scholarly journals Sweet Immunity: Inulin Boosts Resistance of Lettuce (Lactuca sativa) against Grey Mold (Botrytis cinerea) in an Ethylene-Dependent Manner

2019 ◽  
Vol 20 (5) ◽  
pp. 1052 ◽  
Author(s):  
Łukasz Tarkowski ◽  
Bram Van de Poel ◽  
Monica Höfte ◽  
Wim Van den Ende

The concept of “Sweet Immunity” postulates that sugar metabolism and signaling influence plant immune networks. In this study, we tested the potential of commercially available inulin-type fructans to limit disease symptoms caused by Botrytis cinerea in lettuce. Spraying mature lettuce leaves, with inulin-type fructans derived from burdock or chicory was as effective in reducing grey mold disease symptoms caused by Botrytis cinerea as spraying with oligogalacturonides (OGs). OGs are well-known defense elicitors in several plant species. Spraying with inulin and OGs induced accumulation of hydrogen peroxide and levels further increased upon pathogen infection. Inulin and OGs were no longer able to limit Botrytis infection when plants were treated with the ethylene signaling inhibitor 1-methylcyclopropene (1-MCP), indicating that a functional ethylene signaling pathway is needed for the enhanced defense response. Soluble sugars accumulated in leaves primed with OGs, while 1-MCP treatment had an overall negative effect on the sucrose pool. Accumulation of γ-aminobutyric acid (GABA), a stress-associated non-proteinogenic amino acid and possible signaling compound, was observed in inulin-treated samples after infection and negatively affected by the 1-MCP treatment. We have demonstrated for the first time that commercially available inulin-type fructans and OGs can improve the defensive capacity of lettuce, an economically important species. We discuss our results in the context of a possible recognition of fructans as Damage or Microbe Associated Molecular Patterns.

2020 ◽  
Vol 127 (1) ◽  
pp. 143-154
Author(s):  
Nathalie Lacrampe ◽  
Félicie Lopez-Lauri ◽  
Raphaël Lugan ◽  
Sophie Colombié ◽  
Jérôme Olivares ◽  
...  

Abstract Background and Aims The main soluble sugars are important components of plant defence against pathogens, but the underlying mechanisms are unclear. Upon infection by Botrytis cinerea, the activation of several sugar transporters, from both plant and fungus, illustrates the struggle for carbon resources. In sink tissues, the metabolic use of the sugars mobilized in the synthesis of defence compounds or antifungal barriers is not fully understood. Methods In this study, the nitrogen-dependent variation of tomato stem susceptibility to B. cinerea was used to examine, before and throughout the course of infection, the transcriptional activity of enzymes involved in sugar metabolism. Under different nitrate nutrition regimes, the expression of genes that encode the enzymes of sugar metabolism (invertases, sucrose synthases, hexokinases, fructokinases and phosphofructokinases) was determined and sugar contents were measured before inoculation and in asymptomatic tissues surrounding the lesions after inoculation. Key Results At high nitrogen availability, decreased susceptibility was associated with the overexpression of several genes 2 d after inoculation: sucrose synthases Sl-SUS1 and Sl-SUS3, cell wall invertases Sl-LIN5 to Sl-LIN9 and some fructokinase and phosphofructokinase genes. By contrast, increased susceptibility corresponded to the early repression of several genes that encode cell wall invertase and sucrose synthase. The course of sugar contents was coherent with gene expression. Conclusions The activation of specific genes that encode sucrose synthase is required for enhanced defence. Since the overexpression of fructokinase is also associated with reduced susceptibility, it can be hypothesized that supplementary sucrose cleavage by sucrose synthases is dedicated to the production of cell wall components from UDP-glucose, or to the additional implication of fructose in the synthesis of antimicrobial compounds, or both.


2020 ◽  
Author(s):  
Kuldanai Pathompitaknukul ◽  
Kei Hiruma ◽  
Hiroyuki Tanaka ◽  
Nanami Kawamura ◽  
Atsushi Toyoda ◽  
...  

AbstractLike animals, plants accommodate a rich diversity of microbes, typically without discernible disease symptoms. How their pathogenesis is prevented in the host remains obscure. Here, we show that the root-infecting fungus Colletotrichum fructicola of the C. gloeosporioides clade (CgE), isolated from field-grown healthy Brassicaceae plants, inhibits growth of pathogenic fungi in Arabidopsis thaliana, in a phosphate status-dependent manner. Loss of host ethylene signaling or phytoalexins, camalexin or indole glucosinolates, however, allows CgE to display pathogenesis, suggesting host contributions to endophytic CgE colonization and benefit. Compared to a closely-related C. gloeosporioides pathogen (CgP), CgE is characterized by genome expansion and >700 fungal genes (4.34%) specifically induced in the host roots when co-inoculated with CgP, including genes related to fungal secondary metabolism. This may underlie antimicrobial tolerance of CgE and its dominance over pathogenic fungi within the host, pointing to a role for fungus-fungus competition in asymptomatic fungal colonization in plants.


Endocrinology ◽  
2005 ◽  
Vol 146 (3) ◽  
pp. 1532-1540 ◽  
Author(s):  
Anne Florin ◽  
Magali Maire ◽  
Aline Bozec ◽  
Ali Hellani ◽  
Sonia Chater ◽  
...  

In the present study we investigated whether fetal exposure to flutamide affected messenger and protein levels of claudin-11, a key Sertoli cell factor in the establishment of the hemotesticular barrier, at the time of two key events of postnatal testis development: 1) before puberty (postnatal d 14) during the establishment of the hemotesticular barrier, and 2) at the adult age (postnatal d 90) at the time of full spermatogenesis. The data obtained show that claudin-11 expression was inhibited in prepubertal rat testes exposed in utero to 2 and 10 mg/kg·d flutamide. However, in adult testes, the inhibition was observed only with 2, and not with 10, mg/kg·d of the antiandrogen. It is shown here that these differences between prepubertal and adult testes could be related to dual and opposed regulation of claudin-11 expression resulting from positive control by androgens and an inhibitory effect of postmeiotic germ cells. Indeed, testosterone is shown to stimulate claudin-11 expression in cultured Sertoli cells in a dose- and time-dependent manner (maximum effect with 0.06 μm after 72 h of treatment). In contrast, postmeiotic germ cells potentially exert a negative effect on claudin-11 expression, because adult rat testes depleted in spermatids (after local irradiation) displayed increased claudin-11 expression, whereas in a model of cocultured Sertoli and germ cells, spermatids, but not spermatocytes, inhibited claudin-11 expression. The apparent absence of claudin-11 expression changes in adult rat testes exposed to 10 mg/kg·d flutamide therefore could result from the antagonistic effects of 1) the inhibitory action of the antiandrogen and 2) the stimulatory effect of the apoptotic germ cells on claudin-11 expression. Together, due to the key role of claudin-11 in the hemotesticular barrier, the present findings suggest that such regulatory mechanisms may potentially affect this barrier (re)modeling during spermatogenesis.


2021 ◽  
Vol 8 ◽  
Author(s):  
An Liu ◽  
Wenyuan Shi ◽  
Dongdong Lin ◽  
Haihui Ye

C-type allatostatins (C-type ASTs) are a family of structurally related neuropeptides found in a wide range of insects and crustaceans. To date, the C-type allatostatin receptor in crustaceans has not been deorphaned, and little is known about its physiological functions. In this study, we aimed to functionally define a C-type ASTs receptor in the mud crab, Scylla paramamosian. We showed that C-type ASTs receptor can be activated by ScypaAST-C peptide in a dose-independent manner and by ScypaAST-CCC peptide in a dose-dependent manner with an IC50 value of 6.683 nM. Subsequently, in vivo and in vitro experiments were performed to investigate the potential roles of ScypaAST-C and ScypaAST-CCC peptides in the regulation of ecdysone (20E) and methyl farnesoate (MF) biosynthesis. The results indicated that ScypaAST-C inhibited biosynthesis of 20E in the Y-organ, whereas ScypaAST-CCC had no effect on the production of 20E. In addition, qRT-PCR showed that both ScypaAST-C and ScypaAST-CCC significantly decreased the level of expression of the MF biosynthetic enzyme gene in the mandibular organ, suggesting that the two neuropeptides have a negative effect on the MF biosynthesis in mandibular organs. In conclusion, this study provided new insight into the physiological roles of AST-C in inhibiting ecdysone biosynthesis. Furthermore, it was revealed that AST-C family peptides might inhibit MF biosynthesis in crustaceans.


2007 ◽  
Vol 13 (3) ◽  
pp. 177-182 ◽  
Author(s):  
Joo-Hyung Kim ◽  
Ji-Young Min ◽  
Young-Soon Baek ◽  
Yeoung-Seuk Bae ◽  
Heung-Tae Kim
Keyword(s):  

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Nicole F. Robichaud ◽  
Jeanette Sassine ◽  
Margaret J. Beaton ◽  
Vett K. Lloyd

Daphnids are fresh water microcrustaceans, many of which follow a cyclically parthenogenetic life cycle. Daphnia species have been well studied in the context of ecology, toxicology, and evolution, but their epigenetics remain largely unexamined even though sex determination, the production of sexual females and males, and distinct adult morphological phenotypes, are determined epigenetically. Here, we report on the characterization of histone modifications in Daphnia. We show that a number of histone H3 and H4 modifications are present in Daphnia embryos and histone H3 dimethylated at lysine 4 (H3K4me2) is present nonuniformly in the nucleus in a cell cycle-dependent manner. In addition, this histone modification, while present in blastula and gastrula cells as well as the somatic cells of adults, is absent or reduced in oocytes and nurse cells. Thus, the epigenetic repertoire of Daphnia includes modified histones and as these epigenetic forces act on a genetically homogeneous clonal population Daphnia offers an exceptional tool to investigate the mechanism and role of epigenetics in the life cycle and development of an ecologically important species.


2000 ◽  
Vol 74 (2) ◽  
pp. 1057-1060 ◽  
Author(s):  
Kimberly D. Erickson ◽  
Jennifer M. Martin

ABSTRACT The BNLF-1 open reading frame of Epstein-Barr virus (EBV) encodes two related proteins, latent membrane protein-1 (LMP-1) and lytic LMP-1 (lyLMP-1). LMP-1 is a latent protein required for immortalization of human B cells by EBV, whereas lyLMP-1 is expressed during the lytic cycle and is found in the EBV virion. We show here that, in contrast to LMP-1, lyLMP-1 is stable, with a half-life of >20 h in tetradecanoyl phorbol acetate- and butyrate-treated B95-8 cells. Although lyLMP-1 itself has negligible effects on NF-κB activity, it inhibits NF-κB activation by LMP-1 in a dose-dependent manner. The lyLMP-1 protein does not oligomerize with LMP-1, and the negative effect of lyLMP-1 on NF-κB activation by LMP-1 does not result from lyLMP-1-mediated disruption of LMP-1 oligomers. Modulation of LMP-1-activated signaling pathways is the first identified biological activity associated with lyLMP-1, and this activity may contribute to the progression of EBV's lytic cycle.


2019 ◽  
Vol 39 (04) ◽  
pp. 392-397
Author(s):  
Wei Wang ◽  
Songqing Lai ◽  
ZiJin Xiao ◽  
Haiyue Yan ◽  
Yongxi Li ◽  
...  

AbstractPlatelets play a crucial role in haemostasis and several pathophysiological processes. Collagen is a main initiator for platelet activation and aggregation. Given that Wnt signalling negatively regulates platelet function, and IWR-1 (a small molecule inhibitor for Wnt signalling) has the potential of inhibiting collagen synthesis, it is essential to investigate whether IWR-1 regulates collagen-induced platelet activation and protects against thrombogenesis. In the present study we found that IWR-1 pretreatment effectively suppressed collagen-induced platelet aggregation in a dose-dependent manner. In addition, IWR-1 also resulted in a decrease of P-selectin and phosphatidylserine surface exposure using fluorescence-activated cell sorting analysis. In vitro studies further revealed that IWR-1 had a negative effect on integrin a2β1 activation and platelet spreading. More importantly, the results from in vivo studies showed that IWR-1 exhibited a robust bleeding diathesis in the tail-bleeding assay and a prolonged occlusion time in the FeCl3-induced carotid injury model. Taken together, current results demonstrate that IWR-1 could effectively block collagen-induced platelet activity in vitro and in vivo, and suggest its candidacy as a new antiplatelet agent.


Plant Disease ◽  
2020 ◽  
Author(s):  
Shengming Liu ◽  
Liuyuan Fu ◽  
Huanhuan Tan ◽  
Jia Jiang ◽  
Zhiping Che ◽  
...  

Grey mold, caused by the fungus Botrytis cinerea Pers ex Fr., is one of the most destructive spoilage diseases, severely affecting tomato production in Henan Province, China. Spraying fungicides from the flowering to the harvest stage is a necessary measure to reduce losses associated with B. cinerea infection. However, B. cinerea has developed resistance to fungicides in many countries. Boscalid is a succinate dehydrogenase inhibitor (SDHI) fungicide, and was registered for the control of grey mold. In this study, a total of 269 B. cinerea isolates were collected from tomato in commercial greenhouses in different locations of Henan Province, in 2014 and 2015. The sensitivity and resistance of B. cinerea field isolates were determined based on mycelial growth. The effective concentration 50 (EC50) ranged from 0.11 to 15.92 μg ml−1 and 0.16 to 8.54 μg ml−1, in 2014 and 2015, respectively. The frequency of low resistance to boscalid was 12.6% and 7.6%, and moderate resistance were 2.7% and 1.3%, in 2014 and 2015, respectively. No high-resistant isolates were found in Henan Province, China. Mycelial growth, mycelial dry weight, spore production, and pathogenicity were not significantly different between resistant and sensitive phenotypes of the B. cinerea isolates. The results of cross-resistance test showed no correlation between boscalid and carbendazim, procymidone, pyrimethanil, fluazinam or fluopyram. In this study, the succinate dehydrogenase gene B (sdhB), C (sdhC), and D (sdhD) were analyzed and compared in sensitive, low and moderately resistant B. cinerea isolates to boscalid. Results showed point mutations occurred simultaneously at sdhC amino acid positions 85 (G85A), 93 (I93V), 158 (M158V), and 168 (V168I) in 4 out of 10 sensitive isolates, 23 out of 26 low and 5 out of 5 moderately resistant B. cinerea isolates to boscalid. No point mutations were found in the sdhB and sdhD genes of all isolates. Furthermore, no point mutations were found in sdhB, sdhC and sdhD genes in 3 out of 26 low resistant B. cinerea isolates to boscalid. Therefore, we speculate the simultaneous point mutations in the sdhC gene may not be related to the resistance of B. cinerea to boscalid. These results suggested that there might be a substitution mechanism for the resistance of B. cinerea to the SDHI fungicide boscalid.


1999 ◽  
Vol 90 (6) ◽  
pp. 1704-1713. ◽  
Author(s):  
Yoshinori Kamiya ◽  
Tomio Andoh ◽  
Ryosuke Furuya ◽  
Satoshi Hattori ◽  
Itaru Watanabe ◽  
...  

Background Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptors mediate fast excitatory synaptic transmission in the central nervous system. Although barbiturates have been shown to suppress the AMPA receptor-mediated responses, it is unclear whether this effect contributes to the anesthetic action of barbiturates. The authors compared the effects of depressant [R(-)] and convulsant [S(+)] stereoisomers of 1-methyl-5-phenyl-5-propyl barbituric acid (MPPB) on the AMPA and gamma-aminobutyric acid type A (GABA(A)) receptor-mediated currents to determine if the inhibitory effects on AMPA receptors correlate to the in vivo effects of the isomers. Method The authors measured whole-cell currents in the rat cultured cortical neuron at holding potential of -60 mV. Kainate 500 microM was applied as the agonist for AMPA receptors. Thiopental (3-300 microM), R(-)-MPPB or S(+)-MPPB (100-1,000 microM) was coapplied with kainate under the condition in which the GABA(A) receptor-mediated current was blocked. Effects of MPPB isomers on the current elicited by GABA 1 microM were studied in the separate experiments. Results Thiopental inhibited the kainate-induced current reversibly and in a dose-dependent manner, with a concentration for 50% inhibition of 49.3 microM. Both R(-)-MPPB and S(+)-MPPB inhibited the kainate-induced current with a little stereoselectivity. R(-)-MPPB was slightly but significantly more potent than S(+)-MPPB. In contrast, R(-)-MPPB enhanced but S(+)-MPPB reduced the GABA-induced current. Conclusions Both convulsant and depressant stereoisomers of the barbiturate inhibited the AMPA receptor-mediated current despite of their opposite effects on the central nervous system in vivo. Although thiopental exhibited a considerable inhibition of AMPA receptors, the results suggest that the inhibition of AMPA receptors contributes little to the hypnotic action of the barbiturates.


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