植物促生真菌具有产生生物活性物质、促进植物生长以及增强植物免疫抗性的能力，其作为有应用价值的有益微生物在作物栽培中受到越来越多关注。本研究从健康番茄植株根际土壤中分离筛选到一株木霉菌株TM2-4，将其鉴定为非洲哈茨木霉（Trichoderma afroharzianum）。菌株TM2-4发酵滤液中含有多种生物活性物质且对番茄种子发芽具有明显促进作用，发酵滤液100倍稀释液处理，番茄胚轴、胚根长度，种子活力指数分别增加28.7%、19.4% 和 62.1%。为了评价菌株TM2-4的促生作用及其相关机制，通过盆栽试验和转录组测序分析了非洲哈茨木霉菌制剂TM2-4处理对番茄植株生物学指标和基因表达型的影响。结果表明，非洲哈茨木霉TM2-4能够通过在植株根际土壤和根系有效定殖，显著提高番茄株高、干重、单株叶片数及根系活力等生物学指标。转录组分析发现，木霉菌制剂处理番茄根系较对照共获得984个差异表达基因，主要集中在激素平衡、抗氧化活性以及苯丙烷类生物合成和谷胱甘肽代谢等生物学过程。相关研究结果为阐明菌株TM2-4对番茄的促生作用机制提供有效信息，并为非洲哈茨木霉微生物菌剂在蔬菜作物生产中的进一步开发应用奠定理论基础。

Spermidine (Spd) is known to be involved in the regulation of plant responses to chilling stress and counteract the adverse effect of stress conditions. Antioxidant activities, endogenous hormones and ultrastructure change under chilling stress were investigated in indica-japonica hybrid rice seedlings. 12-d-old seedlings were subjected to exogenous Spd (1 mmol L–1) and then a chilling stress (6°C, 4 d) was induced, followed by a subsequent recovery (25°C, 4 d). Results showed that malondialdehyde (MDA) and proline content were enhanced significantly, whereas shoot fresh and dry weights decreased during chilling stress and after recovery; chlorophyll content of chilling-stressed seedlings increased slightly but declined after recovery; additionally, total soluble sugar, sucrose, fructose and starch contents increased significantly during chilling stress, and only soluble sugar and fructose contents were observed in increase after recovery; chilling stress-induced increases in superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities, but declined after recovery, and the level of ascorbate peroxidase was lower during chilling stress and after recovery; however, endogenous indole-3-acetic acid (IAA), zeatin riboside (ZR), gibberellic acid (GA3), and abscisic acid (ABA) levels were induced decreased compared with Spd pretreatment. The microscopic analysis revealed that chilling stress-induced destruction of the chloroplast envelope during chilling stress and increased the number of plastoglobuli along with aberrations in thylakoid membranes after recovery. In contrast, exogenous Spd protected rice seedlings from chilling-induced injuries in terms of lower malondialdehyde, proline and carbohydrates accumulation coupled with increased endogenous hormones metabolism. After recovery, Spd pretreatment chilling-exposed seedlings showed higher activities of antioxidant enzymes and normal physiological function of chloroplasts. These results suggest that Spd could promote effectively chilling tolerance which might be largely attributable to the integrity of cell structure and normal metabolism of endogenous hormones in indica-japonica hybrid rice seedlings.