The RNase activity of rice probenazole-induced protein1 (PBZ1) plays a key role in cell death in plants.
Cell death is an important process of plant responses to development and biotic/abiotic stresses. In rice plants, PBZ1, a PR10 family protein, has been shown to accumulate in tissues undergoing cell death. However, the function of PBZ1 in cell death remains yet to be demonstrated. Here, we report that exogenous recombinant PBZ1 protein induces cell death in rice suspension-cultured cells (SCCs) and also in leaves of Nicotiana tabacum in a dosedependent manner. This finding was confirmed in vivo in transgenic Arabidopsis lines harboring the PBZ1 gene under the control of a dexamethasone (DEX)-inducible promoter. The DEX-treated leaves of transgenic Arabidopsis induced expression of PBZ1 at transcript and protein levels and showed cell death morphology. TUNEL analysis detected DNA fragmentation, a hallmark of programmed cell death, in rice SCCs treated with the PBZ1 protein. Recombinant PBZ1 protein also exhibited RNase activity and exhibited internalization inside BY-2 cells. Taken together, PBZ1 induces cell death not only in rice, but also in tobacco and Arabidopsis via its RNase activity inside the cell. PBZ1 could be used as a marker to understand the mechanism by which PBZ1 confers the cell death morphology in rice and other model plants.
Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea.
Sang Gon
SG
Kim
Sun Tae
ST
Kim
Yiming
Y
Wang
Seok
S
Yu
In Soo
IS
Choi
Yong Chul
YC
Kim
Woo Taek
WT
Kim
Ganesh Kumar
GK
Agrawal
Randeep
R
Rakwal
Kyu Young
KY
Kang
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D018929:Cell Culture Techniques; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects; D057075:Enzyme Assays; D012275:Oryza / Q000502:physiology*; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D010940:Plant Proteins / Q000096:biosynthesis / Q000378:metabolism* / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis* / Q000494:pharmacology; D012260:Ribonucleases / Q000378:metabolism*; D014026:Nicotiana / Q000187:drug effects / Q000502:physiology
C099062:PBZ1 protein, Oryza sativa; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D012260:Ribonucleases