Posts Tagged ‘lateral gene transfer’

How to Crunch Plant Walls? … by Gene Transfer

October 2nd, 2010

11752Lateral gene transfer (LGT) between bacteria has largely been documented. The transmission of genes between fungi (e.g., Supernumerary chromosomes in a root-rot fungus, In Vino Veritas, Next-Generation Sequencing of Sordaria Genome), and between fungi and insects, such as aphids (see Tap the Vein that Bleeds), have also been reported. In contrast, data on LGT in animals is scarce. In the last issue of PNAS, Pierre Abad’s group from INRA is publishing their study of LGT in plant-parasitic nematodes. Their phylogenetic analysis of  genes coding for degrading enzymes acting on plant cell walls  (e.g., GH28 polygalacturonase, PL3 pectate lyase, GH43 arabinase, …)  from root-knot nematodes (such as Meloidogyne incognita and M. hapla) shows that these nematode enzymes were likely acquired from several independent bacterial sources. The authors hypothesized a series of acquisition through soil bacteria feeding or gene transfers from endosymbiotic bacteria. The  observed abundance of multigenic families (cellulases, pectate lyases, and expansins) in these plant-parasitic nematodes is likely due to a series of duplications that started after acquisition by LGT events. Selective advantage associated with transfer of these CAZyme genes probably has driven their duplications and facilitated fixation in the different populations and species of plant-parasitic nematodes.

In brief, when ‘worms gobble up genes from bugs’ (S. Kamoun) they were able to get access to the largest store of carbon in soil — is this fast-track evolution?

Danchin et al. (2010) Multiple lateral gene transfers and duplications have promoted plant parasitism ability in nematodes. Proc. Ntl. Acad. Sci., published online before print September 27, 2010, doi: 10.1073/pnas.1008486107.

Photo: Root-knot nematode © www.minlnv.nl