Yergeau Etienne, Vujanovic Vladimir, St-Arnaud Marc
Institut de recherche en biologie végétale, Université de Montréal and Jardin botanique de Montréal, 4101 East Sherbrooke Street, Montréal, Québec, Canada, H1X 2B2.
Microb Ecol. 2006 Jul;52(1):104-13. doi: 10.1007/s00248-006-9047-7. Epub 2006 May 18.
Asparagus (Asparagus officinalis) is a high-value perennial vegetable crop that has shown a marked decline in productivity after many years of continuous harvesting. This decline is caused by an increase in both abiotic (autotoxicity, harvesting pressure) and biotic stresses [fungal infections, mainly Fusarium crown and root rot (FCRR)]. To gain insight into disease development and possible mitigation strategies, we studied the effects of harvesting, time in the growing season, and field age on FCRR development, Fusarium species composition, and arbuscular mycorrhizal fungi (AMF) communities in both a controlled field experiment and an ecological survey of commercial fields. In one experiment, a 3-year-old asparagus field was subdivided into plots that were harvested or not and sampled throughout the growing season to assess short-term dominant Fusarium species shifts. In addition, diseased and healthy asparagus plants sampled from six commercial fields in the same geographical region were used to assess Fusarium and AMF communities in relation to different parameters. Fusarium and AMF communities were described by using a polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) approach, and results were analyzed by mainly correspondence analysis and canonical correspondence analysis. Results showed that dominant Fusarium taxa assemblages changed throughout the growing season. Harvested plots had significantly more FCRR symptomatic plants at the end of the growing season, but this effect was not related with any trend in Fusarium community structure. Sampling site and plant age significantly influenced AMF community structure, whereas only sampling site consistently influenced the Fusarium community. Diseased and healthy plants harbored similar Fusarium and AMF communities. Shifts in Fusarium community might not be responsible for different disease incidence because they are ubiquitous regardless of plant health status or harvesting regime. The different incidence noted might rather be related to plant physiology, antagonist microbial communities, or soil parameters.
芦笋（石刁柏）是一种高价值的多年生蔬菜作物，经过多年连续采收后，其生产力已显著下降。这种下降是由非生物胁迫（自毒作用、采收压力）和生物胁迫（真菌感染，主要是镰刀菌冠腐病和根腐病）共同增加所致。为深入了解病害发展及可能的缓解策略，我们在一个可控田间试验以及对商业田地的生态调查中，研究了采收、生长季节时间和田间种植年限对镰刀菌冠腐病发展、镰刀菌物种组成以及丛枝菌根真菌（AMF）群落的影响。在一项试验中，将一块种植了3年的芦笋田划分为采收区和未采收区，并在整个生长季节进行采样，以评估短期优势镰刀菌物种的变化。此外，从同一地理区域的六个商业田地采集的患病和健康芦笋植株，用于评估与不同参数相关的镰刀菌和AMF群落。通过聚合酶链反应（PCR）-变性梯度凝胶电泳（DGGE）方法描述镰刀菌和AMF群落，并主要通过对应分析和典范对应分析对结果进行分析。结果表明，优势镰刀菌分类群组合在整个生长季节都发生了变化。在生长季节结束时，采收区有症状的镰刀菌冠腐病植株明显更多，但这种影响与镰刀菌群落结构的任何趋势均无关。采样地点和植株年龄显著影响AMF群落结构，而只有采样地点持续影响镰刀菌群落。患病和健康植株的镰刀菌和AMF群落相似。镰刀菌群落的变化可能与不同的病害发生率无关，因为无论植株健康状况或采收方式如何，它们都普遍存在。观察到的不同发病率可能与植物生理学、拮抗菌微生物群落或土壤参数有关。
