The plant growth-promoting rhizobacterium Azospirillum brasilense reduces symptoms and aphid population growth on wheat plants infected with Barley yellow dwarf virus

There is increasing interest in the potential of plant growth-promoting rhizobacteria (PGPR) in agriculture to improve plant quality and control pests and diseases. Emerging evidence indicates that some PGPR can influence interactions between plants and their pathogens, while less work has explored whether PGPR may also influence interactions between plants and arthropod vectors. We address this issue in a major agricultural pathosystem involving wheat infection by Barley yellow dwarf virus (BYDV), the most economically important aphid-transmitted viral disease of cereal crops. We found that plant association with the PGPR Azospirillum brasilense mitigated both viral effects on plant growth and population growth of the BYDV aphid vector, Rhopalosiphum padi. Although effects varied across A. brasilense strains, PGPR treatments that attenuated virus effects were also associated with reduced induction of salicylic acid in response to infection, suggesting PGPR inoculation may induce systemic resistance against BYDV. These findings suggest that PGPR may have significant capacity for application in the sustainable management of crop growth. However, further investigation of the complex interactions among PGPR, plants, pathogens, and their vectors is needed to better understand this potential.

目前，学界对农业领域中植物促生根际细菌（plant growth-promoting rhizobacteria, PGPR）改善植物品质、防控病虫害的应用潜力愈发关注。越来越多的研究证据表明，部分PGPR可调控植物与其病原物之间的互作，但针对PGPR是否会影响植物与节肢动物传毒介体之间的互作，相关探索仍较为匮乏。本研究以一个重要的农业病害系统为研究对象，该系统涵盖小麦受大麦黄矮病毒（Barley yellow dwarf virus, BYDV）侵染的场景——大麦黄矮病毒是谷类作物中经济重要性最高的蚜传病毒性病害。研究发现，与植物共生的巴西固氮螺菌（Azospirillum brasilense）可同时缓解病毒对植物生长的不利影响，以及大麦黄矮病毒的传毒介体禾谷缢管蚜（Rhopalosiphum padi）的种群增长。尽管不同巴西固氮螺菌菌株的作用效果存在差异，但能够减弱病毒危害的PGPR处理，同时也与植物受侵染后水杨酸（salicylic acid）诱导水平的降低相关，这提示PGPR接种或可诱导植物产生针对大麦黄矮病毒的系统抗性。上述研究结果表明，PGPR在作物生长的可持续管理中具备显著的应用潜力。不过，为更深入地阐明这一应用潜力，仍需进一步探究PGPR、植物、病原物及其传毒介体之间的复杂互作关系。