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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Perennial Crops Laboratory » Research » Research Project #422910

Research Project: Genomic Characterization and Management of Fungal Diseases of Cacao

Location: Sustainable Perennial Crops Laboratory

Project Number: 8042-21220-252-00-D
Project Type: In-House Appropriated

Start Date: Apr 23, 2012
End Date: Apr 22, 2017

The goal of this project is to investigate the mechanisms involved in the interactions between cacao, pathogens of cacao, and biocontrol agents in order to develop effective disease management strategies leading to sustainable yield improvements of cacao. Over the next 5 years we will focus on the following objectives: Objective 1: Discover and characterize key disease-inciting genes and genetic pathways of Moniliophthora species pathogenic on cacao. Objective 2: Discover and characterize genes and genetic pathways of endophytic biological control organisms critical to limiting diseases caused by Moniliophthora species in cacao. Objective 3: Optimize and deploy biological agents and formulations for managing cacao diseases caused by Moniliophthora species.

Pathosystem/biocontrol interactions will be studied at the molecular level through transcriptome anaylsis using deep sequencing technologies which will exploit recently acquired plant and fungal genomes, and by microscopic analysis of florescent protein tagged microbes. The primary microbes targeted for study will be Trichoderma spp. and Moniliophthora roreri (frosty pod rot) but will also include Phytophthora species (black pod), Moniliophthora perniciosa (witches’ broom), and beneficial Bacillus spp. Specific microbial genes identified in the expression studies will be subjected to functional analysis to reveal their importance to pathogen/biocontrol/host interactions using transformation protocols and advanced RNAi techniques. Transcriptome sequences will be used to develop genetic markers (single nucleotide polymorphisms) for M. roreri to characterize its diversity throughout Latin America and to monitor population changes as they respond to the establishment of partially resistant cacao clones in Central America. Building on molecular knowledge and recent successes with biocontrol in the field, combinations of previously screened Bacillus and Trichoderma isolates will be evaluated in the field in Ecuador for synergy in managing cacao diseases. Biocontrol formulations will be optimized to reduce the cost of application by using low-cost, locally available components and minimizing application volumes. Ultimately, the best available biological agents and formulation combinations will be tested along with optimum management practices on large plots of elite cacao clones.