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Arabidopsis onset of leaf death mutants identify a regulatory pathway controlling leaf senescence
Author(s) -
Jing HaiChun,
Sturre Marcel J. G.,
Hille Jacques,
Dijkwel Paul P.
Publication year - 2002
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2002.01400.x
Subject(s) - senescence , mutant , ethylene , biology , wild type , gene , phenotype , arabidopsis , botany , genetics , microbiology and biotechnology , biochemistry , catalysis
Summary The onset of leaf senescence is controlled by leaf age and ethylene can promote leaf senescence within a specific age window. We exploited the interaction between leaf age and ethylene and isolated mutants with altered leaf senescence that are named as o nset of l eaf d eath ( old ) mutants. Early leaf senescence mutants representing three genetic loci were selected and their senescence syndromes were characterised using phenotypical, physiological and molecular markers. old1 is represented by three recessive alleles and displayed earlier senescence both in air and upon ethylene exposure. The etiolated old1 seedlings exhibited a hypersensitive triple response. old2 is a dominant trait and the mutant plants were indistinguishable from the wild‐type when grown in air but showed an earlier senescence syndrome upon ethylene treatment. old3 is a semi‐dominant trait and its earlier onset of senescence is independent of ethylene treatment. Analyses of the chlorophyll degradation, ion leakage and SAG expression showed that leaf senescence was advanced in ethylene‐treated old2 plants and in both air‐grown and ethylene‐treated old1 and old3 plants. Epistatic analysis indicated that OLD1 might act downstream of OLD2 and upstream of OLD3 and mediate the interaction between leaf age and ethylene. A genetic model was proposed that links the three OLD genes and ethylene into a regulatory pathway controlling the onset of leaf senescence.