Cosic J, Vrandecic K, Jurkovic D, Postic J, Orzali L, Riccioni L
Faculty of Agriculture in Osijek, Petra Svacica 1d, 31 000 Osijek, Croatia.
CRA-Centro di Ricerca per la Patologia Vegetale, Via C.G. Bertero, 22, I-00156 Rome, Italy.
Plant Dis. 2012 Apr;96(4):591. doi: 10.1094/PDIS-12-11-1046-PDN.
In May 2011, samples of lavender plants (Lavandula × intermedia) showing wilt symptoms were collected from two commercial plantings in Slavonia County. Disease was observed on 20 to 30% of the plants. Symptoms of the disease consisted of chlorosis, stunting, wilting, and death. Vascular tissue of stems and roots exhibited brown discoloration. Isolations of the pathogen were made from the discolored tissues on potato dextrose agar (PDA). Colonies were initially white, but with age became red, and red pigments were produced in agar. Microconidia were pear shaped, oval, and fusoid, and ranged from 4.5 to 14.0 × 2.8 to 4.7 μm. Macroconidia were curved, mostly three septate, and ranged from 21.8 to 24.3 × 2.9 to 3.9 μm. Morphology of colonies and conidia matched the description of Fusarium sporotrichioides Sherb. (1). Identity of the fungus was confirmed by examining a portion of the EF1-α gene using the degenerated primers EF1 and EF2 (2). BLAST searches of the obtained sequences showed a 100% homology with several isolates of F. sporotrichioides from GenBank. Pathogenicity tests were conducted on 20 4-month-old rooted cuttings under greenhouse conditions. Each plant was planted in a separate pot containing 0.7 liter of sterile soil. Inoculum for artificial infection was prepared with sterilized mixtures of wheat and barley seeds (10 g of each). Seeds were inoculated with a F. sporotrichioides spore suspension (10 conidia/ml) and incubated at 22°C for 10 days. Noninoculated seeds served as controls. Ten seeds were placed under the soil surface around the root of each plant. Plants were irrigated and placed in a greenhouse (22°C and a 12-h day/night photoperiod). Sixteen days after inoculation, 80% of inoculated plants were wilted. Symptoms on infected plants were similar to those observed in the field. The pathogen was reisolated and confirmed from the infected vascular tissue, thus fulfilling Koch's postulates. A previous paper reported lavender as host of F. solani in China (4) and F. oxysporum in Saudi Arabia (3). To our knowledge, this is the first report of Fusarium wilt of lavender caused by F. sporotrichioides. References: (1) J. F. Leslie and B. A. Summerell. Page 256 in: The Fusarium Laboratory Manual. Blackwell Publishing Professional, Hoboken, NJ, 2006. (2) K. O'Donnell et al. Appl Biol. Sci. 95:2044, 1998. (3) K. Perveen and N. Bokhari. Plant Dis. 94:1163, 2010. (4) Y. Z. Ren et al. New Dis. Rep. 15:55, 2007.
2011年5月，从斯拉沃尼亚县的两个商业种植园采集了表现出枯萎症状的薰衣草植株（Lavandula × intermedia）样本。在20%至30%的植株上观察到病害。该病症状包括黄化、生长受阻、枯萎和死亡。茎和根的维管组织呈现褐色变色。从变色组织在马铃薯葡萄糖琼脂（PDA）上分离病原菌。菌落最初为白色，但随着时间推移变为红色，且在琼脂中产生红色色素。小型分生孢子呈梨形、椭圆形和梭形，大小为4.5至14.0×2.8至4.7μm。大型分生孢子弯曲，大多有三个隔膜，大小为21.8至24.3×2.9至3.9μm。菌落和分生孢子的形态与Fusarium sporotrichioides Sherb.（1）的描述相符。通过使用简并引物EF1和EF2检测EF1-α基因的一部分来确认真菌的身份（2）。对获得的序列进行BLAST搜索显示与GenBank中几个F. sporotrichioides分离株有100%的同源性。在温室条件下对20株4个月大的生根插条进行致病性测试。每株植物种植在一个单独的装有0.7升无菌土壤的花盆中。用灭菌的小麦和大麦种子混合物（各10克）制备人工感染接种物。种子用F. sporotrichioides孢子悬浮液（10个孢子/毫升）接种，并在22°C下培养10天。未接种的种子作为对照。在每株植物根部周围的土壤表面下放置10粒种子。给植物浇水并置于温室中（22°C，12小时光照/12小时黑暗光周期）。接种16天后，80%的接种植物枯萎。感染植物上的症状与在田间观察到的症状相似。从感染的维管组织中重新分离并确认病原菌，从而满足柯赫氏法则。之前有一篇论文报道薰衣草在中国是茄腐镰刀菌的寄主（4），在沙特阿拉伯是尖孢镰刀菌的寄主（3）。据我们所知，这是首次报道由F. sporotrichioides引起的薰衣草枯萎病。参考文献：（1）J. F. Leslie和B. A. Summerell。《镰刀菌实验室手册》第256页。Blackwell Publishing Professional，新泽西州霍博肯，2006年。（2）K. O'Donnell等人。《应用生物科学》95:2044，1998年。（3）K. Perveen和N. Bokhari。《植物病害》94:1163，2010年。（4）Y. Z. Ren等人。《新病害报道》15:55，2007年。
