Guerrero-Molina M F, Lovaisa N C, Salazar S M, Martínez-Zamora M G, Díaz-Ricci J C, Pedraza R O
Facultad de Agronomía y Zootecnia, Universidad Nacional de Tucumán, San Miguel de Tucumán, Tucumán, Argentina; Facultad de Bioquímica, Química y Farmacia, Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, and Instituto de Química Biológica "Dr. Bernabé Bloj", San Miguel de Tucumán, Tucumán, Argentina.
Plant Biol (Stuttg). 2015 May;17(3):766-73. doi: 10.1111/plb.12270. Epub 2014 Dec 24.
The plant growth-promoting strain REC3 of Azospirillum brasilense, isolated from strawberry roots, prompts growth promotion and systemic protection against anthracnose disease in this crop. Hence, we hypothesised that A. brasilense REC3 can induce different physiological, structural and molecular responses in strawberry plants. Therefore, the aim of this work was to study these traits activated in Azospirillum-colonised strawberry plants, which have not been assessed until now. Healthy, in vitro micropropagated plants were root-inoculated with REC3 under hydroponic conditions; root and leaf tissues were sampled at different times, and oxidative burst, phenolic compound content, malondialdehyde (MDA) concentration, callose deposition, cell wall fortification and gene expression were evaluated. Azospirillum inoculation enhanced levels of soluble phenolic compounds after 12 h post-inoculation (hpi), while amounts of cell wall bound phenolics were similar in inoculated and control plants. Other early responses activated by REC3 (at 24 hpi) were a decline of lipid peroxidation and up-regulation of strawberry genes involved in defence (FaPR1), bacterial recognition (FaFLS2) and H₂O₂ depuration (FaCAT and FaAPXc). The last may explain the apparent absence of oxidative burst in leaves after bacterial inoculation. Also, REC3 inoculation induced delayed structural responses such as callose deposition and cell wall fortification (at 72 hpi). Results showed that A. brasilense REC3 is capable of exerting beneficial effects on strawberry plants, reinforcing their physiological and cellular characteristics, which in turns contribute to improve plant performance.
从草莓根部分离得到的巴西固氮螺菌促植物生长菌株REC3，能促进草莓生长并对该作物的炭疽病提供系统保护。因此，我们推测巴西固氮螺菌REC3可在草莓植株中诱导不同的生理、结构和分子反应。所以，本研究的目的是探究定殖有固氮螺菌的草莓植株中激活的这些特性，此前尚未对其进行评估。在水培条件下，将健康的离体微繁植株用REC3进行根部接种；在不同时间采集根和叶组织样本，并评估氧化爆发、酚类化合物含量、丙二醛（MDA）浓度、胼胝质沉积、细胞壁强化和基因表达。接种固氮螺菌后12小时（hpi），可溶性酚类化合物水平升高，而接种植株和对照植株中细胞壁结合酚类物质的含量相似。REC3激活的其他早期反应（在24 hpi）包括脂质过氧化作用减弱以及草莓中参与防御（FaPR1）、细菌识别（FaFLS2）和H₂O₂净化（FaCAT和FaAPXc）的基因上调。最后一点可能解释了细菌接种后叶片中明显没有氧化爆发的现象。此外，REC3接种诱导了延迟的结构反应，如胼胝质沉积和细胞壁强化（在72 hpi）。结果表明，巴西固氮螺菌REC3能够对草莓植株产生有益影响，增强其生理和细胞特性，进而有助于提高植株性能。
