伏隔弯曲杆菌。Flaccavfaciens(H.)柯林斯&琼斯被称为不同豆类作物的病原体,包括大豆(甘氨酸max(L.)合并。)(树篱1922年;邓利维1983年)。OEPP/EPPO(2011年)考虑了流感杆菌pv。根据俄罗斯两个地区(北高加索和远东)的普通豆类疾病的报道,俄罗斯目前存在的flaccavfaciens未经适当的病原体鉴定。在2020年夏季和2021年春季,在斯塔夫罗波尔边疆区(44.72°N,43.29°E)。2021年收获后,我们检查了在俄罗斯不同地区收集的48个大豆种子批次中是否存在C.flaccavfacienspv。Flacqufaciens.使用OEPP/EPPO(2011)方案进行种子测试。用于细菌分离,将种子提取物铺在MSCFF琼脂平板上(Maringoni等人。2006).在28°C电位下孵育5天后,C.光伏。favaccavfaciens菌落用于在NSA和SSM琼脂上进行进一步测试(Tegli等人。2017年,Maringoni等人。2016)。斯塔夫罗波尔生产的六个种子批次,梁赞(53.95°N,40.62°E),Orel(52.39°N,37.69°E)和阿穆尔(51.31°N,128.22°E)区域可疑。十个分离株(来自斯塔夫罗波尔的SB1至SB4,梁赞的F-125-1到F-125-3,和来自阿穆尔的F-30-1至F-30-3)被选择,并通过形态学进一步鉴定,生理,和生化特性,MALDITOFMS,16SrRNA序列,和特异性引物CffFOR2和CffREV4(Tegli等人。2017)。隔离物始终形成黄色,圆形,琼脂上光滑的菌落,并且与伏隔梭菌pv相同。在诊断生理特性中的创客型菌株DSM20129T(Tegli等人。2017)。通过CytoSorb试剂盒(Sintol,莫斯科)。所有测试菌株在PCR检测中均为阳性(图。1).使用引物27F/1492R扩增16SrRNA片段(Marchesi等人。1998)和PCR产物测序(Evrogen,莫斯科,俄罗斯)。获得的16SrRNA序列(1473bp,加入编号.根据BLASTNCBI搜索,OL539808.1-OL539817.1)与DSM20129T(AM410688.1)100%相同。通过用接种物润湿的剪刀切叶(对于大豆)或通过将5微升细菌悬浮液(108CFU/ml)注入茎中(对于普通豆)进行致病性测试。接种物的所有十种分离物在营养琼脂上在28°C下生长72小时。大豆简历。Kasatka植物(V1期)用于接种,和普通豆(简历。还接种了Purpurnaya)植物以确认多宿主毒力。无菌水用作对照。每个处理使用10个小植株作为重复。将植物在24°C下孵育,80%RH,和14小时光照/10小时黑暗周期。棕褐色斑点(大豆)和枯萎病(豆类)已发展为7-21d.p.i(图。2.1-2.6)。对照植物保持无症状。通过将它们浸泡在相同的细菌悬浮液中反复接种种子,产生扭曲的初根(图。2.7-2.8),但叶子上典型的疾病症状只在4-5周内出现。病原体成功地从所有受感染的植物中重新分离出来,而不是从对照中分离出来,从而实现了科赫的假设。使用16SrRNA的形态和生理特征以及DNA序列数据证实了重新分离的菌株的身份。这些结果表明,在俄罗斯三个重要的农业区(南部,中央,和远东)。据我们所知,这是C.favaccfacienspv的第一份报告。在俄罗斯引起大豆的细菌棕褐色斑点。
Curtobacterium flaccumfaciens pv. flaccumfaciens (H.) Collins & Jones is known as a pathogen of different legume crops, including soybean (Glycine max (L.) Merr.) (Hedges 1922; Dunleavy 1983). OEPP/EPPO (2011) considers C. flaccumfaciens pv. flaccumfaciens as present in Russia based on reports of the disease on common beans in two regions of Russia (North Caucasus and Far East) made without proper pathogen identification. During the summer of 2020 and the spring of 2021, soybean plants with tan spot disease (10-40% of plants) were reported during routine assays of several fields in Stavropol Krai (44.72°N, 43.29°E). After harvest in 2021, we inspected 48 soybean seed lots collected in different regions of Russia for the presence of C. flaccumfaciens pv. flaccumfaciens. Seed testing was performed using the OEPP/EPPO (2011) protocol. For bacteria isolation, seed extracts were spread on MSCFF agar plates (Maringoni et al. 2006). After 5 days of incubation at 28°C potential, C. flaccumfaciens pv. flaccumfaciens colonies were used for further tests on NSA and SSM agar (Tegli et al. 2017, Maringoni et al. 2016). Six seed lots produced in Stavropol, Ryazan (53.95°N, 40.62°E), Orel (52.39°N, 37.69°E) and Amur (51.31°N, 128.22°E) regions were suspect. Ten isolates (SB1 to SB4 from Stavropol, F-125-1 to F-125-3 from Ryazan, and F-30-1 to F-30-3 from Amur) were selected, and further identified by morphological, physiological, and biochemical properties, MALDI TOF MS, 16S rRNA sequences, and specific primers CffFOR2 and CffREV4 (Tegli et al. 2017). Isolates consistently formed yellow, circular, smooth colonies on agar, and were identical to C. flaccumfaciens pv. flaccumfaciens type strain DSM 20129T in diagnostic physiological properties (Tegli et al. 2017). DNA was isolated from the bacteria by the CytoSorb Kit (Sintol, Moscow). All tested strains were positive in the PCR assay (Fig. 1). 16S rRNA fragments were amplified using primers 27F/1492R (Marchesi et al. 1998) and PCR products were sequenced (Evrogen, Moscow, Russia). The obtained 16S rRNA sequences (1473 bp, Accession No. OL539808.1-OL539817.1) were 100% identical to DSM 20129T (AM410688.1) according to a BLAST NCBI search. A pathogenicity test was done by leaf-cutting with scissors wetted with inoculum (for soybeans) or by injecting 5 microliters of the bacterial suspension (108 CFU/ml) into the stem (for common beans). All ten isolates for the inoculum were grown on nutrient agar for 72 h at 28°C. Soybean cv. Kasatka plants (stage V1) were used for inoculation, and common bean (cv. Purpurnaya) plants were inoculated as well to confirm multi-host virulence. Sterile water served as a control. Ten plantlets were used as replicates for each treatment. The plants were incubated at 24°C, 80% RH, and a 14 hour light/10 hour dark cycle. Tan spots (soybean) and wilt (beans) have developed 7-21 d.p.i (Fig. 2.1-2.6). Control plants remained asymptomatic. Seed inoculation by soaking them in the same bacterial suspension repeatedly produced twisted primary root (Fig. 2.7-2.8), but typical disease symptoms on leaves developed in 4-5 weeks only. The pathogen was successfully reisolated from all infected plants and not from the controls, thus fulfilling Koch\'s postulates. The identity of the reisolated strains was confirmed using morphological and physiological characteristics and the DNA sequence data for the 16S rRNA. These results indicated that a causal agent of the tan spot is present on soybean in three important agricultural areas of Russia (South, Central, and the Far East). To the best of our knowledge, this is the first report of C. flaccumfaciens pv. flaccumfaciens causing a bacterial tan spot of soybean in Russia.