Short-term greenhouse studies with soybean (Glycine max cv. Bragg) were used to examine interactions between the soybean cyst nematode (Heterodera glycines) and two other common pests of soybean, the stem canker fungus (Diaporthe phaseolorum var. caulivora) and the soybean looper (Pseudoplusia includens), a lepidopterous defoliator. Numbers of cyst nematode juveniles in roots and numbers of cys...

Diaporthe helianthi is a fungus pathogenic to sunflower. Virulent strains of this fungus cause stem canker with important yield losses and reduction of oil content. Here we present the first draft whole-genome sequence of the highly virulent isolate D. helianthi strain 7/96, thus providing a useful platform for future research on stem canker of sunflower and fungal genomics. The genome sequence...

Twenty-eight potential biocontrol organisms were tested for efficacy against Rhizoctonia solani on potato in a series of greenhouse trials. Organisms tested consisted of field isolates of Paenibacillus polymyxa, Pseudomonas fluorescens, Penicillium sp., Trichoderma sp., and Rhizoctonia zeae; known biocontrol isolates including Laetisaria arvalis, Verticillium biguttatum, Cladorrhinum foecundiss...

Quantitative resistance against Leptosphaeria maculans in Brassica napus is difficult to assess in young plants due to the long period of symptomless growth of the pathogen from the appearance of leaf lesions to the appearance of canker symptoms on the stem. By using doubled haploid (DH) lines A30 (susceptible) and C119 (with quantitative resistance), quantitative resistance against L. maculans...

The identification of Diaporthe (anamorph Phomopsis) species associated with stem canker of sunflower (Helianthus annuus) in Australia was studied using morphology, DNA sequence analysis and pathology. Phylogenetic analysis revealed three clades that did not correspond with known taxa, and these are believed to represent novel species. Diaporthe gulyae sp. nov. is described for isolates that ca...

abstract application of chemicals which activate plant defense mechanisms before pathogen attack without environmental side effects of protective chemical agents have stimulated great deal of researches in this area. one of the important crops in the world is tomato and recently recognized as a model plant for plant-pathogen interactions. tomato early blight is one of the most devastating disea...

MicroRNAs (miRNAs), a type of short (21-23 nucleotides), non-coding RNA molecule, mediate repressive gene regulation through RNA silencing at the post-transcriptional level, and play an important role in defense and response to abiotic and biotic stresses. In the present study, Affymetrix® miRNA Array, real-time quantitative PCR (qPCR) for miRNAs and their targets, and miRNA promoter analysis w...

This paper reports on five years of observations in a case-control study examining the role of tree and site factors on the development of Phytophthora ramorum stem canker (sudden oak death) in coast live oak (Quercus agrifolia) and tanoak (Lithocarpus densiflorus). In September of each year from 2000 through 2004, we collected data on P. ramorum symptoms, tree condition, midday stem water pote...

Pitch canker, caused by Gibberella circinata Nirenberg & O’Donnell, is a problem for pines in both native and planted stands. The aerial phase of the disease results in shoot and canopy dieback, whereas soil or seedborne inoculum can cause damping off of emerging seedlings. Based on the extent of lesion development on inoculated shoots, families of Pinus radiata have been shown to differ signif...

All crop species are current or ancient polyploids. Following whole genome duplication, structural and functional modifications result in differential gene content or regulation in the duplicated regions, which can play a fundamental role in the diversification of genes underlying complex traits. We have investigated this issue in Brassica napus, a species with a highly duplicated genome, with ...