Constitutive and Inducible ER Bodies of Arabidopsis thaliana Accumulate Distinct β-Glucosidases

Ogasawara, Kimi; Yamada, Kenji; Christeller, John T.; Kondo, Maki; Hatsugai, Noriyuki; Hara‐Nishimura, Ikuko; Nishimura, Mikio

doi:10.1093/pcp/pcp007

Cited by 71 publications

(93 citation statements)

References 24 publications

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“…Based on their sequence similarity, it can be assumed that these 8 β-glucosidases localize in ER bodies. Consistent with this, the subfamily member BGLU18 accumulates in ER bodies that are induced by wounding in rosette leaves (Ogasawara et al, 2009). …”

Section: Molecular Mechanisms Underlying Er Body Formationmentioning

confidence: 64%

ER bodies in plants of the Brassicales order: biogenesis and association with innate immunity

et al. 2014

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The endoplasmic reticulum (ER) forms highly organized network structures composed of tubules and cisternae. Many plant species develop additional ER-derived structures, most of which are specific for certain groups of species. In particular, a rod-shaped structure designated as the ER body is produced by plants of the Brassicales order, which includes Arabidopsis thaliana. Genetic analyses and characterization of A. thaliana mutants possessing a disorganized ER morphology or lacking ER bodies have provided insights into the highly organized mechanisms responsible for the formation of these unique ER structures. The accumulation of proteins specific for the ER body within the ER plays an important role in the formation of ER bodies. However, a mutant that exhibits morphological defects of both the ER and ER bodies has not been identified. This suggests that plants in the Brassicales order have evolved novel mechanisms for the development of this unique organelle, which are distinct from those used to maintain generic ER structures. In A. thaliana, ER bodies are ubiquitous in seedlings and roots, but rare in rosette leaves. Wounding of rosette leaves induces de novo formation of ER bodies, suggesting that these structures are associated with resistance against pathogens and/or herbivores. ER bodies accumulate a large amount of β-glucosidases, which can produce substances that potentially protect against invading pests. Biochemical studies have determined that the enzymatic activities of these β-glucosidases are enhanced during cell collapse. These results suggest that ER bodies are involved in plant immunity, although there is no direct evidence of this. In this review, we provide recent perspectives of ER and ER body formation in A. thaliana, and discuss clues for the functions of ER bodies. We highlight defense strategies against biotic stress that are unique for the Brassicales order, and discuss how ER structures could contribute to these strategies.

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Section: Molecular Mechanisms Underlying Er Body Formationmentioning

confidence: 64%

ER bodies in plants of the Brassicales order: biogenesis and association with innate immunity

et al. 2014

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“…5B), demonstrating that the action of allantoin relies on an intact JA signaling pathway and requires the formation of bioactive JA-Ile. Because MYC2 is responsive to ABA (Abe et al, 1997), and because ABA levels increase in the aln mutants and in response to exogenous allantoin in WT plants (Watanabe et al, 2014b), expression of JA-responsive genes was also examined in the ABA-deficient mutants aba2-1 (abscisic acid deficient 2-1) and bglu18 (ß-glucosidase 18), which impair de novo ABA synthesis and regeneration of ABA from inactive ABA glucosides, respectively (Léon-Kloosterziel et al, 1996;Lee et al, 2006;Ogasawara et al, 2009). Similar to the JA-insensitive mutants, neither aba2-1 nor bglu18 mutants showed increases in the transcript levels of JA-responsive genes in response to exogenous allantoin (Fig.…”

Section: Allantoin Requires Aba To Activate Ja-responsive Genesmentioning

confidence: 99%

Allantoin, a stress-related purine metabolite, can activate jasmonate signaling in a MYC2-regulated and abscisic acid-dependent manner

Ishiga

Watanabe

Konishi

et al. 2016

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Allantoin is a metabolic intermediate of purine catabolism that often accumulates in stressed plants. Recently, we used Arabidopsis knockout mutants (aln) of ALLANTOINASE to show that this purine metabolite activates abscisic acid (ABA) production, thereby stimulating stress-related gene expression and enhancing seedling tolerance to abiotic stress. A detailed re-examination of the microarray data of an aln mutant (aln-1) confirmed the increased expression of ABA-related genes and also revealed altered expression of genes involved in jasmonic acid (JA) responses, probably under the control of MYC2, a master switch in the JA signaling pathway. Consistent with the transcriptome profiles, the aln-1 mutant displayed increased JA levels and enhanced responses to mechanical wounding and exogenous JA. Moreover, aln mutants demonstrated modestly increased susceptibility to Pseudomonas syringae and Pectobacterium carotovorum, probably reflecting the antagonistic action of MYC2 on the defense against these bacterial phytopathogens. Exogenously administered allantoin elicited the expression of JA-responsive genes, including MYC2, in wild-type plants, supporting the idea that allantoin might be responsible for the observed JA-related phenotypes of aln mutants. However, mutants deficient in bioactive JA (jar1-1), insensitive to JA (myc2-3), or deficient in ABA (aba2-1 and bglu18) suppressed the effect of exogenous allantoin. The suppression was further confirmed in aln-1 jar1-1 and aln-1 bglu18 double mutants. These results indicate that allantoin can activate the MYC2-regulated JA signaling pathway through ABA production. Overall, this study suggests a possible connection of purine catabolism with stress hormone homeostasis and signaling, and highlights the potential importance of allantoin in these interactions.

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“…Our immunolocalization protocols are known to preserve the native patterns of the plasma membrane and ER in pavement cells (Zhang et al, 2010). In 2-DAG cotyledon pavement cells, the relatively large punctae strongly colocalized with bright GFP-HDEL-positive structures that, based on their size, shape, and number, corresponded to ER bodies (Hara-Nishimura and Ogasawara et al, 2009). The colocalization can be visualized qualitatively as the white pixels in the merged panel in Figure 6A that reflect overlapping false-colored magenta NAP1 pixels with the green GFP-HDEL pixels.…”

Section: Nap1 Colocalizes With the Er In Pavement Cells And Trichomesmentioning

confidence: 99%

The Endoplasmic Reticulum Is a Reservoir for WAVE/SCAR Regulatory Complex Signaling in the Arabidopsis Leaf

et al. 2013

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During plant cell morphogenesis, signal transduction and cytoskeletal dynamics interact to locally organize the cytoplasm and define the geometry of cell expansion. The WAVE/SCAR (for WASP family verprolin homologous/suppressor of cyclic AMP receptor) regulatory complex (W/SRC) is an evolutionarily conserved heteromeric protein complex. Within the plant kingdom W/SRC is a broadly used effector that converts Rho-of-Plants (ROP)/Rac small GTPase signals into Actin-Related Protein2/3 and actin-dependent growth responses. Although the components and biochemistry of the W/SRC pathway are well understood, a basic understanding of how cells partition W/SRC into active and inactive pools is lacking. In this paper, we report that the endoplasmic reticulum (ER) is an important organelle for W/SRC regulation. We determined that a large intracellular pool of the core W/SRC subunit NAP1, like the known positive regulator of W/SRC, the DOCK family guanine nucleotide-exchange factor SPIKE1 (SPK1), localizes to the surface of the ER. The ER-associated NAP1 is inactive because it displays little colocalization with the actin network, and ER localization requires neither activating signals from SPK1 nor a physical association with its W/SRC-binding partner, SRA1. Our results indicate that in Arabidopsis (Arabidopsis thaliana) leaf pavement cells and trichomes, the ER is a reservoir for W/SRC signaling and may have a key role in the early steps of W/SRC assembly and/or activation.

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Constitutive and Inducible ER Bodies of Arabidopsis thaliana Accumulate Distinct β-Glucosidases

Cited by 71 publications

References 24 publications

ER bodies in plants of the Brassicales order: biogenesis and association with innate immunity

ER bodies in plants of the Brassicales order: biogenesis and association with innate immunity

Allantoin, a stress-related purine metabolite, can activate jasmonate signaling in a MYC2-regulated and abscisic acid-dependent manner

The Endoplasmic Reticulum Is a Reservoir for WAVE/SCAR Regulatory Complex Signaling in the Arabidopsis Leaf

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