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The timing of maize leaf senescence and characterisation of senescence‐related cDNAs
Author(s) -
Smart Catherine M.,
Hosken Sally E.,
Thomas Howard,
Greaves John A.,
Blair Bruce G.,
Schuch Wolfgang
Publication year - 1995
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1995.tb05116.x
Subject(s) - senescence , biology , complementary dna , chlorophyll , gene expression , gene , botany , genetics
Leaf senescence was characterised in two Zea mays lines, earlier senescence (ES) and later senescence (LS). Loss of chlorophyll was delayed in LS compared with ES, but the decline in photosynthesis occurred simultaneously in the two lines. Western analysis detected transition points during senescence of both lines when major quantitative and qualitative changes occurred in a number of leaf proteins. Differences in the pattern of translatable mRNAs were apparent earlier than alterations in pigment or protein levels. A cDNA library was constructed using mRNA from ES leaves early in senescence and differential screening was employed to isolate senescence‐related clones. Two senescence‐enhanced cDNAs showed sequence homology with cDNAs for seed proteins ‐ a cysteine protease and a protein‐processing enzyme. These findings suggest that there are similarities between gene expression during seed maturation, germination and leaf senescence. Other senescence‐enhanced cDNAs were related to genes implicated in gluconeogenesis and chlorophyll breakdown.