2013). Sitka spruce (Picea sitchensis) infected by H. annosum-resistant clones contained considerably less fungal DNA than the susceptible ones, and host defence responses were found to be weaker in wood than in bark (Bodles et al. 2006). In general, low levels of pathogen DNA in resistant plants would characterize a mechanism that

results in the inhibition of pathogen multiplication, whereas the presence of relatively high amounts of pathogen DNA in asymptomatic plants should indicate a mechanism based on tolerance rather than on true resistance (Vandemark and Barker 2003). The fungal biomass of Alternaria dauci was equivalent in two carrot cultivars between 1 and 15 days Y-27632 cost after inoculation, while it was fourfold higher in the more susceptible cultivar 21 and 25 days after inoculation (Boedo et al. 2008). Authors speculated that the pathogen can colonize both cultivars in a similar manner during the first steps of the interaction, but fungal development is subsequently restricted in the partially resistant cultivar due to putative plant defence reactions. Instead, F. oxysporum f.sp. cubense levels in severely symptomatic banana pseudostems and leaves proved to be much higher than in Ibrutinib in vivo mild symptomatic ones (Lin et al. 2013). Furthermore, unlike the visual examination of

symptoms, the accurate quantification of the pathogen DNA could enable the detection of even minor differences in the host resistance. Blast resistance levels of rice cultivars were more accurately evaluated with qPCR, because by the time lesions on leaves had just become visible, the growth of Magnaporthe grisea was 80 times higher in susceptible than in resistant cultivar (Qi and Yang 2002). Similarly, qPCR fine-tuned

bioassays for the quantification of Cercospora leaf spot disease in sugar beet breeding (De Coninck Glutamate dehydrogenase et al. 2012). In addition, qPCR can contribute to the protection of plant species by favouring the evaluation of control measures or the selection of new anti-oomycete and antifungal compounds (Llorente et al. 2010). A specific qPCR method was developed to detect Botrytis cinerea in vineyards and utilized to compare the efficacy of different control strategies including various fungicide treatments (Diguta et al. 2010). The method could also serve as a decision-making tool in vineyards by fostering the assessment of the contamination risk and optimizing the number of sprays and the concentration of fungicides to be used. Furthermore, qPCR can be utilized to specifically monitor and quantify the frequencies of fungicide-resistant genotypes in a specific pathogen population. For example, the β-tubulin allele E198A conferring resistance to benzimidazole was quantified in Monilinia fructicola (Luo et al.