This work addresses the genetic characterization and manipulation of solubilising mechanisms of organic and mineral phosphorus in Buckholderia cepacia strains (base of phosphorine biofertilizer) and in Pseudomonad aeruginnosa PSS (used as biocontrol agent) in the view to develop inproved strains in its capability of phosphorus solubiliser, and as a consecuence, its used as biofertilizer

It is a novel work of fundamental research with a pure biotechnological character, which most relevant aspects are:

• - It is for the first time reported the clonning and characterization of a gene facilitating phosphatase activity of Burkholderia cepacea ( base of phosphorine biofertilizer) in particular and in Rhizobacteria in general
• - It is the first report on the use of genetic engineering techniques to obtained improved strains regarding phosphorus solubilising character , hence , of its potentials as bifertilizer , in soil bacteria strains
• - It is stated its completely novel character in world literature on characterization of phosphorus in both organic and mineral solubilising features for B. Cepacia and P.

Gluconic acid was identified as the unique organic acid produced by both strains (PSS and IS-16), which suggests its responsability of the solubilising activity.

The obtained strains, with an increased capability to solubilise mineral P, seems very promising to be used as biofertilizers in crops of agricultural interest.

The presented document contains: A total of 5 publications: 4 of them of international character and 1 with national character in ICIDCA journal. They include a CITMA 00300035 project national report(one stage) and 9 events: 5 of them international (3 in Cuba, 1 in Ecuador, 1 in Mexico) and 4 national ones: 11th and 12th Forums, Diversification 20000 and qualified paperwork

It totals 6 acknowledgements(all of them at the institution level), an acknowledgment of Waterllo University in Canada, a refference of the Scientific Council of Cuban Institute for Sugarcane Derivatives (ICIDCA) and a refference of the Advisory Technical Council of the Ministry of Sugar Industry (MINAZ).