Identification of sieve elements and companion cell protoplasts by a combination of brightfield and fluorescence microscopy

Kaur, Prabhjot; González, Pedro; Etxeberria, Ed

doi:10.1002/aps3.1179

Cited by 5 publications

(4 citation statements)

References 27 publications

(38 reference statements)

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“…Any change in ion leakage in the leaf blades and midribs of CLas-infected samples (Fig. S4 ) is probably masked by parenchyma cells because companion and sieve element cells make up only ~1% of the total cell population 32 .…”

Section: Resultsmentioning

confidence: 99%

Citrus Huanglongbing is a pathogen-triggered immune disease that can be mitigated with antioxidants and gibberellin

et al. 2022

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Huanglongbing (HLB) is a devastating disease of citrus, caused by the phloem-colonizing bacterium Candidatus Liberibacter asiaticus (CLas). Here, we present evidence that HLB is an immune-mediated disease. We show that CLas infection of Citrus sinensis stimulates systemic and chronic immune responses in phloem tissue, including callose deposition, production of reactive oxygen species (ROS) such as H2O2, and induction of immunity-related genes. The infection also upregulates genes encoding ROS-producing NADPH oxidases, and downregulates antioxidant enzyme genes, supporting that CLas causes oxidative stress. CLas-triggered ROS production localizes in phloem-enriched bark tissue and is followed by systemic cell death of companion and sieve element cells. Inhibition of ROS levels in CLas-positive stems by NADPH oxidase inhibitor diphenyleneiodonium (DPI) indicates that NADPH oxidases contribute to CLas-triggered ROS production. To investigate potential treatments, we show that addition of the growth hormone gibberellin (known to have immunoregulatory activities) upregulates genes encoding H2O2-scavenging enzymes and downregulates NADPH oxidases. Furthermore, foliar spray of HLB-affected citrus with gibberellin or antioxidants (uric acid, rutin) reduces H2O2 concentrations and cell death in phloem tissues and reduces HLB symptoms. Thus, our results indicate that HLB is an immune-mediated disease that can be mitigated with antioxidants and gibberellin.

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Section: Resultsmentioning

confidence: 99%

Citrus Huanglongbing is a pathogen-triggered immune disease that can be mitigated with antioxidants and gibberellin

et al. 2022

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“…1b). Neutral red has been used for decades as a reliable stain for plant vacuoles (Timmers et al 1995;Dubrovsky et al 2006;Kaur et al 2018) due to the ion trap mechanism, during which neutral red is protonated in acidic pH and loses its ability to pass membranes. Since the pH of the plastid stroma is generally in neutral or alkaline ranges (Su and Lai 2017) and thylakoid lumen acidity is light-dependent, neutral red accumulation in plastids is unlikely.…”

Section: Establishment Of O Basilicum Cmcs and Their Morphologymentioning

confidence: 99%

Establishment and triterpenoid production of Ocimum basilicum cambial meristematic cells

Mehring

Haffelder

Chodorski

et al. 2020

Plant Cell Tiss Organ Cult

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The application of plant suspension culture to produce valuable compounds, such as the triterpenoids oleanolic acid and ursolic acid, is a well-established alternative to the cultivation of whole plants. Cambial meristematic cells (CMCs) are a growing field of research, often showing superior cultivation properties compared to their dedifferentiated cell (DDC) counterparts. In this work, the first-time establishment of O. basilicum CMCs is demonstrated. DDCs and CMCs were cultivated in shake flasks and wave-mixed disposable bioreactors (wDBRs) and evaluated regarding triterpenoid productivity and biomass accumulation. CMCs showed characteristic small vacuoles and were found to be significantly smaller than DDCs. Productivities of oleanolic and ursolic acid of CMCs were determined at 3.02 ± 0.76 mg/(l*d) and 4.79 ± 0.48 mg/(l*d) after 19 days wDBR cultivation, respectively. These values were consistently higher than any productivities determined for DDCs over the observed cultivation period of 37 days. Elicitation with methyl jasmonate of DDCs and CMCs in shake flasks resulted in increased product contents up to 48 h after elicitor addition, with the highest increase found in CMCs at 232.30 ± 19.33% (oleanolic acid) and 192.44 ± 18.23% (ursolic acid) after 48 h.

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“…The negative ion leakage data related to leaf blades and midribs of CLas infected samples (fig. S4) probably result from the mask effect of parenchyma cells because companion and sieve element cells make up only approximately 1% of the total cell population in plants 14 .…”

Section: Clas Infection Triggers Immune Response and Cell Death In The Phloem Tissuesmentioning

confidence: 99%

“…Embryogenic calli were subcultured on solid MT (Murashige and Tucker) media (Phytotech) every 2 weeks. From the maintained calli suspension, cells were prepared and maintained in DOG liquid media as described elsewhere 14 . The final isolated protoplast cells were suspended in W5 solution (154 mM NaCl,125 mM CaCl2, 5 mM KCl, 2mM MES at pH 5.7) at 1 × 10 7 cells/ml for different treatments.…”

Section: Protoplastmentioning

confidence: 99%

Citrus Huanglongbing is an immune-mediated disease that can be treated by mitigating reactive oxygen species triggered cell death of the phloem tissues caused by Candidatus Liberibacter asiaticus

Pang

Huang

et al. 2021

Preprint

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The immune system is critical for keeping animals and plants healthy from pathogens. However, immune-mediated diseases are also common for human. Immune-mediated diseases have not been reported for plants. Here, we present evidence that citrus Huanglongbing (HLB), caused by phloem-colonizing Candidatus Liberibacter asiaticus (CLas), is an immune-mediated disease. CLas infection of Citrus sinensis stimulated systemic and chronic immune response in the phloem tissues including reactive oxygen species (ROS) production as indicated by H2O2, callose deposition, and induction of immune related genes. Systemic cell death of companion and sieve element cells, but not surrounding parenchyma cells, was observed following ROS production triggered by CLas. ROS production triggered by CLas localized in phloem tissues. The H2O2 concentration in exudates extracted from phloem enriched bark tissue of CLas infected plants reached a threshold of killing citrus protoplast cells, which was suppressed by uric acid (a ROS scavenger) and gibberellin. Foliar spray of HLB positive citrus with antioxidants (uric acid and rutin) and gibberellin significantly reduced both H2O2 concentrations and cell death in phloem tissues induced by CLas and reduced HLB symptoms. RNA-seq analyses of CLas infected and health C. sinensis support that CLas causes oxidative stress. In sum, HLB is an immune-mediated disease and both mitigating ROS via antioxidants and promoting plant growth can reduce cell death of the phloem tissues caused by CLas, thus controlling HLB.

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Identification of sieve elements and companion cell protoplasts by a combination of brightfield and fluorescence microscopy

Cited by 5 publications

References 27 publications

Citrus Huanglongbing is a pathogen-triggered immune disease that can be mitigated with antioxidants and gibberellin

Citrus Huanglongbing is a pathogen-triggered immune disease that can be mitigated with antioxidants and gibberellin

Establishment and triterpenoid production of Ocimum basilicum cambial meristematic cells

Citrus Huanglongbing is an immune-mediated disease that can be treated by mitigating reactive oxygen species triggered cell death of the phloem tissues caused by Candidatus Liberibacter asiaticus

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