Serteyn Laurent, Quaghebeur Céleste, Ongena Marc, Cabrera Nuri, Barrera Andrea, Molina-Montenegro Marco A, Francis Frédéric, Ramírez Claudio C
Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liege, Passage des Déportés 2, B-5030 Gembloux, Belgium.
Microbial Processes and Interactions Research Unit, Gembloux Agro-Bio Tech, University of Liege, B-5030 Gembloux, Belgium.
Insects. 2020 Apr 8;11(4):234. doi: 10.3390/insects11040234.
The effects of microorganisms on plant-insect interactions have usually been underestimated. While plant growth-promoting rhizobacteria (PGPR) are known to induce plant defenses, endosymbiotic bacteria hosted by herbivorous insects are often beneficial to the host. Here, we aimed to assess whether PGPR-induced defenses in broad bean plants impact the pea aphid, depending on its genotype and the presence of endosymbionts. We estimated aphid reproduction, quantified defense- and growth-related phytohormones by GC-MS, and measured different plant growth and physiology parameters, after PGPR treatment. In addition, we recorded the feeding behavior of aphids by electropenetrography. We found that the PGPR treatment of broad bean plants reduced the reproduction of one of the pea aphid clones. We highlighted a phenomenon of PGPR-induced plant defense priming, but no noticeable plant growth promotion. The main changes in aphid probing behavior were related to salivation events into phloem sieve elements. We suggest that the endosymbiont played a key role in plant-insect interactions, possibly helping aphids to counteract plant-induced resistance and allowing them to develop normally on PGPR-treated plants. Our results imply that plant- and aphid-associated microorganisms add greater complexity to the outcomes of aphid-plant interactions.
微生物对植物与昆虫相互作用的影响通常被低估了。虽然已知促植物生长的根际细菌（PGPR）能诱导植物防御，但植食性昆虫体内的共生细菌通常对宿主有益。在此，我们旨在评估蚕豆植株中PGPR诱导的防御是否会影响豌豆蚜，这取决于豌豆蚜的基因型和共生菌的存在情况。在PGPR处理后，我们估计了蚜虫的繁殖情况，通过气相色谱 - 质谱联用仪对与防御和生长相关的植物激素进行了定量，并测量了不同的植物生长和生理参数。此外，我们通过刺探电位图谱记录了蚜虫的取食行为。我们发现，对蚕豆植株进行PGPR处理会降低其中一个豌豆蚜克隆的繁殖率。我们突出了PGPR诱导植物防御引发的现象，但未发现明显的植物生长促进作用。蚜虫刺探行为的主要变化与向韧皮部筛管元素的唾液分泌事件有关。我们认为共生菌在植物与昆虫的相互作用中起关键作用，可能帮助蚜虫抵消植物诱导的抗性，使其能够在经PGPR处理的植株上正常发育。我们的结果表明，与植物和蚜虫相关的微生物使蚜虫与植物相互作用的结果更加复杂。
