Mk. Zubko et al., NOVEL HOMEOTIC CMS PATTERNS GENERATED IN NICOTIANA VIA CYBRIDIZATION WITH HYOSCYAMUS AND SCOPOLIA, Journal of Experimental Botany, 47(301), 1996, pp. 1101-1110
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.