天瓜基里洛威格言。(葫芦科),一种中草药,是安徽省重要的经济作物,中国。近年来,树胶性干枯萎病,一种主要的瓜类疾病,在许多凯里洛威种植园中很普遍。自然感染的茎上的最初症状表现为深棕色的水浸病变,随着疾病的发展,凯里洛威的葡萄藤逐渐枯萎。在树叶上,最初可见棕色水浸的病变,然后病变扩大并合并,导致叶子广泛坏死。关于水果,被白色菌丝体覆盖的病变几乎是圆形的,最初是棕褐色。随后,患病的果实变黑腐烂,俗称果腐病或黑腐病。从有症状的茎中始终分离出Stagonosporopsis样生物,叶子和水果。真菌分离株最初是白色的,后来变成深灰色或黑色,在PDA培养基上具有羊毛感,以絮凝气生菌丝体。选择了来自不同种植园的24个分离株进行进一步的形态学研究。在黄瓜果实上接种3天后,形成了分生孢子和分生孢子。比尼迪亚呈球状至亚球状,棕色,卵形和106.7至213.6μm(平均160.1μm,直径n=50)。分生孢子是透明的,椭圆体,无盐或单隔膜,在隔膜处略微收缩,6.1~13.6×3.5~4.8μm(平均9.9×4.1μm,n=50),并含有两个或更多的油滴。基因组DNA的三个不同位点,包括核核糖体DNA内部转录间隔区(ITS),RNA聚合酶II第二大亚基(RPB2),和β-微管蛋白(TUB2)基因。,使用引物ITS1/ITS4扩增(White等人。1990),RBP2DF/RBP2DR(Lawrenceetal.2013),和T1/β-Sandy-R(O\'Donnell和Cigelnik1997;Stukenbrock等人。2012),分别和测序。在分析ITS的基础上,建立了系统进化树,存放在GenBank中的RPB2和TUB2序列(用于ITS的MW485497-MW485502,MW531661-MW531666用于RPB2,MW531667-MW531672用于TUB2),使用最大似然法。系统发育树表明,分离株与葫芦枯菌一起落入一个分支中。根据形态和分子特征,从赤霉病中获得的分离株被鉴定为南瓜孢霉。对4周龄的木氏T.kirilowii幼苗的茎和叶以及从成年木氏T.kirilowii植物收集的未成熟果实进行致病性测试。表皮,以前用注射器针头受伤,接种直径为5毫米的菌丝体栓,然后将接种区域包裹在浸水的棉花中。用琼脂栓类似地接种对照。在两个垂直方向上测量病变的直径。在PDA培养基上进行从茎和叶病变的再分离。南瓜孢霉,根据其菌落和分生孢子特征重新鉴定,因此,完成了科赫的假设。据报道,在许多宿主中都有由葫芦枯病引起的软糖茎枯病,包括黄瓜,Luffa,南瓜,葫芦,甜瓜,哈密瓜,和西瓜(Jiang等人。2015年;基纳特2011年;赵等人。2019)。据我们所知,这是我国首次报道由葫芦未树引起的赤霉病。该研究为制定和实施有效的管理策略提供了依据。对4周龄的木氏T.kirilowii幼苗的茎和叶以及从成年木氏T.kirilowii植物收集的未成熟果实进行致病性测试。表皮,以前用注射器针头受伤,接种直径为5毫米的菌丝体栓,然后将接种区域包裹在浸水的棉花中。对对照进行类似处理,但是用琼脂栓接种。在两个相互垂直的方向上测量病变的直径。在PDA培养基上重新分离病灶,并根据其菌落和分生孢子特征重新鉴定,以完成科赫的假设。据报道,在许多宿主中都有由葫芦枯病引起的软糖茎枯病,包括黄瓜,Luffa,南瓜,葫芦,甜瓜,哈密瓜,和西瓜(Jiang等人。2015年;基纳特2011年;赵等人。2019)。据我们所知,这是我国首次报道由葫芦未树引起的赤霉病。该研究为制定和实施有效的管理策略提供了依据。
Trichosanthes kirilowii Maxim. (Cucurbitaceae), one of the Chinese herbal medicines, is an economically important crop in Anhui Province,
China. In recent years, gummy stem blight disease, a major disease of cucurbits, was widespread in many T. kirilowii plantations. The initial symptoms on the naturally infected stems appeared as dark brown water-soaked lesions, and as the disease progressed, vines of T. kirilowii gradually withered. On leaves, brown water-soaked lesions were visible initially, and then lesions enlarged and coalesced, resulting in extensive necrosis of leaves. On fruit, lesions covered with the white mycelium were nearly circular and tan to brown initially. Subsequently, the diseased fruit turned black and rotten commonly known as fruit rot or black rot. A Stagonosporopsis-like organism was consistently isolated from symptomatic stems, leaves and fruits. Fungal isolates were initially white and later turned dark grey or black with woolly to floccose aerial mycelium on PDA medium. Twenty-four isolates from different plantations were selected for further morphological studies. Pycnidia and conidia were formed after inoculating on cucumber fruit for 3 days. Pycnidia were globose to sub-globose, brown, ostiolate and 106.7 to 213.6 μm (average 160.1 μm, n = 50) in diameter. Conidia were hyaline, ellipsoidal, aseptate or one-septate, slightly constricted at the septa, 6.1 to 13.6 × 3.5 to 4.8 μm (average 9.9 × 4.1 μm, n = 50), and contained two or more oil drops. Three different loci of the genomic DNA, including the nuclear ribosome DNA internal transcribed spacer (ITS), RNA polymerase II second-largest subunit (RPB2), and β-tubulin (TUB2) genes., were amplified using primers ITS1/ITS4 (White et al. 1990), RBP2DF/RBP2DR (Lawrence et al. 2013), and T1/β-Sandy-R (O\' Donnell and Cigelnik 1997; Stukenbrock et al. 2012), respectively and sequenced. A phylogenetic tree was built based on analysis of ITS, RPB2, and TUB2 sequences that deposited in GenBank (MW485497-MW485502 for ITS, MW531661-MW531666 for RPB2, and MW531667-MW531672 for TUB2), using the maximum likelihood method. The phylogenetic tree showed that the isolates fell into a single clade with S. cucurbitacearum. On the basis of morphological and molecular characteristics, the isolates obtained from T. kirilowii were identified as Stagonosporopsis cucurbitacearum. Pathogenicity tests were carried out on stems and leaves of 4-week-old T. kirilowii seedlings and on immature fruit collected from adult T. kirilowii plants. The epidermis, previously injured with a syringe needle, was inoculated with 5-mm-diameter mycelial plugs, and the inoculated areas were then wrapped in water-soaked cotton. Controls were similarly inoculated with agar plugs. The diameters of lesions were measured in two perpendicular directions. Re-isolations from the stem and leaf lesions were performed on the PDA medium. Stagonosporopsis cucurbitacearum, was re-identified based on its colony and conidial characteristics and, therefore, completed Koch\'s postulates. Gummy stem blight caused by S. cucurbitacearum has been reported in a wide range of hosts, including cucumber, luffa, pumpkin, gourd, muskmelon, cantaloupe, and watermelon (Jiang et al. 2015; Keinath 2011; Zhao et al. 2019). To our knowledge, this is the first report of gummy Stem blight disease on T. kirilowii caused by S. cucurbitacearum in
China. The research provides a basis for the development and implementation of effective management strategies. Pathogenicity tests were carried out on stems and leaves of 4-week-old T. kirilowii seedlings and on immature fruits collected from adult T. kirilowii plants. The epidermis, previously injured with a syringe needle, was inoculated with 5-mm-diameter mycelial plugs, and the inoculated areas were then wrapped in water-soaked cotton. Controls were treated similarly but inoculated with agar plugs. Diameters of lesions were measured in two mutually perpendicular directions. Reisolations from the lesions were performed on PDA medium, and was re-identified based on its colony and conidial characteristics to complete Koch\'s postulates. Gummy stem blight caused by S. cucurbitacearum have been reported in a wide range of hosts, including cucumber, luffa, pumpkin, gourd, muskmelon, cantaloupe, and watermelon (Jiang et al. 2015; Keinath 2011; Zhao et al. 2019). To our knowledge, this is the first report of gummy Stem blight disease on T. kirilowii caused by S. cucurbitacearum in
China. The research provides a basis for the development and implementation of effective management strategies.