the cell concentration exceeded 107 cfu/mL. At injured sites, the activity of phenylalanine ammonia lyase was suppressed and the accumulation of lignin inhibited. Suppression of the host wound healing by the bacteria may make the niche at the wound sites unfavourable for the bacteria to survive. If P. cepacia (ID 2131) was mixed with a strain of P. cepacia (ID 2129) that promoted infection by P. digitatum before being applied onto the fruit, the effect of biocontrol was lost.
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Huang, Y., Deveral, B.J. & Morris, S.C. Effect of Pseudomonas cepacia on postharvest biocontrol of infection by Penicillium digitatum and on wound responses of citrus fruit. Australasian Plant Pathology 22, 84–93 (1993). https://doi.org/10.1071/APP9930084
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DOI: https://doi.org/10.1071/APP9930084