Plant snakin peptides inhibit bacterial and fungal growth at extremely low
concentrations. However, not much is known about them and their activity
against beneficial microbes. A study conducted by the team of Gabriela Soto,
from Instituto de Genética Ewald A. Favret, aimed to identify and
characterize snakin-1 from alfalfa (MsSN1).

Analysis proves the antimicrobial activity of MsSN1 against bacterial and
fungal pathogens of alfalfa. Transgenic alfalfa overexpressing MsSN1 showed
increased antimicrobial activity against fungal strains without affecting
nitrogen-fixing bacteria native to alfalfa. The results indicate that
through a coevolutionary process, alfalfa exerted a selection pressure on
microorganisms by selecting rhizobial bacteria resistant to MsSN1.

The increased antimicrobial activity against fungal strains without
affecting the nitrogen-fixing bacteria observed in MsSN1-overexpressing
plants opens the way to the production of effective legume transgenic
cultivars for biotic stress resistance.

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