Download Séminaire de Biologie

Séminaire de Biologie
Horizontal gene transfers (HGT) and evolution of plant
parasitism by invertebrates
mardi 17 janvier 2017
Salle Guillermond (Herbier)
11:00 AM
Etienne G. Danchin
INRA
ISA, UMR1355 Sophia Antipolis
[email protected]
Intro: HGT have long been recognized as an important
evolutionary mechanism in prokaryotes. Horizontal acquisitions
contribute for a substantial part of bacterial gene sets and are
involved in key ecological functions such as antibiotic resistance
or pathogenicity. In eukaryotes, and particularly in animals, the
impact of HGT on the biology and genomes of the recipient
species has long been overlooked or considered as minor.
Recently, accumulating evidence have shown that HGT have
contributed non-negligible proportions of animal gene sets.
However, cases where acquisition of genes of foreign origin in
animals clearly correlate with a biological trait remain rare.
Results: Researches in our group and others have shown that
plant-parasitic nematodes have acquired a whole set of genes
from bacteria and fungi with a clear role in their ecology. Indeed,
enzymes of bacterial and fungal origins are involved in
degradation of the plant cell wall, processing of nutrients from
the plant and manipulation of plant defense. These enzymes and
other associated proteins are usually absent from other animals.
Interestingly, plant-parasitic arthropods have also acquired
enzymes from bacteria and fungi to perform similar functions.
Surprisingly, arthropods have acquired these protein-coding
genes from different sources than nematodes did.
Conclusion: HGT have apparently played an important role in the
emergence of plant parasitism in at least 2 invertebrate lineages,
independently & in a convergent manner: in nematodes and arthropods.
Hôte BioEnviS: Mathias Choquer
[email protected]