Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig, 44519, Egypt.
BMC Plant Biol. 2024 Feb 17;24(1):118. doi: 10.1186/s12870-024-04785-3.
Spot blotch is a serious foliar disease of barley (Hordeum vulgare L.) plants caused by Bipolaris sorokiniana, which is a hemibiotrophic ascomycete that has a global impact on productivity. Some Trichoderma spp. is a promising candidate as a biocontrol agent as well as a plant growth stimulant. Also, the application of nanomaterials in agriculture limits the use of harmful agrochemicals and helps improve the yield of different crops. The current study was carried out to evaluate the effectiveness of Trichoderma. cf. asperellum and the biosynthesized titanium dioxide nanoparticles (TiO NPs) to manage the spot blotch disease of barley caused by B. sorokiniana and to assess the plant's innate defense response.
Aloe vera L. aqueous leaf extract was used to biosynthesize TiO NPs by reducing TiCl salt into TiO NPs and the biosynthesized NPs were detected using SEM and TEM. It was confirmed that the NPs are anatase-crystalline phases and exist in sizes ranging from 10 to 25 nm. The T. cf. asperellum fungus was detected using morphological traits and rDNA ITS analysis. This fungus showed strong antagonistic activity against B. sorokiniana (57.07%). Additionally, T. cf. asperellum cultures that were 5 days old demonstrated the best antagonistic activity against the pathogen in cell-free culture filtrate. Also, B. sorokiniana was unable to grow on PDA supplemented with 25 and 50 mg/L of TiO NPs, and the diameter of the inhibitory zone increased with increasing TiO NPs concentration. In an in vivo assay, barley plants treated with T. cf. asperellum or TiO NPs were used to evaluate their biocontrol efficiency against B. sorokiniana, in which T. cf. asperellum and TiO NPs enhanced the growth of the plant without displaying disease symptoms. Furthermore, the physiological and biochemical parameters of barley plants treated with T. cf. asperellum or TiO NPs in response to B. sorokiniana treatment were quantitively estimated. Hence, T. cf. asperellum and TiO NPs improve the plant's tolerance and reduce the growth inhibitory effect of B. sorokiniana.
Subsequently, T. cf. asperellum and TiO NPs were able to protect barley plants against B. sorokiniana via enhancement of chlorophyll content, improvement of plant health, and induction of the barley innate defense system. The present work emphasizes the major contribution of T. cf. asperellum and the biosynthesized TiO NPs to the management of spot blotch disease in barley plants, and ultimately to the enhancement of barley plant quality and productivity.
斑点病是一种严重的大麦（Hordeum vulgare L.）叶片病害，由旋孢腔菌（Bipolaris sorokiniana）引起，旋孢腔菌是一种半活体真菌，对生产力有全球性影响。一些木霉属（Trichoderma spp.）是一种有前途的生物防治剂候选物，同时也是一种植物生长刺激剂。此外，纳米材料在农业中的应用限制了有害农药的使用，并有助于提高不同作物的产量。本研究旨在评估木霉。cf. asperellum 和生物合成的二氧化钛纳米颗粒（TiO NPs）对大麦由旋孢腔菌引起的斑点病的防治效果，并评估植物的先天防御反应。
使用库拉索芦荟（Aloe vera L.）叶的水提物通过将 TiCl 盐还原为 TiO NPs 来生物合成 TiO NPs，并用 SEM 和 TEM 检测生物合成的 NPs。证实 NPs 为锐钛矿结晶相，存在于 10 至 25 nm 的尺寸范围内。木霉属真菌通过形态特征和 rDNA ITS 分析来检测。该真菌对旋孢腔菌（B. sorokiniana）表现出强烈的拮抗活性（57.07%）。此外，在无细胞培养滤液中，培养 5 天的木霉属真菌表现出对病原菌的最佳拮抗活性。此外，在补充有 25 和 50 mg/L TiO NPs 的 PDA 上，旋孢腔菌无法生长，并且随着 TiO NPs 浓度的增加，抑菌圈直径增大。在体内试验中，使用木霉属真菌（T. cf. asperellum）或 TiO NPs 处理大麦植物以评估其对旋孢腔菌的生物防治效率，其中木霉属真菌（T. cf. asperellum）和 TiO NPs 增强了植物的生长而没有表现出疾病症状。此外，定量估计了用 T. cf. asperellum 或 TiO NPs 处理的大麦植物对旋孢腔菌处理的生理和生化参数。因此，T. cf. asperellum 和 TiO NPs 提高了植物的耐受性并降低了旋孢腔菌的生长抑制作用。
随后，T. cf. asperellum 和 TiO NPs 通过增强叶绿素含量、改善植物健康状况和诱导大麦先天防御系统来保护大麦植物免受旋孢腔菌的侵害。本工作强调了木霉属真菌（T. cf. asperellum）和生物合成的 TiO NPs 对大麦斑点病防治的重要贡献，最终提高了大麦植物的质量和生产力。
