Abstract: Plants are able to establish beneficial interactions with bacteria and fungi. In this symposium we will tackle three major interactions. The most well known of them is the legume-rhizobium symbiosis. We will present an overview of nitrogen fixation and the requirements of antioxidants and hemoglobins for this highly beneficial process for agriculture and the environment. Particular emphasis will be placed on the homeostasis of reactive oxygen and nitrogen species and their signaling roles, and on the participation of hemoglobins in oxygen transport and nitric oxide modulation in nodules and other plant organs. Another interaction is the arbuscular mycorrhizal symbiosis, which has multiple benefits for the plant, from improved nutrient acquisition to enhanced resistance to stresses. This resistance is associated to an improved ability to activate defense by increasing plant metabolic and phenotypic plasticity upon challenge. Using pharmacological, genetic and omics approaches, we will analyze how mycorrhizal tomato plants prime defense responses to cope with stresses and the role of phytohormone signaling in the primed response. We will focus on how mycorrhization can increase plant resistance to herbivore insects, fine-tuning plant primary and secondary metabolism, and how the effects can cascade up other trophic levels. A third interaction involves endophytic bacteria that promote plant growth. Special attention will be given to changes in the microbiome according to soil conditions and the physiological state of the plant. The functionality of the plant microbiome is crucial to keep homeostasis and to confer plant's resistance to stress. This will be illustrated with the microbiome of Quercus ilex and its relation with the "oak decline" disease caused by Phytophthora. The genetic and functional diversity of the plant microbiome is enormous and the study of its dynamics is essential to search for solutions to enhance resilience of plants to stresses in the context of global change.
Speaker 1: Dr. Manuel Becana. Estación Experimental de Aula Dei, CSIC, Zaragoza, Spain.
"The legume-rhizobium symbiosis: nitrogen fixation, antioxidants and hemoglobins in root nodules"
Speaker 2: Dr. Maria J. Pozo. Estación Experimental del Zaidín, CSIC, Granada, Spain.
"The arbuscular mycorrhizal symbiosis enhances plant phenotypic and metabolic plasticity to cope with stress"
Speaker 3: Dr. Alvaro Peix. Instituto de Recursos Naturales y Agrobiología, CSIC, Salamanca, Spain.
"Plant bacteriome and its impact in disease and resilience".
Topics (Up to three): Physiology (23)
Topic 2: Plant, Animal, and Microbe Interactions (24)
Topic 3: Plant Biotechnology (25)
Justification: The beneficial interactions between plants and microorganisms is a hot topic because of its implications in agronomy, environment, and bioeconomy. In this symposium we will deal with three major interactions: legume-rhizobium symbiosis, arbuscular mycorrhizal symbiosis, and root endophytes. Novel aspects such as the signaling role of reactive molecules, antioxidants, and hemoglobins in legume nodules, the priming of crops by mycorrhizal fungi, and the microbiome of forest tree species will be of interest to a wide audience of plant biologists. The symposium will bridge at least the following topics: physiology (23); plant, animal, and microbe interactions (24); and plant biotechnology (25).