Poison ivy hairy root cultures enable a stable transformation system suitable for detailed investigation of urushiol metabolism

Abstract

Poison ivy (Toxicodendron radicans) is best known for causing exasperating allergenic delayed‐contact dermatitis symptoms that last for weeks on persons who have contacted the plant. Urushiols are alkylcatechols produced by poison ivy responsible for causing this dermatitis. While urushiol chemical structures are well known, the metabolic intermediates and genes responsible for their biosynthesis have not been experimentally validated. A molecular genetic characterization of urushiol biosynthesis in poison ivy will require stable genetic transformation and subsequent regeneration of organs that retain the capacity synthesize urushiol. To this end, Agrobacterium rhizogenes was used to generate hormone‐independent poison ivy hairy root cultures. Optimal conditions for hairy root formation were skotomorphic poison ivy hypocotyls prick‐inoculated with A. rhizogenes, and preferential propagation of cultures with an atypical clumpy hairy root growth habit. The origin of the poison ivy accession used for A. rhizogenes prick‐inoculation did not affect the initial formation of calli/hairy root primordia, but rather significantly influenced the establishment of long‐term hormone‐independent hairy root growth. A. rhizogenes harboring a recombinant T‐DNA binary plasmid with an intron‐containing Firefly Luciferase gene produced stable transgenic hairy root lines expressing luciferase activity at high frequency. Poison ivy hairy root lines produced significantly lower steady‐state urushiol levels relative to wild‐type roots, but higher urushiol levels than a poison ivy undifferentiated callus line with undetectable urushiol levels, suggesting that urushiol biosynthesis requires intact poison ivy organs. The lower urushiol levels in poison ivy hairy root lines facilitated the first identification of anacardic acid metabolites initially in hairy roots, and subsequently in wild‐type roots as well. This study establishes a transformation hairy root regeneration protocol for poison ivy that can serve as a platform for future reverse‐genetic studies of urushiol biosynthesis in poison ivy hairy roots.

A Comprehensive Review on Phytochemistry and Pharmacology of Homoeopathic Medicine Rhus Toxicodendron

“…17 Cardanol congeners and isomers were accumulated in developing germinated seedlings (in vitro) of poison ivy. 18 Both urushiol and anacardic acid metabolites were identified by Lott et al (2020) in poison ivy hairy root cultures showing parallelism to ginkgolic acid and hydro-ginkgolic acid. These compounds resemble C15:1 anacardic acid and C15:0 anacardic acid respectively isolated initially from cashew shells.…”

“…These compounds resemble C15:1 anacardic acid and C15:0 anacardic acid respectively isolated initially from cashew shells. 19 Depending upon the residual concentrations of various phytochemicals in different plant parts of Toxicodendron radicans, available in the literature, the efficacy of the homoeopathic medicine can be comparatively evaluated further with the help of available clinical and non-clinical reports. However, the problem arises while reconciling the phytoconstituents' pharmacological activity with the homoeopathic data because the homoeopathic medicine has almost invariably been mentioned to be prepared from Toxicodendron pubescens.…”

“…These compounds resemble C15:1 anacardic acid and C15:0 anacardic acid respectively isolated initially from cashew shells. 19…”

Antibiofilm activity of phytochemicals against Enterococcus faecalis: A literature review

“…Urushiol is a mixture of closely related alkylcatechols that consist of 1,2-dihydroxy-3-alk(en)yl-benzene core structure and pentadecyl or heptadecyl alkyl side chain (Lott et al, 2020). Urushiol is derived from the decarboxylation and hydroxylation of anacardic acid (Lott, Baklajian, Dickinson, Collakova, & Jelesko, 2019).…”

Death After Poison Ivy Smoke Inhalation

“…Mortality secondary to urushiol exposure is even more rare. The contact dermatitis from poison ivy exposure usually occurs 12 to 72 hours from initial exposure, and symptoms can persist for weeks before resolving 1 . The inflammatory process induced by urushiol can affect the epithelial lining of the respiratory system once aerosolized by burning and subsequently inhaled, 2 leading to acute respiratory distress secondary to intense local inflammation, with or without accompanying anaphylaxis.…”