A Jasmonate-Induced Defense Elicitation in Mature Leaves Reduces Carbon Export and Alters Sink Priority in Grape (Vitis vinifera Chardonnay)

This work aims to understand how Vitis vinifera (Chardonnay) vines prioritise the export and distribution of recently fixed photoassimilate between root tissue, fruit, and defence, following the elicitation of a defence response. Jasmonic acid (JA) and its methyl ester, MeJA, are endogenous plant hormones, known collectively as jasmonates, that have signalling roles in plant defence and consequently are often used to prime plant defence systems. Here, we use exogenous jasmonate application to mature source leaves of Chardonnay grapevines to elucidate the prioritisation strategy of carbon allocation between plant defence and growth. Our results demonstrate that jasmonate application to Chardonnay leaves can elicit a defence response to Botrytis cinerea, but the effect was localised to the jasmonate-treated area. We found no evidence of a systemic defence response in non-treated mature leaves or young growing tissue. JA application reduced the photosynthetic rate of the treated leaf and reduced the export rate of recently fixed carbon-11 from the leaf. Following JA application, a greater proportion of available recently fixed carbon was allocated to the roots, suggesting an increase in sink strength of the roots. Relative sink strength of the berries did not change; however, an increase in berry sugar was observed seven days after JA treatment. We conclude that the data provide evidence for a “high sugar resistance” model in the mature treated leaves of the vine, since the export of carbon was reduced to ensure an elevated defence response in the treated leaf. The increase in berry sugar concentration seven days after treatment can be explained by the initial prioritisation of a greater portion of the exported carbon to storage in the roots, making it available for remobilisation to the berries once the challenge to defence had passed.

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Sink strength of citrus rootstocks under water deficit

Tree Physiology ◽

10.1093/treephys/tpab008 ◽

2021 ◽

Author(s):

Simone F da Silva ◽

Marcela T Miranda ◽

Vladimir E Costa ◽

Eduardo C Machado ◽

Rafael V Ribeiro

Keyword(s):

Plant Growth ◽

Root Growth ◽

Water Deficit ◽

Carbon Allocation ◽

Sink Strength ◽

Rangpur Lime ◽

Carbon Supply ◽

Valencia Orange ◽

Source Sink ◽

Orange Trees

Abstract Carbon allocation between source and sink organs determines plant growth and is influenced by environmental conditions. Under water deficit, plant growth is inhibited before photosynthesis and shoot growth tends to be more sensitive than root growth. However, the modulation of source-sink relationship by rootstocks remain unsolved in citrus trees under water deficit. Citrus plants grafted on Rangpur lime are drought tolerant, which may be related to a fine coordination of the source-sink relationship for maintaining root growth. Here, we followed 13C allocation and evaluated physiological responses and growth of Valencia orange trees grafted on three citrus rootstocks (Rangpur lime, Swingle citrumelo and Sunki mandarin) under water deficit. As compared to plants on Swingle and Sunki rootstocks, ones grafted on Rangpur lime showed higher stomatal sensitivity to the initial variation of water availability and less accumulation of non-structural carbohydrates in roots under water deficit. High 13C allocation found in Rangpur lime roots indicates this rootstock has high sink demand associated with high root growth under water deficit. Our data suggest that Rangpur lime rootstock used photoassimilates as sources of energy and carbon skeletons for growing under drought, which is likely related to increases in root respiration. Taken together, our data revealed that carbon supply by leaves and delivery to roots are critical for maintaining root growth and improving drought tolerance, with citrus rootstocks showing differential sink strength under water deficit.

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Carbon allocation in Euphorbia esula and neighbours after defoliation

Canadian Journal of Botany ◽

10.1139/b99-140 ◽

2000 ◽

Vol 77 (11) ◽

pp. 1641-1647 ◽

Cited By ~ 1

Author(s):

Bret E Olson ◽

Roseann T Wallander

Keyword(s):

Root System ◽

Carbon Allocation ◽

Poa Pratensis ◽

Kentucky Bluegrass ◽

Euphorbia Esula ◽

Sink Strength ◽

Relative Distribution ◽

Grazing Tolerance ◽

Allocation Patterns ◽

Festuca Idahoensis

Weeds increase their dominance in a grazed plant community by avoiding herbivory and (or) by tolerating herbivory more than neighbouring plants. After defoliation, allocating carbon to shoots at the expense of roots may confer tolerance. We determined carbon allocation patterns of undefoliated and recently defoliated (75% clipping level) plants of the invasive leafy spurge (Euphorbia esula L.) growing with alfalfa (Medicago sativa L.), Kentucky bluegrass (Poa pratensis L.), or Idaho fescue (Festuca idahoensis Elmer). Plants were labeled with 13CO2 24 h after clipping to determine allocation patterns; all plants had equal access to the 13CO2. Based on relative distribution of 13C, defoliation did not affect the amount of carbon allocated to roots of E. esula. The amount of carbon allocated to shoots of E. esula was higher when growing with P. pratensis than when growing with the other species. Based on relative enrichment of 13C, defoliation increased sink strength of remaining shoots on defoliated E. esula plants. Conversely, roots of unclipped E. esula plants were stronger sinks for carbon than roots of clipped plants. Even though defoliation increased "sink strength" of remaining shoots of E. esula, the amount of carbon allocated to the root system was unaffected by defoliation, suggesting that uninterrupted allocation of carbon to its extensive root system, not increased allocation to its shoot system, confers grazing tolerance.

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Local and systemic signalling during a plant defence response

Perspectives in Plant Cell Recognition ◽

10.1017/cbo9780511565243.008 ◽

1992 ◽

pp. 123-136

Author(s):

D. Bowles

Keyword(s):

Plant Defence ◽

Defence Response ◽

Plant Defence Response

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Oxadiazon Absorption, Translocation, and Metabolism in Rice (Oryza sativa) and Barnyardgrass (Echinochloa crus-galli)

Weed Science ◽

10.1017/s0043174500059890 ◽

1984 ◽

Vol 32 (6) ◽

pp. 727-731 ◽

Cited By ~ 4

Author(s):

Nagi Reddy Achhireddy ◽

Ralph C. Kirkwood ◽

William W. Fletcher

Keyword(s):

Oryza Sativa ◽

Mode Of Action ◽

Foliar Application ◽

Fixed Carbon ◽

Rice Plants ◽

Treated Leaf

The mode of action and selectivity of oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-δ2-1,3,4-oxadiazolin-5-one] were investigated in tolerant rice (Oryza sativaL.) and susceptible barnyardgrass [Echinochloa crus-galli(L.) Beauv. ♯3ECHCG]. Oxadiazon produced only brown spots on the foliage of rice plants at higher rates (> 500 ppmv), while LC50for barnyardgrass was 250 ppmv. Translocation of14C-oxadiazon from the treated leaf was minimal in both species; after 7 days, about 2 and 3% of applied14C translocated in rice and barnyardgrass, respectively. In rice,14C recovered in water and chloroform washings of the treated leaf was 25% in each and in barnyardgrass, 20 and 18%, respectively. After water and chloroform washings,14C-oxadiazon present in the treated leaf of barnyardgrass and rice was 36 and 26%, respectively. In rice and barnyardgrass, unaltered14C-oxadiazon represented 86 and 79% of applied14C, respectively, 7 days after application. In barnyardgrass 7 days after foliar application, oxadiazon inhibited14CO2fixation and the export of fixed carbon. The effects were less marked in rice.

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Common metabolic networks contribute to carbon sink strength of sorghum internodes: implications for bioenergy improvement

Biotechnology for Biofuels ◽

10.1186/s13068-019-1612-7 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Yin Li ◽

Min Tu ◽

Yaping Feng ◽

Wenqin Wang ◽

Joachim Messing

Keyword(s):

Candidate Genes ◽

Sweet Sorghum ◽

Metabolic Networks ◽

Carbon Allocation ◽

Carbon Sink ◽

Sink Strength ◽

Primary Metabolism ◽

Data Sets ◽

Rna Seq ◽

The Common

Abstract Background Sorghum bicolor (L.) is an important bioenergy source. The stems of sweet sorghum function as carbon sinks and accumulate large amounts of sugars and lignocellulosic biomass and considerable amounts of starch, therefore providing a model of carbon allocation and accumulation for other bioenergy crops. While omics data sets for sugar accumulation have been reported in different genotypes, the common features of primary metabolism in sweet genotypes remain unclear. To obtain a cohesive and comparative picture of carbohydrate metabolism between sorghum genotypes, we compared the phenotypes and transcriptome dynamics of sugar-accumulating internodes among three different sweet genotypes (Della, Rio, and SIL-05) and two non-sweet genotypes (BTx406 and R9188). Results Field experiments showed that Della and Rio had similar dynamics and internode patterns of sugar concentration, albeit distinct other phenotypes. Interestingly, cellulose synthases for primary cell wall and key genes in starch synthesis and degradation were coordinately upregulated in sweet genotypes. Sweet sorghums maintained active monolignol biosynthesis compared to the non-sweet genotypes. Comparative RNA-seq results support the role of candidate Tonoplast Sugar Transporter gene (TST), but not the Sugars Will Eventually be Exported Transporter genes (SWEETs) in the different sugar accumulations between sweet and non-sweet genotypes. Conclusions Comparisons of the expression dynamics of carbon metabolic genes across the RNA-seq data sets identify several candidate genes with contrasting expression patterns between sweet and non-sweet sorghum lines, including genes required for cellulose and monolignol synthesis (CesA, PTAL, and CCR), starch metabolism (AGPase, SS, SBE, and G6P-translocator SbGPT2), and sucrose metabolism and transport (TPP and TST2). The common transcriptome features of primary metabolism identified here suggest the metabolic networks contributing to carbon sink strength in sorghum internodes, prioritize the candidate genes for manipulating carbon allocation with bioenergy purposes, and provide a comparative and cohesive picture of the complexity of carbon sink strength in sorghum stem.

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Phospholipase D and phosphatidic acid in plant defence response: from protein–protein and lipid–protein interactions to hormone signalling

Journal of Experimental Botany ◽

10.1093/jxb/eru540 ◽

2015 ◽

Vol 66 (7) ◽

pp. 1721-1736 ◽

Cited By ~ 70

Author(s):

Jian Zhao

Keyword(s):

Phosphatidic Acid ◽

Phospholipase D ◽

Protein Interactions ◽

Plant Defence ◽

Defence Response ◽

Lipid Protein Interactions ◽

Hormone Signalling ◽

Plant Defence Response

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Phenols and lignin are involved in the defence response of banana (Musa) plants to Radopholus similis infection

Nematology ◽

10.1163/15685411-00002788 ◽

2014 ◽

Vol 16 (5) ◽

pp. 565-576 ◽

Cited By ~ 13

Author(s):

Suganthagunthalam Dhakshinamoorthy ◽

Kahpui Mariama ◽

Annemie Elsen ◽

Dirk De Waele

Keyword(s):

Cross Sections ◽

Plant Defence ◽

Defence Response ◽

Nematode Infection ◽

Vascular Bundles ◽

Radopholus Similis ◽

Phenol Content ◽

Root Cortex ◽

Root Cells ◽

Burrowing Nematode

The role of lignin and phenols in plant defence ranges from preformed characteristic to inducible physical and chemical response against nematode infection. Our study shows the involvement of lignin and phenols in the defence of two newly identified resistant banana (Musa) genotypes to burrowing nematode Radopholus similis infection. Results were compared with reference resistant and susceptible banana cultivars. Histochemical analysis of root cross sections showed a more extensive secondary cell wall lignification of vascular bundles in R. similis-infected plants than in the nematode non-infected plants. Increased extensive lignification was not associated with the cortex cells that are directly attacked by the nematode. This showed that the increased lignification is a general defence response to protect the vascular bundle from damage rather than resisting the nematode development and reproduction at the root cortex. Histochemical localisation showed no preformed phenolic cells in the cortex of the non-infected, R. similis-resistant and -susceptible Musa genotypes. By contrast, phenolic substances were the major constituents of the nematode-infected necrotic cells. Phenols and lignin contents were also quantitatively assayed. The Folin-Ciocalteu assay confirmed the increase in phenol content of nematode-infected root cells. Phenol content in nematode-infected plants was twice the amount of phenol content in nematode non-infected plants at 3 weeks after infection. This is possibly due to the biosynthesis or accumulation of secondary metabolites such as phenolic phytoalexins in the nematode infection sites of all the banana genotypes. This study clearly demonstrates that phenols and lignin play an important role in the defence mechanisms of Musa to R. similis infection.

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The NgAOX1a gene cloned from Nicotiana glutinosa is implicated in the response to abiotic and biotic stresses

Bioscience Reports ◽

10.1042/bsr20080025 ◽

2008 ◽

Vol 28 (5) ◽

pp. 259-266 ◽

Cited By ~ 17

Author(s):

Jian Wang ◽

Xia Wang ◽

Cheng Liu ◽

Jiedao Zhang ◽

Changxiang Zhu ◽

...

Keyword(s):

Potato Virus ◽

Tricarboxylic Acid Cycle ◽

Plant Defence ◽

Potato Virus X ◽

Single Copy ◽

Northern Blotting ◽

Defence Response ◽

Nicotiana Glutinosa ◽

Signalling Molecules ◽

Blotting Analysis

A novel gene, named NgAOX1a, was isolated from Nicotiana glutinosa by RT-PCR (reverse transcription-PCR). The full-length cDNA of NgAOX1a was 1448 bp, including a 1062-bp ORF (open reading frame), a 124 bp 5′ UTR (untranslated region) and a 262 bp 3′ UTR. The ORF encodes a 353-amino-acid protein which contains two conserved cysteine residues, four iron-binding motifs, five α-helix regions and six conserved histidine residues. The phylogenetic tree showed that NgAOX1a belongs to the AOX1 (alternative oxidase 1)-type group. Alignment analysis showed that NgAOX1a shares a high similarity with other known AOXs. Four exons and three introns were detected in the genomic DNA sequence, and Southern-blotting analysis suggested that NgAOX1a is a single-copy gene. A series of putative cis-acting elements were examined in the 5′-flanking region of NgAOX1a. Northern-blotting analysis showed that the transcript levels of NgAOX1a can be markedly accumulated when tobacco seedlings are treated with various abiotic stimuli, such as exogenous signalling molecules for plant defence response, salicylic acid and H2O2, and the exogenous TCA (tricarboxylic acid) cycle metabolite citrate. However, it could be suppressed by abiotic stress, such as CoCl2, an inhibitor of ethylene, which indicates that the expression of NgAOX1a may be regulated by ethylene. In addition, NgAOX1a can also be strongly induced by three viral pathogens, tobacco mosaic virus, potato virus X and potato virus Y. These results indicate that NgAOX1a may be involved in multi-signal transduction pathways and may play an important role in defence response.

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