skip to main content


Title: Pyrethric acid of natural pyrethrin insecticide: complete pathway elucidation and reconstitution in Nicotiana benthamiana
Summary

In the natural pesticides known as pyrethrins, which are esters produced in flowers ofTanacetum cinerariifolium(Asteraceae), the monoterpenoid acyl moiety is pyrethric acid or chrysanthemic acid.

We show here that pyrethric acid is produced from chrysanthemol in six steps catalyzed by four enzymes, the first five steps occurring in the trichomes covering the ovaries and the last one occurring inside the ovary tissues.

Three steps involve the successive oxidation of carbon 10 (C10) to a carboxylic group by TcCHH, a cytochrome P450 oxidoreductase. Two other steps involve the successive oxidation of the hydroxylated carbon 1 to give a carboxylic group by TcADH2 and TcALDH1, the same enzymes that catalyze these reactions in the formation of chrysanthemic acid. The ultimate result of the actions of these three enzymes is the formation of 10‐carboxychrysanthemic acid in the trichomes. Finally, the carboxyl group at C10 is methylated by TcCCMT, a member of theSABATHmethyltransferase family, to give pyrethric acid. This reaction occurs mostly in the ovaries.

Expression inN. benthamianaplants of all four genes encoding aforementioned enzymes, together with TcCDS, a gene that encodes an enzyme that catalyzes the formation of chrysanthemol, led to the production of pyrethric acid.

 
more » « less
NSF-PAR ID:
10461523
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
New Phytologist
Volume:
223
Issue:
2
ISSN:
0028-646X
Page Range / eLocation ID:
p. 751-765
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Summary

    The biological and functional diversity of ectomycorrhizal (ECM) associations remain largely unknown in South America. In Patagonia, theECMtreeNothofagus pumilioforms monospecific forests along mountain slopes without confounding effects of vegetation on plant–fungi interactions.

    To determine how fungal diversity and function are linked to elevation, we characterized fungal communities, edaphic variables, and eight extracellular enzyme activities along six elevation transects in Tierra del Fuego (Argentina and Chile). We also tested whether pairingITS1rDNAIllumina sequences generated taxonomic biases related to sequence length.

    Fungal community shifts across elevations were mediated primarily by soilpHwith the most species‐rich fungal families occurring mostly within a narrowpHrange. By contrast, enzyme activities were minimally influenced by elevation but correlated with soil factors, especially total soil carbon. The activity of leucine aminopeptidase was positively correlated withECMfungal richness and abundance, and acid phosphatase was correlated with nonECM fungal abundance. Several fungal lineages were undetected when using exclusively paired or unpaired forwardITS1 sequences, and these taxonomic biases need reconsideration for future studies.

    Our results suggest that soil fungi inN. pumilioforests are functionally similar across elevations and that these diverse communities help to maintain nutrient mobilization across the elevation gradient.

     
    more » « less
  2. Summary

    Diacylglycerol kinase (DGK) phosphorylates diacylglycerol (DAG) to generate phosphatidic acid (PA), and bothDAGandPAare lipid mediators in the cell. Here we show thatDGK1 in rice (Oryza sativa) plays important roles in root growth and development.

    Two independentOsDGK1‐knockout (dgk1) lines exhibited a higher density of lateral roots (LRs) and thinner seminal roots (SRs), whereasOsDGK1‐overexpressing plants displayed a lowerLRdensity and thickerSRsthan wild‐type (WT) plants.

    Overexpression ofOsDGK1led to a decline in theDGKsubstrateDAGwhereas specificPAspecies decreased indgk1roots. Supplementation ofDAGtoOsDGK1‐overexpressing seedlings restored theLRdensity andSRthickness whereas application ofPAtodgk1seedlings restored theLRdensity andSRthickness to those of theWT. In addition, treatment of rice seedlings with theDGKinhibitor R59022 increased the level ofDAGand decreasedPA, which also restored the root phenotype ofOsDGK1‐overexpressing seedlings close to that of theWT.

    Together, these results indicate thatDGK1 and associated lipid mediators modulate rice root architecture;DAGpromotesLRformation and suppressesSRgrowth whereasPAsuppressesLRnumber and promotesSRthickness.

     
    more » « less
  3. Summary

    Successive droughts have resulted in extensive tree mortality in the southwestern United States. Recovery of these areas is dependent on the survival and recruitment of young trees. For trees that rely on ectomycorrhizal fungi (EMF) for survival and growth, changes in soil fungal communities following tree mortality could negatively affect seedling establishment.

    We used tree‐focused and stand‐scale measurements to examine the impact of pinyon pine mortality on the performance of surviving juvenile trees and the potential for mutualism limitation of seedling establishment via alteredEMFcommunities.

    Mature pinyon mortality did not affect the survival of juvenile pinyons, but increased their growth. At both tree and stand scales, high pinyon mortality had no effect on the abundance ofEMFinocula, but led to alteredEMFcommunity composition including increased abundance ofGeoporaand reduced abundance ofTuber. Seedling biomass was strongly positively associated withTuberabundance, suggesting that reductions in this genus with pinyon mortality could have negative consequences for establishing seedlings.

    These findings suggest that whereas mature pinyon mortality led to competitive release for established juvenile pinyons, changes inEMFcommunity composition with mortality could limit successful seedling establishment and growth in high‐mortality sites.

     
    more » « less
  4. Abstract

    Plants make a variety of specialized metabolites that can mediate interactions with animals, microbes, and competitor plants. Understanding how plants synthesize these compounds enables studies of their biological roles by manipulating their synthesis in vivo as well as producing them in vitro. Acylsugars are a group of protective metabolites that accumulate in the trichomes of many Solanaceae family plants. Acylinositol biosynthesis is of interest because it appears to be restricted to a subgroup of species within the Solanum genus. Previous work characterized a triacylinositol acetyltransferase involved in acylinositol biosynthesis in the Andean fruit plantSolanum quitoense(lulo or naranjilla). We characterized three additionalS. quitoensetrichome expressed enzymes and found that virus‐induced gene silencing of each caused changes in acylinositol accumulation. pH was shown to influence the stability and rearrangement of the product of ASAT1H and could potentially play a role in acylinositol biosynthesis. Surprisingly, the in vitro triacylinositol products of these enzymes are distinct from those that accumulatein planta. This suggests that additional enzymes are required in acylinositol biosynthesis. These characterizedS. quitoenseenzymes, nonetheless, provide opportunities to test the biological impact and properties of these triacylinositols in vitro.

     
    more » « less
  5. Summary

    The evolution oflDOPA4,5‐dioxygenase activity, encoded by the geneDODA, was a key step in the origin of betalain biosynthesis in Caryophyllales. We previously proposed thatlDOPA4,5‐dioxygenase activity evolved via a single Caryophyllales‐specific neofunctionalisation event within theDODAgene lineage. However, this neofunctionalisation event has not been confirmed and theDODAgene lineage exhibits numerous gene duplication events, whose evolutionary significance is unclear.

    To address this, we functionally characterised 23 distinctDODAproteins forlDOPA4,5‐dioxygenase activity, from four betalain‐pigmented and five anthocyanin‐pigmented species, representing key evolutionary transitions across Caryophyllales. By mapping these functional data to an updatedDODAphylogeny, we then explored the evolution oflDOPA4,5‐dioxygenase activity.

    We find that lowlDOPA4,5‐dioxygenase activity is distributed across theDODAgene lineage. In this context, repeated gene duplication events within theDODAgene lineage give rise to polyphyletic occurrences of elevatedlDOPA4,5‐dioxygenase activity, accompanied by convergent shifts in key functional residues and distinct genomic patterns of micro‐synteny.

    In the context of an updated organismal phylogeny and newly inferred pigment reconstructions, we argue that repeated convergent acquisition of elevatedlDOPA4,5‐dioxygenase activity is consistent with recurrent specialisation to betalain synthesis in Caryophyllales.

     
    more » « less