Tobacco two-component gene NTHK2

By using a previously isolated tobacco two-component gene NTHK1 as a probe, we screened a cDNA library and obtained a homologous gene designated NTHK2 . Sequencing analysis revealed that NTHK2 encoded putative ethylene recepto r homolog and contained a histidine kinase domain and a receiver domain, In the histidine kinase domain, the histidine at the phosphorylation site mas replaced by an asparagine, Southern analysis indicated that NTHK2 was pres ent at low copies in tobacco genome. The expression of NTHK2 was studied us ing a competitive RT-PCR method. It was found that, in young flower buds, N THK2 was expressed abundantly, while in other organs or tissues, it was exp ressed in a low level. When leaf was subjected to wounding (cutting) treatm ent, NTHK2 expression was Increased. When tobacco seedlings were stressed w ith PEG and heat shock, NTHK2 transcription was also enhanced. Other treatm ents showed little effects. These results indicated that NTHK2 might be inv olved in the developmental processes and in plant responses to some environ mental stresses.