Department of Biotechnology, Guru Nanak Dev University, Amritsar, 143 005 India.
Indian J Microbiol. 2008 Dec;48(4):432-7. doi: 10.1007/s12088-008-0053-y. Epub 2009 Jan 8.
During an investigation of the disease profile of Withania somnifera, it was observed that leaf spot is the most prevalent disease. Repeated isolations from infected leaf tissues and pathogenicity tests showed the association of fungal pathogen identified as Alternaria alternata (Fr.) Keissler. Scanning electron microscopy showed various histological changes in the leaf tissues of infected plants. A decrease in total content of reducing sugars (20%) and chlorophyll (26.5%) was observed in diseased leaves whereas an increase was noticed in proline (25%), free amino acids (3%) and proteins (74.3%). High performance thin layer chromatography (HPTLC) analysis of secondary metabolites viz. withanolides, withaferin-A and total alkaloids of the diseased leaves vis-à-vis control revealed reduction in withaferin-A and withanolides contents by 15.4% and 76.3% respectively, in contrast to an increase in total alkaloids by 49.3%, information hitherto unreported in W. somnifera.
在对睡茄疾病谱的调查中，观察到叶斑病是最普遍的疾病。从感染的叶片组织中反复分离和致病性试验表明，与鉴定为交替镰刀菌（Alternaria alternata（Fr.）Keissler）的真菌病原体有关。扫描电子显微镜显示，感染植株叶片组织有各种组织学变化。在患病叶片中，还原糖（20%）和叶绿素（26.5%）总含量下降，而脯氨酸（25%）、游离氨基酸（3%）和蛋白质（74.3%）增加。对次级代谢产物如醉茄内酯、醉茄素 A 和总生物碱的高效薄层色谱（HPTLC）分析表明，与对照相比，患病叶片中的醉茄素 A 和醉茄内酯含量分别下降了 15.4%和 76.3%，而总生物碱含量增加了 49.3%，这是在睡茄中尚未报道的信息。
