Unravelling the involvement of cilevirus p32 protein in the viral transport

• Published in: Scientific reports 2021-02, Vol.11 (1), p.2943-2943, Article 2943
• Main Authors: Leastro, Mikhail Oliveira, Freitas-Astúa, Juliana, Kitajima, Elliot Watanabe, Pallás, Vicente, Sánchez-Navarro, Jesús A.
• Format: Article
• Language: English
• Subjects: 631/337; 631/449; Alfalfa; C-Terminus; Capsid protein; Cilevirus; Dichorhavirus; Disease transmission; Fibrillarin; Host plants; Humanities and Social Sciences; Localization; Movement protein; multidisciplinary; Nucleocapsids; Nucleoli; Orchards; p32 Protein; Plant virus diseases; Plasmodesmata; Protein transport; Proteins; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-021-82453-4

Citrus leprosis (CL) is a severe disease that affects citrus orchards mainly in Latin America. It is caused by Brevipalpus -transmitted viruses from genera Cilevirus and Dichorhavirus . Currently, no reports have explored the movement machinery for the cilevirus . Here, we have performed a detailed functional study of the p32 movement protein (MP) of two cileviruses. Citrus leprosis-associated viruses are not able to move systemically in neither their natural nor experimental host plants. However, here we show that cilevirus MPs are able to allow the cell-to-cell and long-distance transport of movement-defective alfalfa mosaic virus (AMV). Several features related with the viral transport were explored, including: (i) the ability of cilevirus MPs to facilitate virus movement on a nucleocapsid assembly independent-manner; (ii) the generation of tubular structures from transient expression in protoplast; (iii) the capability of the N- and C- terminus of MP to interact with the cognate capsid protein (p29) and; (iv) the role of the C-terminus of p32 in the cell-to-cell and long-distance transport, tubule formation and the MP-plasmodesmata co-localization. The MP was able to direct the p29 to the plasmodesmata, whereby the C-terminus of MP is independently responsible to recruit the p29 to the cell periphery. Furthermore, we report that MP possess the capacity to enter the nucleolus and to bind to a major nucleolar protein, the fibrillarin. Based on our findings, we provide a model for the role of the p32 in the intra- and intercellular viral spread.