芒果(MangiferaindicaL.)被认为是最重要的热带或亚热带水果作物之一(Nelsonetal.2008)。中国是芒果的第二大生产国(Kuhn等人。2017)。2021年6月,广州当地农产品市场的水仙芒果(约20%的水果表现出类似的感染症状)发生了采后茎端腐烂病,中国。在果实表面观察到黑腐病症状性病变,最初从茎端开始,然后进入衰变,变成棕色。为了分离和鉴定病原体,小片(3-5mm2)从果实的病变边缘切除(n=54),用1%NaOCl(1分钟)进行表面灭菌,70%乙醇(30秒),然后用无菌蒸馏水洗涤两次。灭菌后,将组织在马铃薯葡萄糖琼脂(PDA)上培养。获得了三个形态相似的分离株(SXM-1/2/3),并分析了代表性的分离株SXM-1。菌落表面最初有白灰色中度气生菌丝体,反向umber,有浅黄色到有光泽的斑块。在麦芽提取物琼脂(MEA)表面上脏白色,反向灰色棕褐色与西耶娜补丁。猪分生孢子,黑色,在PDA上变得肤浅,带颈部的球状,分泌乳膏分生孢子滴;分生孢子透明,光滑,1-3-隔膜,分支,密集聚集,圆柱形,直接到蜿蜒,22-42×2.8-3.7µm。α分生孢子(n=50),透明玻璃,光滑,梭形到有点短的圆柱形,3.2-11×1.3-3.5µm。β分生孢子(n=30)透明,光滑,弯曲或弯曲14.8-33.6×1.1-2.6μm。根据形态特征,具有代表性的分离株SXM-1与Diaporthe假血管CBS101339相似(Gomes等人。2013).对于分子鉴定,内部转录间隔区(ITS),组蛋白H3(HIS)和β-微管蛋白(TUB)基因(White等人。1990;Carbone等人。1999年;Glass等1995)进行了扩增和测序,存入GenBank(ON243823、ON254656、ON254655)。BLASTN分析显示,分离物的DNA序列(SXM-1/2/3)与假青霉的DNA序列(MG576128.1,KC344149,MN329124.1)具有99%的同一性,分别。基于串联序列的系统进化树分析证实了该分离株为假卟啉。用代表性分离株SXM-1进行致病性测试。健康水果用针头或未受伤后,用5毫米菌丝盘接种代表性分离株SXM-1,对照果实用灭菌的PDA塞接种。所有接种的果实和对照果实在接种后在26°C黑暗中孵育7天。对照水果保持无症状,而接种的水果是深棕色的坏死病变,在接种部位周围大致呈圆形。一式三份进行致病性测试。成功地重新分离了病原分离株,从而证实了科赫的假设。在墨西哥和多米尼加共和国,假芒果与芒果果皮有关,据报道,它也会导致花序腐烂,RachisCanker,和芒果中的花朵流产(Gomes等人。2013;Serratodiaz等人。2014).据我们所知,这是我国芒果果实采后茎端腐病的首次报道。这一发现表明,假芒果是中国芒果果实生产的潜在问题,建立对这种疾病的充分和有效的控制管理非常重要。参考文献:Nelson,S、C.2008。芒果炭疽病(炭疽病)。出版物PD-48。合作推广服务,热带农业与人力资源学院,夏威夷大学马诺阿分校,美国库恩,D.N.,etal.2017.前面。植物科学。8:577.白色,T.J.,etal.1990.第315页:PCR协议:方法和应用指南。学术出版社,圣地亚哥.Carbone,I.,etal.1999.Mycologia.91:553.玻璃,N、L、etal.1995.应用。环境。戈麦斯R.R.,etal.2013.Persoonia.1:31.Serratodiaz,L.M.,etal.2014.植物Dis。98:1004.*这些作者对这项工作做出了同样的贡献,应被视为共同第一作者。作者声明没有利益冲突。关键词:茎端腐烂,海底假芒果,芒果,中国。
Mango (Mangifera indica L.) is considered one of the most important tropical or subtropical fruit crops (Nelson et al.2008). China is the second-largest producer of mango (Kuhn et al. 2017). In June 2021, postharvest stem-end rot disease was observed on Narcissus mango (about 20% of the fruits showed similar symptoms of infections) in local agricultural market of Guangzhou, China. Black rot symptomatic lesions were observed on the fruit surface, which initially started from the stem end and progresses into decay, turning brown. To isolate and identify the pathogen, small pieces (3-5 mm2) were excised from the lesion margins of the fruits (n=54), which were surface sterilized by 1% NaOCl (1 min), 70% ethanol (30 s) and then washed twice with sterile distilled water. After sterilization, the tissues were cultured on potato dextrose agar (PDA). Three morphologically similar isolates (SXM-1/2/3) were obtained and the representative isolate SXM-1 was analyzed. Colonies surface initially had white-gray moderate aerial mycelia, in reverse umber with patches of pale luteous to luteous. On malt extract agar (MEA) surface dirty white, reverse greyish sepia with patches of sienna. Conidiomata pycnidia, black, erumpent to superficial on PDA, globose with neck, ostiole exuding cream conidial droplets; Conidiophores hyaline, smooth, 1-3-septate, branched, densely aggregated, cylindrical, straight to sinuous, 22-42 × 2.8-3.7 µm. Alpha conidia (n = 50) aseptate, hyaline, smooth, fusiform to somewhat short cylindrical, 3.2-11 ×1.3-3.5 µm. Beta conidia (n = 30) hyaline, smooth, curved or hamate 14.8-33.6 × 1.1-2.6 μm. According to morphological characterization, the representative isolate SXM-1 was similar to Diaporthe pseudomangiferae CBS 101339 (Gomes et al. 2013). For molecular identification, the internal transcribed spacer (ITS) region, histone H3 (HIS) and β-tubulin (TUB) genes (White et al. 1990; Carbone et al. 1999; Glass et al.1995) were amplified and sequenced, which were deposited in GenBank (ON243823, ON254656, ON254655). BLASTN analysis revealed that DNA sequences of the isolates (SXM-1/2/3) showed 99% identity with those of D. pseudomangiferae (MG576128.1, KC344149, MN329124.1), respectively. A phylogenetic tree analysis based on the concatenated sequences confirmed the isolates as D. pseudomangiferae. Pathogenicity tests were made with the representative isolate SXM-1. Healthy fruits were inoculated with 5 mm mycelial discs of the representative isolate SXM-1 after being wounded with a needle or non-wounded, control fruits were inoculated with sterilized PDA plugs. All inoculated and control fruits were incubated in the dark at 26°C for 7 days post-inoculation. Control fruits remained asymptomatic, whereas inoculated fruits were dark brown necrotic lesions with a roughly circular shape around the inoculation sites. Pathogenicity tests were performed in triplicate. The pathogenic isolates were successfully reisolated, thus confirming Koch\'s postulates. D. pseudomangiferae was associated with fruit peel of mango in Mexico and the Dominican Republic, and it has also been reported to cause inflorescence rot, rachis canker, and flower abortion in mango (Gomes et al. 2013; Serratodiaz et al. 2014). To our knowledge, this is the first report of D. pseudomangiferae causing postharvest stem-end rot of mango fruits in China. This finding suggests that D. pseudomangiferae is a potential problem for mango fruit production in China, and it is important to establish an adequate and effective control management of this disease. References: Nelson, S. C. 2008.Mango Anthracnose (Colletotrichum gloeosporiodes). Publication PD-48. Cooperative Extension Service, College of Tropical Agriculture and Human Resources, University of Hawai\'i at Manoa, U.S.A. Kuhn, D. N., et al. 2017. Front. Plant Sci. 8:577. White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego. Carbone, I., et al. 1999. Mycologia. 91:553. Glass, N. L., et al. 1995. Appl. Environ. Gomes R. R., et al. 2013. Persoonia. 1:31. Serratodiaz, L. M., et al. 2014. Plant Dis. 98:1004. * These authors contributed equally to this work and should be considered co-first authors. The authors declare no conflict of interest. Keywords: Stem-end rot, Diaporthe pseudomangiferae, Mango, China.