부산대학교 도서관

Cucumber necrosis virus (CNV) is a (+)ssRNA virus that elicits spreading local and systemic necrosis in Nicotiana benthamiana. We previously showed that the CNV coat protein (CP) arm functions as a chloroplast transit peptide that targets a CP fragment containing the S and P domains to chloroplasts during infection. Here we show that several CP arm mutants that inefficiently target chloroplasts, along with a mutant that lacks the S and P domains, show an early onset of more localized necrosis along with protracted induction of pathogenesis related protein (PR1a). Agroinfiltrated CNV CP is shown to interfere with CNV p33 and Tomato bushy stunt virus p19 induced necrosis. Additionally, we provide evidence that a CP mutant that does not detectably enter the chloroplast stroma induces relatively higher levels of several plant defense-related genes compared to WT CNV. Together, our data suggest that targeting of CNV CP to the chloroplast stroma interferes with chloroplast-mediated plant defense. • Infection of N. benthamiana with CNV induces systemic necrosis. • CP mutants inefficient in stromal targeting show HR-type symptoms and increased PR1a. • Agroinfiltrated CP interferes with necrosis induced by CNV p33 or TBSV p19. • Plant defense genes are upregulated in a CP mutant with undetectable stromal entry. • CP interferes with chloroplast-mediated plant defense by entering the stroma. [ABSTRACT FROM AUTHOR]