甜樱桃(PrunusaviumL.)已成为中国重要的经济水果。在过去的三十年里,它的种植面积显著扩大(Wang等人。2020年;赵等人。2023年)。2023年7月,在汶川县(31°51N,东经103°56,海拔:1,510m)在四川省,大约27%的树木表现出包括软根在内的根腐病症状,深棕色至黑色病变,黄化和枯萎的叶子,当在横截面上切割时,内根核心会出现明显的黄棕色核心变色。为了分离致病病原体,从果园中随机选择6株来自Cerasuspsefocerasus的砧木“大青叶”感染的甜樱桃植物,然后用无菌水洗涤交织在一起的病根和健康根(5mm×5mm×2mm),以去除表层土壤。根样品用75%乙醇表面灭菌30秒和NaClO表面灭菌30秒,并用蒸馏水洗涤三次。将消毒的组织放置在马铃薯葡萄糖琼脂(PDA)上,并在黑暗中在27°C下孵育5天(Zhao等人。2024).总共获得了9种具有相似形态特征的真菌分离株。通过单孢子纯化获得的菌落显示红色的背面和正面的同心环图案,表面稀疏。大分生孢子相对细长,呈曲线状,像镰刀的形状,0至3个隔膜测量值(25.8至46.1)μm×(4.2至7.5)μm,分别(n=20)。形态特征与镰刀菌属的描述一致。(李等人。2021)。在这些分离物中,仅选择HB5进行额外的分子鉴定。三个靶基因,包括内部转录间隔区(ITS),部分平移延伸因子1-α(TEF),使用引物ITS1/ITS4,TEF1-728/FTEF1-re扩增RNA聚合酶第二大亚基(RPB2),和fRPB2-5F/fRPB2-7r,分别(Groenewald等人。2013;Carbone和Kohn1999;Reeb等人。2004).HB5的序列存放在GenBank(ITS,PP388208;TEF,PP580036;RPB2,PP580035)。BLAST搜索显示与99%的F.solani序列具有高度相似性,分别为100%和100%(MN013858.1,JF740846.1,OR371902.1),并生成多基因座系统发育树以表示分子鉴定结果。在1升塑料花盆中对Cerasuspseudocerasus的“大青叶”砧木进行了致病性研究。将幼苗在25°C和65%湿度水平的恒温培养箱中孵育两周。随着绿叶的生长,将200ml(1×106孢子/ml)孢子悬浮液倒入盆中。接种4周后,观察到接种植物的相同症状与田间显示的症状一致,而对照植物接种无症状蒸馏水。如前所述,已接种的病原体在形态和分子上都得到了证实,从而实现了科赫的假设。据报道,在中国的各种植物中,枯萎镰刀菌可引起根腐病,包括猕猴桃,花椒,Fragaria×ananassaDuch(Songetal.2022;Lietal.2023年;赵等人。2024).据我们所知,这是在甜樱桃(Prunusavium)中引起根腐病的枯萎病的第一份报告。我们在这里还报告了这种疾病的严重程度和爆发,近年来在其他地区发现,并可能变得普遍。迫切需要进一步研究疾病管理策略以保护甜樱桃生产。
Sweet cherry (Prunus avium L.) has become an economically important fruit in China. And its cultivation area has significantly expanded over the last three decades (Wang et al. 2020; Zhao et al. 2023). In July 2023, wilting of cherry trees was observed in a cherry plantation in Wenchuan County (31°51\'N, 103°56\'E, altitude: 1,510 m) in Sichuan Province and approximately 27% of the trees showed symptoms of root rot including soft roots, dark brown to black lesions, yellowing and wilted leaves, and a distinct yellow-brown core discoloration of the inner root core when cut in cross-section. To isolate the causal pathogens, six infected sweet cherry plants with rootstock \'Daqingye\' from Cerasus pseudocerasus were randomly selected from the orchard and then the intertwined diseased and healthy roots (5mm× 5mm × 2mm) were washed with sterile water to remove surface soil. The root samples were surface sterilized with 75% ethanol for 30 seconds and NaClO for 30 seconds and washed three times with distilled water. The disinfected tissues were placed on potato dextrose agar (PDA) and incubated at 27°C in darkness for 5 days (Zhao et al. 2024). A total of nine fungal isolates with similar morphological characteristics were obtained. The colony obtained through single-spore purification displays a red reverse side and a concentric ring pattern on the front, with a sparse surface. Macroconidia were relatively slender with a curve, like sickle shape, 0 to 3 septate measuring (25.8 to 46.1) μm× (4.2 to 7.5) μm, respectively (n=20). The morphological characteristics were consistent with the description of Fusarium spp. (Li et al. 2021). Among these isolates, only HB5 was selected for additional molecular identification. Three target genes, including the internal transcribed spacer (ITS), partial translation elongation factor 1-alpha (TEF), and RNA polymerase second largest subunit (RPB2) were amplified using the primers ITS1/ITS4, TEF1-728/FTEF1-re, and fRPB2-5F/fRPB2-7r, respectively (Groenewald et al. 2013; Carbone and Kohn 1999; Reeb et al. 2004). Sequences of HB5 was deposited in GenBank (ITS, PP388208; TEF, PP580036; RPB2, PP580035). A BLAST search revealed high similarity to those of F. solani sequences with 99%, 100% and 100% respectively (MN013858.1, JF740846.1, OR371902.1), and a multilocus phylogenetic tree was generated to represent the molecular identification results.
Pathogenicity studies were conducted on the rootstocks from \'Daqingye\' of Cerasus pseudocerasus in 1 liter plastic flowerpots. The seedlings were incubated in a constant temperature incubator at 25°C with a humidity level of 65% for two weeks. Following the growth of green leaves, 200ml (1x106 spores/ml) of spore suspensions were poured into pots. After 4 weeks of inoculation, the same symptoms of the inoculated plants were observed consistent with those shown in the field , while control plants were inoculated with distill water with asymptomatic. The inoculated pathogen was confirmed both morphologically and molecularly as described earlier, thereby fulfilling Koch\'s postulates. It has been reported that Fusarium solani has been reported to cause root rot in various plants in China, including Actinidia sppt, Zanthoxylum bungeanum, Fragaria×ananassa Duch (Song et al.2022; Li et al. 2023; Zhao et al. 2024). To our knowledge, this is the first report of Fusarium solani causing root rot in sweet cherry (Prunus avium). We here also report the severity and outbreak of this disease, which has been found in other regions in recent years and may become prevalent. Further research on disease management strategies is urgently needed to protect sweet cherry production.