Identification And Cloning Of The Photoperiodic-related CDNA Fragments Of The Wheat

Flowering is the important signal which indicate the switch from vegetative to reproductive development in the high plants. Flowering time is controlled by environmental conditions and endogenous signals. Photoperiod is one of the most important factors that control flowering time . At present we have the deeper acknowledge for the molecular mechanism of flowering by studying the long-day plant Arabidopsis which is a model plant for the study of photoperiodic control of floral initiation. However, little is known about that of wheat. The object of this study is looking for the photoperiodic-related genes from the winter wheat (Triticum aestivum) "680". By using of the technique of Differential Display RT-PCR (DDRT-PCR), the differential expression patterns between the winter wheat of the differential time of photoperiod were analyzed. 100 differentially displayed cDNA fragments were isolated. Among them there were 90 fragments can be reamplified by PCR and 55 fragments were single band. By Reverse Northern dot blot, we only identified two photoperiodic-induced fragments and named PZ35 and PZ56, respectively. The two fragments were cloned and sequenced. The results of BLAST in GenBank showed that the PZ35 fragment was highly similar to some flowering time genes- COL of rice, barely, and Arabidopsis. We named the PZ35 fragment as TaCOL. Northern analysis indicates that TaCOL transcript level showed a circadian pattern expression, and the maximum level 0 and 4 h after light. Exposure to low temperature for 10d, 20d, 30d, and 40d, the mRNA expression was not detected. This suggests that TaCOL was not induced by veralization. We add GA, SA, ABA to the plant inspectively. After 2 h and 24 h , we examined the mRNA expression, but not found the mRNA level increased or reduced. So we can conclude that TaCOL expression was also not induced by GA, SA, ABA. Southern analysis suggests that TaCOL belongs to a gene family.