Virus Research 76 (2001) 9–16 Replacement of the coat protein gene of plum pox potyvirus with that of zucchini yellow mosaic potyvirus: characterization of the hybrid potyvirus Istva ´n To ´ bia ´s a,1 , La ´szlo ´ Palkovics b,2 , Lilia Tzekova b,2 , Ervin Bala ´zs b, * a Plant Protection Institute, Hungarian Academy of Sciences, Budapest, H-1515 P.O. Box 102, Hungary b Agricultural Biotechnology Center, Godollo, H-2101 P.O. Box 411, Hungary Received 22 September 2000; received in revised form 6 February 2001; accepted 14 February 2001 Abstract Infectious hybrid virus was generated by replacing part of the coat protein gene of plum pox potyvirus with that of the zucchini yellow mosaic potyvirus. This viable hybrid contains 84.5% of zucchini yellow mosaic potyvirus coat protein gene while the rest of the sequence was derived from plum pox potyvirus. Changing the coat protein gene between these two viruses had no effect on the experimental host range. Pathogenicity, stability and replication capacity of the hybrid virus were nearly identical to the parent viruses. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Hybrid potyvirus; Plum pox potyvirus; Zucchini yellow mosaic potyvirus www.elsevier.com/locate/virusres 1. Introduction Some virus – host combinations lead to systemic infection while others result in restriction of virus to inoculated cells or organs. Systemic virus infec- tion is conditioned by efficient cell-to-cell move- ment and the ability of the virus to enter, circulates within, and exits the vascular system (Maule 1991; Carrington et al., 1996; Seron and Haenni 1996). It is generally accepted that plant viruses spread intercellularly by an active process involving the interplay of specific viral and host factors. The nature of the host factors required for virus movement is poorly understood, but for most plant viruses the movement process involves one or more specialised virus-encoded proteins, termed movement proteins (MPs). MPs facilitate cell-to-cell transfer, although their functional na- ture is different in distinct viruses (Wolf et al., 1989; Citovsky et al., 1990; Waigmann et al., 1994; Ding et al., 1995). Capsid protein (CP) is also involved in the translocation of many plant viruses (Takamatsu et al., 1987; Dawson et al., 1988; Saito et al., 1990), and its role in long * Corresponding author. Tel.: +36-28-430539/616; fax: + 36-28-430-482. E-mail addresses: balazs@abc.hu (E. Bala ´zs), tobias@abc.hu (I. To ´ bia ´s), palkovic@abc.hu (L. Palkovics). 1 Tel.: +36-1-769555/616; fax +36-1-3769729. 2 Tel.: +36-28-430539; fax +36-28-430482. 0168-1702/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII: S0168-1702(01)00241-6