植物内生菌Bacillus spp.与松材线虫病的关系研究

The Occurrence of Pine Wilt Disease Caused by Bursaphelenchus xylophilus Related to Endophyte

松材线虫病是重要的森林病害,其致病机理还没有完全研究清楚。从马尾松健康树和松材线虫病树中分离到属于芽孢杆菌Bacillusspp 的植物内生菌,此菌及其代谢产物对断根松苗和离体松枝均有致病作用,且致病症状与松材线虫病类似,但对正常生长的松苗没有作用。这说明这种植物内生菌与松材线虫病有关,是一种弱致病菌。用1mmol L的苯甲酸溶液处理接种了松材线虫的松枝,松枝内的线虫照常增殖,但松材线虫病得到抑制。这说明植物内生菌是导致松材线虫病的内因,松材线虫是激发因子之一。

Pine wilt disease caused by pine wood nematodes (PWN), Bursaphelenchus xylophilus, was one of main forestry diseases. Its exact pathogenic mechanism was not well-known. An endophyte bacterium, which was isolated from both diseased trees infected with this disease and healthy trees of masson pine, Pinus massoniana, was identified as Bacillus spp. Both bacterium and its metabolite were pathogenic to pine seedlings without roots and twigs, and symptom caused by them was alike to that of this disease, but they had no effect on healthy seedlings. It suggested that the occurrence of this disease related to this endophyte bacterium and it was weak pathogen. Pine twigs inoculated with PWN were cultured in 1.0 mmol/L benzoic acid (BA) solution and tap water, respectively. The results showed that the development of wilt disease of twigs cultured in BA solution was restrained, although PWN in these twigs increased as normally as those in twigs cultured in tap water. It suggested that endophyte of pine tree would be the main pathogenic factor of the disease, and PWN was one of irritative factors.