| 论文题目: | First Report of Fruit Rot of Strawberry Caused by Geotrichum candidum in Pakistan |
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| 作者: | Hussain, M. Hamid, M. I. Ghazanfar, M. U. Akhtar, N. Raza, M. |
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| 刊物名称: | Plant Disease |
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| 年份: | 2016 |
| 影响因子: | 3.268 |
| 论文下载: | 下载地址 |
| 摘要: | Strawberry (Fragaria ananassa Duch.) is grown extensively as commercial fruit crop in many regions of Pakistan. During greenhouse surveys in March 2014 and 2015, strawberry fruit displaying a water-soaked soft rot with a sour, fermented smell, and dense white mycelial growth were observed in commercial fields in Sargodha district (32°5′1″ N, 72°40′16″ E), Punjab, Pakistan. The incidence of preharvest fruit decay ranged from 5 to 10% throughout the operation. Diseased fruit were collected and observed under a stereo microscope and small pieces of mycelium were removed using a sterilized inoculation needle and placed on potato dextrose agar (PDA). Colonies were composed of white, flat, and wet mycelium composed of dichotomously branched septate hyphae (4 × 6 µm), conidia were hyaline, 1-celled, and cylindrical (8.3 to 9.4 × 3.2 to 4.8 µm), formed in long aerial chains. These morphological characteristics matched the description of Geotrichum candidum (De Hoog et al. 1986). To confirm the pathogen identity, genomic DNA was extracted as described previously (Hamid et al. 2014) and the ITS1 region and SSU of rDNA was sequenced as described (White et al. 1990). The resulting sequences were deposited in GenBank (Accession Nos. KF975700 and KU051538). A BLASTn search of ITS and SSU sequences from Pakistan revealed 99% similarity with G. candidum isolates KF713514.1 and KJ543497.1, respectively, which were derived from different regions of the world. Additionally, phylogenetic analysis (MEGA version 5.2, maximum likelihood with Jukes-Cantor model, 1,000 bootstraps) based on ITS and SSU sequences placed our isolates within the same clade with other G. candidum isolates worldwide. In-planta pathogenicity assays were conducted by inoculating fresh strawberry fruit with 10 µl of conidial suspension (107 conidia/ml adjusted with hemocytometer) and sterilized distilled water (control) for the development of symptoms. All fruit were incubated in a humid chamber at 25 ± 1°C. Symptoms appeared on fruit 3 days after inoculation and were similar to those collected from fields, while control fruit remained healthy. G. candidum was reisolated and its identity reconfirmed using morphological and by molecular techniques. G. candidum has been reported to cause sour rot diseases of various fruits and vegetables in the region (Hafeez et al. 2015; Horita and Hatta 2016). To our knowledge, this is the first report of G. candidum causing strawberry fruit rot in Pakistan. |
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