Hsp90 Interacts With Tm-22 and Is Essential for Tm-22-Mediated Resistance to Tobacco mosaic virus

The tomato resistance gene Tm-22 encodes a coiled coil-nucleotide binding site-leucine rich repeat type resistance protein and confers effective immune response against tobamoviruses by detecting the presence of viral movement proteins (MPs). In this study, we show that the Nicotiana benthamiana Heat shock protein 90-kD (Hsp90) interacts with Tm-22. Silencing of Hsp90 reduced Tm-22-mediated resistance to Tobacco mosaic virus (TMV) and the steady-state levels of Tm-22 protein. Further, Hsp90 associates with SGT1 in yeast and in plant cells. These results suggest that Hsp90-SGT1 complex takes part in Tm-22-mediated TMV resistance by functioning as chaperone to regulate Tm-22 stability.