Wakeham Alison J, Kennedy Roy
Warwick HRI, University of Warwick, Wellesbourne, Warwick, Warwickshire CV35 9EF, UK.
Plant Dis. 2010 Jul;94(7):851-859. doi: 10.1094/PDIS-94-7-0851.
Mycosphaerella brassicicola causes ringspot on Brussels sprouts, which can result in substantial yield loss in commercial production. Brussels sprout buttons are downgraded if this pathogen occurs on them. In this study, the effect of temperature and wetness duration was investigated on infection of Brussels sprouts using controlled environments (CE). The effect of temperature and wetness duration on inoculum production and ascospore discharge was also investigated. Infection by M. brassicicola was described using a mathematical model and was compared to estimates of ascospore availability obtained via a volumetric air sampler and immunofluorescence (IF). Infection of M. brassicicola was correlated (r = 0.92) with temperature during leaf wetness periods. The relationship between temperature and time to discharge of 5 and 50% of the cumulative total number of ascospores from ringspot lesions was r = 0.99 and 0.98, respectively (P < 0.001). In field experiments, an optimal wind run (the product of the average wind speed and the period over which that average speed was measured) of 250 to 500 km day was required for the dissemination of ringspot inoculum to field bait plants. Quantification of M. brassicicola inoculum in collected field aerosols was possible using a monoclonal antibody in a plate-trapped antigen enzyme-linked immunosorbent assay. Precoating of the air sampler wells with sodium azide prevented trapped spores from germinating. Ringspot inoculum could be detected and quantified in air samples from commercial crops of Brussels sprouts in the United Kingdom. Low levels of ringspot inoculum measured within crops did not lead to disease development.
芸薹生球腔菌可引起抱子甘蓝叶斑病，这会导致商业生产中的产量大幅损失。如果这种病原体出现在抱子甘蓝芽球上，其等级会被降低。在本研究中，利用可控环境（CE）研究了温度和湿润持续时间对抱子甘蓝感染的影响。还研究了温度和湿润持续时间对接种体产生和子囊孢子释放的影响。使用数学模型描述了芸薹生球腔菌的感染情况，并将其与通过体积空气采样器和免疫荧光（IF）获得的子囊孢子可用性估计值进行了比较。芸薹生球腔菌的感染与叶片湿润期的温度相关（r = 0.92）。温度与环斑病斑中子囊孢子累积总数的5%和50%释放时间之间的关系分别为r = 0.99和0.98（P < 0.001）。在田间试验中，环斑病接种体传播到田间诱饵植物需要250至500千米/天的最佳风速行程（平均风速与测量该平均风速的时间段的乘积）。使用平板捕获抗原酶联免疫吸附测定中的单克隆抗体可以对收集的田间气溶胶中的芸薹生球腔菌接种体进行定量。用叠氮化钠预涂空气采样器孔可防止捕获的孢子发芽。在英国抱子甘蓝商业作物的空气样本中可以检测和定量环斑病接种体。作物中测得的低水平环斑病接种体不会导致病害发生。
