The plant cell wall plays an important role in damage-associated molecular pattern-induced resistance to pathogens and herbivorous insects. Our current understanding of cell wall-mediated resistance is largely based on the degree of pectin methylesterification. However, little is known about the role of pectin acetylesterification in plant immunity. This study describes how one pectin-modifying enzyme, PECTIN ACETYLESTERASE 9 (PAE9), affects the Arabidopsis (Arabidopsis thaliana) transcriptome, secondary metabolome, and aphid performance. Electro-penetration graphs showed that Myzus persicae aphids established phloem feeding earlier on pae9 mutants. Whole-genome transcriptome analysis revealed a set of 56 differentially expressed genes (DEGs) between uninfested pae9-2 mutants and wild-type plants. The majority of the DEGs were enriched for biotic stress responses and down-regulated in the pae9-2 mutant, including PAD3 and IGMT2, involved in camalexin and indole glucosinolate biosynthesis, respectively. Relative quantification of more than 100 secondary metabolites revealed decreased levels of several compounds, including camalexin and oxylipins, in two independent pae9 mutants. In addition, absolute quantification of phytohormones showed that jasmonic acid (JA), jasmonoyl-Ile, salicylic acid, abscisic acid, and indole-3-acetic acid were compromised due to PAE9 loss of function. After aphid infestation, however, pae9 mutants increased their levels of camalexin, glucosinolates, and JA, and no long-term effects were observed on aphid fitness. Overall, these data show that PAE9 is required for constitutive up-regulation of defense-related compounds, but that it is not required for aphid-induced defenses. The signatures of phenolic antioxidants, phytoprostanes, and oxidative stress-related transcripts indicate that the processes underlying PAE9 activity involve oxidation-reduction reactions.
- MeSH
- acetylesterasa metabolismus MeSH
- Arabidopsis genetika metabolismus parazitologie MeSH
- býložravci fyziologie MeSH
- down regulace genetika MeSH
- genové regulační sítě MeSH
- glukosinoláty metabolismus MeSH
- indoly metabolismus MeSH
- metabolom genetika MeSH
- mšice fyziologie MeSH
- mutace genetika MeSH
- oxidační stres MeSH
- oxylipiny metabolismus MeSH
- proteiny huseníčku metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- regulační geny MeSH
- regulátory růstu rostlin metabolismus MeSH
- sekundární metabolismus MeSH
- thiazoly metabolismus MeSH
- transkripční faktory metabolismus MeSH
- transkriptom genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Arbuscular mycorrhizas (AM) are the most common symbiotic associations between a plant's root compartment and fungi. They provide nutritional benefit (mostly inorganic phosphate [Pi]), leading to improved growth, and nonnutritional benefits, including defense responses to environmental cues throughout the host plant, which, in return, delivers carbohydrates to the symbiont. However, how transcriptional and metabolic changes occurring in leaves of AM plants differ from those induced by Pifertilization is poorly understood. We investigated systemic changes in the leaves of mycorrhizedMedicago truncatulain conditions with no improved Pistatus and compared them with those induced by high-Pitreatment in nonmycorrhized plants. Microarray-based genome-wide profiling indicated up-regulation by mycorrhization of genes involved in flavonoid, terpenoid, jasmonic acid (JA), and abscisic acid (ABA) biosynthesis as well as enhanced expression ofMYC2, the master regulator of JA-dependent responses. Accordingly, total anthocyanins and flavonoids increased, and most flavonoid species were enriched in AM leaves. Both the AM and Pitreatments corepressed iron homeostasis genes, resulting in lower levels of available iron in leaves. In addition, higher levels of cytokinins were found in leaves of AM- and Pi-treated plants, whereas the level of ABA was increased specifically in AM leaves. Foliar treatment of nonmycorrhized plants with either ABA or JA induced the up-regulation ofMYC2, but only JA also induced the up-regulation of flavonoid and terpenoid biosynthetic genes. Based on these results, we propose that mycorrhization and Pifertilization share cytokinin-mediated improved shoot growth, whereas enhanced ABA biosynthesis and JA-regulated flavonoid and terpenoid biosynthesis in leaves are specific to mycorrhization.
- MeSH
- cyklopentany metabolismus MeSH
- flavonoidy metabolismus MeSH
- fosfáty metabolismus MeSH
- Glomeromycota fyziologie MeSH
- kyselina abscisová metabolismus MeSH
- listy rostlin genetika mikrobiologie fyziologie MeSH
- Medicago truncatula genetika mikrobiologie fyziologie MeSH
- mykorhiza fyziologie MeSH
- oxylipiny metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- regulátory růstu rostlin metabolismus MeSH
- rostlinné proteiny genetika metabolismus MeSH
- sekundární metabolismus * MeSH
- symbióza MeSH
- terpeny metabolismus MeSH
- upregulace MeSH
- Publikační typ
- časopisecké články MeSH
