Plant Hormone Salicylic Acid Produced by a Malaria Parasite Controls Host Immunity and Cerebral Malaria Outcome

Plant-parasitic nematodes secrete a series of effectors to promote parasitism by modulating host immunity, but the detailed molecular mechanism is ambiguous. Animal parasites secrete macrophage migration inhibitory factor (MIF)-like proteins for evasion of host immune systems, in which their biochemical activities play essential roles. Previous research demonstrated that MiMIF-2 effector was secreted by Meloidogyne incognita and modulated host immunity by interacting with annexins. In this study, we show that MiMIF-2 had tautomerase activity and protected nematodes against H2O2 damage. MiMIF-2 expression not only decreased the amount of H2O2 generation during nematode infection in Arabidopsis, but also suppressed Bax-induced cell death by inhibiting reactive oxygen species burst in Nicotiana benthamiana. Further, RNA-seq transcriptome analysis and RT-qPCR showed that the expression of some heat-shock proteins was down regulated in MiMIF-2 transgenic Arabidopsis. After treatment with flg22, RNA-seq transcriptome analysis indicated that the differentially expressed genes in MiMIF-2 expressing Arabidopsis were pointed to plant hormone signal transduction, compound metabolism and plant defense. RT-qPCR and metabolomic results confirmed that salicylic acid (SA) related marker genes and SA content were significantly decreased. Our results provide a comprehensive understanding of how MiMIF-2 modulates plant immunity and broaden knowledge of the intricate relationship between M. incognita and host plants.

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Salicylic Acid - A Novel Plant Hormone

LS International Journal of Life Sciences ◽

10.5958/2319-1198.2020.00016.0 ◽

2020 ◽

Vol 9 (3) ◽

pp. 234

Author(s):

Poonam Meena ◽

Sampat Nehra ◽

P.C. Trivedi

Keyword(s):

Salicylic Acid ◽

Plant Hormone

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A single rapamycin dose protects against late-stage experimental cerebral malaria via modulation of host immunity, endothelial activation and parasite sequestration

Malaria Journal ◽

10.1186/s12936-017-2092-5 ◽

2017 ◽

Vol 16 (1) ◽

Cited By ~ 4

Author(s):

Pedro Mejia ◽

J. Humberto Treviño-Villarreal ◽

Justin S. Reynolds ◽

Mariana De Niz ◽

Andrew Thompson ◽

...

Keyword(s):

Cerebral Malaria ◽

Late Stage ◽

Endothelial Activation ◽

Host Immunity ◽

Experimental Cerebral Malaria

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Polyamine-Induced Hormonal Changes in eds5 and sid2 Mutant Arabidopsis Plants

International Journal of Molecular Sciences ◽

10.3390/ijms20225746 ◽

2019 ◽

Vol 20 (22) ◽

pp. 5746 ◽

Cited By ~ 4

Author(s):

Tajti ◽

Hamow ◽

Majláth ◽

Gierczik ◽

Németh ◽

...

Keyword(s):

Salicylic Acid ◽

Plant Hormones ◽

Plant Hormone ◽

Polyamine Metabolism ◽

Hormonal Changes ◽

Hormone Metabolism ◽

Hormone Synthesis ◽

The Individual ◽

Induced Changes ◽

Gene Expression Levels

Polyamines are multifaceted compounds which play a role in regulating plant growth and stress tolerance in interactions with plant hormones. The aim of the present study was to reveal how exogenous polyamines influence the synthesis of salicylic acid, with a special emphasis on the effect of salicylic acid deficiency on the polyamine metabolism and polyamine-induced changes in other plant hormone contents. Our hypothesis was that the individual polyamines induced different changes in the polyamine and salicylic acid metabolism of the wild type and salicylic acid-deficient Arabidopsis mutants, which in turn influenced other hormones. To our knowledge, such a side-by-side comparison of the influence of eds5-1 and sid2-2 mutations on polyamines has not been reported yet. To achieve our goals, wild and mutant genotypes were tested after putrescine, spermidine or spermine treatments. Polyamine and plant hormone metabolism was investigated at metabolite and gene expression levels. Individual polyamines induced different changes in the Arabidopsis plants, and the responses were also genotype-dependent. Polyamines upregulated the polyamine synthesis and catabolism, and remarkable changes in hormone synthesis were found especially after spermidine or spermine treatments. The sid2-2 mutant showed pronounced differences compared to Col-0. Interactions between plant hormones may also be responsible for the observed differences.

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Malaria parasite type 4 equilibrative nucleoside transporters (ENT4) are purine transporters with distinct substrate specificity

Biochemical Journal ◽

10.1042/bj20112220 ◽

2012 ◽

Vol 446 (2) ◽

pp. 179-190 ◽

Cited By ~ 18

Author(s):

I. J. Frame ◽

Emilio F. Merino ◽

Vern L. Schramm ◽

María B. Cassera ◽

Myles H. Akabas

Keyword(s):

Drug Targets ◽

Malaria Parasite ◽

Plant Hormone ◽

Nucleoside Transporters ◽

Xenopus Laevis Oocytes ◽

Salvage Pathway ◽

Purine Salvage ◽

Equilibrative Nucleoside Transporters ◽

Major Route ◽

Purine Transporter

Malaria, caused by Plasmodia parasites, affects hundreds of millions of people. As purine auxotrophs, Plasmodia use transporters to import host purines for subsequent metabolism by the purine salvage pathway. Thus purine transporters are attractive drug targets. All sequenced Plasmodia genomes encode four ENTs (equilibrative nucleoside transporters). During the pathogenic intraerythrocytic stages, ENT1 is a major route of purine nucleoside/nucleobase transport. Another plasma membrane purine transporter exists because Plasmodium falciparum ENT1-knockout parasites survive at supraphysiological purine concentrations. The other three ENTs have not been characterized functionally. Codon-optimized Pf- (P. falciparum) and Pv- (Plasmodium vivax) ENT4 were expressed in Xenopus laevis oocytes and substrate transport was determined with radiolabelled substrates. ENT4 transported adenine and 2′-deoxyadenosine at the highest rate, with millimolar-range apparent affinity. ENT4-expressing oocytes did not accumulate hypoxanthine, a key purine salvage pathway substrate, or AMP. Micromolar concentrations of the plant hormone cytokinin compounds inhibited both PfENT4 and PvENT4. In contrast with PfENT1, ENT4 interacted with the immucillin compounds in the millimolar range and was inhibited by 10 μM dipyridamole. Thus ENT4 is a purine transporter with unique substrate and inhibitor specificity. Its role in parasite physiology remains uncertain, but is likely to be significant because of the strong conservation of ENT4 homologues in Plasmodia genomes.

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The effects of host immunity on virulence–transmissibility relationships in the rodent malaria parasite Plasmodium chabaudi

Parasitology ◽

10.1017/s003118200200272x ◽

2003 ◽

Vol 126 (2) ◽

pp. 103-112 ◽

Cited By ~ 50

Author(s):

M. J. MACKINNON ◽

A. F. READ

Keyword(s):

Growth Rate ◽

Malaria Parasite ◽

Transmission Rate ◽

Life Time ◽

Host Immunity ◽

Plasmodium Chabaudi ◽

Rodent Malaria Parasite ◽

Rodent Malaria ◽

Transmission Potential ◽

The Impact

Here we examined the impact of host immunity on relationships between parasite virulence, transmission rate, intrinsic growth rate and host recovery rate in the rodent malaria parasite, Plasmodium chabaudi. Groups of naïve and immunized mice were infected with 1 of 10 cloned lines of parasites and their infection dynamics were monitored for 19 days. We found that (1) host immunity reduced the growth rate, virulence, transmission rate and infection length, with a consequent 3-fold reduction in life-time transmission potential, (2) clone means for these traits ranked similarly across naïve and immunized mice, (3) regression slopes of transmission potential on growth rate, virulence and infection length were similar in naïve and immunized mice, (4) virulence and infection length were positively correlated in immunized but not naïve mice, and (5) for a similar level of parasite growth rate and virulence, transmission potential and infection length were lower in immunized than naïve mice. Thus host immunity reduced all these fitness traits in a manner consistent with direct parasite-driven biological links among them. These results support the basic assumption underlying our theory that predicts that anti-disease vaccines will select for higher virulence in those microparasites for which virulence is integrally linked to transmission.

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