CYBRID PRODUCTION BASED ON MUTAGENIC INACTIVATION OF PROTOPLASTS AND RESCUING OF MUTANT PLASTIDS IN FUSION PRODUCTS - POTATO WITH A PLASTOME FROM S-BULBOCASTANUM AND S-PINNATISECTUM
Va. Sidorov et al., CYBRID PRODUCTION BASED ON MUTAGENIC INACTIVATION OF PROTOPLASTS AND RESCUING OF MUTANT PLASTIDS IN FUSION PRODUCTS - POTATO WITH A PLASTOME FROM S-BULBOCASTANUM AND S-PINNATISECTUM, Theoretical and Applied Genetics, 88(5), 1994, pp. 525-529
A procedure for cybrid production, based on double treatment of donor
protoplasts by physical and afterwards chemical mutagens at superletha
l doses (gamma-irradiation at a dose of 1000 Gy was applied for the in
activation of nuclei; 3-5 mM N-nitroso-N-methylurea was used for the e
fficient induction of plastome mutation) and the rescuing of mutant pl
astids after fusion with untreated recipient protoplasts, was develope
d. For identification of mutant donor-type plastids in fusion products
a selection for streptomycin was performed. In two sets of experiment
s, in which S. tuberosum served as the recipient of foreign cytoplasm
with the wild tuber-bearing species S. bulbocastanum and S. pinnatisec
tum as donors, a total of about 40 streptomycin-resistant colonies was
isolated. Eight regenerants from the S. tuberosum + S. bulbocastanum
fusion combination and four from S. tuberosum + S. pinnatisectum were
further investigated using chromosome counting, analysis of esterase i
soenzymes, restriction analysis of organelle DNA, and blot hybridizati
on. All but one plant from both combinations were characterised as pot
ato cybrids possessing exclusively foreign plastids and retaining a mo
rphology typical of the recipient. Only in one line was rearranged mtD
NA detected. The availability of potato cybrids facilitates the analys
is of plastome-encoded breeding traits and the identification of the m
ost valuable source of cytoplasm among the wild potato species. The de
scribed system for producing cybrids without genetic selectable marker
s in the parental material offers the possibility for the rescue of cy
toplasmic mutations which are impossible to isolate by conventional ap
proaches.