Studi interaksi Fusarium sp. dengan pohon gaharu (Aquilaria sp.) menggunakan pendekatan sitologi

Abstract

The research is aiming to study the pathogenesis mechanism of Fusarium sp. IPBCC. 08.569 on Aquilaria sp. seedling in respect to the respons of the host towards Fusarium sp. IPBCC. 08.569 infection. Penetration mechanism was determined by observing the appresorium formation on the bark surface in vitro, the potency to produce lignocellulase and toxin. While colonization was studied by histopathological methods using both staining process and SEM. The respons of the tree towards infection was observed at either cellular by histochemestry or organ level using scoring system. Fusarium sp. IPBCC. 08.569 showed no appresorium formation but had lignocellulolytic activity. Hypersensitivity reaction of tobacco leaf towards crude extract of extracellular substance indicated that Fusarium sp. IPBCC. 08.569 produce toxin. Direct penetration into the bark was not found, therefore penetration had to be through wounded area. While modification of hyphae was observed in the living cells of the wood tissue (parenchyma rays, included phloem, and pith) these cells might contain terpenoid as conversion of starch. These cellular changes might be observed as discolored wood and the wood became scented. Discolored wood was extended outside the colonization area, indicated that the dark substance might be part of hypersensitive respons to delimit the infection. Using scoring system, after inoculation Fusarium sp. IPBCC. 08.569 can be stated as wound infection fungi with limited colonization in living tissue and induce terpenoid formation in certain tissue.