The beneficial associations between Arachis hypogaea L. (peanut) and fluorescent Pseudomonas species have been poorly explored despite their predominance in the peanut rhizosphere. The present study explores the mutually beneficial interactions between peanut roots and P. aeruginosa P4 (P4) in terms of their impact on plant growth, defence physiology and the root-rhizobacterial interface. The efficient phosphate solubilizer P4 exhibited biocontrol abilities, including the production of siderophores, pyocyanin, indole-3-acetic acid and hydrogen cyanide. The bacterization of peanut seeds with multi-potential P4 significantly enhanced in vitro seed germination and seedling vigour. Under sand-based gnotobiotic (10 days post-inoculation) and sterile soil-based cultivation systems (30 days post-inoculation), sustained P4 colonization enhanced the peanut root length and dry plant biomass. The subsequent increase in catalase, polyphenol oxidase and phenylalanine ammonia lyase activities with increased phenolic contents in the peanut roots and shoots suggested the systemic priming of defences. Consequently, the altered root exudate composition caused enhanced chemo-attraction towards P4 itself and the symbiotic N2-fixing Bradyrhizobium strain. Co-inoculating peanuts with P4 and Bradyrhizobium confirmed the improved total bacterial colonization (∼2 fold) of the root tip, with the successful co-localization of both, as substantiated by scanning electron microscopy. Collectively, the peanut-P4 association could potentially model the beneficial Pseudomonas-driven multi-trophic rhizosphere benefits, emphasizing the plausible role of non-rhizobium PGPR in promoting N2 fixation.

中文翻译：

---

多潜能铜绿假单胞菌 P4 的定植刺激花生 (Arachis hypogaea L.) 生长、防御生理和根系统功能，以有益于根 - 根际细菌界面

尽管 Arachis hypogaea L.（花生）和荧光假单胞菌物种在花生根际占主导地位，但它们之间的有益关联尚未得到很好的探索。本研究探讨了花生根和铜绿假单胞菌 P4 (P4) 之间对植物生长、防御生理和根 - 根际细菌界面的影响的互利相互作用。高效的磷酸盐增溶剂 P4 表现出生物防治能力，包括产生铁载体、绿脓素、吲哚-3-乙酸和氰化氢。用多潜能P4对花生种子进行杀菌显着增强了离体种子发芽和幼苗活力。在沙基无菌（接种后 10 天）和无菌土壤栽培系统（接种后 30 天）下，持续的 P4 定植增强了花生根长和干植物生物量。随后随着花生根和芽中酚类含量的增加，过氧化氢酶、多酚氧化酶和苯丙氨酸解氨酶活性的增加表明防御系统启动。因此，改变的根系分泌物成分导致对 P4 本身和共生 N2 固定慢生根瘤菌菌株的化学吸引力增强。用 P4 和慢生根瘤菌共接种花生证实了根尖总细菌定植的改善（~2 倍），两者成功共定位，扫描电子显微镜证实了这一点。总的来说，花生-P4 关联可以潜在地模拟有益的假单胞菌驱动的多营养根际效益，