Islam S Z, Honda Y, Sonhaji M
Graduate Student.
Professor, Faculty of Life and Environmental Science.
Plant Dis. 1998 Aug;82(8):850-856. doi: 10.1094/PDIS.1998.82.8.850.
The germ tubes of Botrytis cinerea showed negative phototropism to near ultraviolet (NUV) and blue (300 to 520 nm) light followed by far-red (700 to 810 nm), whereas red light (600 to 700 nm) induced positive phototropism significantly. Minimum germ tube growth occurred during exposure to negative phototropism-inducing wavelengths, whereas it was maximum under positive phototropism-inducing wavelengths. NUV radiation and blue light that induced negative phototropism of B. cinerea promoted infection-hypha formation on both onion scale and broad bean (Vicia faba) leaf epidermal strips, whereas positive phototropism-inducing red light suppressed it, resulting in a high proportion of germ tubes without infection hyphae. In broad bean leaf infection, the number of infection points and area of necrosis per drop of conidial suspension were higher under NUV radiation and blue light than that of a dark control or leaflets pretreated with NUV radiation and blue light. In contrast, lower numbers of infection points and very small necrotic lesions developed under red light. In the case of red-light-pretreated leaflets, the number of infection points developed were higher, but areas of necrosis did not increase significantly compared with leaflets kept under red light without pretreatment. These results show the importance of phototropism of conidium germ tubes in plant infection.
灰葡萄孢的芽管对近紫外光（NUV）和蓝光（300至520纳米）表现出负向光性，其次是远红光（700至810纳米），而红光（600至700纳米）则显著诱导正向光性。在暴露于诱导负向光性的波长期间，芽管生长最少，而在诱导正向光性的波长下生长最多。诱导灰葡萄孢负向光性的NUV辐射和蓝光促进了洋葱鳞片和蚕豆（蚕豆）叶片表皮条上侵染菌丝的形成，而诱导正向光性的红光则抑制了它，导致大量芽管没有侵染菌丝。在蚕豆叶片感染中，在NUV辐射和蓝光下，每滴分生孢子悬浮液的感染点数量和坏死面积高于黑暗对照或经NUV辐射和蓝光预处理的小叶。相比之下，在红光下感染点数量较少，坏死病变非常小。对于经红光预处理的小叶，与未经预处理而置于红光下的小叶相比，形成的感染点数量较多，但坏死面积没有显著增加。这些结果表明分生孢子芽管的向光性在植物感染中的重要性。
