ORCID Profile
0000-0003-1057-2267
Current Organisation
Curtin University
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Publisher: Oxford University Press (OUP)
Date: 18-05-2023
DOI: 10.1093/JXB/ERAD183
Abstract: Pathogen attacks elicit dynamic and widespread molecular responses in plants. While our understanding of plant responses has advanced considerably, little is known of the molecular responses in the asymptomatic ‘green’ regions adjoining lesions. Here, we explore gene expression data and high-resolution elemental imaging to report the spatiotemporal changes in the asymptomatic green region of susceptible and moderately resistant wheat cultivars infected with a necrotrophic fungal pathogen, Pyrenophora tritici-repentis. We show, with improved spatiotemporal resolution, that calcium oscillations are modified in the susceptible cultivar, resulting in ‘frozen’ host defence signals at the mature disease stage, and silencing of the host’s recognition and defence mechanisms that would otherwise protect it from further attacks. In contrast, calcium accumulation and a heightened defence response were observed in the moderately resistant cultivar in the later stage of disease development. Furthermore, in the susceptible interaction, the asymptomatic green region was unable to recover after disease disruption. Our targeted s ling technique also enabled detection of eight previously predicted proteinaceous effectors in addition to the known ToxA effector. Collectively, our results highlight the benefits of spatially resolved molecular analysis and nutrient mapping to provide high-resolution spatiotemporal snapshots of host–pathogen interactions, paving the way for disentangling complex disease interactions in plants.
Publisher: Wiley
Date: 02-08-2021
Abstract: Analysis of the epicuticular wax layer on the surface of plant leaves can provide a unique window into plant physiology and responses to environmental stimuli. Well‐established analytical methodologies can quantify epicuticular wax composition, yet few methods are capable of imaging wax distribution in situ or in vivo. Here, the first report of Fourier transform infrared (FTIR) reflectance spectroscopic imaging as a non‐destructive, in situ, method to investigate variation in epicuticular wax distribution at 25 µm spatial resolution is presented. The authors demonstrate in vivo imaging of alterations in epicuticular waxes during leaf development and in situ imaging during plant disease or exposure to environmental stressors. It is envisaged that this new analytical capability will enable in vivo studies of plants to provide insights into how the physiology of plants and crops respond to environmental stresses such as disease, soil contamination, drought, soil acidity, and climate change.
Publisher: MDPI AG
Date: 22-02-2021
Abstract: In Arabidopsis thaliana there are more than 600 C-to-U RNA editing events in the mitochondria and at least 44 in the chloroplasts. Pentatricopeptide repeat (PPR) proteins provide the specificity for these reactions. They recognize RNA sequences in a partially predictable fashion via key amino acids at the fifth and last position in each PPR motif that bind to in idual ribonucleotides. A combined approach of RNA-Seq, mutant complementation, electrophoresis of mitochondrial protein complexes and Western blotting allowed us to show that MEF100, a PPR protein identified in a genetic screen for mutants resistant to an inhibitor of γ -glutamylcysteine synthetase, is required for the editing of nad1-493, nad4-403, nad7-698 and ccmFN2-356 sites in Arabidopsis mitochondria. The absence of editing in mef100 leads to a decrease in mitochondrial Complex I activity, which probably explains the physiological phenotype. Some plants have lost the requirement for MEF100 at one or more of these sites through mutations in the mitochondrial genome. We show that loss of the requirement for MEF100 editing leads to ergence in the MEF100 binding site.
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.ECOENV.2019.110008
Abstract: Excess iron (Fe) is commonly observed in wetland rice (Oryza sativa L.) plants, impairing crop growth and productivity. Some information suggests that silicon (Si) can reduce Fe content in leaves and roots of rice (vegetative phase), but nothing is known if Si could mitigate the effects of Fe toxicity on rice production and photosynthesis. Here, we assessed the role of Si in alleviating the well-known effects of Fe toxicity on nutritional imbalances, biomass accumulation, photosynthesis and grain yield using two rice cultivars having differential abilities to tolerate excess Fe. Plants were hydroponically grown under two Fe levels (25 μM or 5 mM) and the nutrient solutions were amended with Si (0 or 2 mM). Under excess Fe were detected (i) nutritional deficiencies, especially of calcium and magnesium in leaves (ii) negligible changes in grain nutritional composition, independently of Si application (iii) decreases in net photosynthetic rates, stomatal conductance and electron transport rate, in parallel to decreased grain yield components (total grain biomass, 1000-grain mass, percentage of filled grains, number of grains per plant and harvest index), especially in the Fe-sensitive cultivar. These impairments were partially reversed by the application of Si. Results also suggest that Si alleviated the negative impacts of Fe on spikelet sterility. In summary, we conclude that the use of Si can be recommended as an effective management strategy to reduce the negative impacts of Fe toxicity on rice photosynthetic performance and crop yield.
Publisher: MDPI AG
Date: 26-08-2023
Abstract: Pentatricopeptide repeat (PPR) proteins are considered a potential tool for manipulating organelle gene expression in plants because they can recognise a wide range of different RNA sequences, and the molecular basis for this sequence recognition is partially known and understood. A library of redesigned PPR proteins related to restorer-of-fertility proteins was created and transformed into plants in order to target mitochondrial transcripts. Ninety different variants tested in vivo showed a wide range of phenotypes. One of these lines, which displayed slow growth and downward curled leaves, showed a clear reduction in complex V. The phenotype was due to a specific cleavage of atp1 transcripts induced by a modified PPR protein from the library, validating the use of this library as a source of mitochondrial ‘mutants’. This study is a step towards developing specific RNA targeting tools using PPR proteins that can be aimed at desired targets.
Publisher: Springer Science and Business Media LLC
Date: 02-08-2019
Publisher: Springer US
Date: 21-09-2022
DOI: 10.1007/978-1-0716-1653-6_10
Abstract: Blue native electrophoresis (BN-PAGE) is a highly resolutive method suited to the study of high molecular weight protein complexes between 100 and >3000 kDa. One of the drawbacks of this method is that it is very time-consuming and requires high quantities of purified organelles. Here we describe a high throughput BN-PAGE method allowing to screen libraries of plants potentially altered in respiratory metabolism.
Publisher: Springer Science and Business Media LLC
Date: 11-10-2018
DOI: 10.1038/S42003-018-0166-8
Abstract: Mitochondrial genes encode key components of the cellular energy machinery, but their genetic analysis is difficult or impossible in most organisms (including plants) because of the lack of viable transformation approaches. We report here a method to block the expression of the mitochondrial nad6 gene encoding a subunit of respiratory complex I in Arabidopsis tha liana , via the modification of the specificity of the RNA-binding protein RNA PROCESSING FACTOR 2 (RPF2). We show that the modified RPF2 binds and specifically induces cleavage of nad6 RNA, almost eliminating expression of the Nad6 protein and consequently complex I accumulation and activity. To our knowledge, this is the first ex le of a targeted block in expression of a specific mitochondrial transcript by a custom-designed RNA-binding protein. This opens the path to reverse genetics studies on mitochondrial gene functions and leads to potential applications in agriculture.
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.PLAPHY.2019.09.011
Abstract: Iron (Fe) toxicity is often observed in lowland rice (Oryza sativa L.) plants, disrupting cell homeostasis and impairing growth and crop yields. Silicon (Si) can mitigate the effects of Fe excess on rice by decreasing tissue Fe concentrations, but no information exists whether Si could prevent the harmful effects of Fe toxicity on the photosynthesis and carbon metabolism. Two rice cultivars with contrasting abilities to tolerate Fe excess were hydroponically grown under two Fe levels (25 μM or 5 mM) and amended or not with Si (0 or 2 mM). Fe toxicity caused decreases in net photosynthetic rate (A), particularly in the sensitive cultivar. These decreases were correlated with reductions in stomatal (g
Publisher: Oxford University Press (OUP)
Date: 23-12-2017
DOI: 10.1104/PP.16.01840
No related grants have been discovered for Lilian Maria Vincis Pereira Sanglard.