Expression of a Fungal Lectin in Arabidopsis Enhances Plant Growth and Resistance Toward Microbial Pathogens and a Plant-Parasitic Nematode.

lectin 2 (CCL2) is a fucoside-binding lectin from the basidiomycete that is toxic to the bacterivorous nematode as well as animal-parasitic and fungivorous nematodes. We expressed in Arabidopsis to assess its protective potential toward plant-parasitic nematodes. Our results demonstrate that expression of enhances host resistance against the cyst nematode . Surprisingly, CCL2-expressing plants were also more resistant to fungal pathogens including , and the phytopathogenic bacterium . In addition, expression positively affected plant growth indicating that CCL2 has the potential to improve two important agricultural parameters namely biomass production and general disease resistance. The mechanism of the CCL2-mediated enhancement of plant disease resistance depended on fucoside-binding by CCL2 as transgenic plants expressing a mutant version of CCL2 (Y92A), compromised in fucoside-binding, exhibited wild type (WT) disease susceptibility. The protective effect of CCL2 did not seem to be direct as the lectin showed no growth-inhibition toward in assays. We detected, however, a significantly enhanced transcriptional induction of plant defense genes in CCL2- but not CCL2-Y92A-expressing lines in response to infection with compared to WT plants. This study demonstrates a potential of fungal defense lectins in plant protection beyond their use as toxins.