Departamento de Biologia Vegetal, Universidade Federal de Viçosa (UFV), Viçosa, MG, 36570-900, Brasil.
Laboratório da Interação Planta-Patógeno, Departamento de Fitopatologia, UFV, Viçosa, MG, 36570-900, Brasil.
Planta. 2020 Jul 16;252(2):24. doi: 10.1007/s00425-020-03428-9.
The infection of wheat leaves by Pyricularia oryzae induced remarkable reprogramming of the primary metabolism (amino acids, sugars, and organic acids) in favor of a successful fungal infection and certain changes were conserved among cultivars regardless of their level of resistance to blast. Wheat blast, caused by Pyricularia oryzae, has become one of the major threats for food security worldwide. Here, we investigated the behavior of three wheat cultivars (BR-18, Embrapa-16, and BRS-Guamirim), differing in their level of resistance to blast, by analyzing changes in cellular damage, antioxidative metabolism, and defense compounds as well as their photosynthetic performance and metabolite profile. Blast severity was lower by 45 and 33% in Embrapa-16 and BR-18 cultivars (moderately resistant), respectively, at 120 h after inoculation in comparison to BRS-Guamirim cultivar (susceptible). Cellular damage caused by P. oryzae infection was great in BRS-Guamirim compared to BR-18. The photosynthetic performance of infected plants was altered due to diffusional and biochemical limitations for CO fixation. At the beginning of the infection process, dramatic changes in both carbohydrate metabolism and on the levels of amino acids, intermediate compounds of the tricarboxylic acid cycle, and polyamines were noticed regardless of cultivar suggesting an extensive metabolic reprogramming of the plants following fungal infection. Nevertheless, Embrapa-16 plants displayed a more robust and efficient antioxidant metabolism, higher phenylalanine ammonia-lyase and polyphenoloxidase activities and higher concentrations of phenolics and lignin, which, altogether, helped them to counteract more efficiently the infection by P. oryzae. Our results demonstrated that P. oryzae infection significantly modified the metabolism of wheat plants and different types of metabolic defence may act both additively and synergistically to provide additional plant protection to blast.
稻瘟病菌感染小麦叶片导致初级代谢（氨基酸、糖和有机酸）显著重编程，有利于真菌成功感染，而某些变化在不同品种中是保守的，无论其对穗瘟的抗性水平如何。稻瘟病由稻瘟病菌引起，已成为全球粮食安全的主要威胁之一。在这里，我们通过分析细胞损伤、抗氧化代谢和防御化合物以及光合作用性能和代谢物谱的变化，研究了三个小麦品种（BR-18、Embrapa-16 和 BRS-Guamirim）的行为，它们在对穗瘟的抗性水平上存在差异。与易感品种 BRS-Guamirim 相比，接种后 120 小时，中度抗性品种 Embrapa-16 和 BR-18 的穗瘟严重程度分别降低了 45%和 33%。与 BR-18 相比，稻瘟病菌感染引起的细胞损伤在 BRS-Guamirim 中更为严重。由于 CO2 固定的扩散和生化限制，感染植物的光合作用性能发生了改变。在感染过程的开始阶段，无论品种如何，碳水化合物代谢和氨基酸、三羧酸循环中间化合物和多胺水平都发生了剧烈变化，这表明真菌感染后植物发生了广泛的代谢重编程。然而，Embrapa-16 植物表现出更强壮和有效的抗氧化代谢，更高的苯丙氨酸解氨酶和多酚氧化酶活性，以及更高浓度的酚类和木质素，这一切都有助于它们更有效地对抗稻瘟病菌的感染。我们的研究结果表明，稻瘟病菌感染显著改变了小麦植物的代谢，不同类型的代谢防御可能会起到累加和协同作用，为穗瘟提供额外的植物保护。
