Abstract
The hypersensitive response (HR), a type of defence strategy of plants, involves well-organized programmed cell death (PCD). We found that a vacuolar processing enzyme (VPE) exhibiting caspase-1-like activity is essential for virus-induced hypersensitive cell death (1). VPE-silenced Nicotiana plants formed no visible lesions in TMV-infected leaves. VPE deficiency prevented the typical characteristics of TMV-induced cell death, whereas VPE deficiency did not interfere with the production of pathogenesis-related (PR) proteins (defence proteins) in TMV-infected leaves. Recently, we also found that VPE regulates programmed cell death of seed coat during embryogenesis (2). Our findings show that VPE, a vacuolar enzyme, regulates PCD. Plants have evolved a death strategy that is mediated by a vacuolar system and that is not seen in animals.
(1) Hatsugai et al. (2004) Science, 305, 855-858.
(2) Nakaune et al. (2004) Plant Cell, in press.
