Abstract - Introduction

As a response to the increasing demand from society for agriculture to minimize the negative impacts on environment and landscape values, farmed legumes play a key role. Among them, field pea (Pisum sativum L.) is one of the oldest domesticated crops worldwide. It provides flexibility and many benefits to growers and consumers. However, P. sativum diseases, Didymella (Mycosphaerella) pinodes can limit delivering its services and its productivity. D. pinodes may cause severe yield losses when lesions reduce green photosynthetic tissue of the plant. Although significant effects of belowground tripartite symbiosis (legume roots + Rhizobium + mycorrhizal fungi) on legume growth and quality were measured, studies of the symbionts effects on plant health (fitness and its defense response against aboveground plant pathogenic fungi) and the reciprocal suppressions have not yet been well addressed and understood. Nonetheless, these interactions need to be studied case by case and data results from such kinds of studies fill databases with a wealth of information.

The objectives of the project are:

to elucidate the host–mediated effects of above ground D. pinodes on performances of belowground symbionts (Rhizobium and/or mycorrhizal fungi)

to reveal the effects of belowground tripartite symbiosis and aboveground pathogenic fungi interactions on the metabolic dynamics and physiology of the host plant

to elucidate the host–mediated effects of belowground symbionts on above ground D. pinodes severity to P. sativum

A randomized three factorial design with the root treatments as one, genotype as the second and foliar pathogen as the third factors will be established. To understand deeply such complex interactions and identify diverse metabolic changes rapidly and accurately, recent technological advances allowed analyzing complex metabolite and protein mixtures using mass spectrometry based methods. Additionally, microbial infectivity and effectiveness, diseases severity, photosynthesis rate, nutrient composition and balance and yield structures will be assessed.