21241331
not annotated - annotated - LINNAEUS only
Expression of a Brassica napus heme oxygenase confers plant tolerance to mercury toxicity.
Plant heme oxygenases (HOs) regulate biosynthesis of phytochrome which accounts for photo-acceptance and -morphogenesis. Recent studies have demonstrated that plant HOs also regulate many other physiological processes including response to environmental stimuli. To elucidate the mechanism by which HOs regulate plant adaptation to heavy metal exposure, three novel HOs genes were isolated from rapeseed (Brassica napus) and their expression patterns were analysed. Alignment of deduced protein sequences revealed that the three BnHOs share high identity with their corresponding orthologos (AtHO1-3) from Arabidopsis. To investigate whether the BnHO regulates plant tolerance to Hg toxicity, we constructed B. napus transgenic plants overexpressing BnHO-1. Under Hg stress, the transgenic plants had 1.41-1.59 folds higher biomass than the untransformants. However, overexpression of BnHO-1 resulted in less accumulation of Hg in some lines of transformants than in untransformants. The transgenic plants show lower abundance of reactive oxygen species and attenuated oxidative injury compared with the untransgenic plants. We cloned the promoter sequences of BnHO-1 from B. napus. Analysis revealed that the 1119 bp fragment contains a conserved Cd responsive element (CdRE) and others responding to multiple environmental stimuli. Transient expression in tobacco leaves showed differential responses to heavy metals (Zn, Cu, Pb, Hg and Cd).
Ann file
T1 Species 16 30 Brassica napus
N1 Reference T1 Taxonomy:3708
T2 Species 488 496 rapeseed
N2 Reference T2 Taxonomy:3708
T3 Species 498 512 Brassica napus
N3 Reference T3 Taxonomy:3708
T4 Out-of-scope 699 710 Arabidopsis
T5 Species 801 809 B. napus
N5 Reference T5 Taxonomy:3708
T6 Species 1266 1274 B. napus
N6 Reference T6 Taxonomy:3708
T7 Species 1451 1458 tobacco
N7 Reference T7 Taxonomy:4097
N4 Reference T4 Taxonomy:3701 Arabidopsis