Authors
Marcin Nowicki, Research Institute of Horticulture, Department of Genetics, Breeding and Biotechnology of Vegetable Plants, Skierniewice, Poland;
Majid R. Foolad, Department of Horticulture and The Intercollege Graduate Degree Programs in Plant Biology and Genetics, The Pennsylvania State University, University Park; and
Marzena Nowakowska and
Elzbieta U. Kozik, Research Institute of Horticulture, Department of Genetics, Breeding and Biotechnology of Vegetable Plants, Skierniewice, Poland
Abstract
Late blight (LB) 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 LB 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 LB 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 LB control. These measures would include the use of
cultural practices, selective fungicide applications, and genetic resistance. In
potato at least a dozen major resistance genes and several quantitative trait
loci (QTLs) for LB resistance have been identified, and most modern cultivars
have been bred with one or more resistance genes. In tomato, though most
commercial cultivars are susceptible to LB, a few major resistance genes and
several QTLs have been identified and several breeding programs around the world
are developing breeding lines and commercial cultivars with LB resistance. Most
recently, a few fresh-market tomato hybrid cultivars with LB resistance were
released by the North Carolina State University Tomato Breeding Program in the
United States. There is, however, an insufficient number of potato and tomato
cultivars with LB resistance, resulting in continued expensive as well as the
hazardous and increasingly ineffective use of chemicals for disease control. In
an era when both host plants and P. infestans genomes are sequenced and
considerable genomic information is available, it is not unexpected that a more
sustainable solution to controlling LB is on the horizon. In this review, we
summarize the 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.
