Xylella fastidiosa-Elicited Leaf Scorch Diseases in Taiwan

Abstract

Xylella fastdiosa is a gram negative, nonflagellate, nutritionally fastidious bacterium that resides only in xylem tissues and requires specific and enriched media for in vitro growth. Two X. fastidiosa-elicited leaf scorch diseases, pear leaf scorch (PLS) and Pierce’s disease (PD), were found in Taiwan in 1991 and 2002. Phylogenetic analyses using 16S rRNA gene and 16S-23S internal transcribed spacer sequence (ITS) revealed that the Taiwan PLS and PD strains may have been independently introduced into and evolved in the host plants. The completion of PLS genome sequences will provide valuable insights into the genome organization and genetic components that diversify PLS bacteria from the other X. fastidiosa strains.