Centre for Agriculture, Food and Environmental Management Research, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, UK.
Disease and Pest Management, ADAS Boxworth, Cambridge, UK.
Pest Manag Sci. 2024 May;80(5):2416-2425. doi: 10.1002/ps.7275. Epub 2022 Nov 29.
Phoma stem canker is caused by two coexisting pathogens, Leptosphaeria maculans and L. biglobosa. They coexist because of their temporal and spatial separations, which are associated with the differences in timing of their ascospore release. L. maculans produces sirodesmin PL, while L. biglobosa does not. However, their interaction/coexistence in terms of secondary metabolite production is not understood.
Secondary metabolites were extracted from liquid cultures, L. maculans only (Lm only), L. biglobosa only (Lb only), L. maculans and L. biglobosa simultaneously (Lm&Lb) or sequentially 7 days later (Lm+Lb). Sirodesmin PL or its precursors were identified in extracts from 'Lm only' and 'Lm+Lb', but not from 'Lm&Lb'. Metabolites from 'Lb only', 'Lm&Lb' or 'Lm+Lb' caused significant reductions in L. maculans colony area. However, only the metabolites containing sirodesmin PL caused a significant reduction to L. biglobosa colony area. When oilseed rape cotyledons were inoculated with conidia of 'Lm only', 'Lb only' or 'Lm&Lb', 'Lm only' produced large gray lesions, while 'Lm&Lb' produced small dark lesions similar to lesions caused by 'Lb only'. Sirodesmin PL was found only in the plant extracts from 'Lm only'. These results suggest that L. biglobosa prevents the production of sirodesmin PL and its precursors by L. maculans when they grow simultaneously in vitro or in planta.
For the first time, L. biglobosa has been shown to inhibit the production of sirodesmin PL by L. maculans when interacting simultaneously with L. maculans either in vitro or in planta. This antagonistic effect of interspecific interaction may affect their coexistence and subsequent disease progression and management. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
茎溃疡病是由两种共存的病原体引起的，即菜豆壳球腔菌（Leptosphaeria maculans）和大茎点霉（L. biglobosa）。它们之所以共存，是因为它们在时间和空间上的分离，这与它们分生孢子释放的时间差异有关。菜豆壳球腔菌产生西罗母 PL，而大茎点霉则不产生。然而，它们在次生代谢产物产生方面的相互作用/共存尚不清楚。
从液体培养物中提取了次生代谢产物，仅来自菜豆壳球腔菌（Lm only）、仅来自大茎点霉（Lb only）、同时来自菜豆壳球腔菌和大茎点霉（Lm&Lb）或 7 天后顺序来自（Lm+Lb）。在“Lm only”和“Lm+Lb”的提取物中鉴定出了西罗母 PL 或其前体，但在“Lm&Lb”中没有。仅来自大茎点霉（Lb only）、“Lm&Lb”或“Lm+Lb”的代谢产物显著减少了菜豆壳球腔菌菌落面积。然而，只有含有西罗母 PL 的代谢产物才能显著减少大茎点霉的菌落面积。当油菜子叶接种菜豆壳球腔菌“Lm only”、大茎点霉“Lb only”或“Lm&Lb”的分生孢子时，“Lm only”产生大的灰色病变，而“Lm&Lb”产生类似于“Lb only”引起的小的暗病变。仅在“Lm only”的植物提取物中发现西罗母 PL。这些结果表明，当大茎点霉与菜豆壳球腔菌同时在体外或体内生长时，大茎点霉会阻止菜豆壳球腔菌产生西罗母 PL 及其前体。这种种间相互作用的拮抗作用可能会影响它们的共存以及随后的疾病进展和管理。© 2022 作者。害虫管理科学由 John Wiley & Sons Ltd 代表化学工业协会出版。
