Jasmonic acid is not a biosynthetic intermediate to produce the pyrethrolone moiety in pyrethrin II

Abstract

pyrethrum (Tanacetum cinerariifolium) produces insecticidal compounds known as pyrethrins. pyrethrins are esters; the acid moiety is either trans-chrysanthemic acid or pyrethric acid and the alcohol moiety of pyrethrins is either pyrethrolone, cinerolone, or jasmolone. It was generally accepted that cis-jasmone was biosynthetic intermediate to produce the alcohol moieties of pyrethrin, and the biosynthetic origin of the cis-jasmone was postulated to be jasmonic acid. However, there was no direct evidence to prove this hypothesis. In order to uncover the origin of pyrethrolone moiety in pyrethrin II, feeding experiments were performed employing deuterium-and 13 C-labeled compounds as substrates, and the expected labeled compounds were analyzed using UPLC MS/MS system. It was found that the pyrethrolone moiety in pyrethrin II was derived from 12-oxo-phytodienoic acid (OPDA), iso-OPDA and cis-jasmone but not from methyl jasmonate and 3-oxo-2-(2′-[Z]-pentenyl)-cyclopentane-1-hexanoic acid. The results supported that the biosynthesis of the pyrethrolone moiety in pyrethrin II partially used part of the jasmonic acid biosynthetic pathway, but not whole. Pyrethrum (Tanacetum cinerariifolium, formerly Chrysanthemum cinerariifolium) is a plant in the Asteraceae family that synthesizes insecticides known as pyrethrin (Fig. 1), and it was found that the highest levels of production were observed in flowers 1,2 , whereas a smaller amount was observed in leaves. Since pyrethrin shows remarkable toxicity against a wide range of insect species but low toxicity to warm-blooded animals, pyrethrin has been used for pest control 1. Until the middle of the 20 th century, Japan was the world's largest producer of pyrethrum, and it had been thought to be ideal to collect flowers before they were fully opened. However, pyrethroids, which are synthetic analogs of pyrethrin, are used at much higher amounts than pyrethrin as pest control agents due to their lower cost to produce and their effectiveness, even though they are less safe to vertebrates and less biodegradable 3,4. Recently, some researchers have noted the emergence of resistance among insects and toxicity toward mammals and fish 5. From the chemical structural viewpoint, pyrethrin has ester linkages in the chemical structure and is classified into two types (Fig. 1): type I esters have a chrysanthemoyl moiety, whereas type II esters have a pyrethroyl moiety having additional ester linkage composing methoxycarbonyl group. A common and distinctive structural feature of the acid moieties is a cyclopropane ring moiety. The alcohol-containing parts of pyrethrin are either pyrethrolone, cinerolone, or jasmolone, which all have a similar basic structure with that of cis-jasmone. The enzyme producing the ester linkage was identified as a GDSL lipase-like protein 6 , which was encoded on TcGLIP (Fig. S1). The synthesis of the acid and alcohol moieties of pyrethrin is not fully understood. For the acid moiety, it was demonstrated that T. cinerariifolium flowers have the enzyme trans-chr...

How Plants Synthesize Pyrethrins: Safe and Biodegradable Insecticides

“…However, enzymatic activities have not been confirmed for the AOS or AOC gene products. Recent labeling studies demonstrated that both 12-oxophytodienoic acid (OPDA) and cis-jasmone are precursors of rethrolones (Figure 1B) while jasmonic acid is not [74]. This not only illuminates pyrethrin biosynthesis but also provides insight into the thus far incompletely resolved origins of cis-jasmone in plants [74][75][76].…”

TcGLIP GDSL Lipase Substrate Specificity Co-determines the Pyrethrin Composition in Tanacetum cinerariifolium

“…In addition, they are less affected by the knockdown resistance (kdr) mutations than synthetic pyrethroids in mosquitoes, spurring the demand. Hence, several groups have explored enzymes involved in their biosynthesis. ,,, By administering 13 C-labeled glucose, we showed that the acid and alcohol moieties of pyrethrins are biosynthesized by the non-mevalonate and oxylipin pathways, respectively. , Also, we found with labeled precursors that pyrethrins are biosynthesized through cis -jasmone, unlike jasmonic acid produced via a distinct pathway . Studies showed that the cyclopropane ring is formed by chrysanthemol diphosphate synthase, and the diphosphate is hydrolyzed by either chrysanthemol diphosphate synthase or a Nudix family hydrolase .…”

“…1,14 Also, we found with labeled precursors that pyrethrins are biosynthesized through cis-jasmone, unlike jasmonic acid produced via a distinct pathway. 15 Studies showed that the cyclopropane ring is formed by chrysanthemol diphosphate synthase, 16 and the diphosphate is hydrolyzed by either chrysanthemol diphosphate synthase 17 or a Nudix family hydrolase. 18 The methoxycarbonyl moiety in type II pyrethrins is formed by P450 oxidoreductase in conjunction with aldehyde hydrogenases and a methyltransferase.…”

TcbHLH14 a Jasmonate Associated MYC2-like Transcription Factor Positively Regulates Pyrethrin Biosynthesis in Tanacetum cinerariifolium

“…Subsequently, CDP and chrysanthemol are oxidized by alcohol dehydrogenase and aldehyde dehydrogenase (ALDH) to produce trans -chrysanthemic acid [ 7 ], and are further catalyzed to pyrethric acid by chrysanthemol 10-hydroxylase and 10-carboxychrysanthemic acid 10-methyltransferase [ 8 ]. The alcohol moiety substrate rethrolones are at least partially obtained from the jasmonate (JA) biosynthesis pathway [ 4 , 9 ] in the conversion of linolenic acid to oxo -phytodienoic acid, including lipoxygenase, allene oxide synthase, and allene oxide cyclase (AOC) as the key molecules involved in JA synthesis [ 10 , 11 ]. Jasmone hydroxylase converts jasmone to jasmolone [ 12 ], and then pyrethrolone synthase catalyzes jasmolone to pyrethrolone [ 13 ].…”