Isolation and analysis of a stromule-overproducing Arabidopsis mutant suggest the role of PARC6 in plastid morphology maintenance in the leaf epidermis

2017 ◽  
Vol 162 (4) ◽  
pp. 479-494 ◽  
Author(s):  
Ryuuichi D. Itoh ◽  
Hiroki Ishikawa ◽  
Kohdai P. Nakajima ◽  
Shota Moriyama ◽  
Makoto T. Fujiwara
Keyword(s):  
Leaf Epidermis ◽  
Plastid Morphology ◽  
Arabidopsis Mutant

scholarly journals Effects of Jasmonate on Ethylene Function during the Development of Tomato Stamens

Plants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 277 ◽  
Author(s):  
Ramona Schubert ◽  
Stephan Grunewald ◽  
Lea von Sivers ◽  
Bettina Hause
Keyword(s):  
Water Content ◽  
Minor Role ◽  
Wild Type ◽  
Stamen Development ◽  
Hormone Levels ◽  
Pollen Release ◽  
Arabidopsis Mutant ◽  
Ethylene Function ◽  
Pollen Vitality

The phenotype of the tomato mutant jasmonate-insensitive1-1 (jai1-1) mutated in the JA-Ile co-receptor COI1 demonstrates JA function in flower development, since it is female-sterile. In addition, jai1-1 exhibits a premature anther dehydration and pollen release, being in contrast to a delayed anther dehiscence in the JA-insensitive Arabidopsis mutant coi1-1. The double mutant jai1-1 Never ripe (jai1-1 Nr), which is in addition insensitive to ethylene (ET), showed a rescue of the jai1-1 phenotype regarding pollen release. This suggests that JA inhibits a premature rise in ET to prevent premature stamen desiccation. To elucidate the interplay of JA and ET in more detail, stamen development in jai1-1 Nr was compared to wild type, jai1-1 and Nr regarding water content, pollen vitality, hormone levels, and accumulation of phenylpropanoids and transcripts encoding known JA- and ET-regulated genes. For the latter, RT-qPCR based on nanofluidic arrays was employed. The data showed that additional prominent phenotypic features of jai1-1, such as diminished water content and pollen vitality, and accumulation of phenylpropanoids were at least partially rescued by the ET-insensitivity. Hormone levels and accumulation of transcripts were not affected. The data revealed that strictly JA-regulated processes cannot be rescued by ET-insensitivity, thereby emphasizing a rather minor role of ET in JA-regulated stamen development.

scholarly journals The Role of Cytokinin During Infection of Arabidopsis thaliana by the Cyst Nematode Heterodera schachtii

2016 ◽  
Vol 29 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Carly M. Shanks ◽  
J. Hollis Rice ◽  
Yan Zubo ◽  
G. Eric Schaller ◽  
Tarek Hewezi ◽  
...  
Keyword(s):  
Type A ◽  
Sole Source ◽  
Nematode Infection ◽  
Heterodera Schachtii ◽  
Cytokinin Signaling ◽  
Cyst Nematodes ◽  
Nematode Parasitism ◽  
Arabidopsis Mutant ◽  
Nematode Development

Plant-parasitic cyst nematodes induce the formation of hypermetabolic feeding sites, termed syncytia, as their sole source of nutrients. The formation of the syncytium is orchestrated by the nematode, in part, by modulation of phytohormone responses, including cytokinin. In response to infection by the nematode Heterodera schachtii, cytokinin signaling is transiently induced at the site of infection and in the developing syncytium. Arabidopsis lines with reduced cytokinin sensitivity show reduced susceptibility to nematode infection, indicating that cytokinin signaling is required for optimal nematode development. Furthermore, lines with increased cytokinin sensitivity also exhibit reduced nematode susceptibility. To ascertain why cytokinin hypersensitivity reduces nematode parasitism, we examined the transcriptomes in wild type and a cytokinin-hypersensitive type-A arr Arabidopsis mutant in response to H. schachtii infection. Genes involved in the response to biotic stress and defense response were elevated in the type-A arr mutant in the absence of nematodes and were hyperinduced following H. schachtii infection, which suggests that the Arabidopsis type-A arr mutants impede nematode development because they are primed to respond to pathogen infection. These results suggest that cytokinin signaling is required for optimal H. schachtii parasitism of Arabidopsis but that elevated cytokinin signaling triggers a heightened immune response to nematode infection.

scholarly journals The Arabidopsis arc5 and arc6 mutations differentially affect plastid morphology in pavement and guard cells in the leaf epidermis

PLoS ONE ◽  
2018 ◽  
Vol 13 (2) ◽  
pp. e0192380 ◽  
Author(s):  
Makoto T. Fujiwara ◽  
Mana Yasuzawa ◽  
Kei H. Kojo ◽  
Yasuo Niwa ◽  
Tomoko Abe ◽  
...  
Keyword(s):  
Guard Cells ◽  
Leaf Epidermis ◽  
Plastid Morphology

scholarly journals Identification of Ascorbic Acid-Deficient Arabidopsis thaliana Mutants

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 847-856
Author(s):  
Patricia L Conklin ◽  
Scott A Saracco ◽  
Susan R Norris ◽  
Robert L Last
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Mutant Allele ◽  
Leaf Tissue ◽  
Low Levels ◽  
Adverse Environmental Conditions ◽  
Arabidopsis Mutant ◽  
Mutant Collection ◽  
Cell Wall Expansion

Abstract Vitamin C (l-ascorbic acid) is a potent antioxidant and cellular reductant present at millimolar concentrations in plants. This small molecule has roles in the reduction of prosthetic metal ions, cell wall expansion, cell division, and in the detoxification of reactive oxygen generated by photosynthesis and adverse environmental conditions. However, unlike in animals, the biosynthesis of ascorbic acid (AsA) in plants is only beginning to be unraveled. The previously described AsA-deficient Arabidopsis mutant vtc1 (vitamin c-1) was recently shown to have a defect in GDP-mannose pyrophosphorylase, providing strong evidence for the recently proposed role of GDP-mannose in AsA biosynthesis. To genetically define other AsA biosynthetic loci, we have used a novel AsA assay to isolate four vtc mutants that define three additional VTC loci. We have also isolated a second mutant allele of VTC1. The four loci represented by the vtc mutant collection have been genetically characterized and mapped onto the Arabidopsis genome. The vtc mutants have differing ozone sensitivities. In addition, two of the mutants, vtc2-1 and vtc2-2, have unusually low levels of AsA in the leaf tissue of mature plants.

scholarly journals The Role of Silicon in Preventing Appressorial Penetration by the Rice Blast Fungus

2008 ◽  
Vol 98 (9) ◽  
pp. 1038-1044 ◽  
Author(s):  
T. Hayasaka ◽  
H. Fujii ◽  
K. Ishiguro
Keyword(s):  
Silica Gel ◽  
Rice Blast ◽  
Rice Blast Fungus ◽  
Leaf Epidermis ◽  
Adaxial Surface ◽  
Rice Plants ◽  
Blast Fungus ◽  
Spray Inoculation ◽  
Rice Leaves

To test the hypothesis that silicon (Si) confers resistance against appressorial penetration of the rice blast fungus, the proportion of appressorial penetration into the leaf epidermis to total appressoria formed was compared among rice plants amended with various rates of silica gel to those plants nonamended. The amounts of Si in the youngest leaves were consistent with the amounts of silica gel applied to the rice plants. Relative Si levels on the adaxial surface of leaves as detected by energy dispersive X-ray analysis also increased with the amounts of silica gel applied. Based on light microscopic observation of the adaxial surface of rice leaves, the proportion of appressorial penetration was reduced by increasing amounts of silica gel applied and increased with the length of period after spray inoculation. Consequently, these results strongly support the hypothesis and suggest that Si in the leaf epidermis may confer resistance against appressorial penetration. Meanwhile, the number of lesions per leaf also decreased with the amount of Si applied, while only a certain part of penetrated appressoria could become sporulating susceptible lesions. This suggests that Si also confers physiological resistance against blast infection after the penetration.

The role of diacylglycerol acyltransferase-1 and phospholipid:diacylglycerol acyltransferase-1 and -2 in the incorporation of hydroxy fatty acids into triacylglycerol in Arabidopsis thaliana expressing a castor bean oleate 12-hydroxylase geneThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 552-560 ◽  
Author(s):  
Melanie Dauk ◽  
Patricia Lam ◽  
Mark A. Smith
Keyword(s):  
Fatty Acids ◽  
Neutral Lipids ◽  
National Research Council ◽  
Plant Biotechnology ◽  
Hydroxy Fatty Acids ◽  
Acyltransferase Activity ◽  
Unusual Fatty Acids ◽  
Arabidopsis Mutant ◽  
Mutant Lines

Expression of oleate 12-hydroxylase genes in Arabidopsis results in the accumulation of hydroxy fatty acids in seed triacylglycerol (TAG). The pathways by which these unusual fatty acids become incorporated into TAG are not well understood. We expressed a fatty acid hydroxylase cDNA in Arabidopsis mutant lines to assess the role of three enzymes implicated in TAG assembly in this species. Plants deficient in the expression of phospholipid:diacylglycerol acyltransferase-1 or -2 accumulated hydroxy fatty acids and showed no differences to equivalent transformed wild-type plants. Plants lacking diacylglylcerol acyltransferase activity were also able to accumulate hydroxy fatty acids in seed neutral lipids. Triacylglycerol species containing one and two hydroxy fatty acids were abundant, and small amounts of trihydroxy-TAG were detected. These results indicate that individually, the three enzymes do not play a major role in the incorporation of hydroxy fatty acids into TAG.

scholarly journals MtNIP5;1, A Novel Medicago Truncatula Boron Diffusion Facilitator Induced Under Deficiency

2020 ◽  
Author(s):  
Sara Granado-Rodríguez ◽  
Luis Bolaños ◽  
Maria Reguera
Keyword(s):  
Medicago Truncatula ◽  
Functional Role ◽  
Amino Acid Identity ◽  
Food Protein ◽  
Transport Mechanisms ◽  
Boron Diffusion ◽  
Transporter Family ◽  
Arabidopsis Mutant ◽  
B Uptake

Abstract Background: Boron (B) uptake in plants implies a passive diffusion through membranes under optimal conditions. Under deficiency or toxicity, the participation of two distinct protein families (the aquaporin family Major intrinsic proteins (MIPs) and the Boron transporter family BOR) is required to minimize detrimental effects caused by B stress that ends up inhibiting growth and altering development. Legumes comprise important crops that offer major agronomic benefits including the capacity of establishing symbiosis with rhizobia fixing atmospheric N2 and for being important food protein sources. It is well proven their susceptibility to B stress leading to important yield penalties. However, little is known about the transport mechanisms responsible for B uptake and distribution in legumes, especially under deficiency. Results: A novel legume B transporter involved in B uptake under deficiency, the Medicago truncatula homologous protein MtNIP5;1 (Medtr1g097840) to the Arabidopsis thaliana AtNIP5;1 (sharing 73,7% amino acid identity) was identified. Further analyses revealed that this M. truncatula aquaporin expression was boron-regulated in roots, being induced under deficiency and repressed under toxicity. It localizes at the plasma membrane of root epidermal cells and in nodules, where B plays pivotal roles in symbiosis. Furthermore, a partial complementation of the nip5;1 Arabidopsis mutant phenotype under B deficiency supports a functional role of MtNIP5;1 as a B transporter of in this legume model plant. Conclusions: The results here presented support a functional role of MtNIP5;1 uptaking B under deficiency providing new insights into this micronutrient transport mechanisms in legume species.

scholarly journals Proteomic analysis of SUMO1-SUMOylome changes during defense elicitation in Arabidopsis

2020 ◽  
Author(s):  
Kishor D. Ingole ◽  
Shraddha K. Dahale ◽  
Saikat Bhattacharjee
Keyword(s):  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Covalent Attachment ◽  
Wild Type ◽  
Rapid Adaptation ◽  
Post Translational Modification ◽  
Specific Receptors ◽  
Arabidopsis Mutant ◽  
Reversible Covalent

AbstractRapid adaptation of plants to developmental or physiological cues is facilitated by specific receptors that transduce the signals mostly via post-translational modification (PTM) cascades of downstream partners. Reversible covalent attachment of SMALL UBIQUITIN-LIKE MODIFIER (SUMO), a process termed as SUMOylation, influence growth, development and adaptation of plants to various stresses. Strong regulatory mechanisms maintain the steady-state SUMOylome and mutants with SUMOylation disturbances display mis-primed immunity often with growth consequences. Identity of the SUMO-substrates undergoing SUMOylation changes during defences however remain largely unknown. Here we exploit either the auto-immune property of an Arabidopsis mutant or defense responses induced in wild-type plants against Pseudomonas syringae pv tomato (PstDC3000) to enrich and identify SUMO1-substrates. Our results demonstrate massive enhancement of SUMO1-conjugates due to increased SUMOylation efficiencies during defense responses. Of the 261 proteins we identify, 29 have been previously implicated in immune-associated processes. Role of others expand to diverse cellular roles indicating massive readjustments the SUMOylome alterations may cause during induction of immunity. Overall, our study highlights the complexities of a plant immune network and identifies multiple SUMO-substrates that may orchestrate the signalling.

Critical Role of NdhA in the Incorporation of the Peripheral Arm into the Membrane-embedded Part of the Chloroplast NADH Dehydrogenase-like Complex

2020 ◽  
Author(s):  
Hiroshi Yamamoto ◽  
Nozomi Sato ◽  
Toshiharu Shikanai
Keyword(s):  
Nadh Dehydrogenase ◽  
Critical Role ◽  
Pentatricopeptide Repeat ◽  
Ppr Protein ◽  
Final Assembly ◽  
In The Wild ◽  
Ndh Genes ◽  
Arabidopsis Mutant ◽  
Biochemical Analyses

Abstract The chloroplast NADH dehydrogenase-like (NDH) complex mediates ferredoxin-dependent plastoquinone reduction in the thylakoid membrane. In angiosperms, chloroplast NDH is composed of five subcomplexes and further forms a supercomplex with PSI. Subcomplex A (SubA) mediates the electron transport and consists of eight subunits encoded by both plastid and nuclear genomes. The assembly of SubA in the stroma has been extensively studied but it is unclear how SubA is incorporated into the membrane embedded part of the NDH complex. Here, we isolated a novel Arabidopsis mutant chlororespiratory reduction 16 (crr16) defective in NDH activity. CRR16 encodes a chloroplast-localized P-class pentatricopeptide repeat (PPR) protein conserved in angiosperms. Transcript analysis of plastid-encoded ndh genes indicated that CRR16 was responsible for the efficient splicing of the group II intron in the ndhA transcript, which encodes a membrane-embedded subunit localized to the connecting site between SubA and membrane subcomplex (SubM). To analyze the roles of NdhA in the assembly and stability of the NDH complex, the homoplastomic knockout plant of ndhA (ΔndhA) was generated in tobacco (Nicotiana tabacum). Biochemical analyses of crr16 and ΔndhA plants indicated that NdhA was essential for stabilizing SubA and SubE but not for the accumulation of the other three subcomplexes. Furthermore, the crr16 mutant accumulated the SubA assembly intermediates in the stroma more than that in the wild type. These results suggest that NdhA biosynthesis is essential for the incorporation of SubA into the membrane-embedded part of the NDH complex at the final assembly step of the NDH-PSI supercomplex.

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