Hydrolyzes phosphodiester bonds in RNA, poly- and oligoribonucleotides resulting in 3'-nucleoside monophosphates via 2',3'-cyclophosphate intermediates. Introduced by genetic manipulation and expressed in male sterile maize and rape by Plant Genetic Systems and in radicchio rosso by Bejo Zaden. Barnase expressed in transgenic plants will specifically destroy the tissue(s) where it is expressed. After cell transformation, protein expression and plant regeneration, the active nuclease destroys the pollen producing organs thus rendering the plant sterile. Belongs to the ribonuclease N1/T1 family.