Potato and Tomato Late Blight is caused by fungi Phytophthora infestans. The disease caused one of the proportionally largest historical famines – the Great Famine in Ireland. It began in 1845 because of this potato disease, which is still today very harmful to their plant hosts.
In the Plant disease journal an overview of pathology and plant resistance breeding has been published recently. Recent achievements in better understanding of the P. infestans pathogenesis, host-pathogen interactions, and the progress made in developing genetic resistance in potato and tomato is summarized bellow. Late blight caused by the oomycete Phytophthora infestans, is a major disease of potato and tomato worldwide and can cause up to 100% yield losses.
The devastating economic impact of this disease intensified the related pathology and genetics research since the occurrence of Irish famine in 1840s, with a side gain of major scientific discoveries. For example, many of the crucial steps involved in Late blight defense response in host plants have been elucidated through the use of modern cytological and molecular biology techniques. Also, genetic and biochemical studies have revealed differences between oomycetes and pathogenic fungi, which has led to more selective use of chemicals for Late blight control. Furthermore, the discovery of P. infestans two mating types and the resultant generation of more aggressive lineages by sexual recombination stresses the need for an integrated and sustainable approach to Late blight control.
These measures would include the use of cultural practices, selective fungicide applications, and genetic resistance. Most recently, a few fresh-market tomato hybrid cultivars with Late bligh resistance were released in the United States. There is, however, an insufficient number of potato and tomato cultivars with Late blight resistance, resulting in continued expensive as well as the hazardous and increasingly ineffective use of chemicals for disease control.
The authors of the article conclude with a vision that in an era when both: host plants and P. infestans genomes are sequenced and considerable genomic information is available, a more sustainable solution to controlling Late blight could be expected.