One of the main challenges in studying Xylella fastidiosa is that the bacterium has a fastidious in vitro growth, i.e., it is difficult to isolate and culture. That characteristic is one of the reasons why a formal description and naming of X. fastidiosa as the causal agent of Pierce’s vine disease occurred in 1987 only, 95 years after the first report on the infection (1892).
The study uses genome-scale metabolic network reconstruction, modeling, and experimental validation to explain the fastidious growth of the bacterium. Previous studies suggested that X. fastidiosa was limited in aerobic respiration; the researchers carried out a comparative analysis with bacteria such as Escherichia coli and Ralstonia solanacearum. The exercise reveals that X. fastidiosa has undergone a severe metabolic pathway reduction, associated with its reduced genome size and globally less efficient enzymatic activities than the other organisms examined.
According to the results, the pathogen’s metabolic network is strikingly minimalist and lacks robustness, most probably due to the absence of highly efficient enzymes and a global inefficiency in virulence factor production with high carbon losses. These results support the idea that the fragility of the metabolic network may have been shaped during evolution to lead to the self-limiting behavior of Xf.
Read/download via American Society for Microbiology: https://doi.org/10.1128/MSYSTEMS.00698-19