Showing papers in "Physiological and Molecular Plant Pathology in 1995"

TL;DR: It is concluded that in the system induction of systemic resistance by strain WCS417r and SA is not associated with accumulation of PRs proteins, which demonstrates that accumulation ofPR proteins is not a prerequisite for the expression of induced systemic resistance.

TL;DR: Data suggest that the rapidity of flavonoid formation plays an important role in the resistance of V. rotundifolia to P. viticola, and the formation of resveratrol, flavonoids and lignin in the intermediate resistant species probably restricts the development of this pathogen.

TL;DR: Analysis of phenolic compounds and enzymes involved in their synthesis suggests that the general phenylpropanoid pathway is stimulated upon infection, but that lignification is not.

TL;DR: The results suggest that the stimulation of invertase activity in mildewed leaves altered the source-sink relationship of the leaf leading to an accumulation of soluble carbohydrates and a decrease in sucrose synthesis and that application of hexaconazole successfully prevented development of the fungus but that the metabolic alterations following the initial infection were not reversible within the time scale studied.

TL;DR: Results indicate that a novel O 2 - generating NADPH oxidace may be activated in the plasma membrane of potato cells by inoculation with an incompatible race of P. infestans or treatment with the fungal elicitor and that Ca 2+ , cytosolic protein components and ATP may be involved in the activation process.

TL;DR: The data from this investigation suggest that the reduction of fungal development in induced plants results from at least two different mechanisms, one reduces penetration into the plant and the other restricts development of the fungus once it has penetrated.

TL;DR: The data suggest that a signal produced during the first week after inoculation of leaf 1 affects protection and enzyme activities of leaf 2, the expanding leaves above leaf 2 and leaves which subsequently emerged from the bud in the absence of additional signal(s).

TL;DR: These experiments show that enhanced levels of peroxidase activity are correlated with elevated levels of P8.5 polypeptide and mRNA in seedlings following inoculation with the powdery mildew pathogen, and all the data are consistent with the hypothesis that per oxidase P.5 participates in the deposition of phenolic compounds in papillae and thereby contributes to general, nonspecific defense responses in barley.

TL;DR: It is proposed that successful pathogenesis is based on suppression of host defence responses through rapid killing of infected tissues, and knowledge of a pathogen's infection process may be used to predict whether it has a narrow or wide host range.

TL;DR: Assessment of the antifungal activity of crude protein preparations from such leaves, containing a complete set of the extra- and intracellular tomato chitinases and β-1,3-glucanases, by in vitro bioassays revealed that the test fungus Trichoderma viride is highly sensitive to the hydrolytic enzymes.

TL;DR: The effects of AOPP and OH-PAS on the barley powdery mildew resistances conditioned by the dominant Mla1 (hypersensitive cell death based) and the recessive mlo5 (conditioning penetration resistance without cell death) major gene alleles were determined in leaf and coleoptile tissues.

TL;DR: PAL and β-d-glucosidase variations appear to be suitable post-infectional markers of varietal resistance to P. capsici in pepper cell cultures but not in leaves.

TL;DR: RNA gel blots demonstrated accumulation of peroxidase mRNA in the second leaf of cucumber seedlings at 18 h after inoculation of the first leaf with the hypersensitive response-inducing bacterium Pseudomonas syringae pv.

TL;DR: The symptomology, cytology and physiology of Cucurbita pepo plants fed upon by B. argentifolii and B. tabaci -A were compared to find the mechanism of squash silverleaf induction and two new intercellular fluid proteins were induced in silvered leaf tissue.

TL;DR: A detailed genetic analysis of the association between victorin sensitivity and rust resistance did not negate earlier reports that the gene conferring rust resistance and victor in sensitivity could be the same or a tightly linked gene.

TL;DR: Four host-parasite combinations were examined after infusion of conidia into the petiolar xylem vessels to compare early host reactions which are elicited by V. dahliae pathosystems by the aggressiveness of the pathogen and suggests that the following factors correlate with susceptibility: a high capacity for horizontal spread of Verticillium and a highcapacity for Verticillsium to actively suppress at least one host defense response.

TL;DR: The colonization quotient can provide a significant numerical measure for comparing various genotypic interactions and appear, rather, to modulate the rate and degree to which the processes of localization are activated.

TL;DR: In this paper, the effects of harpin treatment on plasmalemma of plant cells were investigated and the harpin-induced potassium efflux, extracellular alkalinization, and membrane potential depolarization were blocked by treatment with K252a, a protein kinase inhibitor.

TL;DR: PAL activity in barley leaves was measured at intervals after inoculation with the powdery mildew pathogen Erysiphe graminis f.sp.

TL;DR: A new mechanism of acquired resistance is proposed that is independent of papilla formation, hypersensitive cell death or accumulation of extracellular PR proteins but may be based on cell-wall modification and the induction of new host genes.

TL;DR: Results indicate that protein phosphorylation may be involved in the induction of appressorium formation by the two host signals.

TL;DR: Results suggest that the material associated with adhered conidia is composed of glycoprotein, similar to other conidia of Colletotrichum graminicola that had adhered to substrata.

TL;DR: PCR was used to detect P. betae in a survey of infection incidence in 65 sugar beet fields, with a lower incidence on peat as compared to mineral soils and protocols which combine PCR with Southern/dot blot analysis of products were developed.

TL;DR: The Pir7b gene product does not appear to play a role in acquired resistance, and its function is more likely related to a specific property of the inducing P. syringae pv.

TL;DR: The results suggest that the isolated elicitor may be involved in the recognition process during the natural infection of rice by P. oryzae and it appears that protection is achieved by enhanced sensitivity of recognition or by promoting a faster and/or more intense host response.

TL;DR: Inoculation of 3-4 lower leaves of tobacco with tobacco mosaic virus (TMV) increased ribonuclease and protease activities in inoculated leaves, but little or no differences in the activities were apparent between induced and noninduced plants.

TL;DR: The DNA sequence of several putative repetitive/high copy number DNA elements cloned from Plasmodiophora brassicae were used to design PCR primers for the amplification of polymorphic DNA from P. Brassicae, and the amplification products obtained were compared to the products obtained by amplification with arbitrary 10-mer oligonucleotides.

TL;DR: 24 h after inoculation, the clones with total resistance and those with a high level of partial resistance displayed an early accumulation of scopoletin that intensified and lasted longer than 48 h in the fully resistant clones.

TL;DR: These results bring additional evidence that paratracheal parenchyma cells in direct contact with invaded vessels are signalled to mobilize a number of defence strategies among which formation of physical barriers at specific sites is one of the earliest and key events involved in protection against invasion of the xylem parenchema cells.

TL;DR: Data indicate a down-regulation of the Calvin cycle as a result of a decreased amount of Calvin cycle enzymes, which is suggested to have caused an inhibition of the photosynthetic electron transfer chain and ultimately, the rate of photosynthesis in both mildewed and fungicide treated leaves.