Wise Cody, Falardeau Justin, Hagberg Ingrid, Avis Tyler J
Phytopathology. 2014 Oct;104(10):1036-41. doi: 10.1094/PHYTO-12-13-0336-R.
Fengycin is an antimicrobial cyclic lipopeptide produced by various Bacillus subtilis strains, including strain CU12. Direct effects of fengycin include membrane pore formation and efflux of cellular contents leading to cell death in sensitive microorganisms. In this study, four plant pathogens were studied in order to elucidate the role of membrane lipids in their relative sensitivity to fengycin. Inhibition of mycelial growth in these pathogens varied considerably. Analysis of membrane lipids in these microorganisms indicated that sensitivity correlated with low ergosterol content and shorter phospholipid fatty acyl chains. Sensitivity to fengycin also correlated with a lower anionic/zwitterionic phospholipid ratio. Our data suggest that decreased fluidity buffering capacity, as a result of low ergosterol content, and higher intrinsic fluidity afforded by short fatty acyl chain length may increase the sensitivity of microbial membranes to fengycin. Our results also suggest that lower content in anionic phospholipids may increase fengycin insertion into the membrane through reduced electrostatic repulsion with the negatively charged fengycin. The intrinsic membrane lipid composition may contribute, in part, to the observed level of antimicrobial activity of fengycin in various plant pathogens.
丰原素是由多种枯草芽孢杆菌菌株产生的一种抗微生物环状脂肽，包括CU12菌株。丰原素的直接作用包括形成膜孔和细胞内容物外流，导致敏感微生物细胞死亡。在本研究中，对四种植物病原体进行了研究，以阐明膜脂在它们对丰原素相对敏感性中的作用。这些病原体中菌丝体生长的抑制差异很大。对这些微生物膜脂的分析表明，敏感性与麦角固醇含量低和磷脂脂肪酰链较短有关。对丰原素的敏感性还与较低的阴离子/两性离子磷脂比率有关。我们的数据表明，由于麦角固醇含量低导致的流动性缓冲能力下降，以及短脂肪酰链长度所提供的更高内在流动性，可能会增加微生物膜对丰原素的敏感性。我们的结果还表明，阴离子磷脂含量较低可能通过减少与带负电荷的丰原素的静电排斥，增加丰原素插入膜内。膜脂的内在组成可能部分有助于观察到的丰原素在各种植物病原体中的抗菌活性水平。
