Previously, sugarcane mosaic virus (SCMV) was developed as a vector for transient expression of heterologous genes in
12-hydroxy-jasmonoyl-isoleucine (12OH-JA-Ile) is a metabolite in the catabolic pathway of the plant hormone jasmonate, and is synthesized by the cytochrome P450 subclade 94 enzymes. Contrary to the well-established function of jasmonoyl-isoleucine (JA-Ile) as the endogenous bioactive form of jasmonate, the function of 12OH-JA-Ile is unclear. Here, the potential role of 12OH-JA-Ile in jasmonate signaling and wound response was investigated. Exogenous application of 12OH-JA-Ile mimicked several JA-Ile effects including marker gene expression, anthocyanin accumulation and trichome induction in Arabidopsis thaliana. Genome-wide transcriptomics and untargeted metabolite analyses showed large overlaps between those affected by 12OH-JA-Ile and JA-Ile. 12OH-JA-Ile signaling was blocked by mutation in CORONATINE INSENSITIVE 1. Increased anthocyanin accumulation by 12OH-JA-Ile was additionally observed in tomato and sorghum, and was disrupted by the COI1 defect in tomato jai1 mutant. In silico ligand docking predicted that 12OH-JA-Ile can maintain many of the key interactions with COI1-JAZ1 residues identified earlier by crystal structure studies using JA-Ile as ligand. Genetic alternation of jasmonate metabolic pathways in Arabidopsis to deplete both JA-Ile and 12OH-JA-Ile displayed enhanced jasmonate deficient wound phenotypes and was more susceptible to insect herbivory than that depleted in only JA-Ile. Conversely, mutants overaccumulating 12OH-JA-Ile showed intensified wound responses compared with wild type with similar JA-Ile content. These data are indicative of 12OH-JA-Ile functioning as an active jasmonate signal and contributing to wound and defense response in higher plants.
more » « less- NSF-PAR ID:
- 10121234
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Plant and Cell Physiology
- Volume:
- 60
- Issue:
- 10
- ISSN:
- 0032-0781
- Page Range / eLocation ID:
- p. 2152-2166
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
Abstract (maize). Here, we show that SCMV can also be applied for virus‐induced gene silencing (VIGS) of endogenous maize genes. Comparison of sense and antisense VIGS constructs targeting maizeZea mays phytoene desaturase (PDS) showed that antisense constructs resulted in a greater reduction in gene expression. In a time course of gene expression after infection with VIGS constructs targetingPDS ,lesion mimic 22 (Les22 ), andIodent japonica 1 (Ij1 ), efficient expression silencing was observed 2, 3, and 4 weeks after infection with SCMV. However, at Week 5, expression ofLes22 andIj1 was no longer significantly reduced compared with control plants. The defense signaling molecule jasmonate‐isoleucine (JA‐Ile) can be inactivated by 12C‐hydroxylation and hydrolysis, and knockout of these genes leads to herbivore resistance. JA‐Ile hydroxylases and hydrolases have been investigated in Arabidopsis, rice, and . To determine whether the maize homologs of these genes function in plant defense, we silenced expression ofNicotiana attenuata ZmCYP94B1 (predicted JA‐Ile hydroxylase) andZmJIH1 (predicted JA‐Ile hydrolase) by VIGS with SCMV, which resulted in elevated expression of two defense‐related genes,Maize Proteinase Inhibitor (MPI ) andRibosome Inactivating Protein 2 (RIP2 ). AlthoughZmCYP94B1 andZmJIH1 gene expression silencing increased resistance to (fall armyworm),Spodoptera frugiperda (American birdwing grasshopper), andSchistocerca americana (corn leaf aphid), there was no additive effect from silencing the expression of both genes. Further work will be required to determine the more precise functions of these enzymes in regulating maize defenses.Rhopalosiphum maidis -
Previously, sugarcane mosaic virus (SCMV) was developed as a vector for transient expression of heterologous genes in Zea mays (maize). Here, we show that SCMV can also be applied for virus-induced gene silencing (VIGS) of endogenous maize genes. Comparison of sense and antisense VIGS constructs targeting maize phytoene desaturase (PDS) showed that antisense constructs resulted in a greater reduction in gene expression. In a time course of gene expression after infection with VIGS con- structs targeting PDS, lesion mimic 22 (Les22), and Iodent japonica 1 (Ij1), efficient expression silencing was observed 2, 3, and 4 weeks after infection with SCMV. However, at Week 5, expression of Les22 and Ij1 was no longer significantly reduced compared with control plants. The defense signaling molecule jasmonate-isoleucine (JA-Ile) can be inactivated by 12C-hydroxylation and hydrolysis, and knockout of these genes leads to herbivore resistance. JA-Ile hydroxylases and hydrolases have been investigated in Arabidopsis, rice, and Nicotiana attenuata. To determine whether the maize homologs of these genes function in plant defense, we silenced expression of ZmCYP94B1 (predicted JA-Ile hydroxylase) and ZmJIH1 (predicted JA- Ile hydrolase) by VIGS with SCMV, which resulted in elevated expression of two defense-related genes, Maize Proteinase Inhibitor (MPI) and Ribosome Inactivating Pro- tein 2 (RIP2). Although ZmCYP94B1 and ZmJIH1 gene expression silencing increased resistance to Spodoptera frugiperda (fall armyworm), Schistocerca americana (American birdwing grasshopper), and Rhopalosiphum maidis (corn leaf aphid), there was no addi- tive effect from silencing the expression of both genes. Further work will be required to determine the more precise functions of these enzymes in regulating maize defenses.more » « less
-
Previously, sugarcane mosaic virus (SCMV) was developed as a vector for transient expression of heterologous genes in Zea mays (maize). Here, we show that SCMV can also be applied for virus-induced gene silencing (VIGS) of endogenous maize genes. Comparison of sense and antisense VIGS constructs targeting maize phytoene desaturase (PDS) showed that antisense constructs resulted in a greater reduction in gene expression. In a time course of gene expression after infection with VIGS constructs targeting PDS, lesion mimic 22 (Les22), and Iodent japonica 1 (Ij1), efficient expression silencing was observed 2, 3, and 4 weeks after infection with SCMV. However, at Week 5, expression of Les22 and Ij1 was no longer significantly reduced compared with control plants. The defense signaling molecule jasmonate-isoleucine (JA-Ile) can be inactivated by 12C-hydroxylation and hydrolysis, and knockout of these genes leads to herbivore resistance. JA-Ile hydroxylases and hydrolases have been investigated in Arabidopsis, rice, and Nicotiana attenuata. To determine whether the maize homologs of these genes function in plant defense, we silenced expression of ZmCYP94B1 (predicted JA-Ile hydroxylase) and ZmJIH1 (predicted JA-Ile hydrolase) by VIGS with SCMV, which resulted in elevated expression of two defense-related genes, Maize Proteinase Inhibitor (MPI) and Ribosome Inactivating Protein 2 (RIP2). Although ZmCYP94B1 and ZmJIH1 gene expression silencing increased resistance to Spodoptera frugiperda (fall armyworm), Schistocerca americana (American birdwing grasshopper), and Rhopalosiphum maidis (corn leaf aphid), there was no additive effect from silencing the expression of both genes. Further work will be required to determine the more precise functions of these enzymes in regulating maize defenses.more » « less
-
Previously, sugarcane mosaic virus (SCMV) was developed as a vector for transient expression of heterologous genes in Zea mays (maize). Here, we show that SCMV can also be applied for virus-induced gene silencing (VIGS) of endogenous maize genes. Comparison of sense and antisense VIGS constructs targeting maize phytoene desaturase (PDS) showed that antisense constructs resulted in a greater reduction in gene expression. In a time course of gene expression after infection with VIGS constructs targeting PDS, lesion mimic 22 (Les22), and Iodent japonica 1 (Ij1), efficient expression silencing was observed 2, 3, and 4 weeks after infection with SCMV. However, at Week 5, expression of Les22 and Ij1 was no longer significantly reduced compared with control plants. The defense signaling molecule jasmonate-isoleucine (JA-Ile) can be inactivated by 12C-hydroxylation and hydrolysis, and knockout of these genes leads to herbivore resistance. JA-Ile hydroxylases and hydrolases have been investigated in Arabidopsis, rice, and Nicotiana attenuata. To determine whether the maize homologs of these genes function in plant defense, we silenced expression of ZmCYP94B1 (predicted JA-Ile hydroxylase) and ZmJIH1 (predicted JA-Ile hydrolase) by VIGS with SCMV, which resulted in elevated expression of two defense-related genes, Maize Proteinase Inhibitor (MPI) and Ribosome Inactivating Protein 2 (RIP2). Although ZmCYP94B1 and ZmJIH1 gene expression silencing increased resistance to Spodoptera frugiperda (fall armyworm), Schistocerca americana (American birdwing grasshopper), and Rhopalosiphum maidis (corn leaf aphid), there was no additive effect from silencing the expression of both genes. Further work will be required to determine the more precise functions of these enzymes in regulating maize defenses.more » « less
-
Abstract Maize is monecious, with separate male and female inflorescences. Maize flowers are initially bisexual but achieve separate sexual identities through organ arrest. Loss-of-function mutants in the jasmonic acid (JA) pathway have only female flowers due to failure to abort silks in the tassel.
Tasselseed5 (Ts5 ) shares this phenotype but is dominant. Positional cloning and transcriptomics of tassels identified an ectopically expressed gene in the CYP94B subfamily,Ts5 (ZmCYP94B1) . CYP94B enzymes are wound inducible and inactivate bioactive jasmonoyl-L-isoleucine (JA-Ile). Consistent with this result, tassels and wounded leaves ofTs5 mutants displayed lower JA and JA-lle precursors and higher 12OH-JA-lle product than the wild type. Furthermore, many wounding and jasmonate pathway genes were differentially expressed inTs5 tassels. We propose that theTs5 phenotype results from the interruption of JA signaling during sexual differentiation via the upregulation ofZmCYP94B1 and that its proper expression maintains maize monoecy.