Biology subjects

Cazal, J.

Publications and source records attributed to Cazal, J..

3 recordsLinked to original sources

bioRxiv2026

Hide and seek in a rainforest canopy : when a fruit-eating carnivore (almost) met its top predator carnivore

Prey-predator interactions in the wild are spectacular. Common reported cases come from ground-dwelling animals, in open areas and by daylight. Here, we report, for the first time, a sequence with the nocturnal arboreal kinkajou (Potos flavus), being followed ca. 20 minutes apart by one of its predators, the puma (Puma concolor), 33 m aboveground in a rainforest in French Guiana.

animal behavior and cognition↗

bioRxiv2026

Longer projected droughts will impair the recovery of tropical seedlings and their leaf microbiota

The increasingly severe droughts in the Amazon Basin make it urgent to understand the resilience of tropical tree species and their microbiota. Plant-associated fungi and bacteria (i.e. extended phenotype) modulate drought stress for their hosts, but their role in recovery dynamics remains poorly understood. To test the impact of different drought durations on the recovery of both physiology and microbiota of tropical trees, we followed the responses of nearly 1,000 seedlings belonging to seven tropical tree species of seasonally flooded (SF) forests in a greenhouse experiment. Seedlings were subjected to different droughts, reflecting a current, a projected and an extreme drought scenario of the French Guiana climate. Plant responses were monitored after the drought and after rewetting. Plant performance was estimated through leaf gas exchange, photochemical functioning, leaf water potentials and water-related traits as well as morphological traits. Bacterial and fungal leaf communities were characterized with respectively 16S and ITS2 markers using high-throughput sequencing. Increasing the duration of the drought reduced the ability of plants to recover physiological functions, with differences among species which were only partially predicted by their drought tolerance strategies. Bacterial diversity increased in most plant host species after mild drought but not under the most severe stress. Bacterial dispersion and turnover responses were strongly host species-specific, without a general directional pattern across species. Fungal communities showed greater compositional stability, but exhibited consistently higher turnover compared to bacterial communities during both drought and recovery, with no convergence toward control composition. Finally, none of the recovery networks mirrored the architecture of the control network, regardless of prior drought duration, demonstrating that the integrated extended phenotype does not recover even when individual traits show signs of recovery. Our results reveal that both physiological recovery and microbial community recovery are strongly shaped by the plant host species identity and drought duration This study widens knowledge of SF tropical forests, vulnerable habitats in the context of climate change, through the lens of the associated microbial communities and functional traits. Beyond the effects of an increasingly uncertain climate combined with a rise in the frequency of extreme events, our study places emphasis on including tree species extended phenotypes in considering their recovery dynamics.

ecology↗

bioRxiv2023

Plant mutations: slaying beautiful hypotheses by surprising evidence

Somatic mutations potentially play a role in plant evolution, but common expectations pertaining to plant somatic mutations remain insufficiently tested. Unlike in most animals, the plant germline is assumed to be set aside late in development, leading to the expectation that plants accumulate somatic mutations along growth. Therefore, several predictions were made on the fate of somatic mutations: mutations have generally low frequency in plant tissues; mutations at high frequency have a higher chance of intergenerational transmission; branching topology of the tree dictates mutation distribution; and, exposure to UV radiation increases mutagenesis. To provide new insights into mutation accumulation and transmission in plants, we produced two high-quality reference genomes and a unique dataset of 60 high-coverage whole-genome sequences of two tropical tree species, Dicorynia guianensis (Fabaceae) and Sextonia rubra (Lauraceae). We identified 15,066 de novo somatic mutations in D. guianensis and 3,208 in S. rubra, surprisingly almost all found at low frequency. We demonstrate that: 1) low-frequency mutations can be transmitted to the next generation; 2) mutation phylogenies deviate from the branching topology of the tree; and 3) mutation rates and mutation spectra are not demonstrably affected by differences in UV exposure. Altogether, our results suggest far more complex links between plant growth, ageing, UV exposure, and mutation rates than commonly thought. Significance StatementThe origin and fate of new mutations have received less attention in plants than in animals. Similarly to animals, plant mutations are expected to accumulate with growth and time, and under exposure to UV light. However, contrary to animals, plant reproductive organs form late in an individuals development, allowing the transmission to the progeny of mutations accumulated along growth. Here, we resequenced DNA from different branches differentially exposed to sunlight of two tropical tree species. We showed that new mutations are generally rare in plant tissues and do not mimic branching patterns but can nevertheless be transmitted to the progeny. Our findings provide a new perspective on heritable plant mutation and its pivotal role as the engine of evolution.

genomics↗