A Unique Glycine-Rich Motif at the N-terminal Region of Bamboo mosaic virus Coat Protein Is Required for Symptom Expression

Abstract

The coat proteins (CP) of many plant viruses are multifunctional proteins. We used N-terminal sequencing and mass spectrometry/mass spectrometry analysis to identify a truncated form of the Bamboo mosaic virus (BaMV) CP missing the N-terminal 35 amino acids (N35). The N35 region is unique in the potexviruses by its containing a glycine-rich motif (GRM) not present in databases but highly conserved among BaMV isolates. Results from site-directed mutagenesis and deletion mutational analysis showed that loss of this region converted necrotic local lesions to chlorotic local lesions on Chenopodium quinoa leaves. Furthermore, this region is required for successful development of mosaic symptoms on Nicotiana benthamiana leaves but is dispensable for BaMV replication and cell-to-cell and long-distance movement as well as virion assembly. This unique GRM-containing region of BaMV CP may be a symptom determinant in specific hosts.

Polyclonal antibodies to the putative coat protein of Citrus leprosis virus C expressed in Escherichia coli: production and use in immunodiagnosis

“…Many CPs are also required for the virus infection to spread from cell-to-cell (Lee et al, 2011;Herranz et al, 2012;Schoelz et a., 2011) and/or for systemic spread throughout the plant (Kobori et al, 2002;Lee et al, 2011;Herranz et al, 2012). In addition, the coat proteins may be involved in vector transmission (Liu et al, 2002;Uzest et al, 2007), determination of the symptom (Lan et al, 2010), among others.…”

The Nucleolar Fibrillarin Protein Is Required for Helper Virus-Independent Long-Distance Trafficking of a Subviral Satellite RNA in Plants

“…Like potexviruses, all three TGBps and CP are required for BaMV cell-to-cell and systemic movement (Lin et al, 2004Lan et al, 2010;Lee et al, 2011;Wu et al, 2011;Chou et al, 2013). To examine the interaction of TGBp3 with P20 and/or fibrillarin, we inoculated N. benthamiana leaves with a 35S promoter-driven HV derivative (pCB-P3HA) carrying a TGBp3:: HA fusion ( Figure 6C; Chou et al, 2013) with or without the satBaMV pCBSF4 plasmid (Lin et al, 2004).…”

“…BaMV HV is a member of the Potexvirus genus that contains a single-stranded, positive-sense RNA genome with five open reading frames. These open reading frames encode a replicase, three MPs (TGBp1, TGBp2, and TGBp3, encoded by a triple gene block), and a capsid protein (CP) , each required for cell-to-cell movement (Lin et al, 2004Lan et al, 2010;Lee et al, 2011;Wu et al, 2011;Chou et al, 2013). However, the factors involved in long-distance trafficking of BaMV remain to be determined.…”

Helical capsids of plant viruses: architecture with structural lability

“…Deletion of the N-terminal 21 amino acid residues of the PVX CP, most of the 31-residue NID domain, as well as the deletion of residues 7-31, results in a functional virus able to produce virions (Chapman et al, 1992;Lico et al, 2006). BaMV with the deletion of Nterminal 35 CP residues is capable of virion formation and systemic transport (Lan et al, 2010). The N-terminal 14 amino acid residues of the Plantago asiatica mosaic virus (PlaMV) CP are dispensable for the formation of virions (Ozeki et al, 2009).…”

“…Deletion of the region encompassing residues 7-31 of PVX CP results in a delayed systemic infection and milder symptoms (Chapman et al, 1992). In BaMV, the NID domain is required for necrotic local lesion induction in Chenopodium quinoa and symptom expression in Nicotiana benthamiana (Lan et al, 2010). Amino acid residues 11-26 of the PepMV CP residing within the NID domain contain a virus pathogenicity determinant influencing the infection phenotype in N. benthamiana (DuffFarrier et al, 2015).…”