Plant disease最新文献_第10页

First report of Sclerotinia minor causing soft rot of Scabiosa atropurpurea in California. 首次报告加利福尼亚州由小硬菌引起的 Scabiosa atropurpurea 软腐病。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-11 DOI: 10.1094/PDIS-08-24-1631-PDN

Jesica Calderon, Sophia Acker, Karina Elfar, Chris Greer, Johanna Del Castillo Múnera

In May of 2019, Scabiosa atropurpurea samples with brown discoloration, soft rot of the crown and lower stem, with presence of white mycelium and black sclerotia (Supp. Fig. 1A, B) were collected from a 0.10 ha open field diversified cut flower production in San Luis Obispo County, CA. Approximately 30 to 40% of the scabiosa crop planted in a quarter of the field, exhibited symptoms. Symptomatic crowns and lower stems from five plants were surface disinfested by rinsing in 0.1% Tween 20, soaking in 70% ethanol for 30 s, 1% sodium hypochlorite for 2 min and sterile water. Disinfested tissue was placed in 1/10 potato dextrose agar (PDA) and incubated at 20°C (12 h photoperiod). Resulting colonies (n = 5) formed abundant white mycelia, with black sclerotia formed on the outer edge of the plates after two weeks (Suppl. Fig. 1C). Sclerotia (n = 50) had an average size of 1.6 (± 0.19) mm in diameter. Morphological identification resulted in Sclerotinia sp. (Hao et al., 2003). The pathogen was further identified by DNA extraction of two hyphal tipped isolates, followed by amplification and sequencing of the rDNA internal transcribed spacer (ITS) region, ITS1/ITS4 (White et al. 1990), calmodulin (CaM), CAL-228F/CAL-737R (Carbone and Kohn, 1999), and DNA replication licensing factor Mcm7 Mcm7-709for/Mcm7-1348rev (Schmitt et al., 2009). NCBI BLAST searches with consensus sequences for each maker revealed 99 to 100% identity with S. minor ex-types for all loci (Supp. Table 1). A maximum parsimony multilocus phylogenetic analysis clustered Californian isolates with reference strains of S. minor (Supp. Fig. 1F). Sequences were deposited in GenBank (Supp. Table 1). Pathogenicity tests were conducted with isolate CS435, which was transferred onto PDA plates and incubated at 20°C for one week. Inoculum consisted of CS435 infested PDA plugs (1 cm3). In the greenhouse, the experiment was set as a complete randomized design and observed for six weeks. Fourteen-week-old scabiosa 'Merlot Red' grown in 3.78 L pots (n = 6), were inoculated by wounding plants at 0.5 cm above the crowns with a 1 mm probe. Inoculum was placed directly on top of the wound and was secured with parafilm. Negative control plants (n = 6) were wounded as above and inoculated with PDA plugs. In experiment 1(19.4 (± 3) °C, RH 46.9), 83% of plants exhibited yellowing of the lower leaves and wilting at one week post inoculation (wpi). Symptoms progressed over time until wilting, major leaf and stem necrosis, was observed in all inoculated plants (Supp. Fig 1E, D). Plant mortality incidence at five wpi was 83%. Pathogen signs including white mycelia and black sclerotia were also observed. In experiment 2 (20.0 (± 10) °C, RH 39.6), 66% of the total plants were symptomatic at five wpi: 33% exhibited yellowing of the lower leaves and wilting, and 33% of plants died. Disease did not develop in non-inoculated plants in either experiment. S. minor was successfully reisolated from surface disinfested

2019 年 5 月，从加利福尼亚州圣路易斯奥比斯波县的 0.10 公顷露地多样化切花生产中采集到的葶苈（Scabiosa atropurpurea）样本出现褐色变色，树冠和下部茎干软腐，并伴有白色菌丝和黑色菌核（附图 1A、B）。在四分之一的田地里种植的大戟科作物中，约有 30% 至 40% 出现了症状。用 0.1% 吐温 20 冲洗、70% 乙醇浸泡 30 秒、1% 次氯酸钠浸泡 2 分钟，再用无菌水冲洗，对五株植物有症状的树冠和下部茎干进行表面消毒。将消毒后的组织放入 1/10 马铃薯葡萄糖琼脂（PDA）中，在 20°C 下培养（12 小时光周期）。结果菌落（n = 5）形成大量白色菌丝体，两周后在平板外缘形成黑色硬菌（附图 1C）。菌丝体（n = 50）的平均直径为 1.6 (± 0.19) 毫米。形态鉴定结果为 Sclerotinia sp.（郝等人，2003 年）。病原体的进一步鉴定是通过提取两个有顶端的分离物的 DNA，然后对 rDNA 内部转录间隔区（ITS）、ITS1/ITS4（White 等人，1990 年）、钙调素（CaM）、CAL-228F/CAL-737R（Carbone 和 Kohn，1999 年）和 DNA 复制许可因子 Mcm7 Mcm7-709for/Mcm7-1348rev （Schmitt 等人，2009 年）进行扩增和测序。用每个制造者的共识序列进行 NCBI BLAST 搜索，发现所有位点都与 S. minor ex-types 有 99% 至 100% 的相同性（补充表 1）。最大解析度多焦点系统发育分析将加利福尼亚分离株与 S. minor 的参考菌株进行了聚类（附图 1F）。序列已存入 GenBank（附录：表 1）。用 CS435 分离物进行致病性试验，将其转移到 PDA 平板上，在 20°C 培养一周。接种物包括侵染 CS435 的 PDA 插条（1 cm3）。在温室中，实验采用完全随机设计，观察期为六周。在 3.78 L 的花盆（n = 6）中种植 14 周大的大戟科植物'Merlot Red'，用 1 mm 的探针在植株树冠上方 0.5 cm 处刺伤植株后接种。接种体直接放在伤口上方，并用保鲜膜固定。阴性对照植株（n = 6）的伤口如上，接种 PDA 插条。在实验 1（19.4 (± 3) °C，相对湿度 46.9）中，83% 的植株在接种后一周（wpi）出现下部叶片变黄和枯萎。随着时间的推移，症状逐渐加重，直至所有接种植株都出现萎蔫、主要叶片和茎秆坏死（附图 1E、D）。植株在 5 wpi 时的死亡率为 83%。还观察到了病原体的迹象，包括白色菌丝体和黑色菌核。在实验 2（20.0 (± 10) °C，相对湿度 39.6）中，有 66% 的植株在 5 wpi 时出现症状：33% 的植株下部叶片变黄和枯萎，33% 的植株死亡。在这两项实验中，未接种的植株均未发病。从至少 50%（实验 1）和 100% （实验 2）接种植株的表面消毒组织中成功再分离出了小孢子菌，其序列与接种分离物的序列完全相同。S. minor 是一种土传病原体，感染加利福尼亚州的番茄、莴苣、黄铜菜和向日葵作物。这项研究将小矢车菊病菌确定为加利福尼亚州一种新的矢车菊土传病原体。土传病原体是切花行业经常出现的问题，确定这些作物中新病原体的特征可以为作物顾问和疾病诊断人员提供信息，从而改善观赏植物行业的疾病管理。

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First report of Trichoderma roseum causing tea leaf rot in China. 中国首次报道玫瑰毛霉引起茶叶腐烂。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-11 DOI: 10.1094/PDIS-07-24-1419-PDN

Jinmei Lei, Bingbing Jiang, Fang Yang, Cunwu Guo, Xiao Fang He, Li Mei Li, Shihao Zhang, Ya Min Wu, Chun Yan Liu, Li Jiao Chen, Bai Juan Wang

Tea (Camellia sinensis) is consumed worldwide for its numerous benefits and China lead the world production. In March 2023, leaf spots were observed on approximately 10% of tea plants in a 50-ha commercial tea plantation in Menghai (21°46'13"N, 100°30'6"E), Yunnan, China. Initial symptoms appeared as small spots, which progressively expanded and spread over the entire leaf surface. Subsequently, pale pink mold layers developed from the lesions (Fig. S1). To isolate the pathogen, small leaf pieces (3 × 3 mm) were cut from the margins of the lesions, sterilized with 75% ethanol for 30 sec and 0.5% NaClO for another 30 sec, and rinsed three times with sterile water. The pieces were placed on acidified potato dextrose agar (PDA) plates and incubated in darkness at 28°C. A total of 15 fungal isolates with identical morphologies were collected. The colonies appeared pale pink with white mycelia initially then turned orange-pink at the center and light white at the edges. After 10-15 days, exhibiting a powdery texture and concentric rings with uniform edges. Conidia were found at the apex peduncle and were inverted pear-shaped or oval, either non-septate (15.3 ± 2 × 7.8 ± 1.8 μm in size, n = 60) or septate, with a slightly constricted spore base featuring papillary projecvtions (14.8 ± 1.5 × 7.4 ± 0.7 μm in size, n = 60). The morphology closely resembled Trichoderma roseum (Oh et al. 2014). To confirm the species, the strain CYB5 was selected for identification by sequencing the ribosomal internal transcribed spacer (ITS) and large subunit (LSU) genes using polymerase chain reaction (PCR) (White et al.1990). The ITS (GenBank accession OR889657) and LSU (PQ270526) gene sequences exhibited 98% similarity with the Trichoderma roseum sequence KP317992 from NCBI database. A phylogenetic tree was constructed using MEGA 11 (Felsenstein 1981) based on the concatenated sequences (ITS and LSU) of the strain CYB5 and reference strains (Fig. S2). The analysis confirmed that CYB5 is T. roseum (Inácio et al. 2011). Pathogenicity tests were conducted on detached healthy tea leaves placed on wet filter paper in petri dishes. Micro-wounds were made on leaves using a sterilized needle, followed by inoculation with a 6-mm plug of CYB5. Control leaves were inoculates with fungus-free agar disks. The dishes were incubated at 25°C in the dark for 7 days. The leaves inoculated with CYB5 developed reddish brown to dark brown lesions around the inoculated sites, while control leaves remained asymptomatic. The fungus was reisolated from the lesion, and the isolates were morphologically identical to the original cultures. A second pathogenicity test was conducted on potted tea plants of the cultivar 'Yunkang No. 10.' Three plants scratched with a needle and three non-wounded plants were inoculated by spraying 20 ml of a spore suspension (105 spores/ml) of CYB5. Plants sprayed with sterile water served as controls. All plants were maintained in a growth chamber at 28°C, and

茶叶（Camellia sinensis）因其诸多益处而被全世界消费，中国的茶叶产量居世界首位。2023 年 3 月，在中国云南勐海（北纬 21°46'13"，东经 100°30'6"）一个 50 公顷的商业茶园中，约 10% 的茶树出现叶斑病。最初的症状表现为小斑点，随后逐渐扩大并遍布整个叶面。随后，病斑上出现淡粉色霉层（图 S1）。为了分离病原体，从病斑边缘剪下小叶片（3 × 3 毫米），用 75% 的乙醇消毒 30 秒，再用 0.5% 的 NaClO 消毒 30 秒，然后用无菌水冲洗三次。将切片放在酸化的马铃薯葡萄糖琼脂（PDA）平板上，28°C 黑暗培养。共收集到 15 个形态相同的真菌分离物。菌落最初呈淡粉色，带有白色菌丝，然后中心变为橙粉色，边缘变为浅白色。10-15 天后，菌落呈现粉状质地和边缘一致的同心环。分生孢子出现在先端花序梗上，呈倒梨形或椭圆形，要么无隔膜（大小为 15.3 ± 2 × 7.8 ± 1.8 μm，n = 60），要么有隔膜，孢子基部略微收缩，具有乳头状突起（大小为 14.8 ± 1.5 × 7.4 ± 0.7 μm，n = 60）。其形态与玫瑰毛霉非常相似（Oh 等人，2014 年）。为确认菌种，利用聚合酶链式反应（PCR）（White et al.1990）对核糖体内部转录间隔（ITS）和大亚基（LSU）基因进行测序，选择了菌株 CYB5 进行鉴定。ITS（GenBank登录号OR889657）和LSU（PQ270526）基因序列与NCBI数据库中玫瑰毛霉序列KP317992的相似度为98%。根据菌株 CYB5 和参考菌株的序列（ITS 和 LSU），使用 MEGA 11（Felsenstein，1981 年）构建了一棵系统发生树（图 S2）。分析结果证实 CYB5 是 T. roseum（Inácio 等人，2011 年）。致病性试验在培养皿中置于湿滤纸上的健康茶叶上进行。用灭菌针在叶片上刺出微小伤口，然后接种 6 毫米的 CYB5 栓塞。对照叶片接种无真菌的琼脂盘。培养皿在 25°C 黑暗中培养 7 天。接种了 CYB5 的叶片在接种部位周围出现了红褐色至黑褐色的病斑，而对照叶片仍无症状。从病变处重新分离出真菌，分离物在形态上与原始培养物完全相同。第二次致病性试验是在栽培品种为 "云冈 10 号 "的盆栽茶树上进行的。用 20 毫升 CYB5 孢子悬浮液（105 个孢子/毫升）喷洒三株用针划伤的植株和三株未受伤的植株。喷洒无菌水的植物作为对照。所有植物均在 28°C 和 70% 相对湿度下的生长室中生长。病斑在接种后 3 天出现，10 天后仅在孢子接种的植株上出现典型症状。根据形态学和分子分析，我们重新分离并鉴定了蔷薇真菌，从而实现了科赫假说。据我们所知，这是中国首次报道 T. roseum 引起茶叶腐烂病。

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引用次数: 0

First report of basal stem rot on sugarcane (var. Badila) caused by Sclerotium rolfsii in China. 在中国首次报道由 Sclerotium rolfsii 引起的甘蔗（变种 Badila）基部茎腐病。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-11 DOI: 10.1094/PDIS-07-24-1460-PDN

Su-Chan Lao, Su-Juan Lao, Ji-Hua Huang, Zhu-Gui Zhou, Shan-Hai Lin

Badila (Saccharum officinarum) is one of the important chewing cane in south China. During the year 2019-2020, as much as 60.2%-87.5% of sugarcane plants stem showed red rot developments were observed in the fields of Yongning District, Nanning city, Guangxi province. Symptomatic plants showed red rot at basal stem nodes and sheath, when the disease serious, the epidermis and aerial roots decomposed and exfoliated, then formed sclerotiums, the upper stem also occurred the symptom. Infected plant tissues were dissected into small pieces with 0.1 × 0.1cm in size and surface sterilized in 0.1% HCl2 for 2 min, followed by 75% ethanol for 30 s, rinsed three times with sterile distilled water. Then the tissues were placed onto potato dextrose agar (PDA) plates and incubated at 25 °C for 3 days. Numerous white globoid sclerotia were formed on PDA after 5 days of growth. The sclerotia (2 to 3 mm in diameter) were white at first and then gradually turned dark brown. Aerial mycelia usually formed many narrow hyphal strands 4 to 9 μm wide. Five uniform isolates were obtained from diseased sugarcane plants. Pathogenicity of representative strain W1 was confirmed by inoculating 120-day-old Badila plants grown in field. Five plants were inoculated with colonized agar discs (6mm in diameter) by applying toothpick tips to the lower part of the stem. Five non-inoculated plants served as control. The inoculated and non-inoculated plants were sprayed sterile water then incubated with plastic film for maintained high moisture. All the plants were placed inside of a growth chamber at 26 ± 2°C with a 14-h photoperiod and 80% relative humidity. All inoculated plants showed red rot at stem and sheath after 2 weeks, whereas the control plants were symptomless. By the third week, mycelium and sclerotia developed on the crown on the inoculated plants. The fungus was re-isolated from the artificially inoculated plants. To confirm the species-level identification, partial of the ribosomal DNA internal transcribed spacer (ITS), mitocondrial small subunit (SSU), and nuclear ribosomal large subunit (LSU) regions of representative strain W1 were amplified and sequenced using the primers pairs ITS1/ITS4 (White et al. 1990), ITS-Fu-F /ITS-Fu-R and SRLSU1//SRLSU2 (Kumar et al., 2016), respectively. The resulting ITS, SSU and LSU sequences were deposited in GenBank (GenBank accession no. MW620994, MW617878, and MW617872) and shared 99.42%, 100% and 100% sequence identity with Athelia rolfsii isolate (JN017199, OM319631, and MT225781). Phylogenetic analysis conducted with neighbor-joining (NJ) method using MEGA6.0 revealed that the isolate share a common clade with reference sequence of A. rolfsii in GenBank Data Library. Based on morphological and molecular characteristics, the fungus was identified as A. rolfsii (anamorph: Sclerotium rolfsii) (Paul et al. 2017; Paparu et al. 2020). Although S. rolfsii has been reported causing sugarcane sett rot in Australia (Bhuiyan et al.,

巴迪拉（Saccharum officinarum）是中国南方重要的咀嚼蔗之一。2019-2020年度，广西南宁市邕宁区田间观察到高达60.2%-87.5%的甘蔗植株茎部出现红腐病。发病植株基部茎节和鞘出现红腐病，病情严重时，表皮和气生根腐烂脱落，形成硬腐子囊，茎上部也出现该症状。将感染的植物组织切成 0.1 × 0.1 厘米大小的小块，在 0.1% HCl2 中表面消毒 2 分钟，然后用 75% 乙醇消毒 30 秒，再用无菌蒸馏水冲洗三次。然后将组织放在马铃薯葡萄糖琼脂（PDA）平板上，在 25 °C 下培养 3 天。生长 5 天后，在 PDA 上形成了许多白色球状的硬菌。硬菌（直径 2 至 3 毫米）最初为白色，然后逐渐变成深褐色。气生菌丝通常形成许多宽 4 至 9 μm 的狭窄菌丝。从染病的甘蔗植株中获得了 5 个一致的分离株。通过接种田间生长 120 天的巴迪拉植株，证实了代表性菌株 W1 的致病性。用牙签尖插入茎干下部，将定植琼脂盘（直径 6 毫米）接种到五株植物上。五株未接种的植物作为对照。将接种和未接种的植物喷洒无菌水，然后用塑料薄膜培养以保持高湿度。所有植株均置于生长室中，温度为 26 ± 2°C，光周期为 14 小时，相对湿度为 80%。2 周后，所有接种植物的茎和鞘都出现了红腐病，而对照植物则没有症状。第三周时，接种植株的树冠上长出了菌丝和菌核。从人工接种的植株上重新分离出了真菌。为确认菌种级别的鉴定，使用引物对 ITS1/ITS4 （White 等，1990 年）、ITS-Fu-F /ITS-Fu-R 和 SRLSU1//SRLSU2 （Kumar 等，2016 年）分别对代表性菌株 W1 的部分核糖体 DNA 内部转录间隔区（ITS）、有丝分裂小亚基（SSU）和核糖体大亚基（LSU）区域进行了扩增和测序。得到的 ITS、SSU 和 LSU 序列存入 GenBank（GenBank 编号：MW620994、MW617878 和 MW617872），与 Athelia rolfsii 分离物（JN017199、OM319631 和 MT225781）的序列同一性分别为 99.42%、100% 和 100%。利用 MEGA6.0 进行的邻接法（NJ）系统进化分析表明，该分离物与 GenBank 数据库中的 A. rolfsii 参考序列具有共同的支系。根据形态和分子特征，该真菌被鉴定为 A. rolfsii（拟态：Sclerotium rolfsii）（Paul 等人，2017 年；Paparu 等人，2020 年）。虽然 S. rolfsii 已被报道在澳大利亚（Bhuiyan 等人，2019 年）和印度（Gopi 等人，2023 年）引起甘蔗定植腐烂病和甘蔗幼苗腐烂病，但据我们所知，这是中国首次报道由该真菌引起的甘蔗基部茎腐病。这项研究将有助于今后甘蔗基部茎腐病的防控。

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引用次数: 0

Pre-Plant Soil Treatments Influence Tree Performance and Nematode Dynamics in Replanted Cherry Orchards. 种植前的土壤处理会影响重植樱桃园中树木的表现和线虫的动态。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-11 DOI: 10.1094/PDIS-06-24-1178-RE

Ali Yaghoubi, Razieh Yazdani, Emilie Cole, Marisol Quintanilla

In this two-year field study, the impacts of pre-plant soil management strategies, including soil fumigation, nematicide application, and organic amendments, on the growth and nematode community dynamics on cherry cultivars 'Emperor Francis' and 'Ulster' grafted to 'Mahaleb' rootstock were investigated in a replanted orchard site. In the first year, fumigation with 1,3-dichloropropene - chloropicrin mixture (Telone C-35) led to significantly increased trunk cross-sectional area and canopy height in both cultivars. Pratylenchus penetrans population densities were suppressed only short-term. Plots treated with the fungicide/nematicide fluopyram (Velum® Prime) had P. penetrans reproduction factors below one throughout both years independent of the scion. Additionally, the combined application of Seed Starter 101®, Dairy Doo® compost, and straw mulch reduced the reproduction factor of P. penetrans to below one in the first year. In the same time period, this combinatory treatment had the highest reproduction factor for bacterivore and fungivore nematodes. Based on results of this study, fumigation with Telone® C-35 resulted in improvement of tree establishment and provided effective short-term suppression of P. penetrans. Velum® Prime exhibited longer-term efficacy for the suppression of P. penetrans.

在这项为期两年的田间研究中，研究人员在一个移栽果园中调查了种植前土壤管理策略（包括土壤熏蒸、施用杀线虫剂和有机添加剂）对嫁接到 "Mahaleb "砧木上的樱桃栽培品种 "Emperor Francis "和 "Ulster "的生长和线虫群落动态的影响。第一年，用 1,3-二氯丙烯-氯化苦混合物（Telone C-35）熏蒸后，两个品种的树干横截面积和树冠高度都显著增加。Pratylenchus penetrans 的种群密度仅在短期内受到抑制。使用杀真菌剂/杀线虫剂氟啶虫酰胺（Velum® Prime）处理的地块，在这两年中穿心锈菌的繁殖系数均低于 1，与接穗无关。此外，联合施用 Seed Starter 101®、Dairy Doo® 堆肥和稻草覆盖物后，穿心蝇的繁殖系数在第一年就降低到了 1 以下。在同一时期，这种组合处理对细菌和真菌线虫的繁殖系数最高。根据这项研究的结果，使用 Telone® C-35 进行熏蒸可以改善树木的生长状况，并能在短期内有效抑制穿心莲线虫。Velum® Prime 在抑制穿心莲线虫方面具有较长期的效果。

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引用次数: 0

Susceptibility of olive cultivars and selections to Colletotrichum species causing anthracnose in Spain. 西班牙橄榄栽培品种和选育品种对引起炭疽病的 Colletotrichum 菌种的易感性。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-11 DOI: 10.1094/PDIS-02-24-0481-RE

Anabel Exposito-Diaz, Boris X Camiletti, M Teresa Garcia-Lopez, Diego Cabello, Dov Prusky, Concepción M Diez, Juan Moral

Anthracnose, the most critical fruit disease affecting olive crops, necessitates the evaluation of the susceptibility of traditional and new varieties. In Spain and Portugal, Anthracnose is caused by several Colletotrichum species, with C. godetiae and C. nymphaeae being dominant and C. acutatum and C. fioriniae being secondary. This study explores the susceptibility of fruits from an F1 progeny resulting from a cross between 'Picual' (resistant) and 'Arbequina' (moderately susceptible) cultivars to C. godetiae. While most genotypes showed resistance levels comparable to their parents, seven showed a 50% reduction in disease severity compared to 'Picual.' The normal distribution of genotypes' response to the pathogen suggests a complex resistance mechanism. Furthermore, we assessed the susceptibility of four traditional cultivars, two new cultivars ('Sikitita-2' and 'Martina'), and five advanced selections (pre-commercial genotypes) to C. godetiae and C. nymphaeae. Despite the significant interaction between the olive genotype and Colletotrichum species in this experiment, the new cultivars and advanced selections were classified as susceptible or moderately susceptible against both species. A subsequent analysis of the interaction between 'Picual' (resistant) and 'Hojiblanca' (susceptible) fruits with the four mentioned Colletotrichum species revealed significant differences among cultivars but no interaction between genotype and pathogen species. Colletotrichum species were categorized as follows: i) C. godetiae and C. nymphaeae as highly virulent, ii) C. acutatum as moderately virulent, and iii) C. fioriniae as weakly virulent. Finally, C. nymphaeae exhibited an enhanced ability to infect and develop acervuli in olive leaves, potentially serving as an inoculum source for this species. The absence of a correlation between leaf and fruit susceptibilities to the pathogen suggests differences in resistance mechanisms. In conclusion, this study provides valuable insights into the complex interactions between olive genotype and Colletotrichum species, essential for cultivar selection and understanding the disease cycle.

炭疽病是影响橄榄作物最严重的果实病害，因此有必要对传统品种和新品种的易感性进行评估。在西班牙和葡萄牙，炭疽病是由多种 Colletotrichum 菌引起的，其中 C. godetiae 和 C. nymphaeae 为主要病菌，C. acutatum 和 C. fioriniae 为次要病菌。本研究探讨了 "Picual"（抗性）和 "Arbequina"（中度易感）杂交后代果实对 C. godetiae 的易感性。虽然大多数基因型的抗病性与其亲本相当，但与'Picual'相比，有 7 个基因型的病害严重程度降低了 50%。基因型对病原体的反应呈正态分布，这表明抗病机制很复杂。此外，我们还评估了四个传统栽培品种、两个新栽培品种（'Sikitita-2'和'Martina'）和五个高级选育品种（商业化前基因型）对 C. godetiae 和 C. nymphaeae 的易感性。尽管在该实验中，橄榄基因型与 Colletotrichum 种类之间存在明显的交互作用，但新栽培品种和先进的选育品种对这两种种类都被归类为易感或中度易感。随后对 "Picual"（抗病）和 "Hojiblanca"（易感）果实与上述四种 Colletotrichum 菌种的相互作用进行分析，结果显示栽培品种之间存在显著差异，但基因型与病原体种类之间没有相互作用。Colletotrichum 种类分类如下：i) C. godetiae 和 C. nymphaeae 为高致病性，ii) C. acutatum 为中等致病性，iii) C. fioriniae 为弱致病性。最后，C. nymphaeae 感染橄榄叶片并在叶片上形成突起的能力增强，有可能成为该物种的接种源。叶片和果实对病原体的易感性之间缺乏相关性，这表明两者的抗病机制存在差异。总之，这项研究为了解橄榄基因型与 Colletotrichum 物种之间复杂的相互作用提供了宝贵的见解，对于选择栽培品种和了解病害周期至关重要。

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引用次数: 0

Anthracnose Caused by Colletotrichum spaethianum on Polygonatum odoratum var. pluriflorum in Korea. 韩国由 Colletotrichum spaethianum 在 Polygonatum odoratum var.

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-11 DOI: 10.1094/PDIS-05-24-0991-PDN

Joon-Ho Choi, Hyeon-Dong Shin, Young-Joon Choi

Polygonatum odoratum var. pluriflorum (Miq.) Ohwi (Asparagaceae), commonly known as Lesser Solomon's seal, is a perennial herbaceous plant widely distributed in the temperate regions of the Northern Hemisphere. It is known for tea and contains various pharmacologically active compounds (Chang et al. 2007). In September 2021, previously unseen anthracnose was encountered on Polygonatum odoratum var. pluriflorum in Chuncheon (37°45'07''N; 127°47'45''E) and Wanju (35°38'47''N; 127°31'16''E), Korea, with a disease incidence of 20 to 30% of the inspected plants. The disease symptoms begin with leaf yellowing (chlorosis) along the margins, progressing toward the central part of the leaf. As the disease progressed, brown necrotic lesions developed, covered with small, dark dots, indicating the presence of conidiomata of Colletotrichum. The disease often led to leaf blight, resulting in concentric lesions of a periodic and concentric arrangement of conidiomata, forming circular patterns within the affected tissue. It expanded rapidly during the rainy season producing water-soaked lesions but nearly slowed down during the dry season, leaving the plant with a ragged appearance. Monoconidial isolates were obtained from five fresh samples collected in Wanju, of which a representative isolate was deposited in the Korean Agricultural Culture Collection (KACC410442), and the dried specimen was housed at the herbarium of Jeonbuk National University (JBNU0135). Morphological characteristics of the fungus were examined with fresh and naturally infected leaves. Setae (n = 30) were dark brown to nearly blackish, 45 to 172 um long, 4.1 to 6.1 µm wide at the base, and becoming narrower upwards, apex pointed, 2 to 4-septate. Conidia were 1-celled, sometimes uniseptate before germination, slightly curved, with an acute or rounded apex and a more or less truncate base, and 11.4 to 23.2 × 3.1 to 4.2 µm. Appressoria were single or in groups, dark brown, lobate, irregularly shaped, and 6.0 to 11.9 × 7.0 to 14.8 µm. Two-week-old colonies grown on PDA at 25 ℃ reached 30-35 mm in diam., initially white, turning gray with age, with cottony aerial mycelia. These morphological characteristics were in good agreement with those of C. spaethianum (Damm et al. 2009; Liu et al. 2020). To confirm the morphology-based determination, genomic DNA was extracted from KACC410442, and multi-loci sequences of the internal transcribed spacer region (ITS) rDNA, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), actin (actA), chitin synthase (CHS1), histone (HIS3) and tubulin (TUB2) genes were determined, as outlined by Cannon et al. (2012) and Damm et al. (2009). The resulting sequences obtained in this study were registered to GenBank (PP739190 for ITS, PP741985 for GAPDH, PP741986 for actA, PP741987 for CHS1, PP741988 for HIS3, and PP741989 for TUB2) and compared with other sequences on GenBank using the BLASTn search tool. The results showed 100% identity to other C. spaethianum sequence

Polygonatum odoratum var.它以茶闻名，含有多种药理活性化合物（Chang 等人，2007 年）。2021 年 9 月，在韩国春川（北纬 37°45'07''；东经 127°47'45''）和万州（北纬 35°38'47''；东经 127°31'16''）的玉竹变种 pluriflorum 上发现了以前从未见过的炭疽病，发病率占被检植株的 20% 至 30%。病害症状首先是叶片边缘发黄（萎黄），然后向叶片中央发展。随着病害的发展，叶片出现褐色坏死病斑，病斑上布满了小黑点，表明叶片上有 Colletotrichum 的分生孢子器。这种病通常会导致叶枯病，病斑上的分生孢子器呈周期性同心排列，在受害组织内形成环状图案。它在雨季迅速扩展，产生水渍状病斑，但在旱季几乎减缓，使植株外观破烂不堪。从万州采集的五个新鲜样本中获得了单孢子分离物，其中一个代表性分离物保存在韩国农业培养物保藏中心（KACC410442），干燥样本保存在全北国立大学标本室（JBNU0135）。用新鲜和自然感染的叶片检验真菌的形态特征。刚毛（n = 30）呈深褐色至近黑色，长 45 至 172 微米，基部宽 4.1 至 6.1 微米，向上变窄，先端尖，2 至 4 孔。分生孢子为单细胞，有时在发芽前为单隔膜，稍弯曲，先端锐尖或圆形，基部或多或少截形，直径 11.4-23.2 × 3.1-4.2 µm。外稃为单个或成群，深褐色，裂片状，形状不规则， 6.0-11.9 × 7.0-14.8 µm。在 25 ℃ 的 PDA 上生长两周的菌落直径达 30-35 毫米，最初为白色，随着时间的推移变为灰色，气生菌丝为棉状。这些形态特征与 C. spaethianum 的形态特征十分吻合（Damm 等，2009 年；Liu 等，2020 年）。为证实基于形态学的判定，从 KACC410442 提取了基因组 DNA，并按照 Cannon 等人（2012 年）和 Damm 等人（2009 年）的方法测定了内部转录间隔区（ITS）rDNA、3-磷酸甘油醛脱氢酶（GAPDH）、肌动蛋白（actA）、几丁质合成酶（CHS1）、组蛋白（HIS3）和微管蛋白（TUB2）基因的多序列。本研究获得的序列已登录到 GenBank（ITS 为 PP739190，GAPDH 为 PP741985，actA 为 PP741986，CHS1 为 PP741987，HIS3 为 PP741988，TUB2 为 PP741989），并使用 BLASTn 搜索工具与 GenBank 上的其他序列进行了比较。结果显示，与其他 C. spaethianum 序列（例如，ITS 为 MT611068，actA 为 MN400659，CHS1 为 OP965007，GAPDH 为 OR060963，HIS3 为 PP480643，TUB2 为 OQ613727）的同一性为 100%。在最大解析树中，韩国分离物与 C. spaethianum 的参考序列形成了一个支持良好的支系（100% 引导值）。致病性的测试方法是将两周培养的分生孢子悬浮液（1×104 个分生孢子/毫升）喷洒到三株盆栽植物的十片叶子上，不进行伤口处理。十片喷水的叶子作为对照。植物在露水室中养护，随后移至 25 至 30 °C 的温室中。两周后，所有接种的植株都出现了炭疽病症状，而对照植株仍无症状。从接种植物中分离出的真菌在形态上与最初观察到的真菌完全相同，符合科赫假说。已知 C. spaethianum 在多种植物物种上发生，但主要是在天门冬科植物上，包括 Anemarrhena（Okorley 等人，2019 年）、玉簪（Damm 等人，2009 年；Cheon 和 Jeon，2016 年）和 Polygonatum（Liu 等人，2020 年；Ma 等人，2021 年）。据我们所知，这是韩国首次报道由 C. spaethianum 在 P. odoratum var.

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引用次数: 0

Confirmation of oat crown rust disease in Taiwan. 台湾燕麦冠锈病确诊。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-11 DOI: 10.1094/PDIS-04-24-0838-RE

Chung-Yin Ho, Eva Henningsen, Ssu-Tung Chen, Hiran Anjana Ariyawansa, Eric S Nazareno, Jana Sperschneider, Peter Dodds, Jakob M Riddle, Shahryar F Kianian, Melania Figueroa, Yung-Fen Huang

Oat is a minor forage crop grown in Taiwan. Only a few historical records of oat rust disease have been reported in the country. Therefore, the pathogen population remains poorly characterized. A rust-like disease outbreak was detected at the Experimental Farm of National Taiwan University in 2019, which caused significant damage to field experiments. To determine the identity of the pathogen responsible for this disease outbreak, we collected infected foliar material. Disease signs suggested infection by the oat crown rust fungus. Hence, common procedures in rust pathology were applied to confirm the identity of the pathogen with phenotypic and molecular diagnostic techniques. A total of 50 field pathogen samples from infected oat cultivars were collected in 2019 and five single pustule rust isolates were obtained in 2020 and 2021. These isolates were initially identified as Puccinia coronata var. avenae f. sp. avenae (Pca) based on the phylogenetic analysis of nrITS sequence data. This identification was subsequently confirmed through whole-genome phylogeny, which showed that the representative Taiwanese isolate NTU1 clustered with other Pca representative strains in Basidiomycota. Phenotyping assays across 36 oat differential lines demonstrated that Taiwanese isolates are phenotypically similar with relatively low virulence. This study presents the first molecular confirmation of Pca in Taiwan and reports the virulence profiles of Taiwanese Pca population.

燕麦是台湾种植的一种次要饲料作物。台湾仅有少数燕麦锈病的历史记录。因此，病原体种群的特征仍然不甚明了。2019 年，台湾大学实验农场爆发了燕麦锈病，对田间试验造成了严重破坏。为了确定导致此次病害爆发的病原体，我们收集了受感染的叶片材料。病害迹象表明是燕麦冠锈菌感染。因此，我们采用了锈病病理学的常用程序，通过表型和分子诊断技术来确认病原体的身份。2019 年共从受感染的燕麦栽培品种中收集了 50 份田间病原体样本，2020 年和 2021 年获得了 5 个单一的脓疱锈菌分离物。根据 nrITS 序列数据的系统发育分析，这些分离物被初步鉴定为 Puccinia coronata var.随后通过全基因组系统发育证实了这一鉴定结果，结果显示台湾的代表性分离株 NTU1 与其他 Pca 代表株聚类在 Basidiomycota 中。36 个燕麦差异品系的表型分析表明，台湾分离株表型相似，毒力相对较低。本研究首次从分子水平确认了台湾的 Pca，并报告了台湾 Pca 群体的毒力特征。

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引用次数: 0

Emergence of watermelon chlorotic stunt virus in melon and watermelon in the southwestern United States. 美国西南部甜瓜和西瓜中出现西瓜枯萎病病毒。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-09 DOI: 10.1094/PDIS-05-24-1009-PDN

William M Wintermantel, Tongyan Tian, Carol Chen, Nicholas Winarto, Shelly Szumski, Laura Jenkins Hladky, Suraj Gurung, John Palumbo

Watermelon (Citrullus lanatus) and melon (Cucumis melo) plants with leaves exhibiting mosaic symptoms or chlorotic spotting, respectively, along with limited foliar distortion, predominantly on newer growth, were observed in commercial fields throughout Yuma County, AZ, and Imperial County, CA, in fall 2023. Older leaves also exhibited yellowing typical of infection by whitefly-transmitted viruses common in the region, and whiteflies (Bemisia tabaci) were prevalent in fields. Symptomatic plants were tested using a multiplex RT-PCR for cucurbit yellow stunting disorder virus (CYSDV), cucurbit chlorotic yellows virus (CCYV), squash vein yellowing virus (SqVYV), and cucurbit aphid-borne yellows virus (CABYV) (Mondal et al., 2023), and separately for cucurbit leaf crumple virus (CuLCrV; F: TCAAAGGTTTCCCGCTCTGC, R: TCAAAGGTTTCCCGCTCTGC). Most plants were infected with CYSDV, which has been widely prevalent during the fall production season since its emergence in 2006, but not with the other tested viruses. Although the yellowing of older leaves near the crown was typical of symptoms resulting from CYSDV infection, the unusual symptoms on newer growth suggested the possibility of infection by a begomovirus. Rolling circle amplification and DNA sequencing of nucleic acid extract from a symptomatic melon plant collected in Dome Valley, AZ, identified the presence of watermelon chlorotic stunt virus (WmCSV), a bipartite begomovirus (Geminiviridae) (Jones et al., 1988; Lecoq, 2017), but no other begomoviruses. Sequencing of the complete WmCSV genome from this melon plant determined that DNA A (GenBank accession #PQ399661) shared 99% identity with WmCSV isolates from cactus (MW588390) and melon (KY124280) in Sonora, Mexico, and DNA B (PQ399662) shared 96% and 94% identity with WmCSV isolates from watermelon in Palestine (KC462553) and Sonora (KY124281), respectively. PCR with primers targeting WmCSV DNA A (F: CATGGAGATGAGGTTCCCCATTCT and R: GCTCGTAGGTCGATTCAACGGCCT) and DNA B (F: AGATACAACGTATGGGCAGCATT and R: TACAGATCCCARTCGATGAGACT) was used for secondary confirmation. Sequencing of amplified products confirmed both WmCSV DNA A and B in 12/15 initial melon samples. PCR using the DNA A or B primers confirmed the presence of WmCSV from additional watermelon and melon samples collected from Yuma County (31 positive/37 tested) and Imperial County (20/22). This is the first report of WmCSV in cucurbits in the United States (U.S.); the virus was previously identified in watermelon (Domínguez-Durán et al., 2018) and cactus (Opuntia auberi) from Sonora, Mexico, and from one cactus (O. cochenillifera), lamb's ears (Stachys byzantine), and an unknown Solanum plant from a botanical garden in Arizona (Fontanelle et al., 2021). The geographic distribution of WmCSV and the presence of similar symptoms in melon in 2022 suggests that it may have been present in the U.S. for at least a year. Interestingly, nearly all melon a

2023 年秋季，在亚利桑那州尤马县和加利福尼亚州帝国县的商品田中，观察到西瓜（Citrullus lanatus）和甜瓜（Cucumis melo）植株的叶片分别出现马赛克症状或萎黄斑点，以及有限的叶片变形，主要出现在新植株上。老叶还表现出典型的黄化现象，这是该地区常见的粉虱传播病毒感染所致，而且粉虱（Bemisia tabaci）在田间普遍存在。采用多重 RT-PCR 技术对有症状的植株进行了检测，以检测葫芦黄矮病病毒 (CYSDV)、葫芦黄萎病病毒 (CCYV)、南瓜叶脉黄化病毒 (SqVYV) 和葫芦蚜传黄萎病病毒 (CABYV)（Mondal et al、2023），并分别感染了葫芦皱叶病毒（CuLCrV；F：TCAAAGGTTTCCCGCTCTGC，R：TCAAAGGTTTCCCGCTCTGC）。大多数植株感染了 CYSDV 病毒，该病毒自 2006 年出现以来在秋季生产季节广泛流行，但未感染其他测试病毒。虽然树冠附近的老叶变黄是 CYSDV 感染导致的典型症状，但新长出的叶片上出现的异常症状表明可能感染了乞蛾病毒。从亚利桑那州穹顶谷采集的一株有症状的甜瓜植株的核酸提取物中进行滚圆扩增和 DNA 测序，确定了西瓜萎蔫矮缩病病毒（WmCSV）的存在，这是一种双分体乞猴病毒（Geminiviridae）（Jones 等人，1988 年；Lecoq，2017 年），但没有发现其他乞猴病毒。对该甜瓜植株的 WmCSV 完整基因组进行测序后发现，DNA A（GenBank 编号 #PQ399661）与来自墨西哥索诺拉州仙人掌（MW588390）和甜瓜（KY124280）的 WmCSV 分离物有 99% 的同一性，DNA B（PQ399662）与来自巴勒斯坦西瓜（KC462553）和索诺拉州西瓜（KY124281）的 WmCSV 分离物分别有 96% 和 94% 的同一性。使用针对 WmCSV DNA A（F：CATGGAGATGAGGTTCCCCATTCT 和 R：GCTCGTAGGTCGATTCAACGGCCT）和 DNA B（F：AGATACAACGTATGGGCAGCATT 和 R：TACAGATCCCARTCGATGAGACT）的引物进行 PCR 进行二次确认。对扩增产物进行测序，在 12/15 份最初的甜瓜样本中确认了 WmCSV DNA A 和 B。使用 DNA A 或 B 引物进行 PCR，证实了从尤马县（31 份阳性/37 份检测结果）和帝国县（20/22 份）采集的其他西瓜和甜瓜样品中存在 WmCSV。这是美国首次报告在葫芦科植物中发现 WmCSV；此前在墨西哥索诺拉州的西瓜（Domínguez-Durán 等人，2018 年）和仙人掌（Opuntia auberi）中以及亚利桑那州植物园的一种仙人掌（O. cochenillifera）、羊耳朵（Stachys byzantine）和一种未知的茄科植物（Fontanelle 等人，2021 年）中发现了该病毒。WmCSV 的地理分布以及 2022 年甜瓜中出现的类似症状表明，它可能已在美国存在了至少一年。有趣的是，几乎所有感染 WmCSV 的甜瓜和一些西瓜植株都同时感染了 CYSDV。索诺兰沙漠产区的大多数秋天葫芦都会感染 CYSDV，许多葫芦还会感染 CCYV 和/或 SqVYV（Mondal 等人，2023 年）。然而，在 2023 年秋季，该地区的 CCYV（4/63）和 SqVYV（2/63）发病率极低。目前正在进行研究，以确定 WmCSV 对索诺拉沙漠和整个美国葫芦病毒群的潜在影响，并了解影响 WmCSV 感染和传播的流行病学因素。

{"title":"Emergence of watermelon chlorotic stunt virus in melon and watermelon in the southwestern United States.","authors":"William M Wintermantel, Tongyan Tian, Carol Chen, Nicholas Winarto, Shelly Szumski, Laura Jenkins Hladky, Suraj Gurung, John Palumbo","doi":"10.1094/PDIS-05-24-1009-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-05-24-1009-PDN","url":null,"abstract":"Watermelon (Citrullus lanatus) and melon (Cucumis melo) plants with leaves exhibiting mosaic symptoms or chlorotic spotting, respectively, along with limited foliar distortion, predominantly on newer growth, were observed in commercial fields throughout Yuma County, AZ, and Imperial County, CA, in fall 2023. Older leaves also exhibited yellowing typical of infection by whitefly-transmitted viruses common in the region, and whiteflies (Bemisia tabaci) were prevalent in fields. Symptomatic plants were tested using a multiplex RT-PCR for cucurbit yellow stunting disorder virus (CYSDV), cucurbit chlorotic yellows virus (CCYV), squash vein yellowing virus (SqVYV), and cucurbit aphid-borne yellows virus (CABYV) (Mondal et al., 2023), and separately for cucurbit leaf crumple virus (CuLCrV; F: TCAAAGGTTTCCCGCTCTGC, R: TCAAAGGTTTCCCGCTCTGC). Most plants were infected with CYSDV, which has been widely prevalent during the fall production season since its emergence in 2006, but not with the other tested viruses. Although the yellowing of older leaves near the crown was typical of symptoms resulting from CYSDV infection, the unusual symptoms on newer growth suggested the possibility of infection by a begomovirus. Rolling circle amplification and DNA sequencing of nucleic acid extract from a symptomatic melon plant collected in Dome Valley, AZ, identified the presence of watermelon chlorotic stunt virus (WmCSV), a bipartite begomovirus (Geminiviridae) (Jones et al., 1988; Lecoq, 2017), but no other begomoviruses. Sequencing of the complete WmCSV genome from this melon plant determined that DNA A (GenBank accession #PQ399661) shared 99% identity with WmCSV isolates from cactus (MW588390) and melon (KY124280) in Sonora, Mexico, and DNA B (PQ399662) shared 96% and 94% identity with WmCSV isolates from watermelon in Palestine (KC462553) and Sonora (KY124281), respectively. PCR with primers targeting WmCSV DNA A (F: CATGGAGATGAGGTTCCCCATTCT and R: GCTCGTAGGTCGATTCAACGGCCT) and DNA B (F: AGATACAACGTATGGGCAGCATT and R: TACAGATCCCARTCGATGAGACT) was used for secondary confirmation. Sequencing of amplified products confirmed both WmCSV DNA A and B in 12/15 initial melon samples. PCR using the DNA A or B primers confirmed the presence of WmCSV from additional watermelon and melon samples collected from Yuma County (31 positive/37 tested) and Imperial County (20/22). This is the first report of WmCSV in cucurbits in the United States (U.S.); the virus was previously identified in watermelon (Domínguez-Durán et al., 2018) and cactus (Opuntia auberi) from Sonora, Mexico, and from one cactus (O. cochenillifera), lamb's ears (Stachys byzantine), and an unknown Solanum plant from a botanical garden in Arizona (Fontanelle et al., 2021). The geographic distribution of WmCSV and the presence of similar symptoms in melon in 2022 suggests that it may have been present in the U.S. for at least a year. Interestingly, nearly all melon a","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142392444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

First Report of Colletotrichum siamense Causing Leaf Anthracnose on Jackfruit in Thailand. 泰国首次报告 Colletotrichum siamense 在菠萝上引起叶炭疽病。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-09 DOI: 10.1094/PDIS-06-24-1273-PDN

Surapong Khuna, Jaturong Kumla, Tanapol Thitla, Chanokned Senwanna, Nakarin Suwannarach

Jackfruit (Artocarpus heterophyllus Lam.) is commonly grown in Thailand. In June 2023, leaf anthracnose on this plant was observed at a field in Chai Prakan District (19°42'24"N, 99°01'59"E), Chiang Mai Province, Thailand, with ~25% disease incidence in a 1000-m2 plantation area. The initial symptom had brown spots with a yellow halo, enlarged, elongated, 0.2 to 2 cm in diameter, irregular, sunken, brown, with a dark brown halo, and leaves withered and dried. Pale yellow conidiomata developed on the lesions in high humidity. Ten symptomatic leaves were used to isolate the fungal causal agents through a single spore isolation method (Tovar-Pedraza et al. 2020). Four fungal isolates (SDBR-CMU492 to SDBR-CMU495) with similar morphology were obtained. Colonies on potato dextrose agar (PDA) were 70 to 85 mm in diameter, white to grayish white with cottony mycelia, the reverse pale yellow after incubation at 25°C for 1 week. All isolates produced asexual structures. Setae were brown with 1 to 3 septa, 40 to 100 × 2.2 to 4.0 µm, a cylindrical base, and acuminate tip. Conidiophores were hyaline to pale brown, septate, and branched. Conidiogenous cells were hyaline to pale brown, cylindrical to ampulliform, 7.4 to 27.2 × 2.0 to 4.5 µm. Conidia were one celled, hyaline, smooth walled, cylindrical, ends rounded, guttulate, 11.1 to 15.7 × 3.4 to 6.1 µm. Appressoria were dark brown to black, oval to irregular, 8.8 to 24.9 × 3.6 to 10 µm. Morphologically, all isolates resembled the Colletotrichum gloeosporioides species complex (Weir et al. 2012). The internal transcribed spacer (ITS) region, actin (act), β-tubulin (tub2), calmodulin (CAL), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were amplified using primer pairs ITS5/ITS4, ACT-512F/ACT-783R, T1/T22, CL1C/CL2C, and GDF1/GDR1, respectively (White et al. 1990; Weir et al. 2012). Sequences were deposited in GenBank (ITS: PP068858, PP068859, PP446789, PP446790; act: PP079636, PP079637, PP460760, PP460761; tub2: PP079638, PP079639, PP460762, PP460763; CAL: PP079634, PP079635, PP460758, PP460759; GAPDH: PP079632, PP079633, PP460756, PP460757). Maximum likelihood phylogenetic analyses of the concatenated five genes identified all isolates as C. siamense. To pathogenicity test, the mature leaves of a healthy plant were surface disinfested using 0.1% NaClO for 3 min, rinsed three times with sterile water, and wounded. Conidia suspensions (15 µl of 1 × 106 conidia/ml) of each isolate grown on PDA at 25°C for 2 weeks were used to inoculate wounded and unwounded samples by the attached method. Control leaves were mock inoculated with sterile distilled water. Ten replications were conducted for each treatment and repeated twice. Plants were placed in a greenhouse at 25 to 30°C and 80 to 90% relative humidity. After 7 days, all inoculated leaves displayed brown lesions, while control leaves had no symptoms. Colletotrichum siamense was reisolated from inoculated tissues on PDA to complete Koch's post

菠萝蜜（Artocarpus heterophyllus Lam.）2023 年 6 月，在泰国清迈府 Chai Prakan 县（北纬 19°42'24"，东经 99°01'59"）的一块田地里观察到这种植物的叶炭疽病，在 1000 平方米的种植区中发病率约为 25%。初期症状为带黄晕的褐色斑点，扩大、拉长，直径 0.2 至 2 厘米，不规则，凹陷，褐色，带深褐色晕，叶片枯萎干枯。在高湿度条件下，病斑上长出淡黄色的分生孢子器。通过单孢子分离法（Tovar-Pedraza et al.）获得了四种形态相似的真菌分离物（SDBR-CMU492 至 SDBR-CMU495）。马铃薯葡萄糖琼脂（PDA）上的菌落直径为 70 至 85 毫米，白色至灰白色，带有棉状菌丝，在 25°C 下培养 1 周后，菌落呈淡黄色。所有分离物均产生无性结构。刚毛呈棕色，有 1 至 3 个隔膜，长 40 至 100 × 2.2 至 4.0 µm，基部呈圆柱形，顶端渐尖。分生孢子梗呈透明至淡褐色，有隔膜，有分枝。分生孢子细胞呈透明至淡褐色，圆柱形至瓶形， 7.4 - 27.2 × 2.0 - 4.5 µm。分生孢子单细胞，透明，壁光滑，圆柱形，末端圆形，具沟， 11.1-15.7 × 3.4-6.1 µm。外稃呈深褐色至黑色，椭圆形至不规则形，8.8 至 24.9 × 3.6 至 10 微米。从形态上看，所有分离物都与 Colletotrichum gloeosporioides 种群相似（Weir 等人，2012 年）。使用引物对 ITS5/ITS4、ACT-512F/ACT-783R、T1/T22、CL1C/CL2C 和 GDF1/GDR1 分别扩增了内部转录间隔区（ITS）、肌动蛋白（act）、β-微管蛋白（tub2）、钙调蛋白（CAL）和甘油醛-3-磷酸脱氢酶（GAPDH）基因（White 等，1990 年；Weir 等，2012 年）。序列已存入 GenBank（ITS：PP068858, PP068859, PP446789, PP446790; act：PP079636, PP079637, PP460760, PP460761; tub2: PP079638, PP079639, PP460762, PP460763; CAL：PP079634、PP079635、PP460758、PP460759；GAPDH：PP079632、PP079633、PP460756、PP460757）。通过对五个基因的最大似然系统发生分析，确定所有分离物均为 C. siamense。在致病性试验中，用 0.1% 的 NaClO 对健康植物的成熟叶片进行表面消毒 3 分钟，然后用无菌水冲洗 3 次，并进行伤口处理。在 25°C 的 PDA 上生长 2 周的每种分离株的分生孢子悬浮液（15 µl 含 1 × 106 个分生孢子/ml）被用来按附着法接种受伤和未受伤的样本。对照叶片用无菌蒸馏水模拟接种。每种处理进行 10 次重复，重复两次。将植物置于温度为 25 至 30°C、相对湿度为 80 至 90% 的温室中。7 天后，所有接种的叶片都出现褐色病斑，而对照叶片则没有症状。从 PDA 上的接种组织中重新分离出了暹罗毛霉菌（Colletotrichum siamense），从而完成了科赫假说（Koch's postulates）。在本研究之前，C. fructicola 和 C. gloeosporioides 在全球范围内引起了菠萝的叶炭疽病（Sangchote 等人，2003 年；Chitambar，2016 年）。澳大利亚（James 等人，2014 年）和 Bazil（Borges 等人，2023 年）报道了由 C. siamense 引起的胡柚叶炭疽病。在泰国，Bhunjun 等人（2019 年）报道了 C. artocarpicola 在菠萝中引起的叶炭疽病。因此，这是泰国首次报道 C. siamense 在菠萝上引起叶炭疽病。这一发现将为流行病学调查和未来管理这种疾病的方法提供信息。

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引用次数: 0

First Report of Rhizopus arrhizusi causing rot of Dictyophora rubrovolvata in China. 在中国首次报道了由根瘤菌（Rhizopus arrhizusi）引起的红豆杉（Dictyophora rubrovolvata）腐烂病。

IF 4.4 2区农林科学 Q1 PLANT SCIENCES

Plant disease

Pub Date : 2024-10-09 DOI: 10.1094/PDIS-08-24-1767-PDN

Shiqi Tu, Feng Zhou, Yin Zhang, YiFan Chen, ShengQian Chao, Beibei Lü, Hailong Yu

Dictyophora rubrovolvata, as an edible fungus with high medicinal value, is widely cultivated in several provinces in China (Hang et al. 2012). However, between December 2023 and March 2024, a rot disease occurred in the main production area in Fengxian District, Shanghai, China (N30°93', E121°49'). The disease incidence was 25% in the affected 1.33-ha growing area. High temperatures (>25℃) and poor ventilation provide favorable conditions for the spread of this disease. The disease mainly occurs at the stage of fruiting bodies formation of D. rubrovolvata. When the epidermis is damaged and broken, it becomes infested with mold, which then produces a layer of moldy rot with pus. The infected D. rubrovolvata tissues at the edge of the lesions were isolated, surface sterilized and cultured on potato dextrose agar (PDA) at 30 ℃ under dark conditions. Pure cultures were obtained by single-spore isolation. After 3 days, isolates were transferred to Czapek Yeast agar (CYA) (Samson et al, 2014). On CYA, the fungal colony consisted of white flocculent hyphae. Scanning electron microscopy analysis showed that the mycelium was white, and the internodes of the stolons formed characteristic pseudoroots, from which upwardly clustered erect, unbranched sporocarp peduncles expanded apically to form rounded sporocarp sacs, within which sporocarp spores were produced. (Hariprasath P, 2019). To confirm the identity of the pathogen, the genomic fragments for the internal transcribed spacer (ITS) and intergenic spacer (IGS) gene of the isolate were amplified by PCR (White et al. 1990; Liu XY. 2008). The resulting sequence was deposited in GenBank with accession PP951880 and PQ001670, respectively. PCR results and morphological observations indicated the isolated strain was a pure culture and the strain was designated as DIC01. Comparative results showed that the sequences with accession numbers MT603964.1 and DQ990323.1 showed high homology of 99.15% and 98.96% to the ITS and IGS sequences of Rhizopus arrhizusi DIC01, respectively. Phylogenetic analysis with ITS and IGS genes of the isolated strain and 7 Rhizopus spp. strains were performed using MEGAX with Neighbor-Joining (NJ) method. Based on the results of growth habits, morphological observations, and phylogenetic analysis, the pathogen was identified as R. arrhizusi. A spore suspension of the R. arrhizusi DIC01 (1 x107 conidia/mL) was inoculated back to healthy D. rubrovolvata. Five healthy fruit bodies of D. rubrovolvata were injected, and another five healthy morels were treated with potato dextrose broth (PDB) as controls. D. rubrovolvata was incubated at 25°C and 90% relative humidity without ventilation for 5 days. The pathogen successfully infected the D. rubrovolvata, which developed white moldy lesions similar to those of natural diseases. The controls remained healthy without any symptoms. The pathogen was reisolated from the affected lesions and identified as R. arrhizusi DIC01 based on its mor

红豆杉（Dictyophora rubrovolvata）是一种药用价值极高的食用菌，在中国多个省份广泛种植（Hang 等，2012 年）。然而，在 2023 年 12 月至 2024 年 3 月期间，中国上海市奉贤区（N30°93'，E121°49'）的主产区发生了腐烂病。发病面积为 1.33 公顷，发病率为 25%。高温（>25℃）和通风不良为该病的传播提供了有利条件。该病主要发生在 D. rubrovvolata 子实体形成阶段。当表皮受损和破损时，就会被霉菌侵染，然后产生一层带有脓液的霉烂层。分离病斑边缘受感染的红铃虫组织，进行表面灭菌，在 30 ℃ 黑暗条件下置于马铃薯葡萄糖琼脂（PDA）上培养。通过单孢分离获得纯培养物。3 天后，将分离物转移到 Czapek 酵母菌琼脂（CYA）上（Samson 等人，2014 年）。在 CYA 上，真菌菌落由白色絮状菌丝组成。扫描电子显微镜分析表明，菌丝是白色的，匍匐茎节间形成特征性的假根，从假根向上簇生直立、不分枝的孢子囊梗，顶部膨大形成圆形的孢子囊，孢子囊内产生孢子。(Hariprasath P，2019 年）。为确认病原体的身份，通过 PCR 扩增了分离株的内部转录间隔（ITS）和基因间间隔（IGS）基因的基因组片段（White 等，1990 年；Liu XY，2008 年）。所得序列分别以 PP951880 和 PQ001670 的登录号存入 GenBank。聚合酶链式反应结果和形态学观察结果表明，分离出的菌株是纯培养物，该菌株被命名为 DIC01。比较结果表明，登录号为 MT603964.1 和 DQ990323.1 的序列与根瘤菌 DIC01 的 ITS 和 IGS 序列的同源性分别为 99.15%和 98.96%。利用 MEGAX 和 Neighbor-Joining (NJ) 方法对分离菌株和 7 株根瘤菌的 ITS 和 IGS 基因进行了系统进化分析。根据生长习性、形态观察和系统发育分析的结果，确定病原体为 R. arrhizusi。将 R. arrhizusi DIC01 的孢子悬浮液（1 x107 分生孢子/毫升）接种回健康的 D. rubrovolvata。注射 5 个健康的 D. rubrovolvata 果体，另用马铃薯葡萄糖肉汤（PDB）处理 5 个健康的羊肚菌作为对照。在 25°C、相对湿度为 90%、不通风的条件下培养 D. rubrovolvata 5 天。病原体成功感染了 D. rubrovolvata，它出现了与自然病害类似的白色霉斑。对照组仍然健康，没有出现任何症状。根据病原体的形态特征和系统发育标记基因，从受害病斑中重新分离出病原体，并确定其为 R. arrhizusi DIC01。据报道，R. arrhizusi 可造成内皮细胞损伤，菌丝侵入血管，导致血栓形成和组织坏死。(Hariprasath P, 2019）。据我们所知，这是第一份关于 R. arrhizusi 导致 D. rubrovolvata 腐烂病的报告。本研究证实，R. arrhizusi 是导致上海奉贤红富士农场红富士腐烂病的病原真菌。

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