Roots of nutrient-deprived Brachiaria species accumulate 1,3-di-O-trans-feruloylquinic acid

A novel di-hydroxycinnamoylquinic acid ester, 1,3-di-O-trans-feruloylquinic acid (DFQA), was isolated from roots of nutrient-deprived Brachiaria species--the most widely sown tropical forage grasses in South America. In contrast to other so far characterized quinic-acid esters, DFQA exists in a chair conformation with the carboxylic group in the axial orientation. It accumulates in older parts of the root system, but not in root apices or shoots. Higher levels were found in B. ruziziensis, which is poorly adapted to infertile acid soils, than in well adapted B. decumbens. DFQA was also found in the soil, most likely as a result of root decay, because it was not detected in root exudates of plants cultivated in solution culture. Nitrogen and phosphorus deficiency--but not aluminum toxicity or deprivation of other nutrients--stimulated its synthesis in roots. Its accumulation was correlated with a shift in biomass partitioning toward the root system.