Search results for "Phytophthora nicotianae"

Physiological and Molecular Characteristics of Elicitin-Induced Systemic Acquired Resistance in Tobacco

1996

Elicitins are low molecular weight proteins secreted by all Phytophthora species analyzed so far. Application of the purified proteins to tobacco Nicotiana tabacum leads to the induction of resistance to subsequent inoculations with the black shank-causing agent, Phytophthora parasitica var nicotianae. In this paper, we describe the systemic characteristics of elicitin-induced acquired resistance in tobacco. Elicitin application is followed by the rapid translocation of the protein in the plant. The basic elicitin, cryptogein, induces necrosis formation in the leaves, which results from accumulation of the protein in these organs. Necrosis does not seem to be essential for the establishment…

Suppressiveness of 18 composts against 7 pathosystems : variability in pathogen response

2006

International audience; Compost is often reported as a substrate that is able to suppress soilborne plant pathogens, but suppression varies according to the type of compost and pathosystem. Reports often deal with a single pathogen while in reality crops are attacked by multiple plant pathogens. The goal of the present study was to evaluate the disease suppression ability of a wide range of composts for a range of plant pathogens. This study was conducted by a consortium of researchers from several European countries. Composts originated from different countries and source materials including green and yard waste, straw, bark, biowaste and municipal sewage. Suppressiveness of compost-amende…

Root and basal stem rot caused by Phytophthora nicotianae on thyme in Liguria

2006

Intraspecific variability in the Oomycete plant pathogen Phytophthora nicotianae

2011

Phytophthora nicotianae is an Oomycete plant pathogen affecting a broad range of plant species comprising more than 250 genera. It causes several economically relevant diseases and is particularly known as the causal agent of black shank of tobacco and root rot, stem rot and gummosis of citrus. Despite the relevance of this pathogen, information on the field reproductive strategy, population structure and global distribution of genetic variability is not completely known. This is because available studies have been conducted to characterize local populations (mainly from tobacco) or have been based on physiological aspects such as resistance to fungicides and pathogenicity on differential h…

First Report of Phytophthora spp. as Pathogens of Pandorea jasminoides in Italy

2019

In the summer of 2005, approximately 5% of a nursery stock of 12-month-old potted plants of bower vine (Pandorea jasminoides (Lindl.) K. Schum.) in Sicily (Italy) showed wilt, leaf chlorosis, defoliation, root rot, and collapse of the entire plant. Three Phytophthora spp. (20, 50, and 30% of the isolations of the first, second, and third species, respectively) were isolated from rotted roots on BNPRAH selective medium (2). Single-hypha isolates of the first species formed petaloid colonies on potato dextrose agar (PDA) and had an optimum growth temperature of 25°C (9.3 mm/day); on V8 juice agar, they produced uni- and bipapillate, ovoid to limoniform sporangia with mean dimensions of 45 × …

Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe

2021

Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates…

Localized versus systemic effect of arbuscular mycorrhizal fungi on defence responses to Phytophthora infection in tomato plants

2002

Development of biological control for plant diseases is accepted as a durable and environmentally friendly alternative for agrochemicals. Arbuscular mycorrhizal fungi (AMF), which form symbiotic associations with root systems of most agricultural, horticultural and hardwood crop species, have been suggested as widespread potential bioprotective agents. In the present study the ability of two AMF (Glomus mosseae and Glomus intraradices) to induce local or systemic resistance to Phytophthora parasitica in tomato roots have been compared using a split root experimental system. Glomus mosseae was effective in reducing disease symptoms produced by P. parasitica infection, and evidence points to …

Phytophthora species causing crown and root rot of tomato in southern Italy

2000

Phytophthora capsici, Phytophthora cryptogea and Phytophthora nicotianae were isolated from tomato plants with symptoms of crown and root rot in plastic-house crops in Sicilia and Calabria (southern Italy). The species were identified primarily on the basis of morphological and cultural characteristics. The identification was confirmed using molecular methods, polyacrylamide gel electrophoresis (PAGE) of mycelial proteins and polymorphism of DNA sequences amplified by polymerase chain reaction using random primers (RAPD-PCR). P. capsici caused significant losses in tomato crops that had succeeded capsicum crops. P. cryptogea was found to be the most frequent species causing basal stem rot o…

Phytophthora palmivora a New Pathogen of Lavender in Italy

2019

Root rot caused by Phytophthora nicotianae is considered the most serious disease of lavender in commercial cultivations in Italy. In summer 2001, in the Gela area (Sicily), ≈60% of 34,000 2-year-old landscape shrubs of English lavender (L. angustifolia) grown in a clay loam soil showed symptoms of dieback associated with root rot. Plants had been transplanted from pots in May and watered using a trickle irrigation system. A species of Phytophthora was isolated consistently from roots of symptomatic plants using potato dextrose agar (PDA) containing benomyl, nystatin, pentachloronitrobenzene, rifampicin, ampicillin, and hymexazol. The species was identified as P. palmivora on the basis of …

Microsatellite analysis of the population structure in Phytophthora nicotianae

2014

Nine validated SSRs were designed and used to characterize 268 isolates from a broad range of hosts and geographic localities. A total of 129 multilocus genotypes (MLG) were identified with markers showing polymorphisms ranging from 4 (locus P2039) to 24 alleles (locus 1509). Analyses revealed a preferential clonal reproduction in field orchards while sexual reproduction seemed to be more diffused in nurseries. A strong association between genetic groups and host of recovery was revealed for most isolates although this association was less evident for isolates from nurseries. In contrast, a significant geographical structuring was recovered only for isolates from tobacco (sourced in Austral…