Sa. Pluhar et al., Effects of tissue culture on a highly repetitive DNA sequence (E180 satellite) in Medicago sativa, PL CELL TIS, 67(2), 2001, pp. 195-199
Genomic DNA extracted from leaves of sixteen alfalfa genotypes, six-week-ol
d callus cultures derived from them and from a suspension culture was used
in Southern blots and slot blots probed with alfalfa E180 satellite DNA. Th
e restriction patterns revealed by the E180 probe did not differ among alfa
lfa genotypes and no differences between the leaf and callus restriction pa
tterns were seen. However, the number of copies of the E180 satellite was l
ower in the callus samples than in the corresponding leaf samples and signi
ficant differences in copy number among callus samples were detected. Genom
ic stress induced by tissue culture may have caused the reduction in copy n
umber. This phenomenon may be important in the generation of somaclonal var
iation in alfalfa.