文献类型： 外文期刊

作者： Duan, W. J. ¹ ; Zhang, X. Q. ¹ ; Yang, T. Z. ¹ ; Dou, X. W. ¹ ; Chen, T. G. ² ; Li, S. J. ² ; Jiang, S. J. ³ ; Huang, Y. ¹ ;

作者机构： 1.Henan Agr Univ, Coll Tobacco Sci, Zhengzhou, Peoples R China

2.Henan Acad Agr Sci, Tobacco Inst, Xuchang, Peoples R China

3.Henan Agr Univ, Coll Plant Protect, Zhengzhou, Peoples R China

4.Henan Tobacco Co, Zhengzhou, Peoples R China

关键词： Alternaria alternata (Fries) Keissler;ammonia;appressorium differentiation;brown spot disease;tobacco-Alternaria interaction;Nicotiana tabacum L.

期刊名称：JOURNAL OF PLANT DISEASES AND PROTECTION （ 影响因子：1.928； 五年影响因子：1.652 ）

ISSN： 1861-3829

年卷期： 2010 年 117 卷 3 期

页码：

收录情况： SCI

摘要： Alternaria alternata (Fries) Keissler is a facultative parasitic fungus which causes brown spot disease of senescing tobacco (Nicotiana tabacum L.) leaves. To test whether ammonia accumulation at the infection site plays a role in differentiation of infection structures and lifestyle transition of A. alternata, an artificial ammonia environment was set up to imitate and manipulate the host ammonia environment that pathogens would encounter both on leaf cuticle and in extracellular spaces. Light microscopy showed that, within 6 h after ammonia exposure, appressoria and penetration pegs could be detected at the tips of germ tubes incubated on glass slides and on host leaf surfaces, and foliar epidermal cells influenced by appressoria turned chlorotic and necrotic. Neither appressorium formation nor necrotic lesion was found in control experiments (ammonia free). Moreover, a compatible interaction between A. alternata and a resistant tobacco cultivar Jingyehuang was induced by ambient ammonia, resulting in expanding, ring-like lesions on its excised leaves within 60 h. In the absence of ammonia treatment, however, no spot symptoms could be found on the leaves of a susceptible cultivar K326 during the same period. These results suggest that A. alternata can respond to ambient ammonia and use it as a stimulator to invade the host by differentiating into infection structures and to switch to a necrotrophic lifestyle, next to secrete pathogenicity factors.