Molecular analysis of programmed cell death during senescence in Arabidopsis thaliana and Brassica oleracea: cloning broccoli LSD1, Bax inhibitor and serine palmitoyltransferase homologues

Abstract

This study was undertaken to characterize the programmed cell death (PCD) processes that occur during detached and natural on-plant senescence and correlate them with the expression of putative regulatory genes that may be involved in the process. DNA fragmentation and TUNEL analysis of broccoli florets showed that DNA was processed into fragments of approximately 180 bp after 48 h of harvest-induced tissue senescence. Characteristic laddering patterns were also visible in Arabidopsis leaves undergoing natural on-plant senescence and during detached senescence. Several recently isolated plant proteins have been assigned a PCD role, for example, the zinc finger containing protein, LSD1 (lesion simulating disease); Bax inhibitor (BI); and serine palmitoyltransferase (SPT), an enzyme in the sphingolipid signalling pathway. Two cDNAs encoding each of these proteins were isolated from broccoli (BoBI-1, BoBI-2, BoLSD1, BoLSD2, BoSPT1, BoSPT2), and the mRNAs increased during harvest-induced senescence in floret tissue. Expression of the Arabidopsis homologues (AtBI-1, AtLSD1, AtSPT1) were also characterized during detached leaf senescence in Arabidopsis leaves. AtBI-1 expression was constitutively expressed during detached senescence, AtLSD1 expression remained constitutively low, and AtSPT1 expression increased during detached senescence.

Cell Death Suppressor Arabidopsis Bax Inhibitor-1 Is Associated with Calmodulin Binding and Ion Homeostasis

“…For example, H 2 O 2 -, SA-, elicitor-, heat-, and cold-induced cell death were suppressed in plant cells overexpressing AtBI-1 (Chae et al, 2003;Matsumura et al, 2003;KawaiYamada et al, 2004). Expression of plant BI-1 genes is rapidly up-regulated during wounding, pathogen attack (Sanchez et al, 2000), and senescence (Coupe et al, 2004), but down-regulated by elicitor treatment (Matsumura et al, 2003). These results suggest the involvement of BI-1 in the stress response and the HR in plants.…”

Quantitative Proteomic Analysis of Bean Plants Infected by a Virulent and Avirulent Obligate Rust Fungus

“…These included a cysteine peptidase similar to VPE, which controls vacuolar proteolysis in tobacco undergoing an HR (17) and serine C-palmitoyltransferase, a sphingolipid synthase the increased activity of which is linked to cell death (59). By 72 hpi in resistant plants, there was increased accumulation of a harpin-binding protein and a zinc metalloproteinase and decreased accumulation of protoporphyrinogen oxidase.…”

Nitric Oxide Signaling During Senescence and Programmed Cell Death in Leaves

“…For example, Bax inhibitor-1 (BI-1) has been shown to suppress PCD in both plant and animal cells (Watanabe & Lam, 2006). Bax inhibitor-1 is upregulated during harvest-induced senescence in broccoli (Coupe et al, 2004). Another PCD suppressor, defender against apoptotic death (DAD1), is upregulated during leaf senescence (Dong et al,1998), whereas it is down regulated before the onset of apoptotic like cell death in shorter-lived petals of pea (Orzaez & Granell,1997), Alstroemeria and gladiolus (Yamada et al, 2004).…”