AUTHOR=Chen Simin , Gistelinck Koen , Verbeke Isabel , Van Damme Els J. M. 

TITLE=Differential effects of the recombinant type 1 ribosome-inactivating protein, OsRIP1, on growth of PSB-D and BY-2 cells

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1019591

DOI=10.3389/fpls.2022.1019591

ISSN=1664-462X

ABSTRACT=<p>Plant suspension cells were treated with recombinant OsRIP1, a type 1 ribosome-inactivating protein (RIP) from rice (<italic>Oryza sativa</italic> L.). OsRIP1 triggered cell death in tobacco BY-2 cells but not in <italic>Arabidopsis</italic> PSB-D cells. Phenotypic changes in BY-2 cells exposed to OsRIP1, included loss of growth capacity, loss of integrity of the plasma membrane and vacuolar collapse. These effects were also accompanied by RNA degradation and DNA fragmentation. Targeting of exogenous OsRIP1 to plant vacuoles and OsRIP1-induced accumulation of transcripts for vacuolar processing enzymes (VPEs) indicated that OsRIP1 provoked plant cell death in tobacco BY-2 cells through the activation of VPEs and subsequent vacuolar disruption, which was probably independent of its <italic>N</italic>-glycosylase activity on cytosolic ribosomes. Necrosis with limited production of H<sub>2</sub>O<sub>2</sub> was observed after infiltration of high concentrations of OsRIP1 in epidermal cells of <italic>Nicotiana tabacum</italic> cv. Samsun NN plants. Our study provides the first evidence that OsRIP1 exerts differential effects on the growth of PSB-D and BY-2 cells. The vacuole-dependent cell death pathway is associated with the lethal effect of the exogenously applied OsRIP1 on BY-2 cells.</p>