Rudelle Jérome, Octave Stéphane, Kaid-Harche Meriem, Roblin Gabriel, Fleurat-Lessard Pierrette
Université de Poitiers, Laboratoire de Physiologie et Biochimie Végétales, UMR CNRS 6161, Bâtiment Botanique, 40 Avenue du Recteur Pineau, F-86022 Poitiers, France.
Laboratoire de Biologie Végétale, Faculté des Sciences, Université d'Oran, Algérie.
Funct Plant Biol. 2005 Jul;32(6):537-547. doi: 10.1071/FP05012.
Eutypa dieback, a devastating disease in grapevines, is caused by the fungal pathogen Eutypa lata, a wood-inhabiting fungus. E. lata acts by degrading wood tissues in the colonisation areas, and produces foliar symptoms. These striking symptoms have been attributed to the production of toxic metabolites by the pathogen, the most widely studied being eutypine. The aims of the study were to compare the effects of E. lata on xylem structure at the site of infection and in remote tissues. In healthy Vitis vinifera, the vessel-associated cells (VACs) in the trunk have a protective layer that covers the entire lignified wall and forms a transfer apparatus in pits located at the VAC / vessel interface. This apparatus occurs similarly in VACs in the basal part of canes but is less developed in the apical part. In the presence of E. lata, which is found only in the trunk and the cordons, the VACs initiated a program of secretory activity that led to the enlargement of the transfer apparatus, which is formed by tightly associated fibrils. This secretory activity was followed by VAC death. Furthermore, the hypertrophy of the transfer apparatus spread according to an acropetal gradient in the canes. Treatment with eutypine also induced the development of the transfer apparatus in VACs of basal and apical parts of canes excised from healthy vines. However, this apparatus was formed by loosely packed fibrils in VACs that were not completely damaged. Therefore, metabolites other than eutypine are expected to be involved in the VAC degeneration observed in infected vines.
葡萄藤猝死病是一种由真菌病原体阔叶树盘多毛孢引起的毁灭性葡萄藤病害，阔叶树盘多毛孢是一种寄生于木材的真菌。阔叶树盘多毛孢通过降解定殖区域的木材组织发挥作用，并产生叶片症状。这些显著症状归因于病原体产生的有毒代谢物，其中研究最广泛的是葡萄盘菌素。本研究的目的是比较阔叶树盘多毛孢对感染部位和远端组织木质部结构的影响。在健康的酿酒葡萄中，树干中的导管相关细胞（VACs）有一层保护层，覆盖整个木质化壁，并在VAC/导管界面的纹孔处形成一个转运装置。这种装置在茎基部的VACs中也有类似情况，但在顶端部分发育较差。在仅存在于树干和主蔓中的阔叶树盘多毛孢存在的情况下，VACs启动了一个分泌活动程序，导致由紧密相连的纤维形成的转运装置增大。这种分泌活动之后是VACs死亡。此外，转运装置的肥大在茎中沿向顶梯度扩散。用葡萄盘菌素处理也诱导了从健康葡萄藤上切下的茎基部和顶端部分的VACs中转运装置的发育。然而，这种装置是由未完全受损的VACs中松散排列的纤维形成的。因此，预计除葡萄盘菌素外的其他代谢物也参与了感染葡萄藤中观察到的VACs退化。
