The response of the genome of Festuca arundinacea seedlings to changes in the temperature at which they were grown was investigated. Fifteen repeated sequences in the nuclear DNA were isolated and hybridized to the genomic DNA of seedlings grown at 10 °C or 30 °C. The redundancies of sequences recognized by four probes (FaA5, FaH8, FaH13 and FaH14), were found to differ significantly in the two DNAs. DNA sequences recognized by FaH8, FaH13 and FaH14 were more represented in the genome of the 30 °C-raised seedlings than in the genome of the 10 °C-raised seedlings (76.5 2 103, 1.9 2 103, and 111.8 2 103 copies per haploid, 1C genome vs 62.7 2 103, 1.3 2 103, and 80.8 2 103 copies, respectively). In contrast, FaA5-related sequences were more represented in the genome of seedlings grown at the lower temperature (15.5 2 103 vs 10.2 2 103 copies, respectively). Southern-blot hybridization of these repeats to digested genomic DNA produced patterns which indicated that the probe sequences were part of longer repeated sequences having a limited degree of structural heterogeneity. These patterns were partly different when the probes were hybridized to the DNA from seedlings grown at 10 °C or 30 °C. In situ hybridization showed that the DNA sequences recognized by each probe were scattered along the length of all the chromosomes, with preferential location of FaA5- and FaH13-related sequences at given, mainly centromeric, regions of certain chromosomes. These findings suggest that redundancy modulations of interspersed repeated sequences allow direct responses of the genome of F. arundinacea to changes in environmental temperature.
Genome plasticity in Festuca arundinacea: direct response to temperature changes by redundancy modulation of interspersed DNA repeats.
CECCARELLI, Marilena;CIONINI, Pier Giorgio
2002
Abstract
The response of the genome of Festuca arundinacea seedlings to changes in the temperature at which they were grown was investigated. Fifteen repeated sequences in the nuclear DNA were isolated and hybridized to the genomic DNA of seedlings grown at 10 °C or 30 °C. The redundancies of sequences recognized by four probes (FaA5, FaH8, FaH13 and FaH14), were found to differ significantly in the two DNAs. DNA sequences recognized by FaH8, FaH13 and FaH14 were more represented in the genome of the 30 °C-raised seedlings than in the genome of the 10 °C-raised seedlings (76.5 2 103, 1.9 2 103, and 111.8 2 103 copies per haploid, 1C genome vs 62.7 2 103, 1.3 2 103, and 80.8 2 103 copies, respectively). In contrast, FaA5-related sequences were more represented in the genome of seedlings grown at the lower temperature (15.5 2 103 vs 10.2 2 103 copies, respectively). Southern-blot hybridization of these repeats to digested genomic DNA produced patterns which indicated that the probe sequences were part of longer repeated sequences having a limited degree of structural heterogeneity. These patterns were partly different when the probes were hybridized to the DNA from seedlings grown at 10 °C or 30 °C. In situ hybridization showed that the DNA sequences recognized by each probe were scattered along the length of all the chromosomes, with preferential location of FaA5- and FaH13-related sequences at given, mainly centromeric, regions of certain chromosomes. These findings suggest that redundancy modulations of interspersed repeated sequences allow direct responses of the genome of F. arundinacea to changes in environmental temperature.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
