Rice tillering dwarf mutant dwarf3 has increased leaf longevity during darkness-induced senescence or hydrogen peroxide-induced cell death.
Senescence or cell death in plant leaves is known to be inducible by darkness or H(2)O(2). When the Arabidopsis gene MAX2/ORE9 is disrupted, leaf senescence or cell death in response to the above stimuli is delayed. Because the rice (Oryza sativa L.) gene DWARF3 (D3) is orthologous to MAX2/ORE9, we wished to know whether disruption of D3 also results in increased longevity in leaves. We found that darkness-induced senescence or H(2)O(2)-induced cell death in the third leaf [as measured by chlorophyll degradation, membrane ion leakage and expression of senescence-associated genes (SAGs)] in a d3 rice mutant was delayed by 1-3 d compared to that in its reference line Shiokari. Moreover, the mRNA levels of D3, HTD1 and D10, which are orthologs of Arabidopsis MAX2/ORE9, MAX3 and MAX4, respectively, increased during cell death. These results suggest that D3 protein in rice, like MAX2/ORE9 in Arabidopsis, is involved in leaf senescence or cell death.
Yan
Haifang
H
Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo, Japan.
Saika
Hiroaki
H
Maekawa
Masahiko
M
Takamure
Itsuro
I
Tsutsumi
Nobuhiro
N
Kyozuka
Junko
J
Nakazono
Mikio
M
D016923:Cell Death / Q000187:drug effects / Q000235:genetics*; D016922:Cellular Senescence / Q000187:drug effects / Q000235:genetics*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003624:Darkness; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D017343:Genes, Plant / Q000187:drug effects / Q000502:physiology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009154:Mutation; D012275:Oryza / Q000187:drug effects / Q000502:physiology*; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology*
D003577:Cytochrome P-450 Enzyme System; D006861:Hydrogen Peroxide