Lack of association between tolerance to the elm phytoalexin mansonone E and virulence in Ophiostoma novo-ulmi

1994 ◽  
Vol 72 (9) ◽  
pp. 1355-1364 ◽  
Author(s):  
Robert H. Proctor ◽  
Raymond P. Guries ◽  
Eugene B. Smalley

The effect of the elm phytoalexin, mansonone E, on linear growth of 17 fungal species was examined to determine whether the Dutch elm disease fungus Ophiostoma novo-ulmi is more tolerant of mansonone E than other fungi. Linear growth of O. novo-ulmi was less inhibited by mansonone E than that of most, but not all, other fungi examined, suggesting that O. novo-ulmi is relatively tolerant of mansonone E. To determine whether this tolerance is required for pathogenicity, we generated mutants of O. novo-ulmi with reduced tolerance to mansonone E by N-methyl-N′-nitro-N-nitrosoguanidine mutagenesis followed by a screen for reduced tolerance to 1,2-naphthoquinone, a compound similar in structure to mansonones. Reduced tolerance to 1,2-naphthoquinone and mansonone E was accompanied by reduced tolerance to another elm phytoalexin, mansonone F. Two mutants exhibited wild-type levels of virulence on three elms, while three other mutants exhibited markedly reduced virulence compared with the wild-type field isolate from which they were derived. When the weakly virulent mutants were crossed with wild-type isolates, progeny that had wild-type levels of virulence but low tolerance to mansonone E were recovered. These results suggest that although O. novo-ulmi is relatively tolerant of mansonone E, this tolerance may not be required for high levels of virulence on elm. Key words: Ophiostoma novo-ulmi, mansonone, phytoalexin, Dutch elm disease.


1994 ◽  
Vol 72 (4) ◽  
pp. 461-467 ◽  
Author(s):  
Wayne C. Richards

A single nuclear gene controls nonsporulation in a novel isolate of the Dutch elm disease fungus Ophiostoma ulmi (Buism.) Nannf. This has been clearly demonstrated through segregation of the nonsporulating phenotype-in meiotic products recovered from crosses between a mutant nonsporulating isolate (WRB2-1) and wild-type sporulating isolates, between F1 progeny and their parents, and between F1 progeny. All crosses between nonsporulating and sporulating isolates yielded a 1:1 ratio for these two phenotypes in the meiotic products, whereas all crossings between isolates of the same phenotype produced meiotic products of that phenotype. The genetic stability of the nonsporulating phenotype was clearly shown when no disease symptoms were observed following artificial inoculation of the nonsporulating progeny into white elm, Ulmus americana L. Exposure to trifluoperazine, a calmodulin inhibitor, did not shift the nonsporulating isolates to the yeast phase, which supports our findings that nonsporulation is under genetic control rather than metabolic control. Key words: nonsporulation, Ophiostoma ulmi, mutant, single nuclear gene, meiotic products.



2005 ◽  
Vol 71 (8) ◽  
pp. 4388-4399 ◽  
Author(s):  
Cesar A. Morales ◽  
Steffen Porwollik ◽  
Jonathan G. Frye ◽  
Hailu Kinde ◽  
Michael McClelland ◽  
...  

ABSTRACT The genotype of Salmonella enterica serovar Enteritidis was correlated with the phenotype using DNA-DNA microarray hybridization, ribotyping, and Phenotype MicroArray analysis to compare three strains that differed in colony morphology and phage type. No DNA hybridization differences were found between two phage type 13A (PT13A) strains that varied in biofilm formation; however, the ribotype patterns were different. Both PT13A strains had DNA sequences similar to that of bacteriophage Fels2, whereas the PT4 genome to which they were compared, as well as a PT4 field isolate, had a DNA sequence with some similarity to the bacteriophage ST64b sequence. Phenotype MicroArray analysis indicated that the two PT13A strains and the PT4 field isolate had similar respiratory activity profiles at 37°C. However, the wild-type S. enterica serovar Enteritidis PT13A strain grew significantly better in 20% more of the 1,920 conditions tested when it was assayed at 25°C than the biofilm-forming PT13A strain grew. Statistical analysis of the respiratory activity suggested that S. enterica serovar Enteritidis PT4 had a temperature-influenced dimorphic metabolism which at 25°C somewhat resembled the profile of the biofilm-forming PT13A strain and that at 37°C the metabolism was nearly identical to that of the wild-type PT13A strain. Although it is possible that lysogenic bacteriophage alter the balance of phage types on a farm either by lytic competition or by altering the metabolic processes of the host cell in subtle ways, the different physiologies of the S. enterica serovar Enteritidis strains correlated most closely with minor, rather than major, genomic changes. These results strongly suggest that the pandemic of egg-associated human salmonellosis that came into prominence in the 1980s is primarily an example of bacterial adaptive radiation that affects the safety of the food supply.



2006 ◽  
Vol 33 (3) ◽  
pp. 289 ◽  
Author(s):  
Ling-Ling Gao ◽  
F. Andrew Smith ◽  
Sally E. Smith

A tomato mutant with reduced mycorrhizal colonisation, rmc, confers resistance to almost all arbuscular mycorrhizal (AM) fungal species tested, although there is variation in colonisation of different root cell layers by different fungi and one species of AM fungus can colonise this mutant relatively normally. These variations indicate a high degree of specificity in relation to AM colonisation. We explored the possibility of specificity or otherwise in interactions between rmc and three non-AM root-infecting fungi, Rhizoctonia solani anastomosis groups (AG) 4 and AG8, and binucleate Rhizoctonia (BNR). There were no differences between the wild type tomato 76R and rmc in the speed or extent to which these fungi infected roots or caused disease. Infection by R. solani induced high levels of defence-related gene expression in both tomato genotypes relative to non-infected plants. In contrast, with BNR the expression of these genes was not induced or induced to a much lower extent than with R. solani. The expression of defence-related genes with these two non-AM fungi was very similar in the two plant genotypes. It was different from effects observed during colonisation by AM fungi, which enhanced expression of defence-related genes in rmc compared with the wild type tomato. The specificity and molecular mechanisms of rmc in control of AM colonisation are discussed.



2014 ◽  
Vol 16 (2) ◽  
pp. 83
Author(s):  
Sonny Abdi Setiyawan ◽  
Anto Budiharjo ◽  
Hermin Pancasakti Kusumaningrum

Magelang duck is a wild type of local duck from Indonesia. The advantagesof Magelangduckcompare tootherlocalduck from Indonesiaareabilityto livein the highlandsandlowlands and high production of egg and meat. Geneticcharacterization of Magelangduck still not available until now.The aim of the research is selectprimers forampliflying COIgeneof mitochondrialDNAof MagelangduckusingLCO-HCO, bird-f1 -HCO, andbcl-bch primers.The research methodwas DNAisolationfrom Magelangduck. Followed by, selection of primer in silicoto find homologywithin COIsequenceusing ClustalX, Genedoc, and FastPCR programs. Amplification of COIgenewas performedusing PCRwith all primerpairs. Result showed partial homology with all primer in COI sequence. TheamplificationusingtheLCO-HCO primer produced  primerdimer.Primerbirdf1-HCOand bch-bcl primers showed no amplification.   Key words: Magelang duck, COI gene, mitochondrial DNA, primer



1989 ◽  
Vol 9 (3) ◽  
pp. 1362-1364 ◽  
Author(s):  
A M Lambowitz ◽  
J R Sabourin ◽  
H Bertrand ◽  
R Nickels ◽  
L McIntosh

Neurospora crassa mitochondria use a branched electron transport system in which one branch is a conventional cytochrome system and the other is an alternative cyanide-resistant, hydroxamic acid-sensitive oxidase that is induced when the cytochrome system is impaired. We used a monoclonal antibody to the alternative oxidase of the higher plant Sauromatum guttatum to identify a similar set of related polypeptides (Mr, 36,500 and 37,000) that was associated with the alternative oxidase activity of N. crassa mitochondria. These polypeptides were not present constitutively in the mitochondria of a wild-type N. crassa strain, but were produced in high amounts under conditions that induced alternative oxidase activity. Under the same conditions, mutants in the aod-1 gene, with one exception, produced apparently inactive alternative oxidase polypeptides, whereas mutants in the aod-2 gene failed to produce these polypeptides. The latter findings support the hypothesis that aod-1 is a structural gene for the alternative oxidase and that the aod-2 gene encodes a component that is required for induction of alternative oxidase activity. Finally, our results indicate that the alternative oxidase is highly conserved, even between plant and fungal species.



2009 ◽  
Vol 77 (10) ◽  
pp. 4371-4382 ◽  
Author(s):  
Javier A. Carrero ◽  
Boris Calderon ◽  
Hector Vivanco-Cid ◽  
Emil R. Unanue

ABSTRACT Listeriolysin O (LLO) is an essential virulence factor for the gram-positive bacterium Listeria monocytogenes. Our goal was to determine if altering the topology of LLO would alter the virulence and toxicity of L. monocytogenes in vivo. A recombinant strain was generated that expressed a surface-associated LLO (sLLO) variant secreted at 40-fold-lower levels than the wild type. In culture, the sLLO strain grew in macrophages, translocated to the cytosol, and induced cell death. However, the sLLO strain showed decreased infectivity, reduced lymphocyte apoptosis, and decreased virulence despite a normal in vitro phenotype. Thus, the topology of LLO in L. monocytogenes was a factor in the pathogenesis of the infection and points to a role of LLO secretion during in vivo infection. The sLLO strain was cleared by severe combined immunodeficient (SCID) mice. Despite the attenuation of virulence, the sLLO strain was immunogenic and capable of eliciting protective T-cell responses.



1993 ◽  
Vol 71 (4) ◽  
pp. 629-638 ◽  
Author(s):  
J. Dawson ◽  
Z. A. Wilson ◽  
M. G. M. Aarts ◽  
A. F. Braithwaite ◽  
L. G. Briarty ◽  
...  

Five new recessive male-sterile mutants of Arabidopsis thaliana were isolated following seed mutagenesis by X-rays and ethyl methanesulfonate. The cytology of plants homozygous for the msY and msW mutations suggested that pollen development in these lines became abnormal at or before meiosis. The msK mutation caused faulty timing of synthesis or turnover and distribution of callose. In plants homozygous for the msZ mutation, pollen development failed at a late stage. In wild-type plants, the stamen filament elongated just prior to anther dehiscence. In contrast, in the msZ mutant stamen elongation did not occur. Pollen in msH homozygotes was fertile, but anthers failed to dehisce. The msI mutant of J.H. Van der Ween and P. Wirtz (1968. Euphytica 17: 371 – 377) was included in the present study. Pollen development in this mutant failed shortly after microspore release from tetrads. Complementation tests confirmed that the ms mutations were at different loci. Reduced transmission of certain ms genes was observed. Key words: Arabidopsis thaliana, male sterile mutants, anther dehiscence, callose, inheritance.



1994 ◽  
Vol 72 (3) ◽  
pp. 384-401 ◽  
Author(s):  
Wilson Crone ◽  
Elizabeth M. Lord

The flowers of Arabidopsis thaliana (Brassicaceae) were examined for histological events during organ initiation and later development. An inflorescence floral plastochron of the main stem raceme was used as a basis for the timing and staging of developmental events. Sepals, petals, stamens, and carpels in wild-type Landsberg erecta Arabidopsis are distinguishable as primordia in terms of cell division events associated with initiation, size, and component cell numbers. Flower organogenesis in the organ identity (homeotic) mutants apetala2-1 and agamous-1 was compared with that of the wild type. In both mutants, each whorl of floral organs initiates much like the wild type and only subsequently produces visibly altered organs with mosaic features. The flower organ identity mutants achieve their mature phenotypes by alterations in tissue differentiation that occur after initiation and early primordial development. Key words: Arabidopsis, apetala2-1, agamous-1, plastochron, homeosis, flower.



Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1059-1064 ◽  
Author(s):  
Y. Chen ◽  
W. G. D. Fernando

Blackleg of canola is a disease complex of at least two fungal species: Leptosphaeria maculans and L. biglobosa. Isolates of L. biglobosa typically are weakly virulent or avirulent and are assigned to pathogenicity group 1 (PG-1). Isolates of L. maculans are highly virulent and encompass pathogenicity groups PG-2, PG-3, and PG-4. In greenhouse tests, percent lesion/leaf area (PLLA) on cotyledons of two Brassica napus cultivars, Westar and Invigor 2153, was smaller when L. biglobosa (PG-1) was either pre- or co-inoculated at 0, 12, 24, and 48 h with virulent isolates of L. maculans in PG-2, PG-3, and PG-4. On six-leaf-stage plants of Westar, the PLLA declined significantly compared with the control when the lower leaves were treated with either PG-1 or salicylic acid, then challenged with a PG-2 isolate 24 h later. In addition, the activity of four enzymes (chitinase, β-1,3-glucanase, peroxidase, and phenylalanine ammonia lyase) was greatly enhanced at 48 and 72 h when cotyledons of Westar were inoculated first with PG-1 followed by PG-2 24 h later, compared with a water control treatment. Field experiments conducted in 2003 and 2004 showed decreased blackleg severity in plants inoculated with PG-1 alone or prior to PG-2 compared with plants inoculated with PG-2 alone or prior to PG-1.



PERENNIAL ◽  
2007 ◽  
Vol 3 (2) ◽  
pp. 49
Author(s):  
Astuti Arif ◽  
Musrizal Muin ◽  
Tutik Kuswinanti ◽  
Fitri Harfiani

Wood deterioration were generally occured by the activities of biological agents. Fungal can attack wood and lignoselulosic substances and cause staining and decaying. Its damage levels were vary depending on the attacking fungal species. Eventhough it poses some disadvantages, actually fungy have potential benefits for human life such as nutrient, energy resources, medicine, etc. Fungy from Tabo-tabo educational forest were collected, isolated,and identified in this study. Identification was conducted throughout their macroscopic and microscopic characteristics. The result showed that the amount of fungal species were nineteen species, i.e: Aspergillus sp.,Poria subacida, Fomes sp., Lenzites sp., Hericium sp., Dacrymyces deliquescens, Ganoderma lucidum, Clitocybe sp., Trametes confragasa, Shizophyllum commune, Periconia sp., dan Helicosporium sp.,Clitocybe sp., Schizophyllum commune, dan Hygrophorus hypotejus,Ganoderma lucidum dan Coprinus atramentarius, Amanitopsis fulva dan Dacrymyces deliquescens, Collybia sp., Amanitopsis fulva, Hygrophorus hypotejus,Coprinus atramentarius, Monilia sitophilia, Gilmaniella sp. dan Conoplea sp. Key words: Wood fungy, deterioration, Tabo-tabo Educational Forest References



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