Host specificity and virulence variation in populations of lettuce powdery mildew pathogen (Golovinomyces cichoracearum s. str.) from prickly lettuce (Lactuca serriola)

Abstract

Mieslerová B., Lebeda A., Petrželová I., Korbelová P. (2013): Incidence of lettuce downy mildew (Bremia lactucae) and powdery mildew (Golovinomyces cichoracearum) in natural populations of prickly lettuce (Lactuca serriola). Plant Protect. Sci., 39 (Special Issue): S24-S32. The study was focused on the wild pathosystem Lactuca serriola-lettuce downy mildew (Bremia lactucae) and lettuce powdery mildew (Golovinomyces cichoracearum). Observations were focused mainly on recording natural infection of prickly lettuce (Lactuca serriola) by downy and powdery mildews in the East Bohemia and Moravia (the Czech Republic) in the May-September period of 2007-2011, and on the influence of environmental conditions on disease incidence. Only data for July and August were used for the detailed comparisons of occurrence of both pathogens, because intensity of disease in this period was the highest. Data were linked with the average monthly temperature and rainfall rate in the Czech Republic. G. cichoracearum prefers rather low levels of precipitation and temperatures around 20°C, therefore significantly higher incidence of this pathogen was recorded in August 2007. On the other hand in July 2009 and 2010, when the intensities of precipitation were higher, incidence of Bremia lactucae prevailed. In August 2010 and 2011 incidence of both pathogens were more or less similar at all locations. Our observations showed that climatic conditions influence the incidence and prevalence of both pathogens in weedy growing populations of Lactuca serriola.

Effect of extreme temperatures on powdery mildew development and Hsp70 induction in tomato and wild Solanum spp.

“…Lactuca spp.-Golovinomyces cichoracearum; Solanum spp.-O. neolycopersici; cucurbitaceous plants-Golovinomyces orontii, Podosphaera fusca; sweet cherry-Podosphaera clandestina; Cohen 1993;Mieslerová et al 2000;Olmstead et al 2000;Lebeda et al 2011Lebeda et al , 2013. In most of the studied pathosystems, results obtained from the leaf disc assay correlated well with results obtained with whole plants, indicating that the disc assay may accurately predict responses of whole plants.…”

Incidence of lettuce downy mildew (Bremia lactucae) and powdery mildew (Golovinomyces cichoracearum) in natural populations of prickly lettuce (Lactuca serriola)

“…Collected isolates of both pathogens were mostly limited to the same host plant species or genus from which they were collected. The only exception is the confirmed ability of isolates of B. lactucae and G. cichoracearum from L. serriola to infect some L. sativa cultivars (Petrželová & Lebeda 2004a;Lebeda et al 2012Lebeda et al , 2013. Recent study of interactions of L. serriola genotypes with well characterised isolates of B. lactucae originating from L. serriola revealed low level of race-specific resistance of investigated L. serriola populations (Křenová 2013).…”

“…Similar studies have not been done on G. cichoracearum isolates. Nevertheless, existence of a broad virulence variability has been shown for isolates of B. lactucae (Petrželová & Lebeda 2004a,b;Lebeda et al 2008) and G. cichoracearum (Lebeda et al 2013) originating from wild populations of L. serriola. Sexual reproduction and heterothallism could play an important role in genetic recombination of both B. lactucae and G. cichoracearum and are considered as major sources of virulence variation (Schnathorst 1959; Lebeda et al 2008).…”

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AbstractMieslerová B., Lebeda A., Petrželová I., Korbelová P. (2013): Incidence of lettuce downy mildew (Bremia lactucae) and powdery mildew (Golovinomyces cichoracearum) in natural populations of prickly lettuce (Lactuca serriola). Plant Protect.

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“…Later studies clearly demonstrated existence of race-specific interactions in the wild pathosystem Lactuca spp.-G. cichoracearum s. str. (Lebeda et al 2013).…”