Radicchio Rosso lines RM3-3, RM3-4, and RM3-6 (male sterile chicory plants) contain a ribonuclease encoded by barnase gene. The ribonuclease, which is expressed only in the tapetum cells of the pollen sac during anther development, blocks pollen development, thus producing a male sterile plant. To direct the expression of barnase to pollen cells, a pollen specific promoter, pTA 29 was used to direct the synthesis of ribonuclease enzyme.

Expression of barnase in pollen cells apparently results in degradation of host RNAs and blocking development of mature viable pollen. The barnase gene encodes for an extracellular ribonuclease protein in Bacillus amyloliquefaciens, a common soil microorganism. B. amyloliquefaciens also contains an intracellular protein called barstar which specifically inhibits barnase by combining with it in a one-to-one complex. Thus, barstar is produced intracellularly by the same organism that secretes barnase.

The second gene (bar) inserted into the Radicchio Rosso lines RM3-3, RM3-4, and RM3-6 genome encodes for phosphinothricin acetyltransferase (PAT) enzyme which inactivates phosphinothricin, the active component in the herbicide glufosinate. The bar gene is produced in the lines under the direction of Arabidospsis thaliana PssuAra promoter and nopaline synthase termination/polyadenylation sequences. Although these lines are tolerant to the herbicide, hybrid progeny (the seeds that would be available to the farmers) developed from these lines may or may not be tolerant to the herbicide.