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Polyamines cross‐talk with phospholipase A2 to regulate gene expression in tomato fruit and other plant models
Author(s) -
Fatima Tahira,
Handa Avtar K,
Mattoo Autar K
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1044-b
Subject(s) - polyamine , spermidine , spermine , putrescine , biology , transgene , genetically modified tomato , lipoxygenase , gene , methyl jasmonate , gene expression , biochemistry , microbiology and biotechnology , genetically modified crops , enzyme
Our focus is on elucidating the involvement of higher polyamines, spermidine (Spd) and spermine (Spm) in plant senescence and nutritional enhancement of tomato fruit. Our approach is to identify and characterize the genes, and the enzymes encoded by them, which are specific targets of Spd/Spm action in tomato fruit. Therefore, we developed the following transgenic tomato plants: 556HO and 579HO lines transformed with yeast SAM‐decarboxylase fused to E8, a fruit ripening‐specific promoter, and which accumulate Spd/Spm in the fruit; 650‐12HO line co‐suppressed for lipoxygenase, and is deficient in the plant hormone methyl jasmonate (meJs); LS‐4 line, which is a genetic cross between transgenic lines 556HO and 650‐12HO and is deficient in meJs but accumulates Spd/Spm. Our laboratory has identified a gene cluster whose expression is regulated by polyamines and whose expression is down‐regulated in 650‐12HO line. We have used quantitative real‐time PCR to assess differential expression of genes in the hope that we will identify the direct target of polyamine action. We will present data that implicate phospholipase A2 (PLA2) as the putative gene target of Spd/Spm action: PLA2 transcript and its esterase activity are up‐regulated in high polyamine accumulating transgenic tomato, tobacco BY2 cells and Spirodela punctata . Inhibitors that block the biosynthesis of putrescine and/or Spd/Spm inhibit the up‐regulation of PLA2 activity in the latter two systems.