• Journal of Microbiology and Biotechnology
• /
• 제34권8호
• /
• pp.1627-1635
• /
• 2024

The inhabitation and parasitism of root-knot nematodes (RKNs) can be difficult to control, as its symptoms can be easily confused with other plant diseases; hence, identifying and controlling the occurrence of RKNs in plants remains an ongoing challenge. Moreover, there are only a few biological agents for controlling these harmful nematodes. In this study, Xenorhabdus sp. SCG isolated from entomopathogenic nematodes of genus Steinernema was evaluated for nematicidal effects under in vitro and greenhouse conditions. The cell-free filtrates of strain SCG showed nematicidal activity against Meloidogyne species J2s, with mortalities of > 88% at a final concentration of 10%, as well as significant nematicidal activity against the three other genera of plant-parasitic nematodes in a dose-dependent manner. Thymine was isolated as active compounds by assay-guided fractionation and showed high nematicidal activity against M. incognita. Greenhouse experiments suggested that cell-free filtrates of strain SCG efficiently controlled the nematode population in M. incognita-infested tomatoes (Solanum lycopersicum L., cv. Rutgers). In addition, a significant increase in host plant growth was observed after 45 days of treatment. To our knowledge, this is the first to demonstrate the nematicidal activity spectrum of isolated Xenorhabdus species and their application to S. lycopersicum L., cv. Rutgers under greenhouse conditions. Xenorhabdus sp. SCG could be a promising biological nematicidal agent with plant growth-enhancing properties.

• 식물병연구
• /
• 제20권1호
• /
• pp.37-49
• /
• 2014

식물 기원의 살선충 물질 탐색 연구의 일환으로, 178과, 1,677종 식물의 부위별 조추출물 2,714종을 이용하여 이들이 선충의 활성에 미치는 영향을 검토하였다. 선충억제 활성 검정은 96-well microplate를 이용하였으며 부식성선충 20마리를 조추출물 $5,000{\mu}g/ml$에 침지하고 7일간 매일 관찰하였다. 시험결과 2,362종(87.0%)의 조추출물은 부식성선충에 전혀 영향을 미치지 않았고, 187종(6.9%)의 조추출물은 부식성선충의 활성을 50% 정도 억제하였고, 95종(3.5%)의 조추출물은 90% 이상 억제를 보였으며, 70종(2.6%)의 조추출물에서는 오히려 부식성선충이 번식되었다. 1차 검정에서 50% 이상 선충억제 활성을 보인 추출물중에서, 25개의 추출물을 임의로 선택하여 2, 3차(부식성선충), 4차(고구마뿌리혹선충 유충) 반복 시험을 수행한 결과, 약 44%의 시료는 지속적인 선충억제 활성을 보였다. 이번 시험에서 선충억제 활성을 나타낸 282개의 식물 조추출물은 앞으로 식물 기원의 살선충 물질 연구시 참고 자료로 활용될 수 있을 것이다.

• 한국응용곤충학회지
• /
• 제27권3호
• /
• pp.159-164
• /
• 1988

Five nematophagous fungi were evaluated for their nematicidal effect in vitro on Rhabditis sp. and Meloidogyne hapla in soil. Inocula of Arthrobotrys arthrobotryoides, A. conoides, A. oligospora, Dactylella lobata, and Fusarium oxyaporum were grown in moistened corn-sandy soil and chopped potato-sandy soil media, and incubated at 26$^{\circ}C$ for one week. The prepared inocula were incorporated in autoclaved sandy soil, mixing thoroughly at rates equ-invalent to 1:50, 1:100, 1:200, and 1:400, repectively, before 80g of the mixture carrying 100 Rhabditis sp. was put into petri plates. Nematophagous fungi effectively teduced the popuation of Rhabditis sp. in soil in a week or two following treatment of the incula at concentration of 1:50 and 1:100. The optimum was at $25^{\circ}C$ for nematicidial effect as high as 80-100%. The at the rate of 1:100 prepared incula were incorporated in auto-claved soil, where 100 Juveniles M. hapla were introduced per 80% soil. All fungi infected the M. hapla effectively in soil, caysing more than 90% mortality within one week. This result indicated the potential value of these fungi as promising biocontrol agents.