Journal of Plant Process and Function

Heat shock proteins (HSPs) as stress proteins have vital roles in plant adaptation to biotic and abiotic stresses. These proteins expressed in almost all kinds of stresses and are well known to be contribute in protection of cells. Among them the HSP90, HSP70 and smHSPs have significant roles in cell. In this study, the gene fragments of smHSP, HSP70 and HSP90 from Capparis spinosa L. plant were cloned into the tobacco rattle virus vector, pTRV2 to heterologously suppress the corresponding endogenes of N. benthamiana. Silenced plants were exposed to salt stress (100 mM NaCl) for 3 weeks and Chl a fluorescence induction kinetics was analyzed. Compare to smHSP and HSP90, silencing of HSP70 was found to have stronger negative effect especially after salinity on some parameters related to the donor site of electron in PSII [F_v/F_o] and, the parameters dependent on the acceptor site of the electron such as φ_Eo, φ_Ro, ψ_o and ψ_o/(1-ψ_o.) It was also represented that simultaneous silencing of the HSP70 gene and salinity treatment resulted in a significant decrease of Sm/t _Fm and the Performance Index (PI_ABS) and an increase of dissipation per active reaction center (DI_o/RC). So these results reflecting among the HSPs tested in the present study, HSP70 silencing cause severe injuries in reaction centers of PSII especially after salt stress.