Biological Control of Postharvest Root Rots of Ginseng = 수확후 인삼 뿌리썩음병의 생물학적 방제

국문 초록 (Abstract)

인삼뿌리썩음병의 억제토양으로부터 썩음병을 일으키는 Botrytis cinerea와 Fusarium solani에 대한 길항성 세균을 선발하여 저장중의 인삼뿌리썩음병에 대한 생물학적 방제를 시도하였다. 분리된 208개 균주에서 길항력이 뛰어난 4개의 세균을 선발하였다. 이들은 Bacillus amyloliquefaciens (B-18, B-19, B-19-17)와 Bacillus sp (B-17)로 동정되었다. 길항세균의 배양여액으르 첨가한 물한천배지에서 두 병원균의 분생포자 발아는 현저히 억제되었다. F. solani의 분생포자는 대조구에서 6시간 후 100% 발아하였으나 처리구에서는 11시간 후부터 발아하기 시작하여 길항균의 종류에 따라 14-83%의 발아율을 나타내었다. 그러나 B. cinerea의 분생포자는 대조구에서 12시간 후 90% 이상 발아하였으나 처리구에서는 48시간 이후에도 전혀 발아하지 않았다. 실온에서 길항세균을 (10^7 cfu/ml) 4년생 인삼에 처리하였을 때 F. solani 또는 B. cinerea에 의한 뿌리썩음병을 60-80% 방제할 수 있었다. 두 병원균의 밀도는 길항세균을 처리하지 않은 인삼표면에서 100-500배 높게 나타났으며 길항세균의 밀도는 병원균과의 동시접종 여부에 상관없이 일정수준으로 유지되었다.

다국어 초록 (Multilingual Abstract)

The production of Korean ginseng, one of the most important medicinal root crops, is limited by many factors including soil sickness, root rots in fields as well as during storage prior to consumption. Although much research has been conducted on the diseases in field condition, little information is available on the control of postharvest roots. To obtain better management strategy of postharvest root rots in ginseng, biological control using antagonistic bacteria is tried. Of 208 bacteria obtained from suppressive soil samples, 4 were selected based on the inhibitory effect on mycelial growth of two major causal fungi for postharvest root rots in ginseng, Botrytis cinerea and Fusarium solani. The culture filtrates of these bacterial antagonists greatly inhibited conidial germination of both pathogenic fungi and produced abnormal morphology such as swollen germ tubes in F. solani and vacuolation of nongerminated conidia in B. cinerea. The population levels of bacterial antagonists on the ginseng roots were gradually increased up to 8 days of incubation. Postharvest root rots of ginseng caused by F. solani and B. cinerea were controlled in dipping tests in the ranges of 60-80% by antagonistic Bacillus spp. obtained from suppressive soil. These results suggest that biological control using these antagonistic bacteria would be an alternative strategy to control postharvest root rots in ginseng.
Korean ginseng(Panax ginseng Meyer) has been recognized in the Orient as one of the most important medicinal root crops belonging to the Araliaceae family and its demand increases yearly. However, stable production of ginseng is limited by many factors including root rots caused by Cylindrocarpon destructans and Fusarium solani and postharvest diseases. Since ginseng requires fertile soil. rich in humus and with continuous shade for six years to grow until harvest, there is no practical control measure for root diseases in fields (4, 5, 6)
Postharvest diseases in fruits, vegetables, and root crops have not received the attention that the magnitude of the problem warrants, although they cause major losses in food production. In United States, it has been estimated that approximately 24% of harvested fruit and vegetables is lost to postharvest spoilage (18). Postharvest losses are even greater in developing countries where sanitation and refrigeration are lacking or Minimal. Although the accurate estimation is not available, postharvest loss of ginseng may exceed over 700 metric tons yearly. Root rots caused by Botrytis cinerea and F. solani account for the majority of postharvest loss in ginseng. Fungicide application is the primary means to control diseases in the field and postharvest stages However, the residual toxicity of chemicals on foods and appearance of resistant strains of pathogens to chemicals require the alternative strategies for stable production and storage of ginseng (7).
Biological control of ginseng root rots caused by C. destructans and F. solani with nonpolluting soil amendments and antagonistic microorganisms has been tried during the past (5, 6) However, no attempt has been made on biological control of ginseng root rots during postharvest stages Biological control of postharvest diseases is relatively new field, but there have been several encouraging developments (19). Much of this work has been concerned with the control of wound pathogens, such as B. cinerea (12, 15) and Momhnia
fructicola (13) There are several advantages in using biological control agents at the postharvest stage, because wounding of fruits and roots occurs mainly during harvesting and postharvest handling Thus the antagonists can be applied when the wound is most likely to occur, and subsequently can occupy the wound surface in advance and prevent subsequent invasion by pathogens Antagonistic bacteria and yeast, such as Bacillus subtilis (13, 14), Pseudomonas cepacia (10), Enterobacter aerogenes (16), and Debaryomyces hansenu (2, 3), have been tested to control postharvest diseases in a variety of stored vegetables and fruits including apple, peach, pear, cherry, potato, and tomato.
In this paper we have assessed the potential of biological control approach for the reduction of postharvest development of root rots in ginseng. Potential antagonistic bacteria were isolated from the suppressive soil, screened for antagonistic activity, and then tested for the control of root rots caused by B. cinerea and F. solani.

목차 (Table of Contents)

• ABSTRACT
• 1.MATERIALS AND METHODS
• 2.RESULTS
• 3.DISCUSSION
• 요약
• REFERENCES