ISHS Acta Horticulturae 767: XXVII International Horticultural Congress - IHC2006: International Symposium on Sustainability through Integrated and Organic Horticulture
OBSERVATION OF ATTACHMENT OF AGROBACTERIUM TUMEFACIENS TO ROSE CELL SURFACE USING TEM IN RELATION TO RESISTANCE RESPONSES TO CROWN GALL DISEASE |
| Authors: | Lianhua Li, Biansee Tan , Wenjin Yu, Y. Ishiguro, H. Fukui, K. Kageyama, S. Matsumoto |
| Keywords: | cell wall, infection, inoculation, secretion, resistance mechanism |
| Abstract:
Attachment of Agrobacterium tumefaciens to host plant cells at wound sites is a key step in the infection process and various responses in resistance were observed in the roses during this time. High resistance roses Rosa hybrida 'PEKcougel' and R. hybrida 'Lifirane' and low resistance roses R. hybrida 'Dukat', R. multiflora 'Matsushima No. 3', and R. canina 'Pfänder' were inoculated with A. tumefaciens GOU1. Observations were made of the attachment to the host cell using transmission electron microscopy (TEM). For high resistant roses, many fibril-like substances and granules were observed in the intercellular space, and the number of fibril-like substances increased 72h post-inoculation. The granules were scattered throughout the intercellular space in most of the tissue assessed. Some bacteria were fully buried in secretions and appeared to be immobilized. For low resistant roses, A. tumefaciens were found to have attached to the rose tissue 48h after inoculation. Some granules were seen adjacent to the outer wall of the plant cell. At 72h post- inoculation, the granules were found to have increased slightly in number, however, most of the intercellular space appeared empty and the plant cell walls were exposed without being covered by granules. Based on the TEM observations, the primary differences between high and low resistant roses were the quantity of secretions and the ability to immobilize A. tumefaciens. Thus, we can conclude that the prevention of attachment of A. tumefaciens to roses may be a key factor that determines resistance levels in host plant cells. | |
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