World Cocoa Foundation Research Update: March 2009

Robert D. Lumsden, Plant Pathologist and WCF Scientific Advisor

RESEARCH GROUPS:

From Lyndel Meinhardt, lyndel.meinhardt@ars.usda.gov, Research Leader, Sustainable Perennial Crops Lab., USDA/ARS, Beltsville, MD. Brazilian researchers from Campinas, Piracicaba and São Paulo, in the state of São Paulo, in Ilhéus, Itabuna, Feira de Santana and Salvador in Bahia and Brasília along with researchers from the USDA and Penn State University in the USA recently published a draft genome of the cacao pathogen Moniliophthora perniciosa, the causal agent of Witches' Broom Disease (WBD).This cooperative accomplishment required pulling together information from diverse locations and institutions. The hemibiotrophic basidiomycete colonizes cacao meristems and pods as a biotrophic pathogen, and together with it closely related sister pathogen M. roreri, the pathogen that causes Frosty Pod Rot Disease, represent two of the most devastating fungal disease of Theobroma cacao. This survey gives an overview of the M. perniciosa genome and provides new evidence of adaptive traits that could play a key role in the disease process. These results will be useful in developing defense methods for reducing losses from the pathogens. The article was listed in the February WCF Research Update and can be accessed through the WCF virtual library. Mondego,J.M.C.; Carazzolle,M.F.; Costa, G.G.L.; Formighieri, E.F.; Parizzi1, L.P.; Rincones, J.; Cotomacci, C.; Carraro, D.M.; Cunha, A.F.; Carrer, H.; Vidal, R.O.; Estrela, R.C.; Garcia, O.; Thomazella, D.P.T.; de Oliveira, B.V.; Pires, A.B.L.; Rio, M.C.S.; Araujo, M.R.R.; de Moraes, M.H.; Castro, L.A.B.; Gramacho, K.P.; Gonçalves, M.S.; Moura Neto, J.P.; Goes Neto, A.; Barbosa, L.V.; Guiltinan, M.J.; Bailey, B.A.; Meinhardt, L.W.; Cascardo, J.C.M.; Pereira, G.A.G. A genome survey of Moniliophthora perniciosa gives new insights into Witches' Broom Disease of cacao. BMC Genomics, vol. 9, 548-573, 2008.

From V.C. Baligar, vc.baligar@ars.usda.gov, Sustainable Perennial Crops Lab., ARS/USDA, Beltsville. Flora Piasentin has won the European Peccei Scholarship award for her work on Suitability for different cacao agroforestry production systems in Bahia. The Selection Committee for the Peccei and Mikhalevich Scholarships has completed its review of the 2008 nominations. The winner of the Peccei Scholarship is Flora Piasentin of the Federal University of Brasilia in Brazil. The Mikhalevich Scholarship goes to German, Jan Ohlberger from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Berlin. Flora is a second year Ph.D. student in Sustainable Development, with emphasis on Environmental Policy and Management, at the University of Brasilia, Brazil. She graduated in 2001 from the University of Padova, Italy, in Agronomy, and received her Master's degree in Management of Agricultural Knowledge Systems in 2003 from the University of Wageningen, the Netherlands. During her three month stay in IIASA's Land Use Change and Agriculture Program, Flora completed a study entitled "Assessing the Suitability for Cacao in Bahia State (Brazil) by combining the Farming Systems Approach and the Agro-Ecological Zones. Her research assessed the land suitability for different cacao agroforestry production systems in Bahia. Her study was rated by reviewers as "...of direct relevance to the targeting of cocoa management, development and policy interventions ...the application of the combined Farming Systems-AEZ approach to tree crops in general and cocoa in particular is novel and valuable ...the research topic acts on an important, but not sufficiently studied subject."

Research Report from Allen Herre, herrea@si.edu, Smithsonian Tropical Research Institute, Panama. March 2009 report to WCF for the research group: Edward Allen Herre, Sunshine Van Bael, Enith Rojas, Luis Mejia, & Terri Shirshac.

Enith Rojas’ work with Gary Samuels and Steve Rehner and Amy Rossman at the ARS/USDA Systematic Mycology and Microbiology Lab in Beltsville, Maryland.Enith’s work has primarily focused on producing a comprehensive revision of the economically important fungal genus Colletotrichum.

Of particular interest has been documenting the host associations and relationships of different Collectotrichum species (that either appear to be beneficial symbionts or pathogens on different host plants). One central point is determining the extent to which we can feel confident in applying strains of Colletotrichum as biocontrol agents. Specifically, both our lab in Panama, as well as Pierre Roger Tondje in West Africa, have demonstrated the capacity of some Colletotrichum strains to reduce Phytophthora damage in both greenhouse and field experiments.

In addition, there have also been several side projects of direct or indirect interest and applicability to understanding and using endophytic fungi for biocontrol. For example, Enith and the others have identified and described a new species of leaf endophyte from Panama, Endomelanconium endophyticum.

Other primary work is closely linked with the general work described aboveand has involved work with Siela Maximova and Mark Guiltinan at Penn State University. This ollaboration is documenting the effects of different endophytes (but again, primarily of beneficial endophyte culture of Colletotrichum gloeosporoides that we have been studying in Panama ) on the expression of host genes. We are focusing on host gene systems that are involved with host pathogen or herbivore defenses and / or the physiological responses which we have documented. The basic result is that we can match up the existence, the time course and the effects of induction of different host genes and link them to phenotypic expression in the host (disease resistance, physiological effects, etc.) in the host.

The citation list of articles (from 2008 and upcoming in 2009) supported by WCF:

Mejía, L.C., E. I. Rojas, Z. Maynard, A. E. Arnold, S.A. Van Bael, G. J. Samuels, N. Robbinsa, and E.A. Herre (2008) Endophytic fungi as biocontrol agents of Theobroma cacao pathogens. Biological Control 46: 4-14. Click here to view the full article.

Rojas, E.I., E.A. Herre, L.C. Mejía, P. Chavarri, and G.J. Samuels (2008) Endomelanconium endophyticum, a new Botryosphaeria leaf endophyte from Panama. Mycologia 100(5): 760-775. Click here to view the full article.

Van Bael, S.A., M.I. Valencia, E.I.Rojas, E.I., N. Gomez, D.M. Windsor, and E.A. Herre (in press, Biotropica) Effects of foliar endophytic fungi on the preference and performance of a leaf beetle, Chelymorpha alternans (Chrysomelidae: Cassidinae).

Mejía, L.C, E.A. Herre, A.J. Singh, V. Singh, N. Vorsa, J. F. White Jr. (in press) Fungal endophytes: defensive characteristics and its agricultural application. In Defensive Mutualism in Microbial Symbiosis. J.F. and M. Torres (Eds). Taylor & Francis Group.

Van Bael, S.A., H. Fernandez-Marin, M. Valencia, E.I. Rojas, W.T. Wcislo, and E.A. Herre (in press, Proceedings of the Royal Society) Two fungal symbioses collide: Endophytic fungi are not welcome in leaf-cutting ant gardens.

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