Research Notes A New Multigene Family Inducible by Tobacco Mosaic Virus or Salicylic Acid in Tobacco. Danny Alexander. Calgene, Inc., 1920 Fifth St., Davis, CA 95616 U.S.A. Jeffrey Stinson(1), Julie Pear(1), Christopher Glascock(1), Eric Ward(2), Robert M. Goodman(1), and John Ryals(2). (1)Calgene, Inc., 1920 Fifth St., Davis, CA 95616 U.S.A.; and (2)CIBA-GEIGY Biotechnology, P.O. Box 12257, Research Triangle Park, NC 27709 U.S.A. MPMI 5:513-515. Accepted 30 July 1992. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1992.

A previously undescribed cDNA family was isolated from tobacco challenged with tobacco mosaic virus (TMV). A cDNA library was constructed with mRNA from upper leaves of Xanthi nc tobacco plants that had been inoculated with TMV on the lower leaves 11 days previously. The library was screened differentially with radiolabeled cDNA synthesized with mRNA from upper, uninoculated leaves of either TMV-inoculated or mock-inoculated tobacco plants. The new cDNA family, designated SAR8.2, had at least five expressed members, one or more of which were inducible by TMV inoculation and by salicylic acid treatment. The cDNAs encoded small, highly basic proteins containing N-terminal hydrophobic signal peptides and highly conserved cysteine-rich C-terminal domains. One of the SAR8.2 family members contained a direct repeat of the C-terminal domain in tandem. Hybridization of SAR8.2 cDNA to tobacco genomic DNAs indicated a gene family of 10-12 members.