The transcriptomic interactions of Harringtonia lauricola with Persea americana and the evaluation of avocado germplasm for tolerance to laurel wilt disease

Authors: KONKOL, JOSHUA - University Of Florida; Pisani, Cristina; BRAWNER, JEREMY - University Of Florida; ROLLINS, JEFFREY - University Of Florida

Submitted to: American Phytopathological Society
Publication Type: Proceedings
Publication Acceptance Date: 5/15/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Harringtonia lauricola is an invasive fungal pathogen that causes laurel wilt disease on North American trees in the Lauraceae. H. lauricola is lethal and can kill mature avocado trees (Persea americana) with as few as 40 conidia in several weeks, and it has devastated the Florida avocado industry. Managing laurel wilt disease of avocado depends upon quick rogueing of infested trees and fungicidal applications of trees bordering an outbreak, both of which are expensive for avocado growers. There is a need to further our understanding of the basic biology of the host-parasite interactions of avocado trees with H. lauricola to accelerate the development of new disease control methods. As a component of this goal, we utilized RNA-Seq to examine host and pathogen transcript dynamics pre- and post-symptom development. Additionally, identification of germplasm with tolerance to laurel wilt disease is highly desired for disease management. Previous trials with 45 commercial cultivars incorporating all three cultivated races of avocado have not found tolerance to laurel wilt. Therefore, we screened a large collection of half-sib avocado trees to search for tolerant germplasm outside of current commercial cultivars. We inoculated the trees in the field twice and chose the ten surviving trees with the lowest disease severity ratings. We clonally grafted these trees to perform two replicated trials in a greenhouse. Trials are ongoing, but the results of the field trials were promising.