Understanding ascochyta blight pathogen
Ascochyta blight is a fungal disease that affects peas, chickpeas and other important legume crops. This disease is currently a major limiting factor to the productivity of these crops, which are valued for food and their ability to improve soils. With the support of EU funding, the ASCOTRANSSEQ project aimed to better understand the fungus that causes ascochyta blight by using high-throughput sequencing techniques. Specifically, researchers looked for genes that were associated with pathogenicity (i.e. infectivity and plant damage). An important output of the project was a consensus genome sequence of one ascochyta species, A. rabiei, pieced together from four variants of the fungus. Another aspect of the project identified all of the genes transcribed by the fungus during its growth in presence and absence of its host. More than 22 000 genes were identified as part of this process; 597 of these are more expressed when the fungus is growing on a plant. From this information, researchers determined individual genetic changes that enable the fungus to infect the plant. Among these, ASCOTRANSSEQ identified genes to disable plant defence systems and plant cell wall-degrading enzymes, as well as toxins to kill plant cells and enzymes to digest dead plant cells. ASCOTRANSSEQ has produced a vast amount of information about the genetics of the Ascochyta fungus. This will underscore research into methods to prevent and treat ascochyta blight, and may have a far-reaching impact on legume agriculture.
Keywords
Ascochyta blight, legume, fungal disease, genome sequencing, virulence
