Regulation by Vrn-1/Fr-1 chromosomal intervals of CBF-mediated Cor/Lea gene expression and freezing tolerance in common wheat.
Vrn-1/Fr-1 chromosomal regions of common wheat possess major QTLs for both winter hardiness (Fr) and vernalization requirement (Vrn). The Vrn-1/Fr-1 intervals are assigned to long arms of the homologous group 5 chromosomes. To investigate the role of the Vrn-1/Fr-1 intervals on the low-temperature (LT) inducibility of wheat Cor/Lea genes and its putative transcription factor gene Wcbf2, LT response of these genes was monitored using near-isogenic lines (NILs) for the Vrn-1 loci. The Wcbf2 transcript accumulated rapidly after LT treatment and remained at a high level in lines without any dominant Vrn-1 alleles. By contrast, the Wcbf2 transcript level was greatly reduced in lines carrying the Vrn-1 alleles. The Vrn-1 NILs accumulated much lower amounts of Cor/Lea transcripts and COR/LEA proteins than the non-carrier line. The observed patterns and levels of gene expression, particularly in the Vrn-A1 NIL, agreed with the higher sensitivity to freezing damage in this line than in the non-carrier line. Up-regulation of the expression of the WAP1 gene, a candidate of the Vrn-1 loci, was much delayed in the non-carrier line than all the NILs carrying the Vrn-1 loci. Neither positive nor negative relationships were found between the WAP1 expression and the Cbf2/Cor/Lea expression. These results support the intimate relationship between the Cbf2/Cor/Lea expression and the level of freezing tolerance, and suggest that a functional Fr-A1 allele linked to the vrn-A1 allele, instead of the vernalization gene itself, plays a major role in regulating the CBF-mediated Cor/lea gene expression in wheat.
Kobayashi
Fuminori
F
Laboratory of Plant Genetics, Department of Biological and Environmental Science, Faculty of Agriculture, and Graduate School of Science and Technology, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan.
Takumi
Shigeo
S
Kume
Shinobu
S
Ishibashi
Machiko
M
Ohno
Ryoko
R
Murai
Koji
K
Nakamura
Chiharu
C
D000222:Adaptation, Physiological; D002874:Chromosome Mapping; D005615:Freezing; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics; D014158:Transcription, Genetic; D014908:Triticum / Q000235:genetics* / Q000378:metabolism*
D010940:Plant Proteins