Abscisic Acid Mediates Grafting-Induced Cold Tolerance of Watermelon via Interaction With Melatonin and Methyl Jasmonate

Grafting is widely used to increase plant defense responses to various stresses. Grafting-induced cold tolerance is associated with the increase of the antioxidant potential of plants; however, the underlying mechanisms remain unclear. Here, we found that pumpkin rootstocks promote antioxidant enzyme activities and alleviate cold-induced oxidative damage, accompanied by increased abscisic acid (ABA), melatonin, and methyl jasmonate (MeJA) levels in leaves. Increased ABA accumulation in leaves was attributed partly to the increased ABA levels in rootstocks. ABA induced antioxidant enzymes activities and the accumulation of melatonin and MeJA, while inhibition of ABA synthesis blocked the rootstock-induced antioxidant activity and the accumulation of melatonin and MeJA under cold stress. Melatonin and MeJA application also enhanced ABA accumulation in leaves after cold exposure, whereas inhibition of melatonin or MeJA synthesis attenuated the rootstock-induced increase of ABA. Moreover, melatonin and MeJA application alleviated cold-induced oxidative stress, but inhibition of melatonin or MeJA synthesis lowered the rootstock- or ABA-induced antioxidant potential and tolerance to cold. These findings indicate that ABA plays an important role in the grafting-induced cold tolerance by promoting the accumulation of melatonin and MeJA, which in turn, promote ABA accumulation, forming a positive feedback loop.

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The effect of gibberellin and abscisic acid on plant defense responses and on disease severity caused by Meloidogyne javanica on tomato plants

Journal of General Plant Pathology ◽

10.1007/s10327-017-0708-9 ◽

2017 ◽

Vol 83 (3) ◽

pp. 173-184 ◽

Cited By ~ 6

Author(s):

Mohammad Reza Moosavi

Keyword(s):

Abscisic Acid ◽

Plant Defense ◽

Disease Severity ◽

Meloidogyne Javanica ◽

Defense Responses ◽

Plant Defense Responses ◽

Tomato Plants

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Methyl jasmonate mediates melatonin-induced cold tolerance of grafted watermelon plants

Horticulture Research ◽

10.1038/s41438-021-00496-0 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Hao Li ◽

Yanliang Guo ◽

Zhixiang Lan ◽

Kai Xu ◽

Jingjing Chang ◽

...

Keyword(s):

Cold Stress ◽

Methyl Jasmonate ◽

Cold Tolerance ◽

Feedback Loop ◽

Abiotic Stress Tolerance ◽

Critical Role ◽

Horticultural Crop ◽

Crop Species ◽

Induced Tolerance ◽

Figleaf Gourd

AbstractRoot–shoot communication has a critical role in plant adaptation to environmental stress. Grafting is widely applied to enhance the abiotic stress tolerance of many horticultural crop species; however, the signal transduction mechanism involved in this tolerance remains unknown. Here, we show that pumpkin- or figleaf gourd rootstock-enhanced cold tolerance of watermelon shoots is accompanied by increases in the accumulation of melatonin, methyl jasmonate (MeJA), and hydrogen peroxide (H2O2). Increased melatonin levels in leaves were associated with both increased melatonin in rootstocks and MeJA-induced melatonin biosynthesis in leaves of plants under cold stress. Exogenous melatonin increased the accumulation of MeJA and H2O2 and enhanced cold tolerance, while inhibition of melatonin accumulation attenuated rootstock-induced MeJA and H2O2 accumulation and cold tolerance. MeJA application induced H2O2 accumulation and cold tolerance, but inhibition of JA biosynthesis abolished rootstock- or melatonin-induced H2O2 accumulation and cold tolerance. Additionally, inhibition of H2O2 production attenuated MeJA-induced tolerance to cold stress. Taken together, our results suggest that melatonin is involved in grafting-induced cold tolerance by inducing the accumulation of MeJA and H2O2. MeJA subsequently increases melatonin accumulation, forming a self-amplifying feedback loop that leads to increased H2O2 accumulation and cold tolerance. This study reveals a novel regulatory mechanism of rootstock-induced cold tolerance.

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Water Dipping of Auxin Coated Chrysanthemum Cuttings Confers Protection against Insect Herbivores

Insects ◽

10.3390/insects11110790 ◽

2020 ◽

Vol 11 (11) ◽

pp. 790

Author(s):

Sanae Mouden ◽

Kirsten A. Leiss ◽

Henriette Uthe ◽

Peter G.L. Klinkhamer

Keyword(s):

Management Strategies ◽

Cost Effective ◽

Defense Responses ◽

Primary Objective ◽

Leaf Miner ◽

Stem Cuttings ◽

Plant Defense Responses ◽

Mother Plants ◽

Underlying Mechanisms

Auxins are commonly used for commercial propagation of chrysanthemums by stem cuttings. Recent studies imply that these root-promoting hormones also affect plant defense responses. The underlying motive of this study stems from the serendipitous observation that water dipping of auxin-coated cuttings beneficially affected thrips herbivory. Therefore, the primary objective of this investigation was to explore the role of indole-3-butyric acid (IBA) in relation to herbivore susceptibility in chrysanthemum. We observed contrasting findings concerning the physical presence of IBA and it’s role in promoting susceptibility of cuttings to thrips, which may in part be explained by the phenotypical variations of cuttings generated from mother plants. Nonetheless, we repeatedly demonstrated considerable protection, in some experiments up to 37%, against thrips and leaf miner upon water dipping of IBA-coated cuttings. Assessment of polyphenol oxidase activity (PPO), 14 days after dipping treatment, suggests that neither direct induction nor priming of plant defenses are involved. Future experiments aimed at understanding the early signaling events may help to explain the underlying mechanisms involved in conferring herbivore protection. We propose a dual role for auxins in early integrated pest management strategies to maximize plant development and minimize herbivory through feasible, cost-effective water dipping treatments.

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The Arabidopsis short-chain dehydrogenase/reductase 3, an ABSCISIC ACID DEFICIENT 2 homolog, is involved in plant defense responses but not in ABA biosynthesis

Plant Physiology and Biochemistry ◽

10.1016/j.plaphy.2011.10.013 ◽

2012 ◽

Vol 51 ◽

pp. 63-73 ◽

Cited By ~ 9

Author(s):

San-Gwang Hwang ◽

Nai-Chun Lin ◽

Yi-Yun Hsiao ◽

Ching-Hsuan Kuo ◽

Pi-Fang Chang ◽

...

Keyword(s):

Abscisic Acid ◽

Plant Defense ◽

Defense Responses ◽

Short Chain ◽

Plant Defense Responses ◽

Short Chain Dehydrogenase ◽

Aba Biosynthesis

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An Ethylene-inducible Lipoxygenase Gene from Potato Leaves

HortScience ◽

10.21273/hortsci.32.3.453b ◽

1997 ◽

Vol 32 (3) ◽

pp. 453B-453

Author(s):

Mikhailo V. Kolomiets ◽

Richard J. Gladon ◽

David J. Hannapel

Keyword(s):

Gene Expression ◽

Abscisic Acid ◽

Methyl Jasmonate ◽

Cdna Clone ◽

Sequence Homology ◽

Induced Defense ◽

Defense Responses ◽

Northern Analysis ◽

Potato Leaf ◽

Induced Defense Responses

Due to apparent participation of plant lipoxygenases (LOXs) in the biosynthetic pathways for jasmonic acid, methyl jasmonate, traumatin, and several C-6 volatile compounds, LOXs are believed to have a role in senescence, plant growth and development, and wound- and pathogen-induced defense responses. Multiple functions that are ascribed to this enzyme family are in accordance with the heterogeneity of LOX isozyme forms. It is possible that different LOX isoforms may be involved in different physiological processes. In our search for a gene that encodes a LOX isozyme form specifically involved in potato defense responses against pests and pathogens, we have screened an abscisic acid-induced potato leaf cDNA library, and we have isolated, sequenced, and characterized a cDNA clone that we have designated POTLX-3. The high sequence homology of our cDNA clone to other reported plant LOX genes provided evidence that POTLX-3 is a lipoxygenase. This cDNA clone represents a novel potato LOX gene in that it shares the least nucleotide and amino acid sequence homology to other isolated potato LOX genes. Northern analysis indicated that POTLX-3 transcripts did not accumulate in untreated potato leaves, but it was highly induced by treatment with physiological levels of ethylene. Northern analysis also was performed to study whether the POTLX-3 mRNA accumulation could be induced by other plant hormones that affect expression of the other plant LOX and defense-related genes. Treatment of potato leaves with methyl jasmonate, abscisic acid, gibberellic acid, auxin (NAA), and cytokinin (BA) did not induce POTLX-3 gene expression. Because the pattern of POTLX-3 gene expression is similar to that of pathogenesis-related (PR) proteins, especially the PR-1 and PR-5 groups, we suspect that POTLX-3 may be involved specifically in ethylene-induced defense responses against pathogens.

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