Heme oxygenase-1 is involved in the cytokinin-induced alleviation of senescence in detached wheat leaves during dark incubation
Huang, J and Han, B and Xu, S and Zhou, M and Shen, W, Heme oxygenase-1 is involved in the cytokinin-induced alleviation of senescence in detached wheat leaves during dark incubation, Journal of Plant Physiology: Biochemistry, Physiology, Molecular Biology and Functional Biotechnology of Plants, 168, (8) pp. 768-775. ISSN 0176-1617 (2011) [Refereed Article]
This study tested whether an inducible isoform of heme oxygenase (HO, EC 22.214.171.124), HO-1, is involved
in the cytokinin (CTK)-induced alleviation of senescence in detached wheat (Triticum aestivum L.) leaves
during dark incubation. We discovered that exogenous supplement of 6-benzylaminopurine (6-BA) at
10M for 48 h not only delayed the dark-induced loss of chlorophyll and protein contents in detached
wheat leaves, but also significantly increased HO activity in a time-dependent manner. This induction
reached a maximum within 3 h of 6-BA supply, which was further confirmed by using semi-quantitative
RT-PCR and protein gel blot analysis. Furthermore, the decreases in intracellular thiobarbituric acid reactive
substances (TBARS) content, and the increases in the transcript level, total and isozymatic activities of
some important antioxidant enzymes, such as catalase (CAT, EC 126.96.36.199), peroxidase (POD, EC 188.8.131.52),
superoxide dismutase (SOD, EC 184.108.40.206), and ascorbate peroxidase (APX, EC 220.127.116.11), were observed.
Reversed responses of chlorophyll, protein and TBARS contents, HO activity, and the expression of above
antioxidant enzymes were observed when zinc protoporphyrin-IX (ZnPPIX), a potent HO-1 inhibitor,
was added together with 6-BA. In contrast, HO-1 inducer hemin could partially mimic the effects of 6-BA.
Together, the results suggest that HO-1 might be involved in the CTK-induced alleviation of senescence
and lipid peroxidation in detached wheat leaves.