RT Journal Article SR Electronic(1) A1 Labroussaa, Fabien A1 Ionescu, Michael A1 Zeilinger, Adam R A1 Lindow, Steven E A1 Almeida, Rodrigo P. PYR 2017 T1 A chitinase is required for Xylella fastidiosa colonization of its insect and plant hosts JF Microbiology, VO 163 IS 4 SP 502 OP 509 DO https://doi.org/10.1099/mic.0.000438 PB Microbiology Society, SN 1465-2080, AB Xylella fastidiosa colonizes the xylem network of host plant species as well as the foregut of its required insect vectors to ensure efficient propagation. Disease management strategies remain inefficient due to a limited comprehension of the mechanisms governing both insect and plant colonization. It was previously shown that X. fastidiosa has a functional chitinase (ChiA), and that chitin likely serves as a carbon source for this bacterium. We expand on that research, showing that a chiA mutant strain is unable to grow on chitin as the sole carbon source. Quantitative PCR assays allowed us to detect bacterial cells in the foregut of vectors after pathogen acquisition; populations of the wild-type and complemented mutant strain were both significantly larger than the chiA mutant strain 10 days, but not 3 days, post acquisition. These results indicate that adhesion of the chiA mutant strain to vectors may not be impaired, but that cell multiplication is limited. The mutant was also affected in its transmission by vectors to plants. In addition, the chiA mutant strain was unable to colonize host plants, suggesting that the enzyme has other substrates associated with plant colonization. Lastly, ChiA requires other X. fastidiosa protein(s) for its in vitro chitinolytic activity. The observation that the chiA mutant strain is not able to colonize plants warrants future attention to be paid to the substrates for this enzyme., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000438