May remobilize phosphate, particularly when cells senesce or when phosphate becomes limiting. a ribonucleotidyl-ribonucleotide-RNA + H2O = a 3'-end 3'-phospho-ribonucleotide-RNA + a 5'-end dephospho-ribonucleoside-RNA + H(+) A number of isoforms are produced. According to EST sequences. Most highly expressed in flowers, but also expressed in roots, stems, and leaves. By phosphate starvation. Belongs to the RNase T2 family.