|Malmierca, Monica - University Of Leon|
|Izquierdo-bueno, Immaculada - University Of Cadiz|
|Cardoza, Rosa - University Of Leon|
|Alexander, Nancy - Retired ARS Employee|
|Moraga, Javier - University Of Cadiz|
|Gomes, Eriston - Universidad De Sao Paulo|
|Collado, Isidro - University Of Cadiz|
|Monte, Enrique - University Of Salamanca|
|Gutierrez, Santiago - University Of Leon|
Submitted to: Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2015
Publication Date: 8/6/2016
Publication URL: http://handle.nal.usda.gov/10113/5695390
Citation: Malmierca, M.G., Izquierdo-Bueno, I., McCormick, S.P., Cardoza, R.E., Alexander, N.J., Moraga, J., Gomes, E.V., Proctor, R.H., Collado, I.G., Monte, E., Gutierrez, S. 2016. Botrydial and botcinins produced by Botrytis cinerea regulate the expression of Trichoderma arundinaceum genes involved in trichothecene biosynthesis. Molecular Plant Pathology. 17(7):1017-1031.
Interpretive Summary: In this research we found that sesquiterpenes and polyketides are part of the arsenal of chemical weapons used between the biocontrol fungus Trichoderma arundinaceum and the plant pathogen Botrytis cinerea. T. arundinaceum produces the trichothecene sesquiterpene harzianum A (HA) which is toxic to other fungi but not toxic to plants and helps turn on genes for natural defenses that plants use to fight fungal pathogens. B. cinerea is an airborne fungus that causes pre-harvest soft rotting of field and greenhouse grown horticultural crops and post harvest rotting of vegetable, fruits, and flowers. We found that botrydial (BOT), a sesquiterpene toxin produced by B. cinerea that helps invade and kill plant tissues, also helps it combat the biocontrol fungus. In this research we found that BOT and other B. cinerea chemical weapons affect the genes for production of HA. This research provides scientists with tools to understand the complex interactions between fungi and their chemical weapons. Knowledge of how pathogenic and biocontrol fungi interact will aid in designing effective biocontrol strategies to combat plant fungal diseases.
Technical Abstract: Trichoderma arundinaceum (Ta37) and Botrytis cinerea produce the sesquiterpenes harzianum A (HA) and botrydial (BOT), respectively, and also the polyketides aspinolides (Asp) and botcinines (Botc), respectively. In the present work, we analyzed the role of BOT and Botcs in the T. arundinaceum-B. cinerea interaction, including transcriptomic changes of tri genes involved in HA biosynthesis and other terpene biosynthetic genes, as well as changes in the level of HA, squalene, and ergosterol. We found that when confronted with Botrytis, the Ta37 tri biosynthetic genes were up-regulated in all confrontation cultures analyzed, but at a higher level when Ta37 was confronted with bcbot2delta, a BOT non-producer mutant, indicating that BOT may attenuate tri biosynthetic genes expression. Production of HA was also higher in the confrontation area with this mutant. In Ta37- bcbot2delta confrontation experiments, expression of the HMG-CoA reductase gene hmgR was also up-regulated resulting in increased squalene production compared with the confrontation with B. cinerea B05.10, but the production of ergosterol was just slightly increased, as result of the erg7 down-regulation. Botcs had an up-regulatory effect on the tri biosynthetic genes, with BotcA having a stronger effect than BotcB. The results indicate that the confrontation itself exerted a stimulatory effect on expression of the tri biosynthetic genes, which in the confrontation region could be attenuated by BOT produced by B05.10, but was not affected when BOT was exogenously added. The present work shows that there is a metabolite dialogue between T. arundinaceum and B. cinerea and contributes to a better understanding about how these fungi interact with each other and their environment.