During the 2016 growing season, melon fruits were severely affected by rind necrosis and rot and nearly 80% of the fruits were unmarketable in a field in Koçarlı district of Aydın. In order to determine occurrences of the fruit infections in the following year, surveys were conducted in 2017. Isolations were made from the symptomatic fruits and bacterial growths were observed consistently. In this study, we identified the causal agents of melon fruit necrosis and rot. Pathogenicity of the bacterial strains was determined on melon fruit by needle injection method and thirteen strains were further characterized with phenotypic characterization, analysis of 16S rRNA gene sequences and specific PCR assays. As a result of the pathogenicity tests, brown spots and necrosis formation was observed initially and in the later stage, inoculated fruit burst out by the fermentative strains. The oxidative strains produced limited necrosis on the rind. Fermentative bacterial agents isolated from the melon necrosis and rot were identified as Enterobacter cloacae, Klebsiella pneumoniae and Kosakonia cowanii. Enterobacter cloacae strains were further tested with tDNA-PCR using T5A/T3B primers. The oxidative bacteria were phenotypically grouped within the fluorescent pseudomonads.

Homology search of the oxidative strains using the sequence information of partial 16S rRNA gene identified the strains as Pseudomonas spp. The oxidative strain 413-Si2-L2 and the reisolate 06R2K were the most similar to strains of Pseudomonas putida and P. reidholzensis including the type strains. The strain, 413-MKV-3 and the reisolate 03R2K were the most related to Pseudomonas fluorescens, P. baetica, P. syringae, and Pseudomonas sp. strains.

The ability of Enterobacter cloacae, Klebsiella pneumoniae and Kosakonia cowanii to cause disease on melon fruit was shown for the first time in this study by fulfilling Koch postulate. Furthermore, although limited rind necrosis was produced, pathogenicity of the fluorescent pseudomonads on melon fruit was also confirmed.

在 2016 年的生长季节，瓜果受到果皮坏死和腐烂的严重影响，近 80% 的水果在 Aydın 的 Koçarlı 区的一个田地里滞销。为了确定下一年水果感染的发生情况，2017 年进行了调查。对有症状的水果进行了隔离，并持续观察到细菌生长。在这项研究中，我们确定了甜瓜果实坏死和腐烂的病原体。通过针刺法测定了该菌株对瓜果的致病性，并通过表型表征、16S rRNA基因序列分析和特异性PCR检测进一步表征了13株菌株。病原性试验结果，初期和后期观察到褐色斑点和坏死形成，接种的果实因发酵菌株而爆裂。氧化菌株在外皮上产生有限的坏死。从瓜类坏死和腐烂中分离的发酵菌剂被鉴定为阴沟肠杆菌、肺炎克雷伯菌和科沙克氏菌。使用 T5A/T3B 引物通过 tDNA-PCR 进一步测试阴沟肠杆菌菌株。氧化细菌在荧光假单胞菌内按表型分组。

使用部分16S rRNA基因的序列信息对氧化菌株进行同源性搜索，将菌株鉴定为假单胞菌属。氧化菌株 413-Si2-L2 和重新分离的 06R2K 与恶臭假单胞菌和P菌株最相似。reidholzensis包括类型菌株。的菌株，413-MKV-3和reisolate 03R2K是最相关的荧光假单胞菌，P。贝蒂卡，P。丁香和假单胞菌属。菌株。

本研究通过满足科赫假设，首次证明了阴沟肠杆菌、肺炎克雷伯菌和科萨康氏菌对甜瓜果实的致病能力。此外，虽然产生了有限的果皮坏死，但也证实了瓜果上荧光假单胞菌的致病性。