The present study was undertaken to test the inhibitory activity of several plant extracts against bacteria causing economically important diseases on fruit and nut trees. Essential oils derived from oregano (Origanum vulgare ssp. hirtum), common sage (Salvia officinalis), savory (Satureja pilosa), monarda (Monarda didyma) and an extract from clove (Syzygium aromaticum) flower buds were tested in vitro for their antibacterial activity towards two different strains each of Agrobacterium tumefaciens (At), strains AT4 and C58, Erwinia amylovora (Ea), strains 659 and 691, Pseudomonas syringae pv. syringae (Pss), strains LMG 1247T and 110, Xanthomonas arboricola pv. corylina (Xac), strains CFBP 1159T and 301, and X. arboricola pv. juglandis (Xaj), strains CFBP 2528T and 510. The plant products expressed selective activity in suppressing bacterial growth. Overall, most efficient appeared the essential oils from monarda (for strains At AT4, Ea 659, Pss LMG 1247T Xac CFBP 1159T and Xaj CFBP 2528T) and oregano (against all strains used). In 100% concentrated form these oils exerted on average 48-63% and 40-55% inhibition, respectively. The inhibitory effects of sage and savory oils varied significantly causing either no or from 20 to 60% inhibition. Clove extract was medium efficient against all pathogens providing 18-30% inhibition. Generally, most of the extracts (except clove extract and in some cases sage and savory oils) showed activity exceeding up to 30-40% compared to the inhibitory effect of the maximum concentration (500 ppm) of the antibiotic streptomycin. Monarda, oregano oils and clove extract were almost equally active in undiluted form and at dilution to 50% whereas sage oil and in part savory oil showed lower activity at 50% dilution. The differences in the response of tested pathogens (that were of different origin) suggested that their sensitivity to applied plant products may be related to the genotype. In support to this assumption are our earlier studies where the genetic diversity of the strains used was proven by analysis of housekeeping genes. The results reported here are preliminary and further work is being undertaken to perspective the observed inhibitory effects by in vivo tests in a larger scale.

进行本研究以测试几种植物提取物对在果树和坚果树上引起经济上重要疾病的细菌的抑制活性。牛至（Origanum vulgare ssp。hirtum），鼠尾草（Salvia officinalis），咸味（Satureja pilosa），monarda（Monarda didyma）和丁香（Syzygium aromaum）花芽的提取物的体外抗菌活性进行了体外测试分别针对根癌土壤杆菌（At），菌株AT4和C58，解淀粉欧文氏菌（Ea），菌株659和691，丁香假单胞菌PV的两种不同菌株。丁香（Pss），菌株LMG 1247T和110，黄单胞菌Xanthomonas arboricola pv。corylina（Xac），菌株CFBP 1159T和301，以及X. arboricola pv。Juglandis（Xaj），菌株CFBP 2528T和510。植物产物在抑制细菌生长中表现出选择性活性。总的来说，最有效的油来自monarda（针对AT4，Ea 659菌株，Pss LMG 1247T Xac CFBP 1159T和Xaj CFBP 2528T菌株）和牛至（针对所有菌株）。这些油以100％浓缩的形式分别平均发挥48-63％和40-55％的抑制作用。鼠尾草和香精油的抑制作用变化很大，没有抑制作用，或者有20％至60％的抑制作用。丁香提取物对所有病原体均具有中等效率，可提供18-30％的抑制率。通常，与最大浓度（500 ppm）抗生素链霉素的抑制作用相比，大多数提取物（丁香提取物和某些情况下的鼠尾草和咸味油除外）显示出超过30-40％的活性。莫纳尔达（Monarda），牛至油和丁香提取物在未稀释状态和稀释至50％时几乎具有相同的活性，而鼠尾草油和部分咸味油在50％稀释时显示较低的活性。被测病原体（来源不同）的反应差异表明，它们对应用植物产品的敏感性可能与基因型有关。支持这一假设的是我们较早的研究，其中通过管家基因分析证明了所用菌株的遗传多样性。这里报道的结果是初步的，并且正在进行进一步的工作以更大规模地观察通过体内试验观察到的抑制作用。被测病原体（来源不同）的反应差异表明，它们对应用植物产品的敏感性可能与基因型有关。支持这一假设的是我们较早的研究，其中通过管家基因分析证明了所用菌株的遗传多样性。这里报道的结果是初步的，并且正在进行进一步的工作以更大规模地观察通过体内试验观察到的抑制作用。被测病原体（来源不同）的反应差异表明，它们对应用植物产品的敏感性可能与基因型有关。支持这一假设的是我们较早的研究，其中通过管家基因分析证明了所用菌株的遗传多样性。这里报道的结果是初步的，并且正在进行进一步的工作以更大规模地观察通过体内试验观察到的抑制作用。