VIEW ARTICLE

Etiology

Pepper Mild Mottle Virus, a Tobamovirus Infecting Pepper Cultivars in Sicily. C. Wetter, Department of Botany, University, D 66-Saarbrücken, West Germany; M. Conti(2), D. Altschuh(3), R. Tabillion(4), and M. H. V. van Regenmortel(5). (2)Istituto di Fitovirologia applicata del Consiglio Nazionale delle Ricerche, Torino, Italy; (3)(5)Institut de Biologie Moléculaire et Cellulaire du C.N.R.S., Strasbourg, France; (4)Department of Botany, University, D 66-Saarbrücken, West Germany. Phytopathology 74:405-410. Accepted for publication 15 September 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/Phyto-74-405.

A tobamovirus named pepper mild mottle virus (PMMV) was isolated from tobacco mosaic virus (TMV)-resistant peppers in Sicily, Italy. It could be distinguished by symptomatology and host range from other tobamoviruses. Infected pepper plants yielded up to 1.3 g of purified virus per kilogram of tissue. The virus formed a single band in rate-zonal density gradient centrifugation in sucrose (10- 50%). The ultraviolet absorption spectrum had maxima and minima at 260 and 248 nm with ratios A_max/A_min and A_{260 nm}/A_{280 nm} of 1.11 and 1.21, respectively. The specific extinction coefficient was E_{1 cm, 260 nm}^0.1% = 3.18. From the length-distribution histogram a normal length of 312 nm was determined. Angled layer aggregates were observed in the cytoplasm of infected pepper leaf cells. Antisera to PMMV had homologous titers of 1:2,048 and 1:4,096. After absorption with eight heterologous wild strains of TMV, the PMMV antisera still reacted strongly with the homologous virus. No cross reactivity with heterologous strains was observed in the double antibody sandwich form of ELISA, but the indirect ELISA method showed cross reactions between PMMV and other tobamoviruses. The amino acid composition indicated that PMMV is distinct from all other well-established tobamovirus species.