and is influenced by culture pH and optical density. Also, fasR can be induced by gall extract created by virulent strain. The operon codifies for genes involved in cytokinin synthesis and degradation (orf 4,5,6), in particular for an isopentenyl transferase, a cytokinin oxidase and a glutation-s transferase. The orf1,2,3 transcribe for a cytochrome 450, a ferridoxine containing also a pyruvate dehydrogenase alfa-like domain and a pyruvate dehydrogenase beta subunit. It was supposed that the first three genes supply energy for the synthesis and degradation of cytokinin, performed by the last three genes of the operon: R. fascians can actually produce and degrade zeatin and isopentenil adenine. The compound cytokin oxidase (orf4) can also create adenine with a reactive nitrogen in position 6, which can react with other lateral chains, to form cytokininn-like compounds, more efficient in inducing plant tissue growth. The att is an operon composed of nine genes: , a transcriptional regulator, , a gene including domains for transmembrane localization (perhaps needed for exportation of compounds made by other att genes), and several genes attA-. Many point and Δatt mutants show an attenuated virulence. Gene is a transcriptional factor including a helix-turn-helix motif. Its transcription is regulated by the same factors that regulate fasR transcription, but with a higher intensity, suggesting, with the attenuation of virulence in att mutants, that att may regulate fas transcription. Transcription of att operon is regulated with a quorum-sensing mechanism: indeed, density of cultures can influence transcription of , and leafy gall extracts coming from galls made by att mutant strains are less effective on transcription of . Genes attA- may be involved in synthesis of compounds needed for transcription of and . In fact, attA, attD & are involved in betalactamase synthesis, but no traces of those compounds were found in culture supernatants. The hyp codifies for an RNA-helicase; mutants for this gene are hypervirulent. Also, hyp is involved in post transcriptional control of virulence-related genes, maybe on fas products. Operon vic is an operon made of five genes, located on the bacterial chromosome. The only known gene is vicA, the fourth gene in the operon, whose product is a Mas homologue, a protein needed for the switch from citric acid cycle to glyoxylate cycle, both for metabolic reasons and to avoid glyoxylate accumulation, which is toxic for the bacteria. Mutations in vicA reduce virulence due to incapacity of R. fascians to resist