Award Abstract # 2303713
Mechanisms of Pathogenicity and Host Specificity of the Oomycete Plant Pathogen Phytophthora palmivora

NSF Org: IOS
Division Of Integrative Organismal Systems
Recipient: UNIVERSITY OF HAWAII
Initial Amendment Date: July 26, 2023
Latest Amendment Date: July 26, 2023
Award Number: 2303713
Award Instrument: Continuing Grant
Program Manager: Courtney Jahn
cjahn@nsf.gov
 (703)292-7746
IOS
 Division Of Integrative Organismal Systems
BIO
 Directorate for Biological Sciences
Start Date: August 1, 2023
End Date: March 31, 2024 (Estimated)
Total Intended Award Amount: $225,000.00
Total Awarded Amount to Date: $25,000.00
Funds Obligated to Date: FY 2023 = $0.00
History of Investigator:
  • Miaoying Tian (Principal Investigator)
    mtian@uga.edu
  • Erica Goss (Co-Principal Investigator)
Recipient Sponsored Research Office: University of Hawaii
2425 CAMPUS RD SINCLAIR RM 1
HONOLULU
HI  US  96822-2247
(808)956-7800
Sponsor Congressional District: 01
Primary Place of Performance: University of Hawaii at Manoa
3190 Maile Way, St. John 304
HONOLULU
HI  US  96822-2243
Primary Place of Performance
Congressional District:
01
Unique Entity Identifier (UEI): NSCKLFSSABF2
Parent UEI:
NSF Program(s): Plant-Biotic Interactions
Primary Program Source: 01002324DB NSF RESEARCH & RELATED ACTIVIT
01002627DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 112Z, 1228, 7744, 9178, 9179
Program Element Code(s): 047Y00
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.074

ABSTRACT

Phytophthora palmivora is a fungus-like eukaryotic microorganism that causes devastating diseases of numerous agriculturally and ecologically important plants, including cacao, a tropical perennial tree that produces the major component of the multi-billion-dollar chocolate industry. The annual global loss on cacao due to diseases caused by P. palmivora is at least one billion U.S. dollars. As a very aggressive pathogen, P. palmivora is often capable of infecting almost all plant parts of a host, rendering its control extremely challenging. As a result, it has become an increasing threat to agricultural production and ecosystems. Diseases caused by P. palmivora are managed by frequent application of fungicides with limited success. The long-term goal of this project is to develop novel, effective and environmentally friendly strategies to control P. palmivora based on the fundamental understandings of its infection mechanisms. To this end, the specific objectives of this project are to identify the key pathogenicity factors of P. palmivora, how these factors act on plant cellular components to contribute to disease, and how their presence/absence in a P. palmivora isolate determines which plant species to infect. This project is expected to generate significant foundational knowledge essential for developing desirable disease control measures, thereby significantly contributing to food security, sustainability of natural ecosystems and the bioeconomy. In addition, the project will contribute to STEM workforce sustainability by providing training opportunities to graduate, undergraduate and high school students, and introducing plant pathology and gene-editing technology to middle/high-school teachers to attract a new generation into agriculture and life sciences.

Oomycetes form a distinct phylogenetic lineage of eukaryotes, with many causing devastating diseases of plants and animals. Phytophthora palmivora is a destructive broad-host-range oomycete plant pathogen with host specificity. P. palmivora delivers a diverse array of effectors to manipulate the host cellular processes to facilitate infection, including the superfamily of RxLR effectors that are defined by an N-terminal signal peptide followed by a canonical RxLR (or RxLR-EER) translocation motif that mediates entry into host cells. The P. palmivora RxLR effector designated PpalRxLR1 contains a functional nuclear localization signal with potential DNA-binding activities and was identified as a key pathogenicity factor on cacao. It is present in all examined P. palmivora isolates obtained from cacao infections, but exhibits presence/absence polymorphisms across the species, suggesting that it may be a determinant of host range and specificity. This project is to: 1) determine the mechanisms by which PpalRxLR1 confers pathogenicity on cacao by determining its nuclear-localized molecular interaction dynamics and the subverted host cellular processes during infection, 2) determine the role of PpalRxLR1 as a key component in host range evolution of P. palmivora by analyzing its evolution relative to the species and association with host range, 3) identify additional effectors with key roles in pathogenicity of P. palmivora on specific or a broad range of hosts using the natural variation of P. palmivora isolates. Integrating across specific aims is expected to transform understanding of the molecular basis of pathogenicity and host range evolution of P. palmivora, key aspects of plant-microbe interactions.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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