Elbekali A Y, Siah A, Ramdani A, Tisserant B, Deweer C, Hafidi M, Reignault Ph, Halama P
Institut National de la Recherche Agronomique, BP 578, Meknès, Maroc.
Commun Agric Appl Biol Sci. 2012;77(3):281-6.
Mycosphaerella graminicola is nowadays one of the most important foliar pathogens on wheat crops worldwide and more specifically in Morocco. The interactions of eight monoconidial isolates of this fungus, sampled in different regions of Morocco, with 3 Moroccan wheat cultivars (Massira, Amal and Arrihan) differing in their resistance level to the pathogen, were studied using artificial inoculations in the greenhouse. Disease notations (percentage of third leaf areas covered by lesions bearing pycnidia) at 21 days post inoculation revealed significant differences among the different isolate-cultivar combinations. Most isolates expressed pathogenicity profiles in accordance with the resistance levels of the cultivars studied. However, T01701 showed a similar pathogenicity level on the three cultivars and T01718 induced more disease on the moderately resistant cv. Amal compared to the susceptible cv. Massira and the resistant cv. Arrihan, respectively. Furthermore, the infection process of the isolate T01757 was investigated at 4, 8, 12, 16 and 21 days post-inoculation. This isolate exhibited a disease gradient (65%, 24% and 5%) which negatively correlated with the resistance levels of the cultivars. No significant differences were obtained regarding the rates of spore germination and leaf penetration events. However, rates of mesophyll colonization positively correlated with the disease levels scored on the cultivars. This study supports the presence of strain-cultivar interactions between wheat and M. graminicola in Morocco and confirms the importance of mesophyll colonization in disease establishment and extension.
小麦壳针孢是当今全球小麦作物上，尤其是摩洛哥最重要的叶部病原菌之一。对采自摩洛哥不同地区的该真菌的8个单孢分离株，与3个对该病原菌抗性水平不同的摩洛哥小麦品种（马西拉、阿迈勒和阿里汉）之间的相互作用，在温室中通过人工接种进行了研究。接种后21天的病情记录（带有分生孢子器的病斑覆盖第三片叶面积的百分比）显示，不同分离株-品种组合之间存在显著差异。大多数分离株表现出与所研究品种的抗性水平相符的致病型。然而，T01701在这三个品种上表现出相似的致病水平，且与感病品种马西拉和抗病品种阿里汉相比，T01718在中抗品种阿迈勒上诱发了更多病害。此外，在接种后4、8、12、16和21天对分离株T01757的侵染过程进行了研究。该分离株表现出一种病害梯度（65%、24%和5%），与品种的抗性水平呈负相关。在孢子萌发率和叶片穿透事件方面未获得显著差异。然而，叶肉定殖率与品种上记录的病害水平呈正相关。本研究支持摩洛哥小麦与小麦壳针孢之间存在菌株-品种相互作用，并证实了叶肉定殖在病害发生和扩展中的重要性。
