Delmas Chloé E L, Mazet Isabelle D, Jolivet Jérôme, Delière Laurent, Delmotte François
INRA, UMR1065 Santé et Agroécologie du Vignoble, Villenave d'Ornon, France.
J Microbiol Methods. 2014 Dec;107:169-75. doi: 10.1016/j.mimet.2014.10.012.
Quantitative pathogenicity traits drive the fitness and dynamics of pathogens in agricultural ecosystems and are key determinants of the correct management of crop production over time. However, traits relating to infection potential (i.e. zoospore production) have been less thoroughly investigated in oomycetes than traits relating to dispersal (i.e. sporangium production). We simultaneously quantified sporangium and zoospore production in a biotrophic oomycete, for the joint assessment of life-cycle traits relating to dispersal and infection potentials. We used an automatic particle analyzer to count and size the sporangia and/or zoospores produced at t = 0 min (no zoospore release) and t = 100 min (zoospore release) in 43 Plasmopara viticola isolates growing on the susceptible Vitis vinifera cv. Cabernet Sauvignon. We were able to differentiate and quantify three types of propagules from different stages of the pathogen life cycle: full sporangia, empty sporangia and zoospores. The method was validated by comparing the sporangium and zoospore counts obtained with an automatic particle analyzer and under a stereomicroscope (manual counting). Each isolate produced a mean of 5.8 ± 1.9 (SD) zoospores per sporangium. Significant relationships were found between sporangium production and sporangium size (negative) and between sporangium size and the number of zoospores produced per sporangium (positive). However, there was a significant positive correlation between total sporangium production and total zoospore production. This procedure can provide a valid quantification of the production of both sporangia and zoospores by oomycetes in large numbers of samples, facilitating joint estimation of the dispersal and infection potentials of plant pathogens in various agro-ecological contexts.
定量致病性特征驱动着农业生态系统中病原体的适应性和动态变化，是长期正确管理作物生产的关键决定因素。然而，与感染潜力（即游动孢子产生）相关的特征在卵菌纲中比与传播（即孢子囊产生）相关的特征研究得更少。我们同时对一种活体营养型卵菌的孢子囊和游动孢子产生进行了定量，以联合评估与传播和感染潜力相关的生命周期特征。我们使用自动颗粒分析仪对43个葡萄生单轴霉分离株在感病葡萄品种赤霞珠上生长时，在t = 0分钟（无游动孢子释放）和t = 100分钟（游动孢子释放）时产生的孢子囊和/或游动孢子进行计数和测量大小。我们能够区分和量化病原体生命周期不同阶段的三种类型的繁殖体：完整孢子囊、空孢子囊和游动孢子。通过比较自动颗粒分析仪和立体显微镜下（手动计数）获得的孢子囊和游动孢子计数，验证了该方法。每个分离株每个孢子囊平均产生5.8 ± 1.9（标准差）个游动孢子。在孢子囊产生与孢子囊大小（负相关）以及孢子囊大小与每个孢子囊产生的游动孢子数量（正相关）之间发现了显著关系。然而，总孢子囊产量与总游动孢子产量之间存在显著正相关。该程序可以对大量样本中卵菌纲产生孢子囊和游动孢子的情况进行有效定量，便于在各种农业生态环境中联合估计植物病原体的传播和感染潜力。
