IAC obtains patent for promoter gene isolated from coffee plants

For many people, the day only starts after their first coffee. The Agronomic Institute (IAC), of the Secretariat of Agriculture and Supply of the State of São Paulo, is responsible for the development of approximately 90% of the Arabica coffee cultivars planted commercially in Brazil. Seeking product excellence, the Institute maintains modern research and has patented a technology to be used by scientists from public or private institutions dedicated to the development of new cultivars of species of economic interest. The patent is for a promoter, called CaIsoR, which directs specific expression to plant leaves. This promoter was isolated from coffee plants, but the technology can be adopted in any cultivated species.

"This is an important stage in the development of genetically modified plants", says Oliveiro Guerreiro Filho, a researcher at IAC. He understands why: the difference between CalsoR is that it has specific expression in leaf tissue, that is, the introduced genes will only be expressed in the leaves of the plant. Therefore, this gene promoter differs from promoters normally used for genetic transformation, which act in all plant organisms.

The technology has the potential to allow the expression of structural genes of agronomic interest in leaf tissues. Examples of these are genes for resistance to pests and diseases that affect the aerial part of coffee plants or other species.

According to Guerreiro, the use of this technology to develop genetically modified varieties with resistance to pests or diseases of primary importance could generate direct cost savings by dispensing with or reducing chemical control. The technology could also reduce the time needed to develop a coffee cultivar, which requires around 20 years of research. This new technology patented by the IAC could contribute to one phase of this complex system. "Depending on the genetic material used for transformation, in general, we can say that the technology would reduce the development time of a new coffee cultivar by half, that is, ten years", he explains.

The promoter is a DNA sequence that tells when and where the gene should be activated to produce the protein. According to Mirian Perez Maluf, a researcher at Embrapa Café who works at IAC, the assembly of this DNA sequence with a target gene is called an expression cassette, and contains the essential information to guarantee the expression of the gene. CaIsoR is 950kb in size and was isolated from the sequence of a coffee plant gene belonging to the isoflavone family. Considering the use of the CalsoR promoter associated with a structural gene directly responsible for the synthesis of a protein with insecticidal activity, for example, this protein will only be produced in leaves and when stimulated by the herbivory of an insect pest.

"As the specific expression cassette has action only on the leaf, there will be no gene expression or protein synthesis with insecticidal activity in organs that will be used for consumption, which in this case would be coffee beans", explains the IAC researcher, from the Agency Paulista Institute of Agribusiness Technology (APTA).

CaIsoR is activated only when the plant leaf undergoes a biotic or abiotic action. Among the biotic agents that activate this gene are fungal infection, known as rust, and infestation by insects and pests, such as leaf miner, as well as various mites. Activation by abiotic agents is more closely related to damage of a mechanical nature, caused to the leaves as a result of friction caused by wind and the traffic of machines and implements. The research was developed in partnership with the Brazilian Agricultural Research Corporation (EMBRAPA) and the São Paulo State University (UNESP).