Reciprocal extrachromosomal inheritance in barley: the transmission of an infective element through male and female gametes

My backcross pollinations of 53 spontaneum barleys recurrently with cv. ‘Adorra’ resulted in a maternally inherited, partial spike fertility case assigned “58”. Abnormal kernels, embryos and pollen, triploidy, miniature and streaked plants were among other symptoms. The 58-element greatly enhanced expression of the P-43 multi-ovary mutant in cv. ‘Paavo’. Cv. ‘Sudan’ was a dominant 58-sterility enhancer. Pollinating of lymegrass with 58-barley resulted in lymegrass monoploids, in which 58-specific DNA was not detected. The 58-Adorra usually showed increased RNA levels and RdRp activities. Germinating in ribavirin and in etoricoxib reduced the 58-sterility. Transfections of the shoot apexes of embryos with deproteinized 58-nucleic acids did not result in infection. Any plasmid or virus explaining the 58-symptoms could not be detected. Electrophoresed germ proteins showed a glycosylated protein in 58-Adorra (Mr approximately 78.000) not observed in Adorra. The 58-element has features of a prion. The fallout from the Soviet Chernobyl brought hot particle radioactivity to Finland before the 1986 spring sowing, and impaired this study intensively going on between 1982 and 1989.