Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2003
Publication Date: 2/1/2004
Citation: Huang, Q., Sherald, J. 2004. Isolation and phylogenetic analysis of xylella fastidiosa from its invasive alternative host, porcelain berry. Current Microbiology. 48:73-76. Interpretive Summary: The plant pathogen Xylella fastidiosa has long been known to have an extraordinary host range, infecting a very wide range of environmental hosts, from which it can be transmitted to economically important hosts. Genetic relationships between strains of X. fastidiosa isolated from economically important hosts and alternative environmental hosts are currently unknown and greatly needed for the development of control strategies for diseases caused X. fastidiosa. X. fastidiosa is a slow growing, xylem inhabiting, nutritionally fastidious and insect-transmitted bacterium. It is associated with bacterial leaf scorch and decline in many economically important landscape trees and shrubs including elm, oak, sycamore, maple and oleander. The bacterium also causes significant economic losses in many agriculturally important plants including grape (Pierce¿s disease) and citrus (citrus variegated chlorosis) in the United States and Brazil, respectively. In order to determine how X. fastidiosa strains from alternative environmental hosts are related genetically to other hosts, we first isolated X. fastidiosa from alternative hosts porcelain berry and wild grape. We then determined their genetic relationships with each other and with strains from grape, peach, plum, oak, mulberry, maple and oleander. We found that these alternative host strains of X. fastidiosa are more closely related to the oak, peach and plum strains. Suppression of the alternative host plants may be important for the control of diseases caused by X. fastidiosa in oak, peach and plum. Our work will be of value primarily to plant pathologists and entomologists interested in diseases caused by X. fastidiosa.
Technical Abstract: A strain of X. fastidiosa was isolated from an invasive alternative host species, porcelain berry. Its genetic relationship with strains isolated from a native alternative host, wild grape, and other economically important hosts including grape, peach, plum, oak, mulberry, maple and oleander was determined using sequence analysis of the 16S-23S rRNA intergenic spacer region. Our phylogenetic analysis revealed that the porcelain berry strain is most closely related to the wild grape strain. These two strains are more closely related to the oak, peach and plum strains than to the mulberry and oleander strains. They are separated from the maple and cultivated grape strains. Our data suggest that suppression of porcelain berry and wild grape in the vicinity of susceptible economically important hosts such as oak, peach and plum may provide an important control measure for diseases caused by X. fastidiosa.