Decline and death of young vines is a worldwide problem for viticulture that may lead to economic loss. Fungal pathogens have been associated with trunk and root diseases, including the black foot disease that affects the performance of the vineyards. Fungicides have not worked efficiently to control the disease and alternative methods should be investigated. We evaluated the potential of Bacillus subtilis strain F62 for controlling the disease caused by different strains in grapevine rootstocks 1103P (Vitis berlandieri × V. rupestris) and SO4 (V. berlandieri × V. riparia). The in vitro antagonism of B. subtilis F62 was evaluated on mycelial growth, by diffusible and volatile compounds, and conidia germination, by bacterial suspension and cell-free filtrate. In the in vivo assay, cuttings and micropropagated rootstocks were submitted to four different treatments: control, Bac (B. subtilis inoculation), Pat (pathogen inoculation) and Bac + Pat. According to our results, the bioagent was able to inhibit the mycelial growth of all the three fungal isolates by diffusible compounds and conidial germination by bacterial suspension and cell-free filtrate. In the in vivo assay, cuttings of SO4 treated with B. subtilis F62 showed higher shoot nodes and length of primary shoot, while cuttings of 1103P had a longer primary shoot. In micropropagated plants, B. subtilis F62 promoted plant growth in both rootstocks and reduced the frequency of D. macrodidyma re-isolation to 24.6% in SO4 and 29.5% in 1103P. The results demonstrated the potential of B. subtilis F62 on plant growth promotion and in the biocontrol of black foot disease on micropropagated plants and cuttings of grapevine rootstocks 1103P and SO4.

中文翻译：

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使用枯草芽孢杆菌菌株 F62 生物防治葡萄砧木黑足病

年轻葡萄藤的衰退和死亡是葡萄栽培的一个世界性问题，可能会导致经济损失。真菌病原体与树干和根部疾病有关，包括影响葡萄园性能的黑足病。杀菌剂未能有效控制疾病，应研究替代方法。我们评估了枯草芽孢杆菌 F62 菌株在控制葡萄砧木 1103P (Vitis berlandieri × V. rupestris) 和 SO4 (V. berlandieri × V. riparia) 中不同菌株引起的疾病方面的潜力。枯草芽孢杆菌 F62 的体外拮抗作用通过可扩散和挥发性化合物对菌丝体生长和分生孢子萌发、细菌悬浮液和无细胞滤液进行评估。在体内试验中，对插条和微繁砧木进行四种不同的处理：对照、Bac（枯草芽孢杆菌接种）、Pat（病原体接种）和 Bac + Pat。根据我们的结果，生物制剂能够通过可扩散化合物抑制所有三种真菌分离物的菌丝体生长，并通过细菌悬浮液和无细胞滤液抑制分生孢子萌发。在体内试验中，用枯草芽孢杆菌 F62 处理的 SO4 插条显示出更高的枝条节点和主枝条长度，而 1103P 的插条具有更长的主枝条。在微繁植物中，B. subtilis F62 促进了两种砧木的植物生长，并将 D. macrodidyma 重新分离的频率在 SO4 中降至 24.6%，在 1103P 中降至 29.5%。结果证明了 B.