Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejeon, South Korea.
Can J Microbiol. 2011 Oct;57(10):838-43. doi: 10.1139/w11-068. Epub 2011 Sep 27.
Esteya vermicola , an endoparasitic fungus of pinewood nematode, exhibits great potential as a biological agent against nematodes. In this study to enhance the sporulation, predacity, and environmental resistance of E. vermicola, various nitrogen sources, such as glycine, L-leucine, and ammonium nitrate, were tested. The supplement of glycine and L-leucine had a significant influence on the growth rate of the colony, enhancing colony dry mass by 5-fold more than did ammonium nitrate or the control. Of the nitrogen sources tested, ammonium nitrate and L-leucine promoted sporulation, yielding more than 6 × 10(6) CFU/g, while glycine enhanced the proportion of lunate spores. Meanwhile, the supplement of nitrogen sources had a significant influence on adhesive rate and mortality rate against Bursaphelenchus xylophilus . Moreover, the supplement of glycine enhanced the survival rate against heat stress by more than 3-fold that of L-leucine, ammonium nitrate, and control. The spores produced in media amended with glycine, L-leucine, and ammonium nitrate had slightly but not significantly higher UV resistance and drought resistance than spores produced without nitrogen sources. These results suggested that the addition of glycine resulted in the production of E. vermicola conidia with increased predacity and resistance to environmental stress that may be more suitable for control of pine wilt disease.
松材线虫内生真菌斯氏线虫，具有作为杀线虫生物制剂的巨大潜力。本研究旨在提高斯氏线虫的孢子形成、捕食和环境抗性，测试了各种氮源，如甘氨酸、L-亮氨酸和硝酸铵。甘氨酸和 L-亮氨酸的添加对菌落的生长速度有显著影响，使菌落干质量比硝酸铵或对照增加了 5 倍。在所测试的氮源中，硝酸铵和 L-亮氨酸促进了孢子形成，产生的孢子数超过 6×10(6)CFU/g，而甘氨酸则增强了新月形孢子的比例。同时，氮源的添加对拟松材线虫的黏附率和致死率有显著影响。此外，甘氨酸的添加使热应激下的存活率比 L-亮氨酸、硝酸铵和对照提高了 3 倍以上。与不添加氮源相比，在添加甘氨酸、L-亮氨酸和硝酸铵的培养基中产生的孢子，其对紫外线和干旱的抗性略有提高，但无统计学意义。这些结果表明，添加甘氨酸可产生捕食活性和抗环境胁迫能力增强的斯氏线虫分生孢子，可能更适合松材线虫病的防治。
