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Investigation of the multifunctional gene AOP3 expands the regulatory network fine-tuning glucosinolate production in Arabidopsis.

Jensen LM, Kliebenstein DJ, Burow M - Front Plant Sci (2015)

Bottom Line: In this study, we use transgenic plants in combination with natural variation to investigate the regulatory role of the AOP3 gene found in GS-AOP locus previously suggested to contribute to the regulation of glucosinolate defense compounds.Phenotypic analysis and QTL mapping in F2 populations with different AOP3 transgenes support that the enzymatic function and the AOP3 RNA both play a significant role in controlling glucosinolate accumulation.Furthermore, we find different loci interacting with either the enzymatic activity or the RNA of AOP3 and thereby extend the regulatory network controlling glucosinolate accumulation.

View Article: PubMed Central - PubMed

Affiliation: DNRF Center DynaMo, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen Frederiksberg, Denmark ; Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen Frederiksberg, Denmark.

ABSTRACT
Quantitative trait loci (QTL) mapping studies enable identification of loci that are part of regulatory networks controlling various phenotypes. Detailed investigations of genes within these loci are required to ultimately understand the function of individual genes and how they interact with other players in the network. In this study, we use transgenic plants in combination with natural variation to investigate the regulatory role of the AOP3 gene found in GS-AOP locus previously suggested to contribute to the regulation of glucosinolate defense compounds. Phenotypic analysis and QTL mapping in F2 populations with different AOP3 transgenes support that the enzymatic function and the AOP3 RNA both play a significant role in controlling glucosinolate accumulation. Furthermore, we find different loci interacting with either the enzymatic activity or the RNA of AOP3 and thereby extend the regulatory network controlling glucosinolate accumulation.

No MeSH data available.


Related in: MedlinePlus

GS-ELONG and AOP3 interaction in a Col-0 × Ler-0 F2 population for control of leaf glucosinolate levels. Average glucosinolate levels for the interaction of MAM1 or MAM2 with presence and absence of AOP3 for total aliphatic glucosinolate levels (A), SC glucosinolate levels (B), and LC glucosinolate levels (C). Significance of the main effects and interaction are depicted by P < 0.05*, P < 0.01**, and P < 0.001*** and letters indicate significance of posttest with a levels of P < 0.05. Bean plots show strip charts of the individual plants levels in each group (n = 6, n = 16, n = 13, and n = 47), the density, and the average.
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Figure 2: GS-ELONG and AOP3 interaction in a Col-0 × Ler-0 F2 population for control of leaf glucosinolate levels. Average glucosinolate levels for the interaction of MAM1 or MAM2 with presence and absence of AOP3 for total aliphatic glucosinolate levels (A), SC glucosinolate levels (B), and LC glucosinolate levels (C). Significance of the main effects and interaction are depicted by P < 0.05*, P < 0.01**, and P < 0.001*** and letters indicate significance of posttest with a levels of P < 0.05. Bean plots show strip charts of the individual plants levels in each group (n = 6, n = 16, n = 13, and n = 47), the density, and the average.

Mentions: In the Col-0 × Ler-0 F2 population, the C3 background has higher levels of total aliphatic glucosinolates than the C4 background i.e., with presence of MAM1 (Figure 2A). Similarly, plants expressing AOP3 in the C3 background showed a trend toward higher levels of aliphatic glucosinolates than C3 plants without AOP3, whereas no clear difference was seen in the C4 background (Figure 2A, Table S1). This suggests that specific allelic interactions of GS-ELONG controlling the relative C3 and C4 accumulation and AOP3 might play a role in controlling the levels of aliphatic glucosinolates. AOP3 only converts SC glucosinolates, and we therefore considered whether the changes in total aliphatic glucosinolates were purely caused by higher flux for SC. As we expected, the SC levels varied dependent on AOP3 and GS-ELONG as seen for the total aliphatic glucosinolate amounts (Figure 2B), but this was also observed for LC, where the plants with the highest LC levels were seen in the AOP3 MAM2 background (Figure 2C). These observations suggest that the interaction between AOP3 and C3 accumulation is important for the fine-tuning of the aliphatic glucosinolate levels, and that AOP3 is dependent on a homozygous MAM2 state. Although, the data suggest the importance of the presence of the AOP3 substrate, 3-methylsulfinylpropyl glucosinolate (3msp) (Figure 1), it is not only the flux through the SC pathway that increases the total aliphatic glucosinolate accumulation. Since the increase was also observed for LC glucosinolates that are not substrates for AOP3, the flux needs to be increased from primary to specialized metabolism to cause higher levels of both SC and LC glucosinolates. A potential regulatory role independent of the enzymatic activity of AOP3 might thus be mediated via signaling by metabolites, protein interactions, or the RNA.


Investigation of the multifunctional gene AOP3 expands the regulatory network fine-tuning glucosinolate production in Arabidopsis.

Jensen LM, Kliebenstein DJ, Burow M - Front Plant Sci (2015)

GS-ELONG and AOP3 interaction in a Col-0 × Ler-0 F2 population for control of leaf glucosinolate levels. Average glucosinolate levels for the interaction of MAM1 or MAM2 with presence and absence of AOP3 for total aliphatic glucosinolate levels (A), SC glucosinolate levels (B), and LC glucosinolate levels (C). Significance of the main effects and interaction are depicted by P < 0.05*, P < 0.01**, and P < 0.001*** and letters indicate significance of posttest with a levels of P < 0.05. Bean plots show strip charts of the individual plants levels in each group (n = 6, n = 16, n = 13, and n = 47), the density, and the average.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585220&req=5

Figure 2: GS-ELONG and AOP3 interaction in a Col-0 × Ler-0 F2 population for control of leaf glucosinolate levels. Average glucosinolate levels for the interaction of MAM1 or MAM2 with presence and absence of AOP3 for total aliphatic glucosinolate levels (A), SC glucosinolate levels (B), and LC glucosinolate levels (C). Significance of the main effects and interaction are depicted by P < 0.05*, P < 0.01**, and P < 0.001*** and letters indicate significance of posttest with a levels of P < 0.05. Bean plots show strip charts of the individual plants levels in each group (n = 6, n = 16, n = 13, and n = 47), the density, and the average.
Mentions: In the Col-0 × Ler-0 F2 population, the C3 background has higher levels of total aliphatic glucosinolates than the C4 background i.e., with presence of MAM1 (Figure 2A). Similarly, plants expressing AOP3 in the C3 background showed a trend toward higher levels of aliphatic glucosinolates than C3 plants without AOP3, whereas no clear difference was seen in the C4 background (Figure 2A, Table S1). This suggests that specific allelic interactions of GS-ELONG controlling the relative C3 and C4 accumulation and AOP3 might play a role in controlling the levels of aliphatic glucosinolates. AOP3 only converts SC glucosinolates, and we therefore considered whether the changes in total aliphatic glucosinolates were purely caused by higher flux for SC. As we expected, the SC levels varied dependent on AOP3 and GS-ELONG as seen for the total aliphatic glucosinolate amounts (Figure 2B), but this was also observed for LC, where the plants with the highest LC levels were seen in the AOP3 MAM2 background (Figure 2C). These observations suggest that the interaction between AOP3 and C3 accumulation is important for the fine-tuning of the aliphatic glucosinolate levels, and that AOP3 is dependent on a homozygous MAM2 state. Although, the data suggest the importance of the presence of the AOP3 substrate, 3-methylsulfinylpropyl glucosinolate (3msp) (Figure 1), it is not only the flux through the SC pathway that increases the total aliphatic glucosinolate accumulation. Since the increase was also observed for LC glucosinolates that are not substrates for AOP3, the flux needs to be increased from primary to specialized metabolism to cause higher levels of both SC and LC glucosinolates. A potential regulatory role independent of the enzymatic activity of AOP3 might thus be mediated via signaling by metabolites, protein interactions, or the RNA.

Bottom Line: In this study, we use transgenic plants in combination with natural variation to investigate the regulatory role of the AOP3 gene found in GS-AOP locus previously suggested to contribute to the regulation of glucosinolate defense compounds.Phenotypic analysis and QTL mapping in F2 populations with different AOP3 transgenes support that the enzymatic function and the AOP3 RNA both play a significant role in controlling glucosinolate accumulation.Furthermore, we find different loci interacting with either the enzymatic activity or the RNA of AOP3 and thereby extend the regulatory network controlling glucosinolate accumulation.

View Article: PubMed Central - PubMed

Affiliation: DNRF Center DynaMo, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen Frederiksberg, Denmark ; Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen Frederiksberg, Denmark.

ABSTRACT
Quantitative trait loci (QTL) mapping studies enable identification of loci that are part of regulatory networks controlling various phenotypes. Detailed investigations of genes within these loci are required to ultimately understand the function of individual genes and how they interact with other players in the network. In this study, we use transgenic plants in combination with natural variation to investigate the regulatory role of the AOP3 gene found in GS-AOP locus previously suggested to contribute to the regulation of glucosinolate defense compounds. Phenotypic analysis and QTL mapping in F2 populations with different AOP3 transgenes support that the enzymatic function and the AOP3 RNA both play a significant role in controlling glucosinolate accumulation. Furthermore, we find different loci interacting with either the enzymatic activity or the RNA of AOP3 and thereby extend the regulatory network controlling glucosinolate accumulation.

No MeSH data available.


Related in: MedlinePlus