兼具殺蟲與抗菌作用之線蟲共生細菌──光桿菌

"An entomopathogenic-nematophilic bacterium, Photorhabdus luminescens, with insecticidal and antimicrobial activities"

光桿菌（Photorhabdus luminescens）屬於腸內桿菌科（Enterobacteriaceae），為革蘭氏陰性，可發出螢光（bioluminescent）的桿狀細菌，已證實兼具殺蟲與抑菌效果。光桿菌與其分類地位相近之嗜線蟲桿菌（Xenorhabdus spp.）同為病原線蟲之腸道共生（symbiotic）細菌。光桿菌與異小桿線蟲（Heterorhabditis spp.）共生，而嗜線蟲桿菌則是與斯氏線蟲（Steinernema spp.）共生。

"Photorhabdus luminescens, a gram-negative bioluminescent insect-pathogenic bacterium, belonging to the family Enterobacteriaceae, lives in a symbiotic relationship with Heterorhabditid nematodes. Recently, it was reported that antibiotics from P. luminescens exhibited a wide spectrum of growth inhibition with several fungi of medicinal and agricultural importance. However, there has been no report of this kind on indigenous pest and plant pathogen. In this study, supernatant fluid of bacterial culture was centrifuged, filtered, and bioassayed against 6 species of insect larvae. The LC_(50) values of protein preparations against the 3rd instar larvae of the lepidopteran Plutella xylostella and Galleria mellonella were 56 and 200 ppm, respectively. Antagonistic effects of bacterial culture and protein preparations on 10 species of fungi and 9 species of bacteria were screened by means of dual or concomitant culture methods. High antimicrobial activities were observed against Botrytis cinerea, Glomerella cingulata, Alternaria mali, Phytophthora capsici, Bacillus thuringiensis, B. subtilis, B. cereus, and Erwinia carotovora subsp. carotovora. In conclusion, P. luminescens ATCC 29999 has high insecticidal and antimicrobial activities against local pests and pathogens."