Evolution and Management of the Irish Potato Famine Pathogen Phytophthora Infestans in Canada and the United States

Abstract

Late blight, caused by Phytophthora infestans (Mont.) de Bary, is the most historically significant and economically destructive disease of potatoes (Solanum tuberosum L.). In addition to potato, P. infestans can also infect tomato and some other members of the Solanaceae, and this has contributed to the recent late blight epidemic in Canada and the United States. Propagation of P. infestans in Canada and the United States has been mainly through asexual reproduction and this has led to the development of several dominant clonal lineages. Various P. infestans markers have been developed that are invaluable in monitoring the evolution and movement of these P. infestans genotypes. Population diversity and disease incidence has increased through the development of systemic fungicide insensitivity and the transcontinental shipment of the pathogen on late blight infected potato tubers and tomato plantlets. Introduction of the P. infestans A2 mating type to several regions of Canada and the United States has also increased the opportunity for sexual reproduction and recombination, potentially contributing to greater P. infestans genetic diversity and pathogenicity. Advances in P. infestans molecular analysis have revealed a complex pathogen with a genome capable of evolving relatively quickly. Management of late blight will therefore require new, multifaceted strategies which include monitoring pathogen evolution and implementing sustainable production practices.Resumen El tizón tardío, causado por Phytophthora infestans (Mont.) de Bary, es la enfermedad históricamente más significativa y económicamente destructiva de papa (Solanum tuberosum L.). Además de la papa, P. infestans también puede infectar tomate y a otros miembros de la familia Solanaceae, y esto ha contribuido a la reciente epidemia de tizón tardío en Canadá y los Estados Unidos. La propagación de P.infestans en estos dos países ha sido principalmente mediante reproducción asexual, lo que ha conducido al desarrollo de varias líneas clonales dominantes. Se han desarrollado varios marcadores para P. infestans que son invaluables en el seguimiento de la evolución y movimiento de estos genotipos de P. infestans. La diversidad de la población y la incidencia de la enfermedad han aumentado por vía del desarrollo de la insensibilidad a fungicidas sistémicos y del envío transcontinental del patógeno en tubérculos de papa infectados con tizón tardío y en plántulas de tomate. La introducción del tipo de compatibilidad A2 de P. infestans a varias regiones de Canadá y Estados Unidos también ha incrementado la oportunidad de reproducción sexual y recombinación, contribuyendo, potencialmente, a una mayor diversidad genética y patogenicidad de P. infestans. Avances en los análisis moleculares de P. infestans han revelado a un patógeno complejo con un genomio capaz de evolucionar relativamente rápido. El manejo del tizón tardío, entonces, requerirá de nuevas estrategias multifacéticas que incluyan monitoreo de la evolución del patógeno y la implementación de prá...

Evaluating Late Blight Severity in Potato Crops Using Unmanned Aerial Vehicles and Machine Learning Algorithms

“…Late Blight is historically and economically the most important disease affecting potato (Solanum tuberosum L.) crops worldwide [1]. Late Blight is caused by the Phytophthora infestans oomycete.…”

“…In countries where the occurrence of late blight is persistent, as is the case of Colombia, growers assume that the pathogen is present and apply pesticides prophylactically [3]. Phytophthora infestans (P. infestans, from now on) population diversity and disease incidence has increased through the development of systemic fungicide resistance [1]. Hence, it is important to perform a timely and reliable evaluation of P. infestans incidence in the crop to rationally apply fungicide and to study Late Blight resistance of diverse potato genotypes.…”

Differential Potential of Phytophthora capsici Resistance Mechanisms to the Fungicide Metalaxyl in Peppers

“…A metalaxyl-resistant strain of P. infestans was discovered in the Netherlands in 1980 [6]. Subsequently, European and American countries reported metalaxyl-resistant strains of P. capsici [7][8][9]. China also reported resistant P. capsici in the 1960s [10].…”

Complete mitogenome mapping of potato late blight pathogen, Phytophthora infestans A2 mating type

“…Population displacement by genotypes with increased fitness is a recurrent event, for instance in India both MTs exists, with A 2 MT completely replacing A 1 MT in the hills and almost stabilizing, while in the plains A 1 MT has established itself (Chimote et al 2010;Arora et al 2014). Polymorphism at various regions of mitochondrial-genome and even complete mitochondrial-genome of P. infestans has been successfully employed to study origin, migration, and diversity (Hwang et al 2014). To date mtDNA of A 1 MT have been sequenced, revealing the phylogenetic relationship among haplotype I(a&b) and II(a&b), but no efforts have been made to excavate relationship existing between the MTs(A 1 /A 2 ).…”