NOVEL HOMEOTIC CMS PATTERNS GENERATED IN NICOTIANA VIA CYBRIDIZATION WITH HYOSCYAMUS AND SCOPOLIA

Cytoplasmic hybrids (cybrids) that contain nuclear genetic material fr om Nicotiana tabacum and cytoplasms from Hyoscyamus niger or Scopolia carniolica were constructed by protoplast fusions, Both types of hybri ds exhibited cytoplasmic male sterility (CMS), Furthermore, unusual fl oral morphogenesis marked by 'green flowers' deprived of corolla and s tamens occurred in the majority of the lines, Backcrosses of these pla nts with wild-type tobacco demonstrated a maternal inheritance of the 'green flower' trait, After repeated transfer of cytoplasm ('donor-rec ipient fusion') from cytoplasmic hybrid N. tabacum (+ H. niger) to alb ino plastome mutant N. tabacum DSR A15, male sterile tobacco plants wi th two types of flowers were recovered ('green flowers' and corolla-co ntaining flowers with transformed stamens), RFLP analysis confirmed th at N. tabacum (+ H. niger) and N. tabacum (+ S. carniolica) as well as their sexual progenies contained plastids from H. niger and S. carnio lica, respectively. Mitochondrial DNA within the hybrids N. tabacum ( H. niger) originated from H. niger, but was obviously altered, Repeat ed parasexual transmission, cybrids in the combination of N. tabacum N. tabacum (+ H. niger), reflected similar characteristics. Cybrids, N. tabacum (+ S. carniolica) and their sexual progeny, which resulted after pollination with wild-type tobacco, contained a modified mtDNA g enerally originating from tobacco, Further histological analysis estab lished the dramatic difference in the composition of 'green flowers' a nd flowers of wild-type tobacco, Therefore, the construction of tobacc o cybrids with foreign cytoplasms provides a functional method for the de novo generation of alternative CMS types.