Characterization of Arabidopsis thaliana heat shock protein Hsp81.2 in the plant apoplast

ATELA, A.; UCHIYA, P.; SOLMI, L.; MENDOZA MORALES, L.F.; RAMOS DUARTE, V. A.; GARRIZ, A.; ROSSI, F.; SANDER, V.A.; CLEMENTE, M.; CORIGLIANO, M.G.

Rosario

Congreso; XXXIV Argentinian Meeting of Plant Physiology; 2023

Sociedad Argentina de Fisiologia Vegetal

The results presented in this work were obtained in agreement with RIZOBACTER ARGENTINA S.A (CONVE-2022-120066190-APN-GVT_CONICET) .Hsp90s are found in all plant cellular compartments examined to date, and Hsp90s have also been found in the apoplast. Even though their roles in this location remain elusive, we added some light to this issue by assessing the regulation of defense-associated mechanisms in Arabidopsis thaliana plants infiltrated with the recombinant Hsp90 protein (AtHsp81.2). In this trend, we previously showed that ROS production and callose deposition were incremented upon rAtHsp81.2 infiltration. Besides, a 24h pre-treatment of leaves with AtHsp81.2 resulted in a reduction in the proliferation of Pseudomonas syringae pv. tomato DC3000, whereas the in vitro growth of the bacteria is not affected in the presence of rAtHsp81.2 suggesting that this protein may participate in the induction of defense. In the present study, we attempted to gain a deeper insight into the role played by AtHsp90s by evaluating their effects on defense against PstDC3000. We assayed 1-, 2-, 3-, 4-, 5-, 6- y 7-days pre-treatment with 100 µg ml-1 of AtHsp81.2 and it resulted in a reduction in the proliferation of PstDC3000 compared with control group (only PstDC3000). We also assayed a spray-based protocol in order to explore whether AtHsp81.2 either at 100 or 500 µg ml-1 activate plant immune response, but the reduction in the proliferation of PstDC300 was observed just until 3-days pretreatment. Our results suggest that Hsp90s localized in the plant apoplast play an active role in the activation of the plant defense mechanisms against pathogens since it is important for mounting appropriate plant immune response and it is also long lasting.