Plant health status effects on arbuscular mycorrhizal fungi associated with Lavandula angustifolia and Lavandula intermedia infected by Phytoplasma in France

Marie- Noëlle Binet,Camille Marchal,Bert Candaele,Viviane Barbreau,Benjamin David,Bello Mouhamadou,Delphine Fraty,Olivier Bagarri,Sophie Perigon,Roberto A Geremia,Justine Lipuma

doi:10.1038/s41598-020-77240-6

Abstract

We investigated root communities of arbuscular mycorrhizal fungi (AMF) in relation to lavender (Lavandula angustifolia) and lavandin (Lavandula intermedia) health status from organic and conventional fields affected by Phytoplasma infection. The intensity of root mycorrhizal colonization was significantly different between diseased and healthy plants and was higher in the latter regardless of agricultural practice. This difference was more pronounced in lavender. The root AMF diversity was influenced by the plant health status solely in lavender and only under the conventional practice resulting in an increase in the AMF abundance and richness. The plant health status did not influence the distribution of root AMF communities in lavandin unlike its strong impact in lavender in both agricultural practices. Finally, among the most abundant molecular operational taxonomic units (MOTUs), four different MOTUs for each plant species were significantly abundant in the roots of healthy lavender and lavandin in either agricultural practice. Our study demonstrated that the plant health status influences root colonization and can influence the diversity and distribution of root AMF communities. Its effects vary according to plant species, can be modified by agricultural practices and allow plants to establish symbiosis with specific AMF species.

Highlights

Arbuscular mycorrhizal fungi (AMF, Glomeromycota) are obligate symbiotic fungi which colonize roots of the majority of land plants, including the most important food c rops[1]
The purpose of this article was to study the responses of arbuscular mycorrhizal fungi (AMF) to plant health status on two aromatic plants, L. angustifolia and L. intermedia cultivated under different agricultural practices in south-eastern France
Different agricultural practices such as conventional or organic farming were used for both L. angustifolia and L. intermedia so as to find a strategy to reduce the impact of the disease

Summary

Introduction

Arbuscular mycorrhizal fungi (AMF, Glomeromycota) are obligate symbiotic fungi which colonize roots of the majority of land plants, including the most important food c rops[1] They provide essential ecosystem services by improving plant nutrient availability, plant diversity and soil structure formation[2]. An important shift in diversity and composition of root AMF communities when comparing healthy to diseased plants in Salix bioenergy plantations was shown[8] In both studies, the effects of plant health status were investigated on sites characterized by the same mode of agricultural practices. To our knowledge there is no information on the importance of the plant health status on root AMF communities associated to plant crops under different agricultural systems such as conventional or organic practices Both practices are often increasingly developed to improve crop yields and are reported to affect AMF c ommunities[9]. We sought to determine whether these plant health status effects varied according to the agricultural practice and to the plant species identity

Objectives

Methods

Results

Discussion

Conclusion