A wheat cold-regulated cDNA encoding an early light-inducible protein (ELIP): Its structure, expression and chromosomal location

Sequencing and computer analysis revealed that a wcr (wheat cold-regulated) cDNA, wcr12, contained a 525 bp open reading frame encoding a polypeptide of 174 amino acids. The deduced WCR12 protein had a high sequence similarit y with Early light-inducible proteins (ELIPs) which are known as nuclear-en coded chloroplast proteins induced by light stress. The accumulation of wcr 12 transcripts was induced by low temperature below 8 degrees C and was als o increased under a high light flux of 1,000 mu Em(-2) s(-1), which are typ ical expression patterns of the genes for ELIPs in other plants. The dramat ic increase in the level of wcr12 transcripts was detected at 4 degrees C e ven under a low light condition (50 mu Em(-2)s(-1)) and the level of transc ripts became 20-fold higher than the control at 20 degrees C under a modera te light condition (250 mu Em(-2) s(-1)). Surprisingly, the accumulation of wcr12 mRNAs was also induced by cold treatment alone at 4 degrees C in the darkness. The level of wcr12 transcripts accumulated in the darkness at 4 degrees C reached the same level as that under a high light flux at 20 degr ees C. These results indicate that light is not essential for the accumulat ion of wcr12 transcripts at a low temperature. To determine the chromosomal location of wcr12 gene, we performed Southern analysis using the nullitetr asomic lines. The data showed that the wcr12 gene or related homologues are located on the chromosomes of homoeologous group-5 in wheat.