The massive terrestrial and marine biodiversity reflects the evolution of organisms through geologic time and the multiple ecological interactions in their ecosystems. Understanding the driving forces that impact the genomephenotype, and behaviors within populations and communities is an incredibly difficult, although very stimulating, task in biology.

In Amazonian forests, the bio-chemodiversity is extremely rich and represents the fundamental information of most biotic interactions at levels ranging from individual to community. To understand the molecular complexity from genomes to proteins to molecules, it is highly relevant to describe the bio-chemodiversity in an ecological and evolutionary framework which could lead to the development of bio-inspired applications.

Ant-microbe symbiosis

The evolution of ants (∼150 million years) has been impacted by a diversity of factors including their interactions with microbes. Mutualistic bacteria have permitted ants to radiate into new ecological niches by improving their fitness, reproductive success, nutrient assimilation and immune defense.

Whether symbionts are intra- or extracellular associated with different organs and body parts (gut, cuticle, ovary, eggs etc.), they have played major roles in the metabolism, physiology, and defense of their host and understanding mechanistically all these functions is currently an active field of research.

We are interested in the biologybiochemistry and chemistry of ants-bacteria symbiosis. Specifically we attempt to identify the molecular mechanisms driving symbiosis at different phylogenetic scales.

For example we have studied the diversity of bacterial communities on the cuticle of different ant species using 16S rRNA amplicon sequencing. With metagenome mining  and amplicon sequencing methods, we also have studied the diversity of biosynthetic gene clusters (BGCs) in the genomes of bacteria associated with ants and have tested for phylogenetic or ecological correlations. In both cases one objective is to discover new defensive mutualistic associations that may help guide future prospecting in search of bioactive molecules with applications in pharmaceutical sciences.

Thanks to isotopic enrichment and solid-state NMR, we have recently revealed how gut bacteria contribute to the cuticle formation of Cephalotes ants by recycling nitrogen atoms that are integrated into the cuticular components (chitin, cross-linkers, cuticular proteins).

This work is developed in close collaboration with Corrie Moreau (Cornell University).

Latex plant evolution

Latex is an emblematic plant exudate that has facilitated the radiation of many plant lineages in tropical forests. Latex plants are distributed widely in various habitats and have evolved in a convergent manner several times across the plant kingdom indicating poly-phylogenetic origins. However, apart from a few taxa that have been commercialized for rubber production or used as model systems in plant defense studies, the ecology and evolution of latex plant exudates remains understudied on a broad phylogenetic scale.

Understanding the impact of latex on plant diversification requires an interdisciplinary and integrative approach as latex is a multidimensional trait involving ecophysiology, herbivory, chemistry, ecology, and evolution.

We study the chemistry and biochemistry of latex in Amazonia trees at different phylogenetic scale, between and within plant families. We combine analysis in NMR metabolomics, physiology and transcriptomics to unveil the biochemical evolution of terpenoids.

For example we have a Agence Nationale de la Recherche grant (ANR JCJC AMAZYME 2019-2022) to study the diversity and evolution of terpene synthase (with a focus on oxidosqualene cyclase and prenyltransferase) in latex producing Amazonian trees to understand the role of these protein families in the adaptation and diversification of latex plants across microhabitats.

This work is in collaboration with Chris Baraloto (Florida Internal University, FIU), Diego Salazar (FIU) and Oscar Valverde (FIU).

Other projects

Since I joined EcoFoG Lab in 2012 I have been involved in several satellite projects.

I worked with the Pasteur Institute of French Guiana to develop transmission-blocking biossays based on the inhibition of P. falciparum male gametocytes exflagellation. (See Leba et al. Malaria J.2015, 14, 234 and Leba et al. Int. J. Parasitol. Drugs Drug Resist. 2017, 7, 314 and the video abstract).

I participated in the study of heartwood formation and wood metabolites biosynthesis in Amazonian trees using TOF-SIMS MS/MS Imaging. (See Bossu et al. Plos ONE, 2016, 11(3): e0150777 and Fu et al. Anal. Chem. 2018, 90, 7535 and Fu et al. Sci. Rep. 2019, 9, 1928 and the video abstract).

I’ve been also interesting in fluorescent natural products (see R. Duval & C. Duplais, Nat. Prod. Rep. 2017, 34, 161-193).