Matteo Garbelotto

Associate Cooperative Extension Specialist, Adjunct Assistant Professor
Ph.D.  
B.S.  

338 Hilgard Hall
Berkeley, California
matteo@nature.berkeley.edu
office: 510-643-6412   lab: 510-643-6412   fax:  510-643-5438

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The main interest of my research is the study of microorganisms, and in particular fungi, in forest systems. One emphasis of my research program has been to elucidate the effects of ecological modifications, whether man-made or natural, in the ecology and the evolution of fungi. My approach has been to employ population genetics and phylogenetic approaches to unravel the basic biology and the evolutionary history of important pathogenic or mycorrhizal fungi. Clarification of biogeographical patterns within and among species boundaries, as well of genetic structure at the small, medium and large geographic scale enables us to understand the mechanisms regulating microbial evolution and biology. I have worked extensively on the root rot fungus Heterobasidion annosum and clarified several aspects of its biology. I have been able to detect hybridization between two highly pathogenic Heterobasidion species in California, and to link such phenomenon to logging and fire exclusion. I am currently trying to quantify the effects of such hybridization. I have also been studying variations of airborne fungal inoculum (e.g. spores) in the last few years both in California and in the Italian Alps. In the case of many wood decay pathogens, spores are responsible for primary infections of healthy trees. The ability to quantify spore loads allows for the determination of hazard levels related to weather conditions and time of year.

A second important emphasis of research ongoing in my laboratory is the study of introduced microorganisms in forest ecosystems. The introduction of exotic pests and pathogens often results in devastating epidemics that have the potential to forever change natural ecosystems. One interesting aspect of introductions though, is the unpredictability of the final outcome of such epidemics. A classical example is the outbreak of chestnut blight, a disease introduced from Asia both into North America and Europe. While both American and European Chestnuts are equally susceptible to the disease, the epidemics had different outcomes. While North America has lost the presence of chestnut as trees (they survive as coppice shoots), Europe has seen a "rebirth" of chestnuts, partly due to the presence of a viral disease of the pathogen itself.

There are at least 5 major introduced diseases in California:

1. White pine blister rust which is decimating sugar pines and seriously threatening other native 5 needle pines
2. Lateralis disease of Port Orford Cedar (Lawson cypress), which is decimating this Northern California host
3. Dutch Elm Disease, a disease which is changing our "urban forests"
4. Pitch canker disease of pines, a serious threat to a few coastal California pines (including Monterey pine, one of the most widely planted tree species worldwide)
5. Phytophthora ramorum, a newly discovered pathogen causing a lethal canker on species within the genus Quercus (oaks) and Lithocarpus (tanoak), and causing significant die-backs or leaf blight on at least 8 more plant species.

The goal of ongoing research in my lab is to determine a) the biological and ecological characteristics of introduced pathogens and b) the impact of such introduced organism on different or differently managed forests. I hope we will be able to change the way exotic pathogens have been traditionally dealt with in two ways: 1) by being able to detect them as early as possible thanks to the aid of DNA technology, and, 2) by better understanding the parameters of invasion by pathogens, so as to refine our ability to predict their overall impact.

I am currently working on defining parameters (stand structure, climatic, vectors) linked to the spread of the pathogen responsible for pitch canker disease of pies. Quantification of pathogen in the air, on plant surfaces, and on insects using sophisticated molecular tools will allow us to better predict its spread and will aid its identification on nursery and commercial plant stocks. The laboratory is also very involved in the discovery, exploration, and scientific research of a recently described disease dubbed as "Sudden Oak Death". This is, unfortunately, one of the most remarkably broad, aggressive and complex introduced diseases of our modern times. The laboratory is interested in all aspects of the research, from the evolutionary, to the population genetic, to issues dealing more with ecological and management aspects of the disease. Among other projects we are performing experiments aimed at determining whether the disease was introduced and potentially its area of origin, molecular diagnostic that is going to be used worldwide to screen for the presence of this deadly organism, the epidemiology, or spread, of the disease through the landscape. A special emphasis is given to potential management of the disease: we are performing experiments dealing with specific aspects of integrated pest management approach including chemical treatments and biological control.

A third line of research pursued in my laboratory is the study of those mushrooms that provide viable alternatives to timber production in our forests. As times change, natural resources become more limited, and public awareness of the need for sustainable land management (rather than sustainable production of any single item or service) increases, I believe mushrooms provide an essential resource for the people of California. Edibles are currently challenging the dominance of timber production in sales revenue: this is the first time in recorded history that renewable resources (in this case the Matsutake mushroom and truffles) have economically challenged timber production. Mushrooms like all microorganisms are an invaluable genetic resource. Their essential role as wood decayers and mycorrizal symbionts is an obvious reminder of the enormous resource they provide. Besides the practical direct uses of mushrooms (medicinal, culinary) that are easily linked to an economic value, these organism often provide us with invaluable cues on the basic biology of forest ecosystems, as well as on their overall health.

Ongoing projects on mushrooms (and related organisms) include studies the biogeography, phylogenetics, and population biology of Matsutake mushrooms, and a study on the genetic structure of fungal populations associated with the ever more endangered mangroves in the tropics. The ultimate goal of my studies on matsutakes is to provide biological information that may lead to a better understanding of both the potential for Matsutake production (maybe "collection" would be more appropriate as this species cannot be really grown mangroves are inspired by the need of better understanding the effects of habitat destruction and fragmentation on the microbial component of coastal habitats. My current interests are in studying various aspects of the biology and ecology of edible mushrooms in California, with a particular emphasis on mushrooms present in oak woodlands: these include well-appreciated species such as Matsutakes and Chantarelles.

Because of the mixed extension and research role of my laboratory emphasis is always given to research that will be of direct relevance to the environment and the people that live in it. Students and researchers in my lab will have ample opportunity to study pathogens and mushrooms, and, at the same time, share that knowledge not only with colleagues, but also with local communities and the general public.

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Davidson, J. M.; Garbelotto, M.; Hansen, E. M.; Reeser, P.; Rizzo, D. M. (2002 Annual Meeting of the American Phytopathological Society Milwaukee, WI, USA July 27-31, 2002). Another canker-causing Phytophthora from California and Oregon forest trees. In: Phytopathology June, 2002. 92 (6 Supplement): S17-S18.

Gonthier, P.; Garbelotto, M.; Nicolotti, G.. European pines may be simultaneously infected by more than one species of Heterobasidion. In: Plant Disease July, 2002. 86 (7): 814.

Rizzo, David M.; Garbelotto, Matteo; Davidson, Jennifer M.; Slaughter, Garey W.; Koike, Steven T. Ecological Society of America. (86th Annual Meeting of the Ecological Society of America Madison, Wisconsin, USA August 05-10, 2001). Recently discovered Phytophthora species may underlie epidemic oak mortality in California. In: Ecological Society of America Annual Meeting Abstracts 2001. 86 190.

Rizzo, D. M.; Garbelotto, M.; Davidson, J. M.; Slaughter, G. W.; Koike, S. T.. Phytophthora ramorum as the cause of extensive mortality of Quercus spp. and Lithocarpus densiflorus in California. In: Plant Disease March, 2002. 86 (3): 205-214.

Gonthier, Paolo; Garbelotto, Matteo; Varese, Giovanna Cristina; Nicolotti, Giovanni. Relative abundance and potential dispersal range of intersterility groups of eterobasidion annosum in pure and mixed forests. In: Canadian Journal of Botany September, 2001. 79 (9):

Garbelotto, M.; Rizzo, D. M.; Davidson, J. M. (Joint Meeting of the American Phytopathological Society, the Mycological Society of America, and the Society of Nematologists Salt Lake City, Utah, USA August 25-29, 2001). Studies in the genetics of a new Phytophthora species associated with Sudden Oak Death in California. In: Phytopathology June, 2001. 91 (6 Supplement): S110.

Garbelotto, M.; Rizzo, D. M. (Joint Meeting of the American Phytopathological Society, the Mycological Society of America, and the Society of Nematologists Salt Lake City, Utah, USA August 25-29, 2001). Preliminary studies on chemical and cultural control of Phytophthora associated with sudden oak death. In: Phytopathology June, 2001. 91 (6 Supplement): S30. 1057-1065.

Garbelotto, M., Svhira P., and D. Rizzo. 2001 Sudden oak death syndrome in California. Perspective on potential control of a new disease. California Agriculture, In Press

Garbelotto, M.; Chapela, I.. First report of Heterobasidion annosum on the endemic Abies hickeli of Southern Mexico. In: Plant Disease Septmeber, 2000. 84 (9): 1047.

Garbelotto M., Cobb F. W., Bruns T. D., Otrosina W. J., Popenuck T., and Slaughter G. 1999. The genetic structure of Heterobasidion annosum in white fir mortality centers in California. Phytopathology: 89 (7): 546-554.

Garbelotto, M., Otrosina W.J., Cobb F. W., and T. D. Bruns 1998. The European S and F intersterility groups of Heterobasidion annosum may represent sympatric protospecies. Canadian Journal of Botany 76: 397-409.

Bruns, T D; Szaro, T M; Gardes, M; Cullings, K W; Pan, J J; Taylor, D L; Horton, T R; Kretzer, A; Garbelotto, M; Li, Y. 1998. A sequence database for the identification of ectomycorrhizal basidiomycetes by phylogenetic analysis. Molecular Ecology 7: 257-272.

Garbelotto, M., Slaughter, G., Popenuck, T., Cobb, F. W., and T. D. Bruns 1996. Secondary spread of Heterobasidion annosum in white fir root-disease centers. Canadian Journal of Forest Research 27: 766-773.

Garbelotto, M., Lee, H. K., Slaughter, G., Popenuck, T., Cobb, F. W., and T. D. Bruns 1997. Heterokaryosis is not required for virulence of Heterobasidion annosum isolates. Mycologia, 89: 92-102.

Garbelotto, M., Ratcliff, A., Bruns, T. D., Cobb, F. W., Jr., and Otrosina, W. J. 1995. Use of taxon specific competitive priming PCR to study host specificity, hybridization, and intergroup gene flow. Phytopathology 86: 543-551.

Garbelotto, M., Bruns, T. D., Cobb, F. W., and Otrosina, W. J. 1993. Differentiation of intersterility groups and geographic provenances among isolates of Heterobasidion annosum detected by random polymorphic DNA assays. Can. J. Bot. 71: 565-569.348.