Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Root rot”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2003

Isolation of a novel antimicrobial peptide gene (Sp-AMP) homologue from Pinus sylvestris (Scots pine) following infection with the root rot fungus Heterobasidion annosum.

A new family of antimicrobial peptide homologues termed Sp-Amp has been discovered in Pinus sylvestris (Scots pine). This is the first report of such proteins to be characterized in a conifer species. Sp-AMP1 was identified in a substructured cDNA library of root tissue infected with the root rot fungus Heterobasidion annosum and encodes a mature peptide of 79 amino acid residues. Three additional members of the Sp-AMP family (Sp-AMPs 2-4) encode cysteine-rich proteins of 105 amino acids, each containing an N-terminal region with a probable cleavage signal sequence. Northern analysis confirmed that Sp-AMP expression is elevated in Scots pine roots upon infection with H. annosum. These peptides share 64% amino acid identity with a mature protein from Macadamia integrifolia (MiAMP1), which allowed us to build a homology model for preliminary analysis. Southern analyses further confirmed that several copies of the gene are present in the Scots pine genome. The potential significance of Sp-AMP in the H. annosum-conifer pathosystem is discussed.

Antimicrobial Cationic Peptides↗
PubMed1996

Glucanolytic Actinomycetes Antagonistic to Phytophthora fragariae var. rubi, the Causal Agent of Raspberry Root Rot.

A collection of about 200 actinomycete strains was screened for the ability to grow on fragmented Phytophthora mycelium and to produce metabolites that inhibit Phytophthora growth. Thirteen strains were selected, and all produced (beta)-1,3-, (beta)-1,4-, and (beta)-1,6-glucanases. These enzymes could hydrolyze glucans from Phytophthora cell walls and cause lysis of Phytophthora cells. These enzymes also degraded other glucan substrates, such as cellulose, laminarin, pustulan, and yeast cell walls. Eleven strains significantly reduced the root rot index when inoculated on raspberry plantlets.

Journal Article↗
PubMed2000

Development of formulations of biological agents for management of root rot of lettuce and cucumber.

The effect of various carrier formulations of Bacillus subtilis and Pseudomonas putida were tested on germination, growth, and yield of lettuce and cucumber crops in the presence of Pythium aphanidermatum and Fusarium oxysporum f.sp. cucurbitacearum, respectively. Survival of B. subtilis and P. putida in various carriers under refrigeration (about 0 degree C) and at room temperature (about 22 degrees C) was also studied. In all carrier formulations, B. subtilis strain BACT-0 survived up to 45 days. After 45 days of storage at room temperature (about 22 degrees C), populations B. subtilis strain BACT-0 were significantly higher in vermiculite, kaolin, and bacterial broth carriers compared with other carriers. Populations of P. putida were significantly higher in vermiculite, peat moss, wheat bran, and bacterial broth than in other carriers when stored either under refrigeration (about 0 degree C) or at room temperature (about 22 degrees C) for 15 or 45 days. Germination of lettuce seed was not affected in vermiculite, talc, kaolin, and peat moss carriers, but germination was significantly reduced in alginate and bacterial broth carriers of B. subtilis compared to the non-treated control. Germination of cucumber seed was not affected by any of the carriers. Significantly higher fresh lettuce and root weights were observed in vermiculite and kaolin carriers of B. subtilis compared with P. aphanidermatum-inoculated control plants. Lettuce treated with vermiculite, and kaolin carriers of B. subtilis, or non-inoculated control lettuce plants had significantly lower root rot ratings than talc, peat moss, bacterial broth, and P. aphanidermatum-inoculated control plants. Growth and yield of cucumber plants were significantly higher in vermiculite-based carrier of P. putida than the other carriers and Fusarium oxysporum f.sp. cucurbitacearum-inoculated plants.

Alginates↗
PubMed1998

Root cortex--the final frontier for the biocontrol of root-rot with fungal antagonists: a case study on a sterile red fungus.

Root cortices remain as the last frontier for the biocontrol agents to protect the vascular elements from the invader, where the virulent pathogen has breached the bulk soil, rhizosphere, and rhizoplane. Root cortices are commonly colonized by a variety of soilborne fungi. Many nonmycorrhizal biocontrol fungi that occupy the rhizosphere appear to extend their activity into the live cells of the cortex. It has been proposed that the occupation of the cortices by biocontrol fungi introduced on seed at sowing could extend their activity in time and space. The biology and ecology of such fungi with parasitic competency to colonize live cortical cells are discussed in relation to a case study involving a sterile cortical fungus.

Journal Article↗
PubMed1996

Identification of root rot fungi in nursery seedlings by nested multiplex PCR.

The internal transcribed spacer (ITS) of the ribosomal DNA (rDNA) subunit repeat was sequenced in 12 isolates of Cylindrocladium floridanum and 11 isolates of Cylindrocarpon destructans. Sequences were aligned and compared with ITS sequences of other fungi in GenBank. Some intraspecific variability was present within our collections of C. destructans but not in C. floridanum. Three ITS variants were identified within C. destructans, but there was no apparent association between ITS variants and host or geographic origin. Two internal primers were synthesized for the specific amplification of portions of the ITS for C. floridanum, and two primers were designed to amplify all three variants of C. destructans. The species-specific primers amplified PCR products of the expected length when tested with cultures of C, destructans and C. floridanum from white spruce, black spruce, Norway spruce, red spruce, jack pine, red pine, and black walnut from eight nurseries and three plantations in Quebec. No amplification resulted from PCR reactions on fungal DNA from 26 common contaminants of conifer roots. For amplifications directly from infected tissues, a nested primer PCR using two rounds of amplification was combined with multiplex PCR approach resulting in the amplification of two different species-specific PCR fragments in the same reaction. First, the entire ITS was amplified with one universal primer and a second primer specific to fungi; a second round of amplification was carried out with species-specific primers that amplified a 400-bp PCR product from C. destructans and a 328-bp product from C. floridanum. The species-specific fragments were amplified directly from infected roots from which one or the two fungi had been isolated.

Base Sequence↗
PubMed2004

Characterization of double-stranded RNA elements in the violet root rot fungus Helicobasidium mompa.

Double-stranded (ds) RNA of various types was detected by electrophoresis in 23 of 25 isolates of Helicobasidium mompa. These dsRNAs varied in size from ca. 2 kbp to more than 10 kbp. dsRNAs from an isolate V1 had two distinct nucleotide sequences for putative RNA-dependent RNA polymerase (RDRP). Their complete sequences revealed that V1 dsRNA1 was 2247 bp in length, with a single ORF that encoded a 706-amino acid residue polypeptide with a predicted molecular mass of 82.6 kDa, and that V1 dsRNA3 was 1776 bp in length, with a single ORF that encoded a 538-amino acid residue polypeptide with a predicted molecular mass of 62.6 kDa. RDRP-conserved motifs were identified in both predicted amino acid sequences. Phylogenetic analysis indicated that V1 dsRNA1 was most closely related to Fusarium poae virus 1, while V1 dsRNA3 was most closely related to Helicobasidium mompa 70 virus. These results indicate coinfection of isolate V1 by two distinct partitiviruses.

Basidiomycota↗
PubMed2005

Chitinase gene transformation through Agrobacteriumand its explanation in soybean in order to induce resistance to root rot caused by Rhizoctonia solani.

Chitinase gene (chi) of bean which has been cloned in recombinant binary plasmid vector, pBI121 with 35s promoter of Cauliflower mosaic virus (CaMV), were used for transformation of soybean using strain LBA4404 of Agrobacterium. The plasmid contained nptII gene that is a resistant gene to kanomycin as selector marker and Gus gene as reporter. Cotyledon explants of Williams and Clark cultivars were inoculated by Agrobacterium suspension with pBI121 and were cultured in regeneration medium. After complete regeneration of explants to seedling in B5 medium amended with kanomycin, polymerase chain reaction analysis were conducted to ensure conjugation of nptII, Gus, CHN genes in transformants seedling of soybean. Results showed that some lines of soybean contained Gus and CHN genes. More ever, chitinase activity in leaf extract of transformed soybean lines was significantly more than untransformed soybean, exception one sample. Bioassay of chitinase activity of transgenic lines on in vitro condition prevented mycelial growth of Rhizoctonia solani in comparison with untransformed control leaf extract.

Chitinases↗
PubMed2002

Telomeric fingerprinting of the white root rot fungus, Rosellinia necatrix: a useful tool for strain identification.

The telomere associated DNA sequence pTel46, which was isolated from Coprinus cinereus, was hybridized with Rosellinia necatrix genomic DNA. The DNA fragments hybridized with pTel46 were more sensitive to Bal31 nuclease. This result suggests that the DNA fragments hybridized with pTel46 were located at the end of chromosomes in R. necatrix. Telomere-linked restriction fragment length polymorphism (RFLP) was found in strains of R. necatrix isolated from various field and single ascospores. Thus, this marker appears to be an excellent tool to show the great polymorphism of R. necatrix. However, RFLP could not be found among several field isolated strains belonging to the same mycelial compatibility group (MCG) isolated in the same field. Therefore the strains belonging to the same MCG might be the same strain that could be anastomosed with each other without cell death except for strain W718 carrying a double-stranded RNA (dsRNA) virus. Therefore the RFLP corresponded to a MCG group, and none of the strains belonging to the same MCG group showed different RFLP in R. necatrix. Moreover, the presence of a kind of dsRNA virus might imply anastomosis between compatible strains.

Ascomycota↗
PubMed2005

Yeast polysaccharide affects fusaric acid content in maize root rot.

Protective action of sulfoethyl glucan (SEG), a derivative of the cell wall glucan prepared from the baker's yeast Saccharomyces cerevisiae, was investigated in the maize seedlings infected by a plant pathogen Fusarium verticillioides (Sacc.). Several markers were assayed with the SEG addition and in the control experiments. Two evaluations were performed on the 7th and the 14th days. Addition of SEG led to the increased productivity parameters of the infected plants and maintained them at the level of non-infected plants during the 14 days of experiment. After seven days of cultivation, concentration of fusaric acid (=5-butylpyridine-2-carboxylic acid; FA) decreased in all infected plants cultivated in the presence of SEG when compared to that detected in the infected plants grown in the absence of SEG. After 14 days of cultivation, polysaccharide addition resulted in the reduction of FA concentration almost to 75% in comparison to the infected plants grown without polysaccharide addition. In the experiment, when exogenous FA was added to the growth medium, its concentration decreased up to 60% in the presence of SEG. Thus, it is feasible to assume that SEG binds and adsorbs FA, and, in this way, reduces its content and exerts protective action in plants against its toxic effect.

Fusaric Acid↗
PubMed2004

Effects of inoculum density and substrate type on saprophytic survival of Phytophthora drechsleri, the causal agent of gummosis (crown and root rot) on pistachio in Rafsanjan, Iran.

In this study, sampling was carrid out on soils around pistachio trees in various regions of Rafsanjan, Iran. Following isolation and identification of Phytophthora isolates, the predominant species was found to be P. drechsleri and used for further investigation. For studying saprophytic survival of the fungus, soils collected from different areas were combined and autoclaved. Sterile soil was divided into 10 parts and mixed with fungal inoculum at various concentrations of 0-9% (w/w) separately. Each soil part (100g) was placed in 15cm diameter plastic pot. Some soils in pots were supplemented with sterile wheat straw whereas others were mixed with pistachio leaves surface sterilized with 5% (v/v) sodium hypochlorite. After 3, 6 and 9 weeks of incubation, five leaves or straws samples were taken from each replicate and cultured on CMA-PARPH medium and the fungal colony formation was monitored. The experiment was performed using completely randomized design with factorial experiments including three factors (substrate type, inoculum density and time), 10 treatments (0-9 g inoculum levels) and nine replicates. The results showed that the type of substrate (wheat straw and pistachio leaf) was very important for the fungal saprophytic survival in that this was significantly greater for the pistachio leaves. Time was also considered another critical factor for the fungal survival. With passing incubation time, saprophytic survival of the fungus declined. Further, it was demonstrated that increasing inoculum density would result in longer survivability of P. drechsleri and maximum fungal survival on substrate was obtained when inoculum density was at 9% (w/w).

Cell Survival↗
PubMed2006

Influence of glyphosate on Rhizoctonia and Fusarium root rot in sugar beet.

This study tests the effect of glyphosate application on disease severity in glyphosate-resistant sugar beet, and examines whether the increase in disease is fungal or plant mediated. In greenhouse studies of glyphosate-resistant sugar beet, increased disease severity was observed following glyphosate application and inoculation with certain isolates of Rhizoctonia solani Kuhn and Fusarium oxysporum Schlecht. f. sp. betae Snyd. & Hans. Significant increases in disease severity were noted for R. solani AG-2-2 isolate R-9 and moderately virulent F. oxysporum isolate FOB13 on both cultivars tested, regardless of the duration between glyphosate application and pathogen challenge, but not with highly virulent F. oxysporum isolate F-19 or an isolate of R. solani AG-4. The increase in disease does not appear to be fungal mediated, since in vitro studies showed no positive impact of glyphosate on fungal growth or overwintering structure production or germination for either pathogen. Studies of glyphosate impact on sugar beet physiology showed that shikimic acid accumulation is tissue specific and the rate of accumulation is greatly reduced in resistant cultivars when compared with a susceptible cultivar. The results indicate that precautions need to be taken when certain soil-borne diseases are present if weed management for sugar beet is to include post-emergence glyphosate treatments.

Beta vulgaris↗