Dataset Information

H₂O₂ Induces Association of RCA with the Thylakoid Membrane to Enhance Resistance of Oryza meyeriana to Xanthomonas oryzae pv. oryzae.

ABSTRACT: Oryza meyeriana is a wild species of rice with high resistance to Xanthomonas oryzae pv. oryzae (Xoo), but the detailed resistance mechanism is unclear. Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) is an important enzyme that regulates photosynthesis by activating Rubisco. We have previously reported that Xoo infection induced the relocation of RCA from the chloroplast stroma to the thylakoid membrane in O. meyeriana, but the underlying regulating mechanism and physiological significance of this association remains unknown. In this study, "H₂O₂ burst" with rapid and large increase in the amount of H₂O₂ was found to be induced by Xoo invasion in the leaves of O. meyeriana. 3, 3-diaminobenzidine (DAB) and oxidative 2, 7-Dichlorodi-hydrofluorescein diacetate (H₂DCFDA) staining experiments both showed that H₂O₂ was generated in the chloroplast of O. meyeriana, and that this H₂O₂ generation as well as Xoo resistance of the wild rice were dramatically dependent on light. H₂O₂, methyl viologen with light, and the xanthine-xanthine oxidase system all induced RCA to associate with the thylakoid membrane in vitro, which showed that H₂O₂ could induce the relocation of RCA. In vitro experiments also showed that H₂O₂ induced changes in both the RCA and thylakoid membrane that were required for them to associate and that this association only occurred in O. meyeriana and not in the susceptible cultivated rice. These results suggest that the association of RCA with the thylakoid membrane helps to protect the thylakoid membrane against oxidative damage from H₂O₂. Therefore, in addition to its universal function of activating Rubisco, RCA appears to play a novel role in the resistance of O. meyeriana to Xoo.

SUBMITTER: Mei Q

PROVIDER: S-EPMC6784163 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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H2O2 Induces Association of RCA with the Thylakoid Membrane to Enhance Resistance of Oryza meyeriana to Xanthomonas oryzae pv. oryzae.

Mei Qiong Q Yang Yong Y Ye Shenhai S Liang Weifang W Wang Xuming X Zhou Jie J Yu Chulang C Yan Chengqi C Chen Jianping J

Plants (Basel, Switzerland) 20190916 9

Oryza meyeriana is a wild species of rice with high resistance to Xanthomonas oryzae pv. oryzae (Xoo), but the detailed resistance mechanism is unclear. Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) is an important enzyme that regulates photosynthesis by activating Rubisco. We have previously reported that Xoo infection induced the relocation of RCA from the chloroplast stroma to the thylakoid membrane in O. meyeriana, but the underlying regulating mechanism an ...[more]

PMID: 31527548

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Project description:BackgroundSpotted-leaf mutants are important to reveal programmed cell death and defense-related pathways in rice. We previously characterized the phenotype performance of a rice spotted-leaf mutant spl21 and narrowed down the causal gene locus spl21(t) to an 87-kb region in chromosome 12 by map-based cloning.ResultWe showed that a single base substitution from A to G at position 836 in the coding sequence of Oryza sativa beta-1,6-N-acetylglucosaminyl transferase (OsGCNT), effectively mutating Tyr to Cys at position 279 in the translated protein sequence, was responsible for the spotted-leaf phenotype as it could be rescued by functional complementation. Compared to the wild type IR64, the spotted-leaf mutant spl21 exhibited loss of chlorophyll, breakdown of chloroplasts, down-regulation of photosynthesis-related genes, and up-regulation of senescence associated genes, which indicated that OsGCNT regulates premature leaf senescence. Moreover, the enhanced resistance to the bacterial leaf blight pathogen Xanthomonas oryzae pv. oryzae, up-regulation of pathogenesis-related genes and increased level of jasmonate which suggested that OsGCNT is a negative regulator of defense response in rice. OsGCNT was expressed constitutively in the leaves, sheaths, stems, roots, and panicles, and OsGCNT-GFP was localized to the Golgi apparatus. High throughput RNA sequencing analysis provided further evidence for the biological effects of loss of OsGCNT function on cell death, premature leaf senescence and enhanced disease resistance in rice. Thus, we demonstrated that the novel OsGCNT regulated rice innate immunity and immunity-associated leaf senescence probably by changing the jasmonate metabolic pathway.ConclusionsThese results reveal that a novel gene Oryza sativa beta-1,6-N-acetylglucosaminyl transferase (OsGCNT) is responsible for the spotted-leaf mutant spl21, and OsGCNT acts as a negative-regulator mediating defense response and immunity-associated premature leaf senescence probably by activating jasmonate signaling pathway.

Project description:BackgroundXanthomonas oryzae pv oryzae is a devastating pathogen of rice and has been extensively studied as a model pathogen of monocotyledons. Expressional studies in both the contenders have been undertaken in past to understand the molecular mechanism underlying the compatible and incompatible interactions in the pathosystem. Continuous update on database and gene annotations necessitates constant updating on the roles of the new entities as well as reinterpretation of regulations of the previous ones. Moreover the past endeavors have addressed the middle or late defense responses of the rice plant whereas in the present study an attempt has been made to investigate the early defense responses taking place immediately after inoculation.ResultsMicroarray was used to study the transcriptional modulations in eighteen days old rice seedling leaves of both susceptible and resistant genotypes one hour after inoculation. In resistant plants as compared to susceptible ones 274 genes were found to be differentially expressed. Annotations could be assigned to 112 up- and 73 down-regulated transcripts and gene interaction maps were generated for 86 transcripts. Expressional data and interaction maps were used to develop a hypothetical scheme of the molecular events taking place during early defense response. Network analysis with the differential transcripts showed up-regulation of major clusters of cell signaling proteins and transcription factors while growth and basal metabolic components were largely found to be down-regulated.ConclusionsThis study provides an understanding of the early defense signaling in rice cells. Components of the calcium and lipid signaling as well as MAPK cascade were modulated, by signals from surface receptors and cytosolic R-proteins, to arouse jasmonic acid and ethylene signaling and suppress auxin signaling through various transcription factors. Abscisic acid modulation was also evident through the expression regulation of transcription factors involved with its functions. Moreover adjustments in expression levels of components of primary as well as secondary metabolism, protein trafficking and turnout were apparent, highlighting the complexity of defense response.

Dataset Information

H₂O₂ Induces Association of RCA with the Thylakoid Membrane to Enhance Resistance of Oryza meyeriana to Xanthomonas oryzae pv. oryzae.

Publications

H<sub>2</sub>O<sub>2</sub> Induces Association of RCA with the Thylakoid Membrane to Enhance Resistance of Oryza meyeriana to Xanthomonas oryzae pv. oryzae.

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