INTRODUCTION The WHIRLY protein family comprises few plant-specific proteins sharing the eponymous single-stranded (ss)-DNA-binding domain Whirly (Desveaux et al., 2000, 2002). The members of this family have the ability to bind preferentially to ssDNA but can also bind to dsDNA and RNA (Cappadocia et al., 2010; Desveaux et al., 2002). Each WHIRLY protein contains an N-terminal organelle target peptide (OTP), which targets them into either mitochondria or chloroplasts.