Anthracnose disease caused by Colletotrichum spp. is a serious disease of chili (Capsicum annuum), particularly in tropical countries. Host plant resistance breeding is one of the most effective disease management strategies. It requires identification of parents with genes resistant to Colletotrichum species predominant in a given region. For phenotypic evaluation, 35 chili lines consisting of…
The strong association between Phytophthora cinnamomi and the mortality and decline of Quercus suber and Q. ilex subsp. rotundifolia has been known for two decades. The ability of elicitins secreted by this pathogen to trigger defence responses in these Quercus against itself was evaluated in this work. Biomass quantification by quantitative real-time PCR revealed a significant decrease in path…
Biological control agents (BCAs), and among them some species of fungal endophytes, are potential substitutes for chemical pesticides in the control of plant diseases due to their non-toxicity to human beings and their surrounding environment. One mode of action of fungal BCAs is through their bioactive, extracellular products, which can inhibit the growth of pathogens. In this study, the effec…
Improving yield, diseases resistance, abiotic stress tolerance, seed quality and other agronomic traits are the most important aims of faba bean breeding. Stemphylium blight, a fungal disease caused by Stemphylium botryosum and S. vesicarium, causes great devastation in faba bean production in Golestan province. The levels of resistance to Stemphylium blight disease were evaluated in 99 faba be…
The leaf blight disease of sunflower (Helianthus annuus) caused by Alternaria helianthi is a serious threat to its cultivation worldwide. Early and accurate detection of the pathogen is critical to efficient disease management and in avoiding further losses due to epidemics in sunflower. Conventional methods of detection and identification are time consuming, labour intensive, and lack specific…
In recent years, a devastating fungal disease characterized by small black spots (
Root rots are a major concern in field pea production in North Dakota. However, it is unclear which pathogens are involved in causing these diseases. This report brings together findings from surveys conducted over four years (2004, 2005, 2008, and 2009). The 2004 and 2005 surveys were mainly aimed at establishing the importance of pea root rot in North Dakota and providing an indication of the…
Fungi associated with the bark beetles Orthotomicus erosus, Tomicus destruens and Pityogenes calcaratus were sampled in various pine forests throughout Israel. Three ophiostomatoid fungi, Ophiostoma ips, Graphilbum rectangulosporium and Leptographium wingfieldii, and a fourth nonophiostomatoid fungus, Geosmithia sp. 24, were identified by using morphological characteristics and molecular geneti…
Spot blotch (SB) caused by Cochliobolus sativus is a serious biotic stress to wheat in warm and humid areas, particularly South Asia (SA). In order to support South Asian farmers to combat SB, International Maize and Wheat Improvement Center (CIMMYT) established an efficient SB screening system at Agua Fria, Mexico and developed a nursery under the project - Cereal Systems Initiative for South …
Phenolic allelochemicals have been found in both natural and managed ecosystems, where they cause numerous ecological and economic problems. Whether these problems can be mediated by some other specific phenolic acid components is unknown. In this study, we identified phenolic acids and their concentrations in plow layer soil, rhizosphere soil and decomposing strawberry (Fragaria ananassa Duch.…
A new longidorid nematode, Longidorus asiaticus n. sp., is described and illustrated from a population extracted from soil associated with the movement of crape myrtle (Lagerstroemia indica) flowering bonsai trees imported from China into Italy. The new needle nematode is characterised by a small body size (2.74–3.52mm), a bluntly-rounded lip region, ca 12 μm wide, continuous with body conto…
Abstract Sooty molds are a lineage of follicolous fungi that cover the upper surface of leaves with black mycelia. Sooty molds do not infect plants, but grow on surfaces where honeydew deposits accumulate. It causes a reduction of incident sunlight by physical obstruction and in some species it interferes with photosynthesis. However, there are no studies proving that light interception by the…
The purification of viruses from bananas is a complex and laborious process due to the large quantities of polysaccharides and secondary metabolites in the plant tissue. The banana streak viruses (BSVs) are generally difficult to purify to a level that allows generation of high quality antisera. This study presents an improved method of purification of Banana streak MY virus (BSMYV), which al…
Greenhouse experiments were conducted to investigate the importance of tomato seeds as a route of pospiviroid dissemination. More than 7000 seeds were collected from tomato plants mechanically inoculated with Tomato apical stunt viroid, Citrus exocortis viroid, Columnea latent viroid and Potato spindle tuber viroid. Fruits and part of the seeds were found to be 100 % infected by the inoculated …
Verticillium wilt disease has become increasingly serious in many regions in China over the past few years. In this study, the widespread pathogen was identified as Verticillium longisporum (V. longisporum) by mt-SSU rDNA and cytochrome b sequence analysis. By using the primer pair HW1-F/HW1-R, which was designed based on the V. longisporum-specific rDNA-ITS sequence, a real-time PCR assay was …
Plants of Nicandra physaloides, Solanum americanum and Euphorbia heterophylla with leaf lesions have been found naturally grown among tomato plants in commercial fields in Brazil. Tomato bacterial spot was occurring in these fields. Xanthomonad-like isolates were obtained from affected weed leaf samples. These isolates were species identified using BOX-PCR and specific primers. Isolates from N.…
The leaves of apple cultivars resistant (cv.Free Redstar) and susceptible (cv. Idared) to fire blight were infiltrated with Erwinia amylovora. After 24 hours, differential gene expression was analysed using cDNA-AFLP technique. The expression pattern in the resistant cultivar, especially up-regulated genes encoding proteins involved in hypersensitive reaction and controlled cell death (BAX inhi…
Fusarium oxysporum f. sp. albedinis (FOA) is a seed- and soil-borne vascular wilt pathogen that causes a very serious and destructive disease of date palm (Bayoud disease). FOA is not currently known to occur in Saudi Arabia, but the disease has been moving eastward from its origin in Morocco and Algeria. The main objective of this study was to evaluate Saudi Arabian date palm germplasm at the …
Synchytrium endobioticum is a severe pathogen of potato causing wart disease. For this obligate fungus many pathotypes exist, which are pathogenic or nonpathogenic to different cultivars of potato. To determine to which pathotype an isolate belongs, two biological assays are used on a set of different potato cultivars: the Spieckermann and the Glynne-Lemmerzahl test. A differential set of culti…
Labyrinthula terrestris, the causal agent of rapid blight disease in cool-season turfgrasses, is the first Labyrinthula species found to be associated with higher plants in terrestrial ecosystems. An initial study suggested a single common genotype associated with turfgrass in the US, but a later study revealed genetic diversity in this pathogen. In the present study, genetic diversity as well …
The airborne sporangia of Oomycota, including Phytophthora species and other species, are usually recorded by volumetric spore traps. The aim of this work was to create a predictive model for the seasonality and weather parameters that may affect sporangia distribution by analysing their presence over the course of a year. Three Hirst spore traps were located in the SW of Spain (Plasencia, Don …
Cross infection of multiple hosts by fungal trunk pathogens has been reported to occur worldwide. It supports the hypothesis that infected hosts adjacent to vineyards may serve as sources of inoculum for these pathogens. Among the alternative hosts, different studies have shown that almond represents a rich catch-crop for many fungal trunk pathogens. The hyphomycetes Collophora hispanica, Phaeo…
The Ascomycota fungus Microcyclus ulei is a major threat for natural rubber production. The ascospores play a major role in the survival and dissemination of the fungus. The present study indicates that the ascospores are present on the leaves shortly after infection. Although their abundance is higher on leaflets 50–70 days after they reach maturity, ascospores are still found on 6months-old…
Bacterial speck disease of tomato, caused by Pseudomonas syringae pv. tomato (Pst) is one of the most devastating diseases of tomato in the world. To investigate plant responses activated during plantpathogen interaction, we studied the expression analysis of selected defense-response genes and the microbe or pathogen associated molecular patterns (MAMP or PAMP) triggered immunity (PTI) marker…
Bacterial wilt (causal organism-Ralstonia solanacearum) is one of the most important soil-borne diseases of eggplant (Solanum melongena) worldwide. The best way to control it economically is to develop cultivars resistant to this soil-borne pathogen. Resistance gene (R-gene) cloning and sequencing to obtain resistance gene analogs (RGAs) is one of the most recent approaches for obtaining disea…
Vascular wilt caused by Fusarium oxysporum f.sp. lentis is a major disease of lentil (Lens culinaris) worldwide. In this study, 196 lentil landraces were screened for resistance under controlled and field conditions. In order to characterize different levels of incomplete resistance, a detailed methodwas developed to evaluate resistance to this pathogen under controlled conditions assessing sym…
There is little knowledge about the effects of simultaneously applied biological control agents (BCAs) on the incidence of grey mould (Botrytis cinerea) in strawberries under field conditions. Our objective was, therefore, to investigate the use of three BCAs (Bacillus amyloliquefaciens FZB42, Aureobasidium pullulans DSM 14940 and DSM 14941 and Beauveria bassiana ATCC 74040) with respect to the…
Fusarium wilt is one of the most serious threats to banana production worldwide. The disease is caused by the soil-borne fungal pathogen Fusarium oxysporum f. sp. cubense (Foc), especially tropical race 4 (Foc TR4). It has been reported that crop rotation and intercropping of Chinese leek (Allium tuberosum) with banana can effectively reduce incidence of the disease in the field. In this study,…
Differences in Sclerotinia rot (SR) disease severity, caused by two categorized pathotypes and one more recent isolate of S. sclerotiorum and measured in terms of cotyledon lesion diameter, were studied across diverse Brassicaceae hosts to characterize host response and pathogen virulence. There were significant differences (P ≤0.001) between genotypes, isolates and a significant genotype x i…
This study presents the first whole genome sequence of Onion yellow dwarf virus (OYDV isolate RR1) from onion (Allium cepa) in India along with phylogenetic and recombination studies. We examined the sequence variability, distribution of simple sequence repeats (SSRs), and recombination breakpoints of different OYDV geographical isolates. The P1 and P3 regions of OYDV show a higher rate of sequ…
The suppressive influence of compost towards the soil-borne fungus Fusarium oxysporum f. sp. lycopersici on tomatoes with special emphasis on root morphological modifications was examined. Roots of inoculated and non-inoculated tomato plants, grown in three different substrates (control, 20 % compost and 40 % compost), were scanned and analyzed in order to identify their morphological traits. T…
Bacterial wilt, caused by Ralstonia solanacearum (Smith, US Department of Agriculture, 12, 1–28, 1986) Yabuuchi et al. (Microbiology and Immunology, 39, 897–904, 1995) (formerly Pseudomonas solanacearum), causes 35–90 % yield loss in tomato production in hot-humid tropical regions. Commonly used strategies for minimizing incidence of bacterial wilt include choosing resistant varieties, co…
The inhibitory effect of yeast Pichia membranaefaciens on black spot decay of postharvest broccoli, caused by Alternaria alternata (Fr.) Keissler, was investigated and possiblemechanisms were explored in both in vitro and in vivo experiments. There was a positive correlation between the concentration of yeast cells and reduction of hyphal growth or spore germination from 1×104 to 1×108 cells/…
The most characterised Dasheen mosaic virus andmany other unreported putative viruses are involved in the mixed viral mosaic infection of elephant foot yam (Amorphophallus paeoniifolius). The in vitro propagation of corm bud tips for virus free plantlet production was carried out in three different culture phases consisting of callusing, shoot regeneration and rooting. A 100 % survival ratewas…
In this study, we investigated 78 sugarcane samples with severemosaic symptoms collected from four provinces of southern China: Guangxi, Yunnan, Hainan, and Guangdong, which cover nearly 85 % of commercial sugarcane planting zones in China. Using RT-PCR, sequencing and phylogenetic analysis, we identified 72 hybrid sugarcane samples containing causal agents of sugarcane mosaic disease. Among th…
For the northern Baltic region, Diplodia sapinea (Fr.) Fuckel, a well-known around the world pine pathogen, was first recorded in Estonia on Austrian pine (Pinus nigra Arn.) in 2007. Wider monitoring of the fungus was promptly started. Shortly, in 2012, the native Scots pine (P. sylvestris L.) was found symptomatic: first in Estonia, then in Latvia, and in 2013 in north-west Russia. Several ind…
Phytophthora cactorum causes crown rot of the strawberry rhizome and leather rot of strawberry fruit. Five strawberry cultivars, including two newly released cultivars (Nobel and Saga) from a Norwegian strawberry breeding program and eight selections from the same program, were tested for resistance to crown rot and leather rot and possible correlation in resistance between the two diseases. St…
An aqueous extract from the plant Chromolaena odorata [syn Eupatorium odoratum], Eupatorieae, Asteraceae, protected rice against sheath blight by induced resistance. As an initial step towards identification of the specific disease-reducing compounds, leaves from C. odorata were extracted with water and methanol and the extracts separated using a group separation system followed by analysis usi…
Apple ring rot, caused by Botryosphaeria dothidea, is one of the most serious diseases affecting apple industry in East Asia. To study the correlation between fruit natural exocarp structures and susceptibility to B. dothidea, lesion length of Malus domestica cultivars and Malus germplasm accessions was measured 14 days after in vitro inoculation with B. dothidea mycelia at different developmen…
Twelve Heterodera species are considered of major economic significance in cereals, of which Heterodera avenae, H. latipons and H. filipjevi are the most important. Precise identification and quantification of these nematodes are necessary to develop effective integrated pest control. This study reports on the use of the mitochondrial cytochrome oxidase subunit 1 (COI) gene to develop qPCR ass…
The relationships between the level of chlorophyll a, and the content of soluble carbohydrates, phenolics and low molecular antioxidants in the leaves of three oilseed winter rape varieties with different resistance to Leptosphaeria maculans were determined. During pathogenesis, an increase in the content of chlorophyll a in the resistant and medium-sensitive rape varieties was observed. In t…
Dothistroma needle blight (DNB) is regarded as one of the most significant foliar diseases of pine and has caused significant damage to pine plantations in France since the late 1990s. The genetic diversity, reproductive strategy and population structure of D. septosporum, one of the causal agents of DNB, was investigated at six sites across Brittany, France, using species-specific mating type …
In our experimental approach we investigated how post-infection nitric oxide-dependent signaling activated in potato leaves was related to defense against avirulent (avr) and virulent (vr) races of Phytophthora infestans. Results revealed that only in an incompatible response, early NO and superoxide (O2•-) generation led to peroxynitrite (ONOO−) formation and together with hydroen peroxi…
Banana Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (FOC) is a worldwide soilborne disease that causes serious economic losses every year. Effective ways of preventing the disease are still not available. In this study, biological soil disinfestation (BSD) with incorporation of various organic matters under flooding conditions combined with plastic mulching was applied to suppress …
Sequencing of cDNA synthesized from double-stranded RNA (dsRNA) from papaya leaves revealed the presence of a putative new virus with homology to genomes of several members of the genus Umbravirus. A wide survey showed that the virus was present in two out of three papaya producing provinces in Ecuador included in this study. The virus was found in up to 31 % of symptomatic trees co-infected wi…
A new root-lesion nematode was isolated from sugarcane (Saccharum sinensis Roxb.) in Guangxi Zhuang Autonomous Region, China. Morphology and molecular analyses of rRNA small subunit (SSU), D2D3 expansion domains of large subunit (LSU D2D3) and internal transcribed spacer (ITS) confirmed that this nematode is different from other previously described root-lesion nematodes. Herein it is described…
A reliable EvaGreen-based qPCR assay was developed for the relative quantification of fungal and plant DNAs in the Botrytis cinerea-Pelargonium× hortorum pathosystem. Primers, designed on RPB2 (DNA-dependent RNA polymerase subunit II) gene sequences directed the amplification of a specific 149 bp product for B. cinerea. No cross-reactivity was observed in DNA extracted from several nontarget f…
This contributed book applies mathematical models and systems analysis techniques to the study of insect pests, plant pathogens, and human diseases. The research programmes of over 40 scientists from aU over the world are compared and contrasted in detail to provide a stateof-the-art review on how such modelling can increase the effectiveness of more traditional ecological, biological, and chem…
The angular leaf spot disease caused by Xanthomonas fragariae is an important plant disease with major impact for the strawberry nursery industry. Currently there is no plant protection product available for controlling the disease effectively. Planting of resistant cultivars seems to be promising, but all commercially used cultivars are susceptible and no donor with a high level of resistance …
Because they are tethered in space, plants have to make the most of their local growth environment. In order to grow in an ever-changing environment, plants constantly remodel their shapes. This adaptive attribute requires the orchestration of complex environmental signals at the cellular and organismal levels. A battery of small molecules, classically known as phytohormones, allows plants …