Ricinosomes and endosperm transfer cell structure in programmed cell death of the nucellus during
            <i>Ricinus</i>
            seed development

Greenwood, John S.; Helm, Markus; Gietl, Christine

doi:10.1073/pnas.0409429102

Cited by 100 publications

(113 citation statements)

References 26 publications

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“…The integuments undergo a rapid phase of cell division and expansion and follow different cell fates (Haughn and Chaudhury, 2005). In several plant species, the proximal region of the nucellus undergoes programmed cell death (PCD) and partially or totally disappears (Domínguez et al, 2001;Hiratsuka et al, 2002;Krishnan and Dayanandan, 2003;Greenwood et al, 2005;Lombardi et al, 2007;Radchuk et al, 2011;Yang et al, 2012;Yin and Xue, 2012). By contrast, the perisperm of quinoa seeds accumulates starch and follows a slower cell death program that retains the cell wall (López-Fernández and Maldonado, 2013).…”

Section: Introductionmentioning

confidence: 99%

Endosperm and Nucellus Develop Antagonistically in Arabidopsis Seeds

et al. 2016

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In angiosperms, seed architecture is shaped by the coordinated development of three genetically different components: embryo, endosperm, and maternal tissues. The relative contribution of these tissues to seed mass and nutrient storage varies considerably among species. The development of embryo, endosperm, or nucellus maternal tissue as primary storage compartments defines three main typologies of seed architecture. It is still debated whether the ancestral angiosperm seed accumulated nutrients in the endosperm or the nucellus. During evolution, plants shifted repeatedly between these two storage strategies through molecular mechanisms that are largely unknown. Here, we characterize the regulatory pathway underlying nucellus and endosperm tissue partitioning in Arabidopsis thaliana. We show that Polycomb-group proteins repress nucellus degeneration before fertilization. A signal initiated in the endosperm by the AGAMOUS-LIKE62 MADS box transcription factor relieves this Polycomb-mediated repression and therefore allows nucellus degeneration. Further downstream in the pathway, the TRANSPARENT TESTA16 (TT16) and GORDITA MADS box transcription factors promote nucellus degeneration. Moreover, we demonstrate that TT16 mediates the crosstalk between nucellus and seed coat maternal tissues. Finally, we characterize the nucellus cell death program and its feedback role in timing endosperm development. Altogether, our data reveal the antagonistic development of nucellus and endosperm, in coordination with seed coat differentiation.

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Section: Introductionmentioning

confidence: 99%

Endosperm and Nucellus Develop Antagonistically in Arabidopsis Seeds

et al. 2016

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“…The Arabidopsis thaliana Cys proteases, SENESCENCE-ASSOCIATED GENE12 and RESPONSIVE TO DEHYDRATION21 (RD21), which are induced during leaf senescence (Gan and Amasino, 1997;Yamada et al, 2001), facilitate nitrogen recycling. During Brassica napus and Ricinus communis seed, flower, leaf, and root development, Cys proteases like the KDEL-tailed Cys endopeptidases are expressed in tissues undergoing PCD, such as nucellar, leaf, and root cap cells (Domínguez and Cejudo, 1998;Linnestad et al, 1998;Xu and Chye, 1999;Wan et al, 2002;Helm et al, 2008), during which nuclear DNA degrades, ricinosomes proliferate, or the extensin scaffolds of the cell wall are digested (Greenwood et al, 2005;Helm et al 2008). The ricinosomes are derived from the endoplasmic reticulum (ER) and contain ER-resident binding protein (BiP) and protein disulfide isomerase (PDI; EC 5.3.4.1) (Schmid et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

ArabidopsisProtein Disulfide Isomerase-5 Inhibits Cysteine Proteases during Trafficking to Vacuoles before Programmed Cell Death of the Endothelium in Developing Seeds

et al. 2008

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Protein disulfide isomerase (PDI) oxidizes, reduces, and isomerizes disulfide bonds, modulates redox responses, and chaperones proteins. The Arabidopsis thaliana genome contains 12 PDI genes, but little is known about their subcellular locations and functions. We demonstrate that PDI5 is expressed in endothelial cells about to undergo programmed cell death (PCD) in developing seeds. PDI5 interacts with three different Cys proteases in yeast two-hybrid screens. One of these traffics together with PDI5 from the endoplasmic reticulum through the Golgi to vacuoles, and its recombinant form is functionally inhibited by recombinant PDI5 in vitro. Peak PDI5 expression in endothelial cells precedes PCD, whereas decreasing PDI5 levels coincide with the onset of PCD-related cellular changes, such as enlargement and subsequent collapse of protein storage vacuoles, lytic vacuole shrinkage and degradation, and nuclear condensation and fragmentation. Loss of PDI5 function leads to premature initiation of PCD during embryogenesis and to fewer, often nonviable, seeds. We propose that PDI5 is required for proper seed development and regulates the timing of PCD by chaperoning and inhibiting Cys proteases during their trafficking to vacuoles before PCD of the endothelial cells. During this transitional phase of endothelial cell development, the protein storage vacuoles become the de facto lytic vacuoles that mediate PCD.

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“…Assuming that the cysteine protease involved is located in the vacuole, the question arises, how Rubisco as a holoenzyme would reach the protease (or vice versa). Transfer of vesicles, autophagic processes or loss of membrane integrity represent possible mechanisms (Greenwood et al 2005;Hö rtensteiner and Feller 2002). It has been shown in Chlamydomonas rheinhardtii that soluble plastidial proteins can be transferred via protrusions from the chloroplast to vacuoles (Park et al 1999).…”

Section: Discussionmentioning

confidence: 99%

“…Ricinosomes (precursor protease vesicles) containing large amounts of a papain-type cysteine endopeptidase develop at the beginning of programmed cell death in the nucellus of Ricinus communis Greenwood et al 2005). The ricinosomes bud from the endoplasmatic reticulum ).…”

Section: Discussionmentioning

confidence: 99%

Senescence in wheat leaves: is a cysteine endopeptidase involved in the degradation of the large subunit of Rubisco?

2007

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In wheat (Triticum aestivum L.), leaf senescence can be initiated by different factors. Depending on the plant system (intact plants or detached leaves) or the environmental conditions (light, nutrient availability), the symptoms of senescence differ. The aim of this work was to elucidate the catabolism of ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco, EC. 4.1.1.39) under various senescence-inducing conditions. Leaf senescence was initiated in intact plants by darkness or by N-deprivation and in leaf segments by exposure to light or darkness. Depending on the treatment, a 50 kDa fragment of Rubisco was observed. The formation of this fragment was enhanced by leaf detachment and low light. In segments exposed to high light and in intact plants induced to senesce by N-deprivation, the fragment was essentially absent. Since an antibody against the N-terminus of a large subunit of Rubisco (LSU) did not cross-react with the fragment, it appears likely that a smaller fragment was removed from the Nterminus of LSU. Inhibitor studies suggest that a cysteine endopeptidase was involved in the formation of the 50 kDa fragment. Non-denaturing-PAGE followed by SDS-PAGE revealed that the fragment was produced while LSU was integrated in the holoenzyme complex, and that it remained there after being produced. It remains open how the putative endopeptidase reaches the stromal protein Rubisco. The results indicate that depending on the senescence-inducing conditions, different proteolytic enzymes may be involved. The involvement of vacuolar proteases must be considered as occurring during LSU degradation, which takes place in darkness, low light or under carbon limitation.

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Ricinosomes and endosperm transfer cell structure in programmed cell death of the nucellus during Ricinus seed development

Cited by 100 publications

References 26 publications

Endosperm and Nucellus Develop Antagonistically in Arabidopsis Seeds

Endosperm and Nucellus Develop Antagonistically in Arabidopsis Seeds

ArabidopsisProtein Disulfide Isomerase-5 Inhibits Cysteine Proteases during Trafficking to Vacuoles before Programmed Cell Death of the Endothelium in Developing Seeds

Senescence in wheat leaves: is a cysteine endopeptidase involved in the degradation of the large subunit of Rubisco?

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