Dissertation Research: Effects of legume-rhizobia symbiosis on plant-insect interactions

豆科植物和固氮根瘤菌之间的协同进化互惠关系的特点是能够增加土壤肥力。 虽然豆科植物根瘤菌相互作用的许多方面已经得到很好的表征，很少有人知道这种互利共生对其他生物，特别是草食动物的影响。 豆科植物接种根瘤菌后引起的生理变化可能会改变植物防御和宿主的营养品质。 此外，这些影响的性质和强度可能因根瘤菌菌株而异，因此可能赋予宿主植物不同水平的抗性。 本项目的目标是：1）描述根瘤菌对不同取食生态位的食草动物的影响; 2）确定接种如何改变植物对食草动物的反应; 3）区分根瘤菌菌株特异性对植物对食草动物抗性的影响。 实验将在从根瘤菌、硝酸盐肥料或两者的组合中接受氮的大豆植株上进行。本研究将为了解草食动物在豆科植物-根瘤菌共生进化中的作用提供新的视角。 探索根瘤菌保护宿主植物免受食草动物侵害的机制可能有助于开发新型和更有效的作物接种剂，从而有助于可持续农业实践。

The coevolved mutualism between legumes and nitrogen fixing rhizobia bacteria is distinguished by its capacity to increase soil fertility. While many aspects of the legume-rhizobia interaction have been well-characterized, little is known about the effects of this mutualism on other organisms, particularly herbivores. Physiological changes induced in legume plants upon inoculation with rhizobia may alter plant defenses and nutritional quality of the host. Moreover, the nature and intensity of such effects may vary across rhizobial strains, which may thus confer different levels of resistance to host plants. The objectives of this project are to: 1) characterize the effects of rhizobia on the performance of herbivores from different feeding niches; 2) determine how plant responses to herbivory are altered by inoculation; and 3) distinguish rhizobia strain-specific effects on plant resistance to herbivores. Experiments will be performed on soybean plants receiving nitrogen from rhizobia, nitrate fertilizers, or a combination of the two. This study will provide new insights into the role of herbivores in the evolution of the legume-rhizobia mutualism. Exploring mechanisms by which rhizobia may protect host plants from herbivores may facilitate the development of novel and more efficient inoculants for crop plants and thus contribute to sustainable agricultural practices.