Characterization of Receptor-like Protein Kinase Gene Expressed During Plant Regeneration in Hordeum vulgare L.

In order to provide information on molecular events during plant regeneration, cDNA library was constructed using tissues of the 6 day-old shoot formation (SF) cultures. Differential hybridization method was used to isolate genes expressed differentially during plant regeneration. We characterized one clone encoding receptor-like protein kinase (HvRLK). Using northern analysis, the expression of HvRLK was highly increased from 3, 6 day-old SF cultures and expressed in the shoot of plantlet. Tissue specific expression of HvRLK during different stages of shoot induction and callus development was identified by in situ hybridization. High levels of HvRLK expression were observed in day 6 SF cultures, where the signal was localized primarily in the developing shoot primordial. The transcript of HvRLK gene was slightly increased 3 hrs after plant growth hormone [ABA, cytokinin (BAP), and GA₃] treatment, but not detected after 12 hrs in ABA. The expression of HvRLK was high in BAP application. In the case of GA₃ treatment, HvRLK mRNAs was strongly expressed at 3 hrs after treatment and reached the highest at 6 hrs, but dramatically decreased from 12 hrs after treatment. Expression pattern of HvRLK gene was determined in the leaves treated by wounding. The transcript level of HvRLK was highly increased from 1 hr after treatment, and slightly decreased from 3 to 24 hrs after wounding treatment.