A novel Meloidogyne incognita
 chorismate mutase effector suppresses plant immunity by manipulating the salicylic acid pathway and functions mainly during the early stages of nematode parasitism

Compound 6u exhibits ultrahigh fungicidal activity by acting at its potent target PcORP1 and induces systemic acquired resistance by activating the salicylic acid pathway.

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MiMIF-2 Effector of Meloidogyne incognita Exhibited Enzyme Activities and Potential Roles in Plant Salicylic Acid Synthesis

International Journal of Molecular Sciences ◽

10.3390/ijms21103507 ◽

2020 ◽

Vol 21 (10) ◽

pp. 3507

Author(s):

Jianlong Zhao ◽

Zhenchuan Mao ◽

Qinghua Sun ◽

Qian Liu ◽

Heng Jian ◽

...

Keyword(s):

Salicylic Acid ◽

Transcriptome Analysis ◽

Meloidogyne Incognita ◽

Plant Immunity ◽

Acid Synthesis ◽

Host Immunity ◽

Parasitic Nematodes ◽

Marker Genes ◽

Rna Seq ◽

Shock Proteins

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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Common bean resistance to Xanthomonas is associated with upregulation of the salicylic acid pathway and downregulation of photosynthesis

10.21203/rs.3.rs-17010/v1 ◽

2020 ◽

Author(s):

Justine Foucher ◽

Mylène Ruh ◽

Anne Préveaux ◽

Sébastien Carrère ◽

Sandra Pelletier ◽

...

Keyword(s):

Salicylic Acid ◽

Common Bean ◽

Molecular Mechanisms ◽

Quantitative Resistance ◽

Biological Response ◽

Sugar Metabolism ◽

Transcription Activator ◽

Potential Link ◽

Salicylic Acid Pathway ◽

Acid Pathway

Abstract Background: Common bacterial blight (CBB) caused by Xanthomonas phaseoli pv. phaseoli and Xanthomonas citri pv. fuscans is one of the major threats to common bean crops (Phaseolus vulgaris L.). Resistance to CBB is particularly complex as 26 quantitative resistance loci to CBB have been described so far. To date, transcriptomic studies after CBB infection have been very scarce and the molecular mechanisms underlying susceptibility or resistance are largely unknown. Results: We sequenced and annotated the genomes of two common bean genotypes being either resistant (BAT93) or susceptible (JaloEEP558) to CBB. Reciprocal BLAST analysis led to a list of homologs between these genotypes and the common bean reference genome (G19833), which provides a solid dataset for further comparative analyses. RNA-Seq after inoculation with X. phaseoli pv. phaseoli showed that the susceptible genotype initiated a more intense and diverse biological response than the resistant genotype. Resistance was linked to upregulation of the salicylic acid pathway and downregulation of photosynthesis and sugar metabolism, while susceptibility was linked to downregulation of resistance genes and upregulation of the jasmonic acid/ethylene pathway and of genes involved in cell wall modification.Conclusions: This study helps better understanding the mechanisms occurring during the early colonization phase of common bean by Xanthomonas and unveils new actors potentially important for resistance and susceptibility to CBB. We discuss the potential link between the pathways induced during bean colonization and genes induced by transcription activator-like effectors (TALEs), as illustrated in other Xanthomonas pathovars.

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