Strigolactones positively regulate defense against root-knot nematodes in tomato

Xu, Xuechen; Fang, Pingping; Zhang, Hui; Chi, Cheng; Song, Liu-Xia; Xia, Xiaojian; Shi, Kai; Zhou, Yanhong; Zhou, Jie; Yu, Jingquan

doi:10.1093/jxb/ery439

Cited by 70 publications

(60 citation statements)

References 61 publications

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“…Xu and colleagues proposed that this counterintuitive increase in susceptibility was due to the suppression of ABA by SL signaling. Because ABA is a negative regulator of defense against RKN infection, enhanced ABA levels in SL-deficient plants could contribute to the increased susceptibility by decreasing the accumulations of other defense compounds [39]. Here, nicotine was recovered in a JIC (JIC#1) ( Fig 4D) in the metabolic network analysis; hence, we inferred that other factors were negating the positive effect of JA signaling.…”

Section: Discussionmentioning

confidence: 81%

“…Arabidopsis max2 mutants are more susceptible to the attack from two kinds of bacterial pathogens [37], and the SL-deficient tomato mutant Slccd8 is more susceptible to the foliar fungal pathogens Botrytis cinerea and Alternaria alternata [38]. Recently, two groups reported opposing roles of SLs on plant defense in tomato and in rice against root-knot nematodes (RKNs) [39,40]. Whether SLs play a role in deterring attack from insect herbivores is largely unknown.…”

Section: Introductionmentioning

confidence: 99%

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Strigolactone signaling regulates specialized metabolism in tobacco stems and interactions with stem-feeding herbivores

Joo

Cao

et al. 2020

PLoS Biol

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Plants are attacked by herbivores, which often specialize on different tissues, and in response, have evolved sophisticated resistance strategies that involve different types of chemical defenses frequently targeted to different tissues. Most known phytohormones have been implicated in regulating these defenses, with jasmonates (JAs) playing a pivotal role in complex regulatory networks of signaling interactions, often generically referred to as "cross talk." The newly identified class of phytohormones, strigolactones (SLs), known to regulate the shoot architecture, remain unstudied with regard to plant-herbivore interactions. We explored the role of SL signaling in resistance to a specialist weevil (Trichobaris mucorea) herbivore of the native tobacco, Nicotiana attenuata, that attacks the root-shoot junction (RSJ), the part of the plant most strongly influenced by alterations in SL signaling (increased branching). As SL signaling shares molecular components, such as the core Fbox protein MORE AXILLARY GROWTH 2 (MAX2), with another new class of phytohormones, the karrikins (KARs), which promote seed germination and seedling growth, we generated transformed lines, individually silenced in the expression of NaMAX2, DWARF 14 (NaD14: the receptor for SL) and CAROTENOID CLEAVAGE DIOXYGENASE 7 (NaCCD7: a key enzyme in SL biosynthesis), and KARRIKIN INSENSITIVE 2 (NaKAI2: the KAR receptor). The mature stems of all transgenic lines impaired in the SL, but not the KAR signaling pathway, overaccumulated anthocyanins, as did the stems of plants attacked by the larvae of weevil, which burrow into the RSJs to feed on the pith of N. attenuata stems. T. mucorea larvae grew larger in the plants silenced in the SL pathway, but again, not in the KAI2-silenced plants. These phenotypes were associated with elevated JA and auxin (indole-3-acetic acid [IAA]) levels and significant changes in the accumulation of defensive compounds, including phenolamides and nicotine. The overaccumulation of phenolamides and anthocyanins in the SL pathway-silenced plants likely resulted from antagonism between the SL and JA pathway in N. attenuata. We show that the repressors of SL signaling, suppressor of max2-like (NaSMXL6/7), and JA signaling, jasmonate zim-domain

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Section: Discussionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Strigolactone signaling regulates specialized metabolism in tobacco stems and interactions with stem-feeding herbivores

Joo

Cao

et al. 2020

PLoS Biol

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“…Additionally, the carotenoid-derived phytohormones strigolactones (SLs) can enhance symbiosis between plants and AM fungi by inducing hyphal branching (Akiyama et al, 2005) and are also important in tomato defense against RKNs (Xu et al, 2019). It was in fact observed that the silencing of CCD7 , coding for an enzyme involved in SLs biosynthesis, increased plant susceptibility to RKNs (Xu et al, 2019). Our data showed that CCD7 was strongly down-regulated in non-colonized galls, while it appeared to be induced in galls from AM-colonized roots, in agreement with their known role in AM-symbiosis, associated to early senescence of AM-colonized galls.…”

Section: Discussionmentioning

confidence: 99%

Transcriptomic Responses to Water Deficit and Nematode Infection in Mycorrhizal Tomato Roots

et al. 2019

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Climate changes include the intensification of drought in many parts of the world, increasing its frequency, severity and duration. However, under natural conditions, environmental stresses do not occur alone, and, in addition, more stressed plants may become more susceptible to attacks by pests and pathogens. Studies on the impact of the arbuscular mycorrhizal (AM) symbiosis on tomato response to water deficit showed that several drought-responsive genes are differentially regulated in AM-colonized tomato plants (roots and leaves) during water deficit. To date, global changes in mycorrhizal tomato root transcripts under water stress conditions have not been yet investigated. Here, changes in root transcriptome in the presence of an AM fungus, with or without water stress (WS) application, have been evaluated in a commercial tomato cultivar already investigated for the water stress response during AM symbiosis. Since root-knot nematodes (RKNs, Meloidogyne incognita ) are obligate endoparasites and cause severe yield losses in tomato, the impact of the AM fungal colonization on RKN infection at 7 days post-inoculation was also evaluated. Results offer new information about the response to AM symbiosis, highlighting a functional redundancy for several tomato gene families, as well as on the tomato and fungal genes involved in WS response during symbiosis, underlying the role of the AM fungus. Changes in the expression of tomato genes related to nematode infection during AM symbiosis highlight a role of AM colonization in triggering defense responses against RKN in tomato. Overall, new datasets on the tomato response to an abiotic and biotic stress during AM symbiosis have been obtained, providing useful data for further researches.

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“…In rice, signaling mediated by strigolactones suppresses jasmonate accumulation and promotes RKN infection (Lahari et al, 2019). In contrast, strigolactones play a positive role in nematode defense in tomato (Xu et al, 2018). Although, further research needs to be undertaken, another way to modulate plant responses by mycorrhization could be altering strigolactones -plants production, which might influence plant-nematode interaction.…”

Section: Mycorrhizal Fungimentioning

confidence: 99%

Biological Control of Plant-Parasitic Nematodes by Filamentous Fungi Inducers of Resistance: Trichoderma, Mycorrhizal and Endophytic Fungi

2020

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Plant-parasitic-nematodes represent a major threat to the agricultural production of different crops worldwide. Due to the high toxicity of chemical nematicides, it is necessary to develop new control strategies against nematodes. In this respect, filamentous fungi can be an interesting biocontrol alternative. The genus Trichoderma, mycorrhizal and endophytic fungi are the main groups of filamentous fungi studied and used as biological control agents (BCAs) against nematodes as resistance inducers. They are able to reduce the damage caused by plant-parasitic nematodes directly by parasitism, antibiosis, paralysis and by the production of lytic enzymes. But they also minimize harm by space and resource-competition, by providing higher nutrient and water uptake to the plant, or by modifying the root morphology, and/or rhizosphere interactions, that constitutes an advantage for the plant-growth. Besides, filamentous fungi are able to induce resistance against nematodes by activating hormone-mediated (salicylic and jasmonic acid, strigolactones among others) plant-defense mechanisms. Additionally, the alteration of the transport of chemical defense components through the plant or the synthesis of plant secondary metabolites and different enzymes can also contribute to enhancing plant defenses. Therefore, the use of filamentous fungi of the mentioned groups as BCAs is a promising durable biocontrol strategy in agriculture against plant-parasitic nematodes.

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Strigolactones positively regulate defense against root-knot nematodes in tomato

Abstract: Strigolactones positively regulate defense against infection by root-knot nematode in tomato through a process that is dependent on MYC2 integrating SL, ABA, and JA signaling

Cited by 70 publications

References 61 publications

Strigolactone signaling regulates specialized metabolism in tobacco stems and interactions with stem-feeding herbivores

Strigolactone signaling regulates specialized metabolism in tobacco stems and interactions with stem-feeding herbivores

Transcriptomic Responses to Water Deficit and Nematode Infection in Mycorrhizal Tomato Roots

Biological Control of Plant-Parasitic Nematodes by Filamentous Fungi Inducers of Resistance: Trichoderma, Mycorrhizal and Endophytic Fungi

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