Internalization and Survival of Pseudomonascorrugata from Flowers to Fruits and Seedsof Tomato Plants

摘要

Pseudomonas corrugata, the causal agent of tomato pith necrosis, maycause severe losses on tomato worldwide. Control is based on the use of pathogen-free propagating materials and on the reduction of the inoculum in soil where thepathogen is apparently resident. Although P. corrugata has been isolated from soil,seeds and plantlets, little is known about its transmission, epidemiology and sourceof inoculum. Bioluminescent P. corrugata strain PVCT 4.3t lux 18 was spray-inoculated to flowers and immature tomato fruits of plants grown in greenhousewith the aim to monitor survival and transmission during fruit development andripening. Bacterial population was evaluated on surface, pulp and seeds of tomatofruits harvested at the mature stage. Identity of P corrugata PVCT 4.3t was confirmedby colony morphology on NDA, growth on selective medium, and PCR assay. Alltomato fruits produced from inoculated flowers and green tomatoes contained atthe mature stage the pathogen on the surface (100% in enriched samples) as wellas in the pulp homogenates (100% before enrichment). P. corrugata was recoveredfrom the surface and from the pulp of tomatoes after 20 days of fruit storage at4°C. The pathogen was also recovered from the seeds of tomato fruits producedfrom inoculated flowers. Results suggests that P corrugata can be internalized andtransmitted from flowers to fruits and seeds, thus surviving in the tissues and seedsduring fruit development and ripening.