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

ATELA AGUSTÍN IGNACIO; UCHIYA PATRICIA; SOLMI LEANDRO ; MENDOZA MORALES, LUISA F; RAMOS DUARTE, ANDRÉS V; GÁRRIZ, ANDRÉS; ROSSI, FRANCO R; SANDER, VALERIA A; CLEMENTE MARINA; CORIGLIANO, MARIANA G

Rosario

Congreso; XXXIV Reunión de la SAFV; 2023

Hsp90s are found in all plant cellular compartmentsexamined to date, and Hsp90s have also been found in the apoplast. Even thoughtheir roles in this location remain elusive, we added some light to this issueby assessing the regulation of defense-associated mechanisms in Arabidopsis thaliana plants infiltratedwith the recombinant Hsp90 protein (AtHsp81.2). In this trend, we previously showedthat ROS production and callose deposition were incremented upon rAtHsp81.2 infiltration.Besides, a 24h pre-treatment of leaves with AtHsp81.2 resulted in a reductionin the proliferation of Pseudomonassyringae pv. tomato DC3000, whereas the invitro growth of the bacteria is not affected in the presence of rAtHsp81.2 suggestingthat this protein may participate in the induction of defense. In the presentstudy, we attempted to gain a deeper insight into the role played by AtHsp90s byevaluating 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 AtHsp81.2and it resulted in a reduction in the proliferation of PstDC3000 comparedwith control group (only PstDC3000). We also assayed a spray-basedprotocol in order to explore whether AtHsp81.2 either at 100 or 500 µg ml-1activate plant immune response, but the reduction in the proliferation of PstDC300was observed just until 3-days pretreatment. Our results suggest that Hsp90s localizedin the plant apoplast play an active role in the activation of the plant defensemechanisms against pathogens since it is important for mounting appropriate plantimmune response and it is also long lasting.