Bai Qing, Zhai Lifeng, Chen Xiaoren, Hong Ni, Xu Wenxing, Wang Guoping
State Key Laboratory of Agricultural Microbiology; College of Plant Science and Technology, Huazhong Agricultural University; and National Indoor Conservation Center of Virus-free Germplasms of Fruit Crops, Wuham, Hubei 430070, China.
Plant Dis. 2015 Dec;99(12):1704-1712. doi: 10.1094/PDIS-03-15-0259-RE. Epub 2015 Oct 4.
In recent years, a widespread canker disease that infects the branches of pear trees has been observed in many provinces in China; it kills the branches and results in high losses in fruit production. Symptomatic branches were collected for etiological isolation from 11 varieties of three pear species and from Malus pumila. Samples were collected from six provinces in China. In total, 143 Phomopsis isolates were obtained from 181 samples and these were identified as belonging to five species: Phomopsis fukushii (n = 69 isolates), Diaporthe eres (n = 31), P. amygdali (n = 22), P. longicolla (n = 13), and D. neotheicola (n = 8). Pathogenicity tests showed that only the first three species induced lesions on nonwounded branches of Pyrus pyrifolia var. Cuiguan. All the fungal species induced branch cankers following wound inoculations, and tests with additional pear varieties showed significantly higher virulence levels for the first three species than the latter two. A host range evaluation suggested that the five species could infect most fruit trees belonging to the Rosaceae family as well as some non-Rosaceous species. Virulence varied depending on the species of both host and pathogen. Isolates of Phomopsis amygdali had significantly higher virulence in all the tested Rosaceae plants. Correlations among the host, pathogen, and sampling regions were noted, and the morphology, growth rate, and sporulation of these species in varied media were also characterized. This study presents the first attempt to perform a broad survey and characterization of the Phomopsis spp. associated with the pear shoot cankers in China. This study shows that D. eres and P. amygdali are just as responsible for the pear shoot canker diseases as P. fukushii, and it expands the host and geographic ranges of the five species. This report provides useful information for understanding and improving management strategies for controlling this economically important disease.
近年来，中国多个省份均发现一种广泛流行的溃疡病，该病侵染梨树的枝条，致使枝条死亡，给水果生产造成了巨大损失。从三种梨属的11个品种以及苹果中采集了有症状的枝条用于病原菌分离。样本来自中国六个省份。从181个样本中共获得143株拟茎点霉分离株，鉴定为五个种：福氏拟茎点霉（n = 69株分离株）、间座壳属（n = 31）、扁桃拟茎点霉（n = 22）、长孢拟茎点霉（n = 13）和新可可间座壳（n = 8）。致病性测试表明，只有前三个种能在翠冠梨未受伤的枝条上引起病斑。所有真菌种在伤口接种后均能引起枝条溃疡，对其他梨品种的测试表明，前三个种的毒力水平明显高于后两个种。寄主范围评估表明，这五个种能侵染大多数蔷薇科果树以及一些非蔷薇科物种。毒力因寄主和病原菌的种类而异。扁桃拟茎点霉分离株在所有测试的蔷薇科植物中具有显著更高的毒力。记录了寄主、病原菌和采样地区之间的相关性，并对这些种在不同培养基中的形态、生长速率和产孢情况进行了表征。本研究首次对与中国梨枝条溃疡病相关的拟茎点霉进行了广泛调查和表征。该研究表明，间座壳属和扁桃拟茎点霉与福氏拟茎点霉一样，对梨枝条溃疡病负有责任，并且扩大了这五个种的寄主和地理范围。本报告为理解和改进控制这种具有经济重要性的病害的管理策略提供了有用信息。
