Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2020
Publication Date: 8/8/2020
Citation: Wallis, C.M. 2020. Phenotype microarray profiling to characterize differences between Xylella fastidiosa subspecies. American Phytopathological Society Abstracts. 110:S2.16. https://doi.org/10.1094/PHYTO-110-12-S2.1.
Technical Abstract: Various subspecies and strains of Xylella fastidiosa (X. f.) may cause Pierce’s disease of grapevine (X. f. ssp. fastidiosa) or almond leaf scorch and other bacterial leaf scorch diseases (X. f. ssp. multiplex) in California. Other subspecies may cause a variety of other serious diseases throughout the world. Defining traits that vary between X. f. subspecies and strains is key to understanding inherit differences that result in subspecies host ranges and relative aggressiveness. Therefore, phenotype microarrays were conducted on different subspecies of X. f. (ssp. multiplex or spp. fastidiosa) to observe how bacterial growth is affected by 2,000 different growth conditions including exposure to many different compounds. Preliminary work revealed that both X. f. subspecies exhibited greater growth at higher pH levels, generally those from pH 8.0 to 9.5. Of all compounds tested, various phenolic compounds, such certain flavonoid glycosides, affected growth among X. f. subspecies, with X. f. ssp. fastidiosa growing well at levels greater or equal to 2 ppm whereas X. f. ssp. multiplex did not grow at levels greater than 0.5 ppm. Grapevine xylem phenolic levels reach roughly 2 to 5 ppm, and therefore it would appear that X. f. ssp. fastidiosa would be adapted to infect grapevines whereas X. f. ssp. multiplex would not. Additional compounds and subspecies are undergoing testing. Completion of this research will improve understanding about requirements for X. f. infection and could result in the development of novel management techniques to control Xylella-caused diseases.