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inaegualis has been attributed to allelic mutations in the tions were made from buds of cv. Red Haven, Crest Haven, beta-tubulin gene. To study this phenomenon at the molecular Correll and Sentinel bi-weekly from May 27 through September level, genomic DNA was isolated from 6-wk-old broth cultures 26, 1988. Buds were surface sterilized in 0.05% sodium hypoof a benomyl-sensitive (WC-S) and a benomyl-resistant (KV3C) chlorite in 10% ethanol, and plated on acid potato dextrose field isolate of V. inaequalis and partially digested with agar. Elevated isolation frequencies from 4% to 32% were the restriction enzyme Sau3A. Sucrose gradient fractionated recorded immediately after harvest for each cultivar. Cankers DNA (16-20 kb) and BamHI/EcoRI digested lambda EMBL3 DNA develop on bearing wood under the buds from December to were ligated with T4 DNA ligase and packaged to prepare a February. Twigs die immediately after bloom. Benomyl sprays library. The library was screened for clones with a hetero- (1 lb/A a.i.) on August 1 and September 1 reduced the logous Erisyphe graminis beta-tubulin probe. DNA sequence incidence of twig cankers in 1989 from 48% to 8%. analysis of the clones showed extensive sequence similarities with the probe thereby confirming that the beta-tubulin gene had been cloned. 154 ISOLATION, PURIFICATION AND CHARACTERIZATION OF A PHYTOTOXIN 15 ~*A.M. FROM LIQUID CULTURES OF LEUCOSTOMA PERSOONII AND L. CINCTA. Svircev, °A.R. Biggs, *N. Miles and *C. Chong. OVERWINTER SURVIVAL IN THE FIELD OF COLLETOTRICHUM *Horticultural ACUTATUM ON Research Institute 0 Ontario, Canada, of Ontario, LOR 2E0; Vineland Agriculture Station, STRAWBERRY Canada Research FRUIT IN OHIO. Station, L. L. Wilson, M. A. Ellis, and L. V. Madden, Dept. of Plant Pathology, Ohio State Univ., Wooster, OH Vineland 44691. Station, Ontario, Canada, LOR 2E0. Liquid cultures of L. persoonii and L. cincta were grown in 2% Survival of Colletotrichum acutatum on infected strawberry fruit malt extract medium on a rotary shaker. Fourteen-day-old was evaluated in the was he field. valate iel. Infected Ifectd in fruit fuitwer were seaed sealed in n nylon nlon cultures separated were by ultrafiltration filtered and the into cell-free specific culture molecular filtrate size mesh bags (5 was fruit/bag) and placed on and 5-8 cm beneath the soil fractions. surface Excised in Nov ltato intspefrsica 1988. Both treatments shoot were tips covered (ca.i stra much.At nteval 1mo statin inDec with 8 cm of fr actin straw 988onebag mulch. in wexcsed peah, At P 1-mo length) were used to test the runu crude p intervals, starting rica, fractions s in Dec oo 1988, for tip one toxin bag activity. Peach from canker-like each of symptoms three replications were induced was only removed by the from on and beneath < 1,000 dalton the soil fraction. surface Further and fruit purification were assayed of the for phyto- viable C. acutatum. toxin by isoelectric From Nov focusing to Mar and 1989, granulated ambient bed air electrotemperatures (above straw phoresis mulch) has ranged identified from the -18 to toxin 20 C, as and a small soil temperatures polypeptide. ranged from Further purification and identification of the -3 to phytotoxin 13.2 C. is C. in acutatum was recovered fruit from 100% from and on >95% and within of soil, respectively, for the first 3 mo. progress. tissue culture The program toxin is to being obtain tested peach as plants selective with agent an increased After 4 mo the fungus was recovered in the from 80 and 67% of the fruit resistance to Leucostoma spp. from on and within soil, respectively. Sampling will continue through May 1989. Results will be discussed. 151 CYTOCHEMICAL PROCEDURES FOR ILLUSTRATING THE RESPONSE OF PECAN TO INFECTION BY CLADOSPORIUM CARYIGENUM. S. V. Diehl, C. H. CONTROL OF CYTOSPORA CANKER AND BACTERIAL CANKER IN A YOUNG Graves, and P. A. Hedin. Dept. of Plant Path. & Weed Sci. and SWEET CHERRY ORCHARD IN OREGON. LA. Spotts, T.J. Facteau, Crop Sci. Res. Lab, USDA, Mississippi State, MS 39762, and L.A. Cervantes. Oreg. St. Univ., Mid-Columbia Agric Research and Extension Center. Hood River, OR 97031. Several fungitoxic phenolics affect resistance in pecan to infection by C. caryigenum. Transmission electron microscopy can field study to evaluate control of Cytospora canker was be used to Tocate phenolics within leaf vacuoles. Distribution initiated in 1981 by planting sweet cherry trees cv. Bing. of phenolics within vacuoles varied depending upon the fixation Treatments included white trunk paint. 3 levels of nitrogen, procedure used. Localization and quantification of juglone, application of benomyl (1.35g/1) after dormant pruning or at isoquercitrin and condensed tannins in fresh microscopic tissues popcorn, petal fall, and shuck split. Trees were evaluated can be accomplished with the use of the Hoepfner-Vorstatz stain annually from 1982 to 1986 for active trunk cankers, and iso- and butanol-HCl and a microspectrophotometer. This technique lations made from margins of cankers. Between 1 and 7% of the showed that juglone was found consistently in higher concentratrees were infected with C. cincta each year. and 26% were tions in all greenhouse seedling leaf tissue than the other two infected by 1986. Bacterial canker, caused by Pseudomonas sy- compounds. Both infected and noninfected leaf tissue can be ringae, occurred in 13% of the trees in 1982 and 25% by 1986. compared with scanning electron microscopy. Combined use of Death of trees infected with C. cincta and P. syringae was 14 these procedures should give a composite illustration of host and 26%, respectively. Nitrogen or benomyl did not reduce response to infection by C. caryigenum. incidence of cankers. White trunk paint reduced the incidence r of both Cytospora and bacterial trunk cankers. Disease incidence was highest in trees close to an old cherry orchard. 156 DIFFERENTIATION OF COLLETOTRICHUM SPP. PATHOGENIC TO STRAW- 152 BERRY. P. S. Gunnell and W. D. Gubler, Pathology, Department University of Plant of California, Davis, CA 95616. PATHOGENICITY OF PHIALOPHORA SP. AND RHIZOCTONIA-LIKE ON CRANBERRY (VACCINIUM MACROCARPON). FUNGI Varney, and J. L. Peterson. L. P. Cn E.H. Plant The morphology Pathology, of both conidia and setae Rutgers produced on strawberry leaf University, piece agar New were found to Brunswick, be reliable NJ criteria 08903. to distinguish Colletotrichum spp. pathogenic to strawberry. von Cranberry cuttings Arx inoculated proposedthaft with a high Cfragariae level of Brooks Phialophora was synonomnous gloeosporioides with C. developed Penz., however, severe conidia symptoms, of C. fragariae including leaf isoyellowing, lates, defoliation, including specimens desiccation, collected and by root Brooks, necrosis. Symptoms were were predominantly clavate whereas significantly conidia milder of C. gloeosporioides at low inoculum were levels. Controls were predominantly cylindrical symptomless. with rounded-ends. There was a significant Conidia of difference C. in fresh fragariae weight were also and root longer length and narrower between than Phialophora-inoculated those of C.- and gloeosporioides. control Setae cuttings. of C. fragariae Rhizoctonia-like were brown, fungi several isolated from septate, somewhat cranberry sinuous, roots n-ot and tapered, shoots and had usually binucleate produced hyphae. Three conidia when mature. selected Setae isolates of C. (Rh-l, gloeosporioides Rh-2, and Rh-3) although had different modes also brown and septate, of infection. were strongly Rh-i penetrated tapered, did and not colonized produce the epidermal and conidia, and cortical were cells. finely warted Rh-2 penetrated toward the and top. produced C. acutatum typical hyphae Simmonds produced fusiform and spores monilioid and cells comparativel-y in the short, epidermis. dark Rh-3 did not penetrate brown, thick-walled setae which were usually aseptate. the epidermal cells, but colonized the root surface. 153 157 PHOMOPSIS BUD AND TWIG BLIGHT OF PEACH. F. F. Hendrix, Jr., RELATIONSHIP OF TEMIPERATURE TO THE FUNGI INVOLVED Department of Plant Pathology, University of Georgia, Athens, IN CRANBERRY FRUIT ROT. F.L. Caruso, Cranberry GA 30602. Experinent Station, University of Massachusetts, East Warehamn, Phomopsis MA twig 02538. blight of been peach, a major caused problem by Phomopsis in North sp., Georgia has for the last 5 years. More than The ten fungus different infects fungi through are healthy capable buds of after causing harvest. Isola- field or storage rot in cranberry fruit. Cranberriem 1154 PHYTOPATHOLOGY 155
(cultivars 'Early Black' and 'Crowley') with diverse caused by Penicillium funiculosum is not economically feasible, possibly rot symptoms were sampled in July, August, and Sep- because FCR can also be caused by Fusarium moniliforme f. sp. subglutinans. tenber (field collection) ,and in October and January Application of acaricides only when triggered by suitable 'predictors' has been (while in storage) . Individual berries were cut into proposed to reduce chemical application. The accuracy of prediction for any thirds, surface-sterilized, plated on three ACMA area will be limited by the natural variation of disease and the 'predictor' plates. Plates were incubated at 15, 22, and 30 C within this area. A survey was made of 10 fields to examine the correlation of for three weeks. Seven additional cultivars were pre- and post-force mite and fungal populations (P. funiculosum and F. sampled in February. Proper diagnosis of the primary moniliforme f. sp subglutinans) to FCR incidence at harvest. The use of entire causal agent is dependent on incubation temperature. fields as the statistical unit showed a correlation (r) between pre-force mite Godronia, Sporonema, and Apostrasseria preferred populations and FCR of 0.82. Due to variation within these fields, however, cooler temperatures whereas Phyllosticta, Physalo- the correlation dropped to 0.42 when the 60 subplots (6 within each field) were spora and Phomopsis preferred warmer temperatures. analyzed. Fungal isolations pre- and post-force showed high levels of F. There were diverse differences in fungi isolated at moniliforme f. sp. subglutinans but this was not statistically significant as a different sampling times among different cultivars. disease predictor. 158 POWDERY MILDEW OF PECAN: VARIETAL SUSCEPTIBILITY AND ROOT ROT OF KIWIFRUIT VINES CAUSED BY PYTHIUM SPP. EFFECTS ON KERNEL DEVELOPMENT. T. B. Brenneman and P. F. A. J. Latham, W. A. Dozier, Jr., J. M. Mullen, and H. L. Bertrand, Coastal Plain Experiment Station and Rural Campbell. Ala. Agric. Exp. Stn., Auburn University, AL 36849. Development Center, respectively, Dept. of Plant Pathology, University of Georgia, Tifton, GA 31793. Plantings of kiwifruit (Actinidia chinensis) have been made in several southeastern states. A planting on land Studies were conducted on powdery mildew (Microsphaera previously in long-time peanut production sustained over 50% penicillata) of pecan to monitor disease progress and loss to root rot following an extended wet period during determine its effects on kernel development. A total of 716 June. Pythium spp. were consistently obtained from rotted nuts (cv. Woodard) were rated six times during the season roots. One isolate cultured on corn meal agar at 25 C between July 10 and September 17, 1987. Severe powdery developed oogonia 23.4 um diam typical of Pythium ultimum mildew developed, and disease levels at the third through var. ultimum. Eight isolates cultured in the dark on a blue last evaluations were significantly negatively correlated grass-water medium at 22 C produced oogonia ranging from with kernel weight. The percent kernel weight was not 21.7 to 24.0 um typical of Pythium ultimum var. correlated with disease severity. Within a cluster, the sporangiiferum. Pure cultures were increased on corn further a nut was from the terminus, the less powdery mildew meal-sand mixtures and used to inoculate potted kiwi plants. it had. An additional study monitored disease progress on Within six weeks, both species caused root decay similar to 14 pecan cultivars. Woodard was extremely susceptible but that observed in the field. the other cultivars had moderate to good resistance. 159 163 REGULATION OF PECTIN LYASE (PNL) PRODUCTION IN ERWINIA CAROTOVORA EFFECT OF FLOOD DURATION ON SEVERITY OF PHYTOPHTHORA ROOT AND SUBSP. CAROTOVORA (Ecc) STRAIN 71 BY DNA DAMAGING AGENTS: CROWN ROT OF KIWIFRUIT IN CALIFORNIA. K. E. Conn and W. D. ISOLATION OF A NONINDUCIBLE MUTANT USING A pnlA-Ia:Z Gubler. Department of Plant Pathology, University of California Davis, CA 95616. TRANSCRIPTIONAL FUSION. James L. McEvoy. Russell 0. Nordeen. and Arun K. Chatterjee. Department of Plant Pathology, University of Missouri-Columbia, Columbia, MO 65211, U. S. A. Six month old kiwifruit seedlings grown for 3 months in soil artificially infested with Phytophthora citrophthora, P. crypto- To analyze the regulation of PNL production we cloned the gea, P. megasperma, or one of two unidentified Phytophthora app., structural gene, pnlA, and constructed pnlA-lacZ fusions using were subjected to biweekly flooding periods of 0, 6, 12, 24, or the mini-Mu element, P011734. In six of eleven insertions, lacZ 48 hours. Root rot (RR) and crown rot (CR) caused by P. crypto- expression was controlled by the pnlA promoter. The induction of gea and an unidentified Phytophthora sp. increased with the B-galactosidase (B-gal) by mitomycin C (MC) occurred in RecA but length of the flooding period. With 48 hours flooding, consis- not in RecA- Ecc strains. A typical fusion was placed by marker tently severe RR (83-96%) was observed. In contrast, P. citro- exchange into the chromosome of a Lac- derivative of Ecc7l. In phthora, P. megasperma, and another unidentified Phytophthora this construct (AC5022), B-gal was induced 60-fold with MC. By sp. caused variable RR (13-80%) with 0 to 48 hours flooding EMS mutagenesis of AC5022 followed by screening for B-gal while CR developed only sporadically on seedlings flooded for production, we obtained a mutant (AC5023) that was noninducible 48 hours. These results indicate that soil-water management that by MC. AC5023 was not defective in RecA nor was it. complemented avoids prolonged and repeated saturation may minimize losses by a PnlA' plasmid. These data suggest that in AC5023 there is a due to Phytophthora, depending on the species present. defect in production. pnlR, a gene locus that positively regulates PNL 162 164 161 165 CLONING OF eep GENES THAT DETERMINE EXTRACELLULAR ENZYME PRODUCTION IN ERWINIA CHRYSANTHEMI (EC16) AND E. CAROTOVORA SUBSP. CAROTOVORA (ECC71). H. Murata. W. Chun, and A. K. Chatterjee. Dept. of Plant Pathology. Univ. of Missouri, Columbia, MO 65211, U.S.A. During the isolation of pectinase-deficient mutants, we obtained Eep- mutants of ECI6 and Ecc71 that produced very low levels of pectate lyase, polygalacturonase, cellulase and protease activities. The ECI6 mutant also was mucoid and produced lower levels of phospholipase C. The Eep- mutants did nlot macerate potato tuber tissue. By mobilizing EC16 and Ecc71 gene libraries, we isolated clones that restored production of these enzymes and tissue-macerating ability in the cognate mutants. The Eep÷ plasmids did not restore extracellular enzyme production in export deficient (Out-~) mutants of EC16 or Ecc7l. Our data reveal the presence of a gene(s), other than out, that pleiotropically affects the production of extracellular proteins in these bacteria. VARIATION IN PREDICTION OF FRUITLET CORE ROT WITHIN AND BETWEEN PINEAPPLE FIELDS. JE, Yuen and G.Y. Taniguchi, Department of Plant Pathology, 3190 Maile Way, Honolulu, HI 96822. EVIDENCE FOR CATECHOL SIDEROPHORE PRODUCTION BY ERWINIA CAROTOVORA SUBSP. CAROTOVORA. C .T. Bull', C .A. Ishimaru', and J .E. Loper 2 . 'Department of Botany and Plant Pathology, Oregon 2 State University, USDA-ARS, HCRL, Corvallis, OR 97330. Routine application of acaricides for control of fruitlet core rot (FCR) and other fruit diseases (interfruitlet corking, eye inhibition, and leathery pocket) Erwinia carotovora subsp. carotovora strain W3C105, which Vol. 79, No. 10, 1989 1155
Page 1 and 2: Abstracts of Presentations at the 1
Page 3 and 4: Twenty Fusarium solani (Mart.) Sacc
Page 5 and 6: means used to derive them were not
Page 7 and 8: 46 A COMPARISON OF THE EPIPRE AND K
Page 9 and 10: 62 THE INCIDENCE AND IMPACT OF SPHA
Page 11 and 12: 79 83 82 SELECTION AND USE OF OXALA
Page 13 and 14: nificantly among plots but there wa
Page 15 and 16: Chrysanthemum morifolium (florists'
Page 17 and 18: anine ammonia lyase (PAL) and hydro
Page 19: studies. YST plants were uniformly
Page 23 and 24: 173 177 THE EFFECT OF EXPRESSION OF
Page 25 and 26: shown to be double-stranded circula
Page 27 and 28: in the greenhouse for resistance to
Page 29 and 30: Spatial patterns of disease were st
Page 31 and 32: 236 240 INDUCTION OF RESISTANCE TO
Page 33 and 34: y suppression of Mn oxidizers in th
Page 35 and 36: Colbaugh. Texas Agricultural Experi
Page 37 and 38: 284 BASELINE-SENSITIVITY OF THREE P
Page 39 and 40: Department of Agronomy, University
Page 41 and 42: 316 SEROLOGICAL NONIDENTITY OF IRIS
Page 43 and 44: amended with 25 g/L of KC1O Prelimi
Page 45 and 46: lacZ gene fusions have been used to
Page 47 and 48: Department of Plant Pathology, Univ
Page 49 and 50: causative agent of greening, howeve
Page 51 and 52: and chitosan heptamer will be discu
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Page 55 and 56: M. Laakso and J. W. Moyer, Dept. of
Page 57 and 58: 443 The stability of antigenic dete
Page 59 and 60: seed decay by 10%. Phomopsis seed d
Page 61 and 62: LARYAFD, QMKAA, FGLDG and TERH, in
Page 63 and 64: In an initial survey of ten commerc
Page 65 and 66: The primary cell walls of grasses c
Page 67 and 68: 523 AVIRULENCE OF WHEAT LEAF RUST T
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verified. A translocation linked to
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egimes and were sampled at 1, 3, 5,
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587 591 MEASURING VIRULENCE ASSCIAT
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603 PHYSICAL CHARACTERIZATION OF MU
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agar diffusion tests and spore germ
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Spring beauty latent virus (SBLV) h
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SOYBEANS. Barry M. Cunfer and Juju
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666 670 COMPUTER-ASSISTED WHITE MOL
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682 PHYTOPHTHORA CINNAMOMI. Univers
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698 SCREENING OF VESICULAR-ARBUSCUL
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