Consiglio per la Ricerca in Agricoltura e l'Analisi dell'Economia Agraria, Centro di Ricerca Difesa e Certificazione, Via C.G. Bertero, 22, 00156 Roma, Italy.
Università Sapienza, Dip. Biologia Ambientale, P.le Aldo Moro 5, 00185 Roma, Italy.
Biomolecules. 2020 Apr 14;10(4):608. doi: 10.3390/biom10040608.
The Septoria Leaf Blotch Complex (SLBC), caused by the two ascomycetes Zymoseptoria tritici and Parastagonospora nodorum, can reduce wheat global yearly yield by up to 50%. In the last decade, SLBC incidence has increased in Italy; notably, durum wheat has proven to be more susceptible than common wheat. Field fungicide treatment can efficiently control these pathogens, but it leads to the emergence of resistant strains and adversely affects human and animal health and the environment. Our previous studies indicated that active compounds produced by Trametes versicolor can restrict the growth of mycotoxigenic fungi and the biosynthesis of their secondary metabolites (e.g., mycotoxins). Specifically, we identified Tramesan: a 23 kDa α-heteropolysaccharide secreted by T. versicolor that acts as a pro-antioxidant molecule in animal cells, fungi, and plants. Foliar-spray of Tramesan (3.3 μM) on SLBC-susceptible durum wheat cultivars, before inoculation of causal agents of Stagonospora Nodorum Blotch (SNB) and Septoria Tritici Blotch (STB), significantly decreased disease incidence both in controlled conditions (SNB: -99%, STB: -75%) and field assays (SNB: -25%, STB: -30%). We conducted these tests were conducted under controlled conditions as well as in field. We showed that Tramesan increased the levels of jasmonic acid (JA), a plant defense-related hormone. Tramesan also increased the early expression (24 hours after inoculation - hai) of plant defense genes such as PR4 for SNB infected plants, and RBOH, PR1, and PR9 for STB infected plants. These results suggest that Tramesan protects wheat by eliciting plant defenses, since it has no direct fungicidal activity. In field experiments, the yield of durum wheat plants treated with Tramesan was similar to that of healthy untreated plots. These results encourage the use of Tramesan to protect durum wheat against SLBC.
叶斑病复合病（SLBC）由两种子囊菌禾旋孢腔菌（Zymoseptoria tritici）和尾孢叶斑病菌（Parastagonospora nodorum）引起，可使全球小麦年产量减少多达 50%。在过去的十年中，意大利的 SLBC 发病率有所增加；值得注意的是，硬粒小麦比普通小麦更容易感染。田间杀菌剂处理可以有效地控制这些病原体，但会导致抗药性菌株的出现，对人类和动物健康以及环境产生不利影响。我们之前的研究表明，彩绒革盖菌产生的活性化合物可以限制产毒真菌的生长和次生代谢物（如霉菌毒素）的生物合成。具体来说，我们鉴定出了 Tramesan：彩绒革盖菌分泌的一种 23 kDa 的α-杂多糖，在动物细胞、真菌和植物中作为一种前抗氧化剂分子。在接种尾孢叶斑病菌（SNB）和叶枯病菌（STB）之前，用 3.3 μM 的 Tramesan 对 SLBC 敏感的硬粒小麦品种进行叶面喷雾，在对照条件下（SNB：-99%，STB：-75%）和田间试验中（SNB：-25%，STB：-30%）显著降低了病害发生率。我们在对照条件和田间条件下进行了这些测试。我们表明，Tramesan 增加了茉莉酸（JA）的水平，JA 是一种与植物防御相关的激素。Tramesan 还增加了 SNB 感染植物的 PR4 等植物防御基因以及 STB 感染植物的 RBOH、PR1 和 PR9 的早期表达（接种后 24 小时 - hai）。这些结果表明，Tramesan 通过诱导植物防御来保护小麦，因为它没有直接的杀菌活性。在田间试验中，用 Tramesan 处理的硬粒小麦植株的产量与未处理的健康对照田块相似。这些结果鼓励使用 Tramesan 来保护硬粒小麦免受 SLBC 的侵害。
