Cloning and expression analysis of hemoglobin genes from maize (Zea mays ssp mays) and teosinte (Zea mays ssp parviglumis)

With the exception of barley and rice, little is known about the existence of hemoglobins (Hbs) in cereals. This work reports the cloning and analysis of hb genes from maize (Zea mays ssp. mays) and teosinte (Zea mays ssp. pa rviglumis). Coding sequences of maize and teosinte hb genes (hbm and hbt, r espectively) are highly similar to each other and are interrupted by three introns located at identical positions as other plant hb genes. Sequences o f predicted Hbm and Hbt proteins are identical. The hydropathic profile of Hbm and Hbt is highly similar to that of rice Hb1, suggesting that Hbm, Hbt and Hb1 have the same tertiary structure and biochemical properties. Expre ssion analysis showed that low levels of Hb transcripts, but considerable l evels of Hb proteins exist in maize embryonic organs. No Hb transcripts and proteins were detected in teosinte embryonic organs. Low levels of Hb prot eins, but no Hb transcripts, were detected in maize and teosinte vegetative organs. These observations suggest that the regulation of hb genes is diff erent in maize and teosinte embryonic organs, and that the expression of hb genes is down- or up-regulated in maize and teosinte, respectively, from g ermination to vegetative growing. (C) 2001 Elsevier Science B.V. All rights reserved.