WWETAC Projects

Project Title:  DNA-based identification and characterization of root and heart rot disease pathogens from upland and lowland (mangrove) forests of the Pacific Islands and Hawaii

Principal Investigator:  Ned B. Klopfenstein, USDA Forest Service, Rocky Mountain Research Station, Moscow, ID


Collaborators:   Phil Cannon (USDA FS, FHP, Region 5), Fred Brooks (University of Hawaii, Manoa), Robert Schlub (University of Guam), Erick E. Waguk (Island Resource Management Program, Kosrae), Sara Ashiglar (USDA FS, RMRS, Moscow, ID),  John Hanna (USDA FS, RMRS, Moscow, ID), Mee-Sook Kim (Kookmin University, Seoul, South Korea), and others will be included as this project develops

Key Issues/Problem Addressed:                              

Several different root and heart rot pathogenic fungi are causing deleterious losses in forest tree growth and survival in Hawaii and many of the Pacific Islands (Phil Cannon personal observation and multiple trip reports to the Pacific, Brooks 2002). However, the pathogens causing this damage are still not well identified or characterized.  Studies designed to evaluate the full impact of root- and heart- rot diseases and to develop management practices for the most serious diseases are predicated on accurate identification of the fungal pathogen(s) that cause the disease.  In recent years, DNA-based identification of fungal pathogens has been shown to be an exceptionally accurate and convenient way to identify fungal pathogens associated with tree disease (e.g., Hoff et al. 2004; Ross-Davis et al. 2012). This project will (1) provide DNA-based identification of prominent root/heart rot-disease pathogens (e.g., Phellinus spp., Ganoderma spp., and previously undocumented or potentially invasive pathogens) collected in the Hawaii and the South Pacific Islands; (2) interpret results and coordinate root disease projects among Hawaii and Pacific Islands; and (3) provide technical exchange among involved cooperators and stakeholders.

Setting and Approach:  

Root- and heart-rot pathogens will be identified/verified and characterized by DNA sequencing. Isolates of root-/heart rot-disease (from previous and new surveys in the US Pacific Islands and Hawaii) will be provided by cooperators from USDA FS-FHP, universities, and other cooperators. This project will incorporate cooperators’ needs and provide consultation and coordination for their root-/heart- rot disease issues. We propose to use DNA sequencing to identify approximately 100 - 150 isolates of root and/or heart rot pathogenic fungi that will be collected in tropical upland and lowland forests of Hawaii and the Pacific Islands. Multiple DNA regions will be sequenced to identify disease pathogens. For example, we are particularly interested in Phellinus spp. (e.g., P. noxious) and Ganoderma spp. These root-disease pathogens are frequently found on many of the Pacific islands and are threatening to trees growing in mangroves, agroforestry systems, plantations, and native upland forests.

Progress to Date:
Proposed objectives for 2012-2013 were to identify/verify and characterize root/heart-rot disease pathogens by DNA sequencing. In FY2012, potential collaborators were contacted and collection/shipping information, shipping permits, and collection materials were sent to collaborators in Hawaii, Federated States of Micronesia (FSM), and American Samoa. Supplies were purchased for fungal culture, DNA extraction, PCR, and DNA sequencing preparation. Preliminary samples were tested, and fungal samples were received from FSM and Hawaii. Each sample has associated collection information, such as GPS location, host, photos, etc.  DNA analyses for 18 fungal specimens, primarily from Hawaii have been initiated. Some samples were received in culture and other samples were received as “fresh” or dried fruiting bodies. DNA has been extracted from all fruiting bodies, initial PCR has been performed on the ITS (internal transcribed spacer) regions, and PCR products are being prepared for DNA sequencing. In addition, repeated attempts were performed to isolate and culture fungi from “fresh” fruiting bodies, but with low success. DNA from all cultured samples has been processed for sequencing, and some sequencing has been completed. A majority of cultures represent a non-target fungus that likely occurs in association with the fungal fruiting body, but their biological significance remains unknown.

It is highly likely that several root/heart rot-disease pathogens will be found in areas where they were not previously known to exist. Also, the existence of previously documented root/heart rot-disease pathogens will be verified, and pathogens will be taxonomically identified to currently recognized species. Mycologists and forest pathologists with necessary expertise will be contacted for collaboration on pathogens of specific taxa. DNA-based characterization of root/heart rot-disease pathogens will help forest health professionals to 1) validate disease surveys with pathogen identification; 2) assess ecological risks posed by specific pathogens/strains; and 3) detect and monitor new pathogen introductions. Ultimately, this information benefits forest managers by identifying areas where root/heart rot pathogens are a critical consideration for selecting appropriate management practices


WWETAC ID:      FY12NG109