Needle blight caused by the fungus Dothistromaseptosporum.
(Rosie Bradshaw, Ph.D., Massey University, New Zealand)
The disease that causes leaf mold on a tomato was first reported in the 1800s but hasn’t posed a major economic threat for several decades. Needle blight affects pine species around the world, causing severe economic losses. At first glance, the diseases appear unrelated but they are both caused by related fungal plant pathogens from the class Dothideomycetes. Additionally, both pathogens infect the plants through similar approaches, starting at the leaves and working their way into the pores or stomata.
In areport published online November 29, 2012 in PLoS Genetics, a team of researchers including scientists from the DOE Joint Genome Institute sequenced and then compared the genomes of these two fungal plant pathogens. The project is part of a larger Community Sequencing Program project to sequence several fungal species from the Dothideomycetes.
The researchers found that even though the genome of the tomato plant pathogen was half that of the repeat-rich pine pathogen at just 30.2 million basepairs, they both have the genes that cause needle blight, though these are not active in the tomato pathogen. Also both pathogens share more than 6,000 homologous gene models.
“Overall, our comparison of the two genomes suggests that even closely related plant pathogens could adapt to very different hosts and lifestyles by differentiating gene content and regulation, whilst retaining genetic signatures of a common ancestral way of life,” they concluded.