ASSESSMENT OF THE ROLE OF FLUORESCENT ROOT AND SEED EXUDATES IN CROP PLANTS

Abstract

Fluorescent compounds have been reported in plant leaves, having an important biological role in the protection towards UV irradiation. It is also known that stress conditions in plants stimulate the production of some of these compounds in their aerial portion. However, less is known about their production by roots or seeds and their presence in the soil surrounding them. We report here that, soybean, sunflowers and rapeseed produced fluorescent seed and root exudates. Phosphorus deficiency in rapeseed stimulates the excretion of fluorescent compounds by roots, mainly chlorogenic acid and scopoletin. When the effect of the fluorescent fraction from soybean seed exudates on Macrophomina phaseolina was tested, an enhanced induction of sclerotia formation, hyphal squeezing and lysis in the mycelium was observed. The fluorescent compounds and perhaps other chemical molecules also present in exudates might constitute a transitory defense barrier against early attack by pathogens.

Keywords:

• mineral stress
• fluorescent compounds
• oil crops
• Macrophomina phaseolina
• phenolic compounds

ACKNOWLEDGMENTS

This work was supported by the University of Buenos Aires (UBACyT X113 and X114), the University of San Martín (Project SA08/009), the Agencia Nacional de Promoción Científica y Tecnológica (PICTs 11685, 938, 10892, 443 and 931), the Centro Argentino-Brasileno de Biotecnología (CABBIO Pr-07) and the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), PIP 5003 and 5432. PMY, GBC, and ML are supported by fellowships from CONICET.