- Inoculation of Vicia sativa subsp. nigra roots with Rhizobium leguminosarum biovar viciae results in release of nod gene activating flavanones and chalcones. Recourt, K., Schripsema, J., Kijne, J.W., van Brussel, A.A., Lugtenberg, B.J. Plant Mol. Biol. (1991)