The hypersensitive response is associated with host and nonhost resistance to Phytophthora infestans

Abstract

The interaction between Phytophthora infestans (Mont.) de Bary and Solanum was examined cytologically using a diverse set of wild Solanum species and potato (S. tuberosum L.) cultivars with various levels of resistance to late blight. In wild Solanum species, in potato cultivars carrying known resistance (R) genes and in nonhosts the major defense reaction appeared to be the hypersensitive response (HR). In fully resistant Solanum species and nonhosts, the HR was fast and occurred within 22 h. This resulted in the death of one to three cells. In partially resistant clones, the HR was induced between 16 and 46 h, and resulted in HR lesions consisting of five or more dead cells, from which hyphae were occasionally able to escape to establish a biotrophic interaction. These results demonstrate the quantitative nature of the resistance to P. infestans. The effectiveness of the HR in restricting growth of the pathogen differed considerably between clones and correlated with resistance levels. Other responses associated with the defense reaction were deposition of callose and extracellular globules containing phenolic compounds. These globules were deposited near cells showing the HR, and may function in cell wall strengthening.

Genome-wide analysis and expression profiling of calcium-dependent protein kinases in potato (Solanum tuberosum)

“…Expression of all 15 CDPKs and the kinase activity increased after CF treatment in all these genotypes, but with strikingly different patterns in the sensitive and the resistant ones. These results are in agreement with the earlier findings of Vleeshouwers et al (2000). Their cytological study indicated that the severity and timing of defence response varied depending on the form and level of resistance exhibited by a Solanum genotype.…”

A novel non-protein-coding infection-specific gene family is clustered throughout the genome of Phytophthora infestans

“…Microscopic analysis (Fig. 4) indicated that the timing of P. infestans development during these infections closely followed the events described by Vleeshouwers et al (2000). Thus, at 12 hpi, germinating cysts, appressoria and infection hyphae were clearly visible (Fig.…”

“…rarely seen at the infection site, and sporangiophores begin to emerge through stomata (e.g. Vleeshouwers et al, 2000) as the pathogen progresses from biotrophy to necrotrophy. At 72 hpi, leaf necrosis and pathogen sporulation are clearly visible to the eye.…”

High affinity recognition of a Phytophthora protein by Arabidopsis via an RGD motif

“…Second, of the plant pathogens known to secrete an RGD-containing protein, P. infestans is the only one that has some kind of interaction with A. thaliana. P. infestans can penetrate epidermal cells and the plant responds to this penetration with a rapid hypersensitive response [33]. A. thaliana is fully resistant to P. infestans and is thus considered to be a non-host.…”