Gray mold, Botrytis cinerea, is probably the most ubiquitous plant disease in nursery and small fruit production. We are attempting to improve our understanding of how B. cinerea colonizes and infects plants. This knowledge will be used to develop strategies for controlling this problematic disease. In order to gain these insights, we have developed a variant of B. cinerea that expresses a gene from a jelly fish that results in the fungus glowing green when exposed to UV light. We can then observe germination and colonization or infection of plant tissues without destroying the plant tissue. This allows us to observe the same spores over time and to avoid short comings of previous techniques.

Colonization and infection of Strawberry flowers by Botrytis cinerea modified to express the green fluorescent protein. A) conidia adhering to an anther; B) same anther in A - 3 days later infected by B. cinerea with mycelia radiating out to nearby senescing anthers and stigma. C) infected stigma with mycelia ramifying down to the ovum; D) infected stigma with mycelia radiated and infecting neighboring stigma; E) Infected anther from A with mycelia radiating from and infecting sepals. Images B-E are from flowers that were inoculated just as the flower opened and incubated over night under conditions of high humidity and dew formation then maintained under dry conditions for 10 days prior to exposure to simulated extended rainy period of 48 h.

Scientist: Walt Mahaffee