The oral toxicities of symbiotic bacteria Photorhabdus temperata ssp temperata (Ptt), mutually associated with entomopathogenic nematode Heterorhabditis megidis, and P. luminescens ssp. laumondii (TT01) with H. bacteriophora, were demonstrated to adults of the sweetpotato whitefly Bemisia tabaci. Sucrose solution (25%) containing bacteria-free supernatant of culture media of symbiotic bacteria was ingested into adult whiteflies within the glass tube. Whitefly mortalities were shown similar patterns against two bacterial media. Mortalities were significantly increased to 60-64% at 36 hours and almost 100% at 60 hours after treatments. In addition, We demonstrated the effect of oral ingestion of symbiont culture media on the gene expression of B. tabaci. Several genes fluctuated those expression levels. Our results suggest that oral ingestion of symbiont culture media of entomopathogenic nematodes significantly changed metabolic rates and highly lethal to whiteflies. The use of symbiotic bacteria of entomopathogenic nematodes provides a great potential as an alternative genetic resource of Bacillus thuringiensis, a major resource of microbial insecticide.

• Yam Kumar Shrestha(School of Applied Biosciences, Kyungpook National University)
• Hong-Soo Choi(National Institutes of Agricultural Science)
• Kwan-Suk Lee(National Institutes of Agricultural Science)
• Chang-Suk Kim(National Institutes of Agricultural Science)
• Sukchan Lee(Department of Genetic Engineering, Sungkyunkwan University)
• Kyeong-Yeoll Lee(School of Applied Biosciences, Kyungpook National University)