Rhizosphere bacteria, whether phytopathogenic or phytobeneficial, are thought to be perceived by the plant as a threat. Plant Growth-Promoting Rhizobacteria (PGPR), such as many strains of the Azospirillum genus known as the main phytostimulator of cereals, cooperate with host plants and favorably affect their growth and health. An earlier study of rice root transcriptome, undertaken with two rice cultivars and two Azospirillum strains, revealed a strain-dependent response during the rice-Azospirillum association and showed that only a few genes, including some implicated in plant defense, were commonly regulated in all tested conditions. Here, a set of genes was selected from previous studies and their expression was monitored by qRT-PCR in rice roots inoculated with ten PGPR strains isolated from various plants and belonging to various genera (Azospirillum, Herbaspirillum, Paraburkholderia). A common expression pattern was highlighted for four genes that are proposed to be markers of the rice-PGPR interaction: two genes involved in diterpenoid phytoalexin biosynthesis (OsDXS3 and OsDTC2) and one coding for an uncharacterized protein (Os02g0582900) were significantly induced by PGPR whereas one defense-related gene encoding a pathogenesis-related protein (PR1b, Os01g0382000) was significantly repressed. Interestingly, exposure to a rice bacterial pathogen also triggered the expression of OsDXS3 while the expression of Os02g0582900 and PR1b was down-regulated, suggesting that these genes might play a key role in rice-bacteria interactions. Integration of these results with previous data led us to propose that the jasmonic acid signaling pathway might be triggered in rice roots upon inoculation with PGPR.

根际细菌，无论是植物病原菌还是植物有益菌，都被植物视为一种威胁。促进植物生长的根际细菌 (PGPR)，例如被称为谷物主要植物刺激剂的固氮螺菌属的许多菌株，与寄主植物合作并有利地影响它们的生长和健康。稻根转录的早先的研究中，用两个水稻品种和两个进行固氮螺菌的菌株，揭示了米通期间的应变依赖性的响应固氮螺菌关联并表明只有少数基因，包括一些与植物防御有关的基因，在所有测试条件下通常受到调控。在这里，从以前的研究中选择了一组基因，并通过 qRT-PCR 在水稻根中监测它们的表达，水稻根部接种了从各种植物中分离出来的 10 种 PGPR 菌株，属于各种属（固氮螺菌属、草本螺旋菌属、帕拉伯克霍尔德菌属）。四个基因的共同表达模式被强调为水稻-PGPR相互作用的标记：两个参与二萜类植物抗毒素生物合成的基因（OsDXS3和OsDTC2）和一个编码未表征蛋白质的基因（Os02g0582900) 被 PGPR 显着诱导，而一种编码发病机制相关蛋白 (PR1b, Os01g0382000 ) 的防御相关基因被显着抑制。有趣的是，暴露于水稻细菌病原体也触发了OsDXS3的表达，而Os02g0582900和PR1b的表达下调，表明这些基因可能在水稻-细菌相互作用中起关键作用。将这些结果与之前的数据相结合，我们提出可能在接种 PGPR 后在水稻根部触发茉莉酸信号通路。