摘要:

AbstractCleanly cut wounds on the surface of green apricot fruit are susceptible to infection withMonilinia fructicolawhen freshly made, but rapidly become resistant over 6 h. This was shown to be strongly correlated with the concentration of free nutrients, particularly sugars, which remain on the surface of the wound. Nutrients were rapidly removed by diffusion and absorption by underlying living cells. This is proposed as the basis of resistance which develops rapidly as the wounds age.Structural and chemical barriers to infection, such as periderm, suberin and phenolic compounds, developed long after the wounds had become resistant.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01286.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractLatent infections of apricot fruit withMonilinia fructicolawere initiated by inoculation at shuck fall and 43 and 63 days after shuck fall. The fungus entered via the stomata and penetrated a guard cell through the thin walled region at the stomatal pore. The fruit tissue responded by death of cells around the point of infection, suberization of walls of surrounding living cells and accumulation o phenolic compounds in cells up to 20 distant. Periderm developed around lesions formed at shuck fall but was absent from those formed 65 days later. When the fruit ripened, approximately 100 days after shuck fall, viable hyphae in latent infections escaped from the lesions by growing out between the cuticle and epidermis or just below the epidermal cells. Outbreak was more efficient from later inoculations and only a small proportion of latents initiated at shuck fall became invasive.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01287.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractLatent infections produced byMonilinia fructicolaon green apricot fruit are separated from aqueous contact with live host tissues by hydrophobic suberin. However, they respond to host ripening and become invasive. The time and intensity of production of the volatile compounds acetaldehyde and ethanol during fruit ripening strongly correlated with both the invasive outbreak of mycelium from arrested lesions, and with the stimulation of growth of germ tubes invitroin the presence of fruit volatiles. Latent infections on green apricots were activated to escape from the lesions in response to exposure to those volatiles in the concentration detected from ripe apricots. However, the tissue of green apricots was stimulated to fresh necrosis and general fruit invasion did not occur.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01288.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractFusarium oxysporum lycopersici(FOL) andF. graminearum(FG) developed mycostatin (M) and cycloheximide (C) resistant mutants (FOL[M] and FG[C]) after treatment with nitrosoguanidine. Four hybrids, obtained from hyphal anastomoses between the mutants, were isolated from medium containing both mycostatin and cycloheximide at concentrations which did not permit growth of the mutants or the original parents. Both the mutants and the interspecies hybrids (ISH) derived from them expressed significant differences in pathogenicity to tomato and wheat from that expressed by the parents FOL and FG. Protein, esterase, pectinase and polyphenoloxidase electrophoretograms displayed unique patterns for the hybrids and the mutant parents. However, these patterns did not correlate with the pathogenicity expressions obtained. The study has demonstrated interspecies hybridizations between FOL(M) and FG(C) by hyphal anastomoses. Both the processes of mutation and hybridization altered the expression of pathogenicity in tomato and wheat The significance of these observations on the origin and development of new pathogenic forms is discussed.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01289.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA number of isolates of the aggressive an d non‐aggressive pathotype group of the rape seed (Brassica napus) pathogenPhoma lingam(teleomorph:Leptosphaeria maculans) were analyzed by means of a simple, random primer dependent PCR (polymerase chain reaction) approach. Using the four synthetic nona‐ and decamer oligonucleotides 5′‐GGAGCCCAC‐3′, 5″‐ACGGTCTTGG‐3′, 5′GAAACAGCGG‐3′, and 5′‐GGCATCGGCC‐3′ informative bands for both of the pathotype groups could be obtained. These amplified bands were shown to originate not only from repeated but also from single and low copy target sequences. This is the first report on molecular diagnostics of a plant pathogenic fungus, based on random primer dependent PCR. The experimental system is fast and reliable, does not require cloning and sequencing ofL. maculansDNA, and works without time‐consum

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01290.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractWe describe a simple method of purifyingPseudomonas syringaepv.syringae(P. s.pv.s.) specific polyclonal antibodies which are directed against a cell surface protein sized 31 kD. The actual purification step of the polyclonal antibodies occurs with denatured proteins after an SDS‐PAGE gel electrophoresis and western blotting. Polyclonal antibodies were obtained which recognized a 31 kD protein. On a western blot no cross reaction of the purified polyclonal ‘monospecific 31 kD antibodies’ with other proteins from the same strain was observed. However, a positive “monospecific 31 kD antibody” reaction was only visible when either protein extracts from several selected pathogenicP. s.pv.s.strains from different hosts, or two isolates ofPseudomonas syringaepv.pisi(P. s.pv.p.) were used. An indication that this 31 kD protein is specific toP. s.pv.s.is that no cross reaction was found with protein extracts from the tested pathogenic and non‐pathogenic pseudomonads. However, a differentiation of the testedP. s.pv.s.andP. s.pv.p.isolates was possible when cells were grown above 30 °C. Then protein extracts fromP. s.pv.s.revealed the lack of the 31 kD protein but notP. s.pv.p.protein extracts. Polyclonal antibodies raised in rabbits against the 31 kD protein band from the western blot proved to be specific enough to agglutinate wholeP. s.pv.s.strain R32 cells or for detecting a single 31 kD protein band on a western blot when whole cell protein extracts ofP. s.pv.s.strain R

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01291.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe expression of cross protection between two strains of tobacco mosaic virus (TMV‐C and TMV‐P) differed inArabidopsis thalianacv. Columbia andNicotiana tabacumcvs Samsun and Xanthi. Protection inA. thalianacv. Columbia was expressed as a prevention of systemic movement of the challenge strain, regardless of the protecting strain of TMV, Protection inN. tabacumcvs Samsun and Xanthi was expressed as an inhibition of an early event in the infection process. The results presented indicate that the host may influence the mechanism by which cross protection is expressed between the same virus stra

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01292.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractBioassays were used to demonstrate the antibiotic effect ofTrichodermaisolates onP. cactorum. When both fungi were grown on benomyl‐containing PDA medium, the mycelial growth ofTrichodermawas suppressed. However, the production of antibiotics by this fungus remained active, leading to inhibition of the mycelial growth ofP. cactorum. The antibiotic effect ofTrichodermaon zoospores and cysts was tested on a PDA substrate precultured withTrichodermaon cellophane sheets. On the substrate of someTrichodermaisolates, lysis of zoospores, formation of extracellular vesicles, and hypertrophy of the water expulsion vesicle did occur, both resulting in the death of the zoospores. Conidial suspensions ofTrichodermaisolates also induced zoospore lysis. It is presumed that membrane‐active peptide antibiotics (peptaibols) are involved in zoospore lysis. The peptaibol paracelsin caused lysins of zoospores at a concentration of 2.5 × 10−4M. The effect on cysts depended on theTrichodermaisolate tested and the age ofTrichodermapreculture. Old cultures (after beginning of sporulation) affected cysts more severely than young cultures (before sporulation) which usually were not lethal to the cysts but induced preferably microsporangium formation, inhibition of cyst germination, and retardation of germ tube

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01293.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIsolates of powdery mildew were subjected to recurrent selection on partially resistant barley cultivars for 76 inoculation cycles over three years. Previous intermediate tests on up to 32 cycles for adaptation to overcome the host resistance revealed a trend towards adaptation to the cv. 7204 recurrent host in infection frequency data but not towards cv. Golden Promise or 9319, Subsequent cycles demonstrated adaptation to these latter hosts also.

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01294.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractBook Reviwed in this article:Ellis, M. A., R. H. Converse, R. N. Williams, and B. Williamson (eds). Compendium of Raspberry and Blackberry Diseases and InsectsFrancki, R. I. B., C. M. Fauquet, D. L. Knudsen, and F. Brown (eds), Classification and Nomenclature of VirusesStirling, G. R., Biological Control of Plant Parasitic Nematodes: Progress, Problems and Prospects.Parry, D. W., Plant Pathology in Agriculture.Schütt, P., H. J. Schuck, und B. Stimm (Hrsg.), Lexikon der Forstbotanik. 1. Auflage. Ecomed, Landsberg/Lech.Worthing, Charles R. (ed.) and Raymond J. Hance (ass. ed.), The Pesticide Manual, a World Compendium.Worthing, Charles R. (ed.) and Raymond J. Hance (ass. ed.), The Pesticide Manual, a World Compendium.Lozán, J., Angewandte Statistik für Naturwissenschaftler.Grierson, D. (ed.), Plant Genetic Engineeri

ISSN:0931-1785    

DOI:10.1111/j.1439-0434.1992.tb01295.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY