1.11.39
VIRUS DISEASES OF ALSTROEMERIA

NJ SPENCE, ED SHAW, DJ BARBARA and AA BRUNT

Horticulture Research International, Wellesbourne, Warwick, CV35 9EF, UK

Background and objectives
Alstroemeria cut flower production is rapidly increasing in the EU and worldwide. Trade in propagation material is seriously hampered by the fact that Alstroemeria, which is vegetatively propagated, contains many poorly characterized viruses, and it is of utmost importance that these viruses are not disseminated in propagation material to new production areas. The occurrence, identity and characteristics of the viruses of Alstroemeria were investigated to permit the development of standardized methods for diagnosis and detection. These methods could then be used in certification schemes, to improve the overall quality of Alstroemeria products, and in breeding programmes to test germplasm before it is used. In addition, meristem-tip culture techniques are being developed which can be used to produce virus-free cultivars. This research has been carried out in an EEC project where each of the partners (IPO-DLO, Wageningen, The Netherlands; BBA, Braunschweig, Germany; HRI, Wellesbourne, UK; University of Bologna, Italy) had responsibility for different viruses and tasks. HRI investigated carlaviruses and CMV in Alstroemeria.

Materials and methods
Six isolates of Alstroemeria carlavirus (AICV) and two isolates of lily symptomless carlavirus (LSV) were characterized biologically and serologically. In carlaviruses there is a small ORF at the 3' terminus, downstream from the coat protein, which potentially encodes a protein of approximately 11 kDa in size and which contains domains which are highly conserved between all carlaviruses. One set of PCR primers was used which amplifies the region from the initiation of the 11-kDa protein to the poly(A) tail (Carla-Uni) [1]. A second set of primers was designed to amplify the coat protein region of AICV and LSV. Both sets of primers were used in immunocapture PCR [2]. DNA fragments from both PCR reactions were cloned and sequenced.

Ten isolates of CMV from Alstroemeria were characterized biologically and serologically. To develop a more reliable detection and diagnostic method, PCR and RFLP analysis was used to detect and differentiate the two subgroups of CMV [3]. Five CMV isolates from Alstroemeria were cloned and sequenced.

Results and conclusions
The AICV isolates had 94-99% amino acid sequence homology with each other and with LSV. There was only 53-55% similarity of the AICV and LSV isolates with potato virus S carlavirus. These and other data now confirm that AICV is a host-adapted strain of LSV [4].

All ten CMV isolates from Alstroemeria were found to belong to subgroup II of CMV and RFLP group I. Sequence homology of five of the CMV isolates is described and discussed.

References
1. Badge J, Brunt AA, Carson R et al., 1996. European Journal of Plant Pathology 102, 305-310.
2. Barbara DJ, Morton A, Spence NJ, Miller A, 1995. Journal of Virological Methods 55, 121-132.
3. Rizos H, Gunn LV, Pares RD, Gillings MR, 1992. Journal of General Virology 73, 2099-2103.
4. Derks AFLM, Lemmers MEC, Hollinger ThC, 1982. Report of the Glasshouse Crops Research Institute, 1981, p. 142.