Cruz-Munoz Maritsa, Petrone Joseph R, Cohn Alexa R, Munoz-Beristain Alam, Killiny Nabil, Drew Jennifer C, Triplett Eric W
Microbiology and Cell Science Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States.
Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, United States.
Front Microbiol. 2018 Apr 5;9:668. doi: 10.3389/fmicb.2018.00668. eCollection 2018.
is the closest cultured relative of four important uncultured crop pathogens. L. asiaticus, L. americanus, and L. africanus are causal agents of citrus greening disease, otherwise known as huanglongling (HLB). L. solanacearum is responsible for potato Zebra chip disease. Cultures of grow slowly on BM-7 complex medium, while attempts to culture the Liberibacter pathogens in BM-7 have failed. Developing a defined medium for the growth of will be useful in the study of metabolism and will improve the prospects for culturing the . Liberibacter pathogens. Here, M15 medium is presented and described as the first chemically defined medium for the growth of cultures that approaches the growth rates obtained with BM-7. The development of M15 was a four step process including: (1) the identification of Hi-Graces Insect medium (Hi-GI) as an essential, yet undefined component in BM-7, for the growth of , (2) metabolomic reconstruction of Hi-GI to create a defined medium for the growth of cultures, and (3) the discovery of citrate as the preferred carbon and energy source for growth. The composition of M15 medium includes inorganic salts as in the Hi-GI formula, amino acids derived from the metabolomic analyses of Hi-GI, and a 10-fold increase in vitamins compared to the Hi-GI formula, with exception choline chloride, which was increased 5000-fold in M15. Since genome comparisons of and the . Liberibacter pathogens show that they are very similar metabolically. Thus, these results imply citrate and other TCA cycle intermediates are main energy sources for these pathogens in their insect and plant hosts. Thus, strategies to reduce citrate levels in the habitats of these pathogens may be effective in reducing Liberibacter pathogen populations thereby reducing symptoms in the plant host.
是四种重要的未培养作物病原体中亲缘关系最近的可培养物。亚洲韧皮杆菌、美洲韧皮杆菌和非洲韧皮杆菌是柑橘黄龙病（又称黄龙病，HLB）的病原体。茄科韧皮杆菌导致马铃薯斑马薯片病。在BM - 7复合培养基上生长缓慢，而在BM - 7中培养韧皮杆菌病原体的尝试均告失败。开发一种用于生长的确定培养基将有助于研究其代谢，并改善培养韧皮杆菌病原体的前景。在此，介绍并描述了M15培养基，它是第一种用于培养的化学定义培养基，其生长速率接近在BM - 7中获得的生长速率。M15的开发过程包括四个步骤：(1) 确定Hi - Graces昆虫培养基（Hi - GI）是BM - 7中生长所必需的但未定义的成分；(2) 对Hi - GI进行代谢组学重建以创建用于培养的确定培养基；(3) 发现柠檬酸盐是生长的首选碳源和能源。M15培养基的成分包括Hi - GI配方中的无机盐、来自Hi - GI代谢组学分析衍生的氨基酸，以及与Hi - GI配方相比维生素增加了10倍，但氯化胆碱除外，其在M15中增加了5000倍。由于与韧皮杆菌病原体的基因组比较表明它们在代谢上非常相似。因此，这些结果意味着柠檬酸盐和其他三羧酸循环中间体是这些病原体在其昆虫和植物宿主中的主要能量来源。因此，降低这些病原体栖息地中柠檬酸盐水平的策略可能有效地减少韧皮杆菌病原体种群，从而减轻植物宿主中的症状。
