Xylella fastidiosa is a xylem-limited bacterium that colonizes a wide range of host plants. In most cases, X. fastidiosa does not cause disease and does not reach high populations within plants, while in a few exceptions infections become systemic, chronic, and severe disease symptoms occur. Disease symptoms are largely the consequence of xylem vessels becoming clogged with bacteria, leading to water stress and eventually the drying of leaves. It should be mentioned that symptoms vary from host plant species to host plant species, for example, in the case of citrus variegated chlorosis there is no significant leaf scorching, while that is common in oleander and almond trees, and represents the most typical disease symptom. Although much can be written about X. fastidiosa biology, here we provide links to a series of reviews that cover several topics that may be of interest.
Sandy Purcell summarized some of the history of X. fastidiosa research in a nice review article in 2013. A must read for most people interested in X. fastidiosa.
A discussion on how vector and pathogen introductions, as well as evolution, can drive the emergence of new diseases.
To read more about X. fastidiosa insect vectors, there is a 2004 review that is a good resource. The topic should probably be addressed again, as there is substantial new material to be covered. In addition, the rise of spittlebugs as important vectors in Europe deserves more attention, especially when it comes to what needs to be studied.insect vectors PDF
This review article introduced some still very useful concepts on X. fastidiosa plant and insect colonization, and how the pathogen moves from one host to another. A lot has happened since 2008, but the proposed concepts are supported by new data available and being generated.plant and insect colonization PDF
There are a few different reviews on X. fastidiosa genomics/functional genomics, but most of those are fairly old and a lot has changed since then. A more recent one, from 2014, is fairly thorough and would allow readers to identify previous work that addresses specific topics of interest.genomics PDF