scholarly journals Occurrence of Kluyveromyces marxianus var. marxianus Causing Onion Soft Rot in the Columbia Basin of Washington State

Plant Disease ◽  
2007 ◽  
Vol 91 (8) ◽  
pp. 1059-1059 ◽  
Author(s):  
B. K. Schroeder ◽  
J. D. Rogers ◽  
D. A. Johnson ◽  
G. Pelter
Keyword(s):  
Kluyveromyces Marxianus ◽  
Sprinkler Irrigation ◽  
Soft Rot ◽  
Washington State ◽  
Potato Dextrose Agar ◽  
Columbia Basin ◽  
Water Control ◽  
Onion Bulbs ◽  
Allium Cepa L ◽  
Symptomatic Tissue

Kluyveromyces marxianus var. marxianus, a causal agent of onion (Allium cepa L.) soft rot, was originally isolated from Walla Walla sweet onion bulbs grown in Oregon and subsequently isolated from onion throughout the southeast Washington onion-growing area, but was not found to be infecting dry bulb storage onions grown in central Washington (1). During September of 2001, a yeast was isolated from dry storage onion bulbs (cv. Teton) grown under sprinkler irrigation in central Washington, exhibiting soft rot symptoms and identified to be K. marxianus var. marxianus (2). Koch's postulate was completed using cv. Teton bulbs surface disinfested with 0.5% NaOCl for 2 min. This isolate and four isolates of Kluyveromyces marxianus var. marxianus (1) were cultured on potato dextrose agar and resuspended to an OD600 = 0.3 (approximately 105 CFU/ml). One-half of a milliliter of each isolate was inoculated to onion using the cut bulb method with three replicates and incubated in a moist chamber at 25°C for 7 days. Onion slices inoculated with the new isolate exhibited soft rot symptoms similar to those caused by the known isolates while no symptoms were observed for the water control. The yeast reisolated from symptomatic tissue was confirmed to be K. marxianus var. marxianus (2). The identification of K. marxianus var. marxianus infecting dry bulb storage onions grown in the Columbia Basin is of interest because the disease can be confused with bacterial soft rot and could become a serious problem in this important storage onion-growing region. References: (1) D. A. Johnson et al. Plant Dis. 72:359, 1988. (2) N. J. W. Kreger-van Rig, ed. The Yeasts: A Taxonomic Study. Elsevier, Amsterdam, 1984.

scholarly journals First Report of Enterobacter cloacae Causing Onion Bulb Rot in the Columbia Basin of Washington State

Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 323-323 ◽  
Author(s):  
B. K. Schroeder ◽  
L. J. du Toit ◽  
H. F. Schwartz
Keyword(s):  
Enterobacter Cloacae ◽  
Washington State ◽  
Onion Bulb ◽  
Distilled Water ◽  
Columbia Basin ◽  
First Report ◽  
Onion Bulbs ◽  
Bulb Rot ◽  
Physiological Tests ◽  
Reference Strains

In August of 2006, onion plants of cv. Redwing exhibiting premature dieback and bulb rot were obtained from a commercial onion crop under center pivot irrigation in the Columbia Basin of Washington State. High temperatures during the summer were similar to those in 2004, which preceded significant outbreaks of Enterobacter rot of onion bulbs in storage. Fungal pathogens of onion were not observed. Bacteria from infected bulb tissue were isolated and purified on nutrient broth yeast extract (NBY) agar, and 537 isolates were evaluated for the ability to ferment glucose anaerobically. Of the facultative anaerobes (~50% of all isolates), 48 isolates were arginine dihydrolase positive, indole negative, and unable to degrade pectin, i.e., characteristics typical of the genus Enterobacter (2), which includes Enterobacter cloacae, a bacterial pathogen reported to cause onion bulb rot in California and Colorado (1,3). Sixteen of the putative Enterobacter isolates, along with four strains of E. cloacae known to be pathogenic on onion (1) (ATCC 23355 and ATCC 13047, 310 (H. F. Schwartz, Colorado State University), and E6 (J. Loper, USDA ARS), were tested for pathogenicity on onion bulbs (8 to 10 cm in diameter; cv. Tamara). The isolates were grown overnight in NBY broth at 28°C, harvested by centrifugation and resuspended to an OD600 = 0.3 (~108 CFU/ml) in sterile distilled water. After the outermost fleshy scale of each bulb was removed, each bulb was surface disinfected in 0.6% NaOCl for 2 min, dipped in sterile distilled water, and then dipped in 95% ethanol. Each bulb was air dried before a 0.5-ml aliquot of bacterial suspension was injected into the shoulder of the bulb with a 20-gauge needle. Three bulbs were inoculated for each isolate, placed in individual plastic bags, sealed, and incubated at 30°C in the dark. Three bulbs injected with water and three noninjected bulbs served as controls. After 14 days, each bulb was sliced through the center and rated for rot. Thirteen isolates induced rot symptoms on the inner fleshy scales of all inoculated bulbs. Of these, seven also caused tan-to-brown discoloration of the inner fleshy scales; similar symptoms were caused by the four pathogenic reference strains of E. cloacae (1). No symptoms were observed in any of the controls. Symptoms were not observed when the bacteria, prepared as described above, were infiltrated into onion leaves. Bacteria were reisolated from the symptomatic inoculated bulb tissue and confirmed to be Enterobacter spp. by the above physiological tests. In addition, an isolate designated ECWSU2 and the corresponding strain recovered from one of the inoculated symptomatic bulbs, along with the four reference strains, were evaluated for anaerobic growth on a variety of carbon sources by using API 50 CHE test strips (bio Mérieux Vitek, Inc., Hazlewood, MO). The physiological test data along with sequence analysis of a portion of the 16S rRNA gene of each isolate confirmed all of these isolates to be E. cloacae (4; Ribosomal Database Project [ http://rdp.cme.msu.edu/ ]). To our knowledge, this is the first report of E. cloacae causing a bulb rot of onion in Washington State. References: (1) A. L. Bishop and R. M. Davis. Plant Dis. 74:692, 1990. (2) J. G. Holt et al. Bergey's Manual of Determinative Bacteriology. Williams and Wilkins, Baltimore, MD, 1994. (3) H. F. Schwartz and K. Otto. Plant Dis. 84:808, 2000. (4) L. Verdonck et al. Int. J. Syst. Bacteriol. 37:4, 1987.

scholarly journals First Report of Pythium sulcatum Causing Cavity Spot in Processing Carrot Crops in the Columbia Basin of Washington State

Plant Disease ◽  
2014 ◽  
Vol 98 (3) ◽  
pp. 427-427
Author(s):  
L. J. du Toit ◽  
M. L. Derie ◽  
A. C. Alcala
Keyword(s):  
Sequence Analysis ◽  
Tap Water ◽  
Root Surface ◽  
Washington State ◽  
Deionized Water ◽  
Control Treatment ◽  
Columbia Basin ◽  
Species Identity ◽  
Cavity Spot ◽  
Symptomatic Tissue

In October 2012, symptoms of cavity spot (1) were observed on roots of two 50 ha, Red Core Chantenay processing carrot (Daucus carota L. subsp. sativus (Hoffm.)) crops in the Columbia Basin of central Washington. Symptoms consisted of sunken, elliptical lesions (3 to 15 mm long) on the root surface. Approximately 6% of the roots in each crop were affected, which was sufficient to present sorting problems for the processor. Symptomatic roots were washed thoroughly in tap water, and then small sections of tissue from the lesion margins were removed aseptically and plated onto water agar (WA) without surface-sterilization. Isolates with morphological characteristics typical of Pythium sulcatum Pratt & Mitchell (2) were obtained consistently from the symptomatic tissue. The genus and species identity of seven isolates was confirmed by sequence analysis of the internal transcribed spacer (ITS) 1-5.8S-ITS2 region of ribosomal DNA (rDNA) using universal eukaryotic primers UN-UP18S42 and UN-LO28S576B with the PCR protocol described by Schroeder et al. (3). The ITS consensus sequences of the seven isolates (Accession Nos. KF509939 to KF509945) were 98 to 99% homologous to ITS sequences of P. sulcatum in GenBank. Pathogenicity of all seven isolates was confirmed by inoculating mature carrot roots of cv. Bolero. Each root was washed with tap water, sprayed to runoff with 70% isopropanol, and dried in a laminar flow hood on sterilized paper toweling. The roots were then placed in plastic bins lined with paper toweling moistened with sterilized, deionized water. Each root was inoculated by placing two 5 mm-diameter agar plugs, taken from the edge of an actively growing WA culture of the appropriate isolate, on the root surface approximately 3 cm apart. Non-colonized agar plugs were used for a non-inoculated control treatment. Four replicate roots were inoculated for each isolate and the control treatment. After inoculation, the roots were misted with sterilized, deionized water, a lid was placed on each bin, and the roots were incubated in the dark at 22°C. Roots were misted daily to maintain high relative humidity. Dark, sunken lesions were first observed 3 days post-inoculation on roots inoculated with the P. sulcatum isolates, and all inoculated roots displayed cavity spot lesions by 7 days. No symptoms were observed on the non-inoculated control roots. Colonies with morphology typical of P. sulcatum were re-isolated from the symptomatic tissue of roots inoculated with the P. sulcatum isolates, and the species identity of the re-isolates was confirmed by ITS rDNA sequence analysis, as described above. Although P. sulcatum is one of several Pythium species that can cause cavity spot of carrot (1), to our knowledge, this is the first report of P. sulcatum causing cavity spot in Washington State, which has the largest acreage of processing carrot crops in the United States (4). References: (1) R. M. Davis and R. N. Raid. Compendium of Umbelliferous Crop Diseases. The American Phytopathological Society, St. Paul, MN, 2002. (2) A. J. van der Plaats-Niterink. Monograph of the Genus Pythium. Stud. Mycol. No. 21. CBS, Baarn, The Netherlands, 1981. (3) K. L. Schroeder et al. Phytopathology 96:637, 2006. (4) E. J. Sorensen. Crop Profile for Carrots in Washington State. U.S. Dept. Agric. National Pest Manage. Centers, 2000.

scholarly journals Effect of maleic hydrazide on respiratory parameters of stored onion bulbs (Allium cepa L.)

2004 ◽  
Vol 16 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Noureddine Benkeblia
Keyword(s):  
Activation Energy ◽  
Respiration Rate ◽  
Allium Cepa ◽  
Maleic Hydrazide ◽  
Co2 Production ◽  
Onion Bulbs ◽  
Respiratory Parameters ◽  
Allium Cepa L ◽  
Significant Difference ◽  
And Control

The respiration rate (RR) (CO2 production), activation energy (Ea) and Q10 of maleic hydrazide-treated onion bulbs (Allium cepa, cv. Rouge Amposta) at 20.10-6 mol.L-1 (MH1) and 45.10-6 mol.L-1 (MH2) were measured at 4, 10 and 20ºC. Immediately after treatment, the Q10 of MH-treated and control bulbs were not significantly different. After 8 weeks of storage, Q10 of control and both MH-treated bulbs increased and ranged from 2.34 and 2.89. Respiration rate of onions increased during storage, and after 24 weeks, RR values of control, MH1 and MH2 were 0.43, 0.32 and 0.26 mmol CO2.kg-1.h-1 at 20ºC respectively; and 0.26, 0.20 and 0.17 mmol CO2.kg-1.h-1 at 10ºC respectively. At 4ºC, no significant difference was observed between control and MH-treated bulbs. After 24 weeks, sprouting of the control and MH1 and MH2-treated bulbs was 75%, 38% and 33% at 20ºC respectively, and 50%, 22% and 17% at 10ºC respectively. At 4ºC, the sprouting level of control bulbs did not exceed 7% and was 5% for MH-treated bulbs. No difference was observed in rotting of control and MH-treated bulbs, and the low rotting observed at 4ºC could be attributed to low temperature rather than maleic hydrazide treatment.

scholarly journals Effects of plant density and cultivar on yield responses in onions (Allium cepa L.) grown from seeds

2013 ◽  
Vol 50 (1-2) ◽  
pp. 221-229
Author(s):  
Jan Rumpel ◽  
Kazimierz Felczyński
Keyword(s):  
Allium Cepa ◽  
Field Experiments ◽  
Plant Density ◽  
Leaf Fall ◽  
Marketable Yield ◽  
Onion Bulbs ◽  
Allium Cepa L ◽  
Yield Responses ◽  
Bulb Yield ◽  
Size Grading

Two field experiments were conducted to study the effect of plant density on yield, size grading and maturity of onion bulbs grown from seeds. In the first experiment carried out during 1991-1993, three onion cultivars (Hysam F<sub>1</sub> , Mercato F<sub>1</sub> and Sochaczewska) were sown for intended densities of 20, 40, 60, 80,100 and 140 plants m<sup>-2</sup>, whereas in the second one, in 1996, six onion cultivars (Spirit F<sub>1</sub>, Summit F<sub>1</sub>, Hyduro F<sub>1</sub>, Armstrong F<sub>1</sub>, Renate F<sub>1</sub> and Robusta) were sown for intended densities of 40, 60 and 80 plants m<sup>-2</sup>. The onions were grown on beds, 1,35 m wide, in 4 rows per bed (27+27+27+54 cm). Marketable yield increased with plant density, and depending on year was highest at 80 or 100 plants m<sup>-2</sup>. The average marketable yield of the 1991-1993 experiment increased from 20.5 t·ha<sup>-1</sup> at 20 plants m<sup>-2</sup> to 32.8 t·ha<sup>-1</sup> at 80 plants m<sup>-2</sup>, whereas that of the 1996 experiment increased from 48,9 t-ha<sup>-1</sup> at 40 plants m-2 to 59.0 t·ha<sup>-1</sup> at 80 plants m<sup>-2</sup>, respectively. Yield of large bulbs decreased with density and was highest at 20-40 plants m<sup>-2</sup>, oposite to the yield of small bulbs, which was highest at the highest density of 140 plants·m<sup>-2</sup>. The medium bulb yield increased with density, at the some way as compared the total marketable yield. No greater effect of cultivar on bulb size grades was found and the existing differences were proportional to the total marketable yield . Plant density hastened maturity of onions, and at density of 140 plants m<sup>-2</sup> the leaf fall-over occurred 9-10 days earlier as compared at density of 20 plants m<sup>-2</sup>. The cultiwars used. can be placed in the following order of decreasing productivity: 1 . Mercato F<sub>1</sub>, 2. Hysam F<sub>1</sub> and 3. Sochaczewska, - in the first expeiiment (1991-93) and 1. Annstrong F<sub>1</sub>, 2. Spirit F<sub>1</sub>, 3. Robusta, 4. Renate F<sub>1</sub>, 5. Hyduro F<sub>1</sub> and 6. Summit F<sub>1</sub> - in the second experiment (1996), respectively.

scholarly journals Changes in endogenous growth inhibitors in onion bulbs (Allium cepa L.) cv. Sochaczewska during storage

2013 ◽  
Vol 41 (2) ◽  
pp. 265-274
Author(s):  
Elżbieta Kielak ◽  
Maria Bielińska-Czarnecka ◽  
Helena Różycka
Keyword(s):  
Endogenous Growth ◽  
Allium Cepa ◽  
Storage Period ◽  
Weather Conditions ◽  
Growth Inhibitors ◽  
Inhibitor Activity ◽  
Onion Bulbs ◽  
Cold Room ◽  
Allium Cepa L ◽  
Two Peaks

Changes in inhibitor activity in the onion bulbs (<i>Allium cepa</i> L.) cv. Sochaczewska during storage were investigated. Onions were dried under an umbrella roof until October 15th or November 15th and thereafter stored in a cold-room at 0-1°C until May 15th. The activity of inhibitors fluctuated markedly during the storage period. At least two peaks and two decreases of inhibitor activity were observed. The weather conditions seemed to strongly influence the level and the date of appearance of inhibitors in onions. Higher inhibitor activity is usually connected with better storage and less sprouting of onions during storage. Prolonged drying under an umbrella roof enhanced onion quality after storage only in these cases when it actually improved the drying of onions.

scholarly journals Changes in endogenous cytokinin-like substances in onion bulbs (Allium cepa L.) cv. Sochaczewska during storage

2013 ◽  
Vol 46 (1) ◽  
pp. 73-81
Author(s):  
Elżbieta Kielak ◽  
Maria Bielińska-Czarnecka
Keyword(s):  
Storage Period ◽  
Weather Conditions ◽  
Clear Correlation ◽  
Cytokinin Activity ◽  
Onion Bulbs ◽  
Cold Room ◽  
Allium Cepa L ◽  
One Year ◽  
The Moment ◽  
Main Factor

Onion bulbs cv. Sochaczewska were dried under an umbrella roof until October 15th or November 15th and thereafter stored in a cold room at 0-1°C until May 15th. During 4 years of the experiment, the activity of cytokinin-like substances was determined each month during storage. The cytokinin activity showed two to three peaks: at the beginning of storage, in January-February (in one year in December) and at the end of the storage period. No clear correlation was found between cytokinin activity and bulb rooting or sprouting. The length of the drying period occasionally influenced the height of cytokinin activity peaks and displaced the moment of their appearance. Weather conditions in particular years seem to be the main factor influencing the changes in cytokinin activity.

Modified atmosphere packaging of onion bulbs (Allium cepa L.)

2001 ◽  
Vol 21 (3) ◽  
pp. 297-302
Author(s):  
Noureddine Ake ◽  
Brice Benkeblia ◽  
Patrick Varoquaux
Keyword(s):  
Allium Cepa ◽  
Modified Atmosphere Packaging ◽  
Modified Atmosphere ◽  
Onion Bulbs ◽  
Allium Cepa L
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