Non-S-ribonucleases (non-S-RNases) are class III T2 RNases expressed in the styles of species exhibiting S-RNase-based self-incompatibility (SI). So far, no role has been attributed to these RNases, which are not functional in the SI system. By combining RT-PCR, immunoblot and enzymatic activity approaches, Rojas et al. demonstrate that NnSR1 (Nicotiana non-S–RNase1) is induced in roots of Nicotiana alata subjected to phosphate deprivation, resembling the functionality of phylogenetically divergent class I and class II S-like RNases. NnSR1 appears to have regained ancestral functions of class III RNases related to strategies to cope with phosphate limitation and possibly with other environmental challenges.
Rojas et al. demonstrate that NnSR1 (Nicotiana non-S-RNase1) is induced in roots of Nicotiana alata subjected to phosphate deprivation.