Cucumber Industry Research Articles

Development strategies for the sea cucumber industry in China

The sea cucumber, Apostichopus japonicus, is an important marine aquaculture species in China. After nearly thirty years of development, the production of A. japonicus has become commercially lucrative and successful. In this report, current advances in sea cucumber industry are addressed in terms of the basic biology, culturing methods, and health care benefits. Next, the challenges restricting development of the sea cucumber industry are discussed, including weaknesses in the basic biological research, the problem of germplasm degradation, environmental stress caused by global climate change, and food safety problems. Finally, several strategies are presented that might contribute to sustainable development of the sea cucumber industry. These strategies include advances in genome studies, behavioral studies, selective breeding, ecological culture technologies, reforms in food safety management, and the development of health care functions based on contemporary medical practices. Thus, our work provides new insights into how to explore the sustainable development of the sea cucumber industry in the future.

Use of phages to control Vibrio splendidus infection in the juvenile sea cucumber Apostichopus japonicus.

In the present study, we isolated 3 bacteriophages with the ability to control Vibrio splendidus, a bacterium known to cause disease in the juvenile sea cucumber. These bacteriophages were designated as vB_VspS_VS-ABTNL-1 (PVS-1), vB_VspS_VS-ABTNL-2 (PVS-2) and vB_VspS_VS-ABTNL-3 (PVS-3). The ability of the 3 phages to inhibit the growth of V.splendidus VS-ABTNL was tested invitro using each of the 3 phages individually or in the form of a cocktail of all 3 phages in the proportion of 1:1:1. All treated cultures produced a significant (P<0.05) inhibition of growth of V.splendidus VS-ABTNL compared with untreated V.splendidus VS-ABTNL with the cocktail being superior to any of the 3 phages used individually. The lytic capability of the 3 phages was subsequently determined with a Spot Assay Technique performed with 4 isolates of V.splendidus, 3 other Vibrio species and 2 environmental isolates. Both PVS-1 and PVS-2 were lytic to all 4 isolates of V.splendidus while PVS-3 only inhibited the growth of 3 of them. V.splendidus VS-ABTNL was more susceptible to phage PVS-2 than the other 2 phages. In an invivo performance trial, 360 sea cucumbers (23±2g) were randomly assigned to 1 of 6 treatments. Each treatment was housed in 3 PVC tanks (38cm×54cm×80cm) with 20 sea cucumbers per tank. Six diets were prepared including an unsupplemented control diet, antibiotic treatment diet, 3 diets containing 1 of the 3 phages individually and a diet containing a cocktail of all 3 phages. After 60 days of feeding, all sea cucumber were challenged with V.splendidus VS-ABTNL by immersion in sea water containing a bacterial concentration of 6×10(6)CFU/mL for 2 days. The survival rate of sea cucumbers during the next 10 days was 18% for the unsupplemented diet, 82% for the antibiotic treatment, 82% for the phage cocktail, 65% for phage PVS-1, 58% for phage PVS-2 and 50% for phage PVS-3. There were no significant differences in weight gain, ingestion rate or feed conversion among sea cucumber fed the 4 phage treatments compared with those fed the unsupplemented diet (P>0.05). The levels of nitric oxide synthase and acid phosphatase of sea cucumbers fed phage-containing diets were significantly (P<0.05) increased compared with those fed the control diet. However, no significant differences (P>0.05) were detected among the 4 phage-fed treatments. An additional study was conducted in which 60 healthy sea cucumbers (23±2g) were randomly assigned to a control, an untreated group and a test group to investigate the effects of injecting phages by coelomic injection on the survival rate and enzyme activities in the coelomic fluid of the sea cucumbers. The control was injected with 1ml of sterilized seawater while the untreated group and the test group were injected with the same volume of V. splendidus-ABTNL culture (3×10(5)CFU/mL). Then, the test group was injected with 1ml of the 3 phage cocktail (MOI=10). After 48h, the activities of lysozyme, acid phosphatase and superoxide dismutase were elevated in the untreated group while the levels of these enzymes in the test group were similar to the blank control. After 10-day observation, the survival rate of the sea cucumber was 100% for the blank control, 80% for the test group and 20% for the negative control. The overall results of this experiment indicate that phage therapy increased the survival of sea cucumber infected with V.splendidus VS-ABTNL. The above results demonstrate that using phages, especially a combination of different phages, may be a feasible way to control Vibrio infection in the sea cucumber industry.

Efficiency of a bacteriophage in controlling vibrio infection in the juvenile sea cucumber Apostichopus japonicus

Vibro cyclitrophicus is thought to be responsible for the cause of severe infection in juvenile sea cucumber (Apostichopus japonicus). Increases in the prevalence of antibiotic resistant pathogens have promoted us to develop effective agents to antibiotics for combating microbial infection among animals as well as human. In the present study, we isolated a bacteriophage with the ability to cleave V. cyclitrophicus present in the sewage of sea cucumber farms. This bacteriophage was designated as phage vB_VcyS_Vc1 (Vibrio phage Vc1). A one-step growth curve analysis of the phage revealed eclipse and latent periods of 25 and 45min, respectively, with a burst size of 215PFU/infected cell. Morphological analysis revealed the phage belongs to family of Siphoviridae. Furthermore, genomic sequencing results revealed a double-stranded DNA containing 44,541bp with a G+C content of 44.16%. Forty four coding sequences were annotated in the genome, and nineteen of these were associated with a known function. Genes related to virulence and toxins were not detected in the genome. In addition, a prevention experiment conducted in a marine environment demonstrated that the phage increased the survival rate of juvenile sea cucumbers (18±2g) from 18% to 81% when the sea cucumber were fed with feedstuff containing the freeze-dried phage powder, 58% when the sea cucumber was injected with purified phages (MOI=10), and 63% when the sea cucumbers were immersed in a suspension containing purified phages. Notably, when the phage provided nearly the same protection to the sea cucumbers as antibiotic when it was fed to the sea cucumbers in the form of freeze-dried powder mixed with feedstuff. Taken together, the results demonstrated that the use of phage to control the infection of V. cyclitrophicus in sea cucumber may be a feasible alternative to antibiotics. Statement of relevanceThe A. japonicus (sea cucumber) is the most profitable aquaculture animal with the highest output as single variety in China, which is of high nutritional value and economic value. In the past decade, as the growth of the market demand, A. japonicus's artificial breeding scale expands rapidly and the sea cucumber industry has become a vigorous sector in China aquaculture. However, with the high density and intensive development model of A. japonicus breeding, the various diseases have resulted in serious economic losses. Skin ulceration syndrome (SUS) is one of the most epidemic and serious diseases that affect sea cucumbers. At present, sanitizer and antibiotics are still commonly used in farms or hatcheries to control the bacterial disease in juvenile sea cucumbers, which resulted in the environment pollution and antibiotic residues. Nowadays, increased appearance of antibiotic resistant phenomenon promoted us to develop effective agents. Hence, alternative strategies to antibiotics should be further developed. This study was the first to monitor the effectiveness of using feedstuff mixed with freeze-dried phage powder as a form of protection for sea cucumber against vibrio infection, and demonstrated the effectiveness of phage in the control of pathogen in aquaculture.

Physiological and Immunological Responses in Giant California Sea Cucumbers (Parastichopus californicus) Exposed to Aquaculture-related Stress

Sea cucumbers are a valuable resource both for food and the production of nutraceuticals and pharmaceuticals, and as a result, the market for the giant California sea cucumber, Parastichopus californicus, has greatly increased, resulting in the establishment of fisheries along the west coast of North America. The sea cucumber industry is poorly regulated, and the fisheries are not believed to be sustainable, so there is interest in promoting the intensive aquaculture of this species. Since aquaculture conditions can cause stress to animals, which makes them more susceptible to disease, it is important to determine the stress susceptibility of sea cucumbers to two potential stresses, handling and low salinity. In order to study the impact of these stressors, a variety of physiological and immunological assays were done on the coelomic fluid of giant California sea cucumbers. Assays included total and differential cell counts, coelomic fluid protein, phagocytic capacity, lytic activity, and respiratory burst activity. Our results indicated that there were few significant differences from the control, and no differences in parameters analyzing immune function. These results indicate that the giant California sea cucumber is likely to be productive in an aquaculture environment, and the culture of this species should be encouraged.

Phytophthora Blight: A Serious Threat to Cucurbit Industries.

Introduction Phytophthora blight, caused by the oomycete Phytophthora capsici, has become one of the most serious threats to production of cucurbits and peppers, both in the United States and worldwide (2,6,8,9,11,17,18,22,27,30). Phytophthora capsici was first described by Leonian on pepper in New Mexico in 1922 (20). In 1931, Tucker (38) classified it as a species of the genus Phytophthora and considered P. capsici as a host-specific fungus pathogenic on pepper. Subsequently, taxonomists (23,36,37) studied Phytophthora isolates from various hosts in the world and re-described the taxonomy of P. capsici. Recently, the incidence of Phytophthora blight on cucurbits has dramatically increased in Illinois (2,32) and other cucurbit-growing areas in the world (8,9,17,18), causing up to 100% yield loss. Cucurbit industries, particularly processing industries, are seriously threatened by heavy crop loss resulting from Phytophthora blight. For example, outbreaks of Phytophthora blight have threatened the processing pumpkin and other cucurbit industries in Illinois, where 90% of processing pumpkins produced in the US are grown (2,3) (Figs. 1 and 2). Similarly, the pickling cucumber industry of Michigan is jeopardized by the increased occurrence of Phytophthora blight (8). Because of heavy crop losses the growers often have to abandon their own farms for cucurbit production and move into different areas, sometimes traveling more than 50 miles, to find fields not infested with P. capsici.

First Report of Fusarium Stem and Root Rot of Greenhouse Cucumber Caused by Fusarium oxysporum f. sp. radicis-cucumerinum in Ontario

Fusarium stem and root rot on greenhouse long English cucumber (Cucumis sativus L.) cvs. Bodega and Gardon was observed at four commercial greenhouses in Leamington, Ontario, Canada. Losses of 25 to 35%, representing 2.5 ha, were noted. The greenhouse cucumber industry in Ontario comprises 119 ha, with sales in 1999 of $78 million (Canadian). Some foliar chlorosis developed slowly on the lower foliage of affected plants. Basal stem tissue developed a yellow buff discoloration with superficial rot, followed by advanced stages of stem disintegration, which were accompanied by the production of white buff fungus mycelium and orange spore masses externally, and yellowish or reddish brown discoloration of vascular tissue that extended for 5 to 6 cm. Yellowish brown to brown external discoloration extended throughout the affected roots. In contrast, the main symptoms on cucumber infected by F. oxysporum f. sp. cucurbitaceae are wilt, yellowing, and vascular discoloration. The shape of macroconidia, the presence of microconidia on short lateral phialides, and the occurrence of chlamydospores and sporodochia on acidified potato dextrose agar (aPDA) were used to identify the isolates as F. oxysporum. To confirm pathogenicity and formae specialis designation, the roots of a range of 19-day-old host plants of the family Cucurbitaceae and some of the family Solanaceae were clipped and inoculated with the use of a root-dip method (1), with 5 × 105 spores per ml from 6-day-old aPDA cultures of three isolates and a water check with six plants per isolate. Plants were subsequently grown in a greenhouse soil mix (3:2 Fox sandy loam-peat moss, vol/vol) at 22°C day/19°C night, under environmental conditions similar to those reported elsewhere (1). A 0 (healthy) to 5 (dead) scale was used to rate plants after 30 days. In preliminary studies, cucumber cv. Corona, inoculated with various isolates and grown at 26 to 28°C for 30 days, remained asymptomatic, similar to the results of Vakalounakis 1996 (2) at 30°C and Punja and Parker 2000 (1) at 32°C. Muskmelon (Cucumis melo L. cvs. Early Dawn and Summet), watermelon (Citrullus vulgaris Schrad. cv. Yellow Doll), and cucumber cvs. Tasty Green, Odessa, Mustang, and Orient Express were the most susceptible and had ratings of 3.7, 3.0, 2.3, 3.8, 3.3, 1.1, and 1.6, respectively, with stem and root symptoms similar to those we observed in naturally infected plants and reported previously in other work (1). Cucumber cvs. Calypso, Slicemaster, Flamingo, and Marketmore 76 were less susceptible, with ratings of 0.6, 1.0, 0.1, and 1.0, respectively. No symptoms were observed on tomato (Lycopersicon esculentum Mill. cv. Trust), pepper (Capsicum annuum L. cv. Cubico), or squash (Cucurbita pepo L. cv. Taybelle) in our trials, which is in agreement with other work (1). Symptom development on a range of hosts and the cultural and morphological characteristics of the imperfect state of the fungus in vivo and in vitro confirm the identity of the fungus. To our knowledge, this is the first report of F. oxysporum f. sp. radicis-cucumerinum in Ontario.

Establishing Cucumber Production in Lesser Developed Countries: An Absolute Cost Advantage of Mexico versus Hispaniola Producers

During winter months, a substantial volume of various horticultural products are imported to the United States from the Caribbean and Central and South America. United States cucumber (Cucumis sativus L.) processors who market fresh-pack and refrigerated products require raw product daily to meet consumer demands. Mexico serves as a single-source supplier to all United States processors during this period, and thus Mexican production represents certain price risks. United States processors would consider other growing regions to reduce these risks if financially attractive alternatives could be identified. Therefore, a project was initiated to acquire information on production and export costs in Hispaniola (Dominican Republic and Haiti), and to compare those to Mexican and United States production and transport costs. Experimentation lead to the identification of the critical influences of market prices, costs and conditions for the financial feasibility of establishing a processing cucumber industry on Hispaniola. Comparative evaluation indicated that significant variation in total cost was caused by fluctuations in transport, tariffs, and labor cost components. The causes of variation in transportation costs were distance, method (sea, air, truck), competitive demand (volume), and shipping frequency, consistency, and capacity.

447 PB 282 INHERITANCE OF FRUIT FIRMNESS IN GENETICALLY PARTHENOCARPIC PICKLING CUCUMBERS

The firmness of parthenocarpic (P) pickling cucumber cultivars is generally considered unacceptable for processing by the US pickling cucumber industry. Genetic improvement in firmness of P pickling cucumbers may increase their acceptability. Inheritance of fruit firmness (FF) in nonparthenocarpic (NP) cucumbers has been reported as quantitative but highly heritable with additive gene effects accounting for most of the genetic variation and no maternal effects. Genetic investigations were conducted at Brooks, Oregon, in 1992 and 1993 to determine the inheritance of FF in P cucumbers. High heritability for FF was found with most genetic variance attributed to additive gene effects when F1's from four P gynoecious inbreds as females and five NP monecious inbreds as males were used in 1992. Experiments in 1993, with inbred derived populations, revealed that dominant variance and maternal effects for FF may be substantial in certain populations with parthenocarpic germplasm.

‘Redlands Long White’ Cucumber

Abstract ‘Redlands Long White’ cucumber (Cucumis sativus L.) was developed by Redlands Horticultural Station to provide the Queensland cucumber industry, seedsmen, and breeders with a high quality white-skinned long cucumber. In addition to high consumer acceptability, ‘Redlands Long White’ is productive and has resistance to downy mildew [Pseudoperonospora cubensis (Berk, et Curt) Rost.] and should carry resistance to some isolates of powdery mildew [Sphaerotheca fuliginea (Schlecht ex Fr.) Poll.].