Summary Herbaspirillum seropedicae is an associative, endophytic non‐nodulating diazotrophic bacterium that colonises several grasses. An ORF encoding a LysR‐type transcriptional regulator, very similar to NodD proteins of rhizobia, was identified in its genome. This nodD ‐like gene, named fdeR , is divergently transcribed from an operon encoding enzymes involved in flavonoid degradation ( fde operon). Apigenin, chrysin, luteo...