A Rapid Method for Isolating Glandular Trichomes

Abstract

A physical method is described for the rapid isolation of plant trichomes, with emphasis on stalked glandular types. The technique involved breaking frozen trichomes with powdered dry ice and collection of glandular heads by sieving from larger tissue fragments. This method was applied to several plants that bear similar stalked trichomes: geranium (Pelargonium), potato (Solanum tuberosum), tomato (Lycopersicon esculentum), squash (Cucurbita pepo), and velvetleaf (Abutilon theophrasti). The tissue preparation was of sufficient quality without further purification for biochemical and molecular studies. The preparation maintained the biochemical integrity of the trichomes for active enzymes and usable nucleic acids. A large quantity of tissue can be harvested; for example, 351 milligrams dry weight of glandular trichomes were harvested from geranium pedicels in 12 hours. The utility of the technique was demonstrated by examining the fatty acid composition of tall glandular trichomes of geraniums, Pelargonium xhortorum L.H. Bailey. These purified cells contained high concentrations of unusual omega5-unsaturated fatty acids, proportionally 23.4% of total fatty acids in the trichomes. When the trichomes were removed, the supporting tissue contained no omega5-fatty acids, thereby unequivocally localizing omega5-fatty acids to the trichomes. Because omega5-fatty acids are unique precursors for the biosynthesis of omega5-anacardic acids, we conclude that anacardic acid synthesis must occur in the glandular trichomes.

Jasmonic Acid and Its Precursor 12-Oxophytodienoic Acid Control Different Aspects of Constitutive and Induced Herbivore Defenses in Tomato

“…Type VI trichomes were counted on six leaf discs punched out from each leaflet using a 0.4-cm cork borer. For trichome isolation according to Yerger et al (1992), 20 g of leaf material was shockfrozen in liquid nitrogen in a 50-mL tube, and 2 to 3 cm 3 of crushed dry ice was added and vortexed for 1 min. Trichomes were sieved into 10 mL of hexane and the suspension was filtered through a 500-mm mesh.…”

Comparative Functional Genomic Analysis ofSolanumGlandular Trichome Types

“…Fractions enriched in type 7 glandular trichome secretory cells were obtained using the bead-beater procedure. Methods employing liquid N 2 or dry ice (Yerger et al, 1992) did not work well for our purposes, as these preclude the ability to separate different types of trichomes from each other and lead to trichome fractions that consist mostly of the nonglandular stalks. The methods used in this investigation allowed us to obtain very pure preparations consisting almost exclusively of the secretory cells of interest.…”

Expression of a delta 9 14:0-acyl carrier protein fatty acid desaturase gene is necessary for the production of omega 5 anacardic acids found in pest-resistant geranium (Pelargonium xhortorum).

“…In resistant geranium trichomes, we have also identified 16:1A"1 and 18:1A'3 fatty acids but have not identified a 14:1A9 fatty acid (10). We propose that the pest-resistant genotype is characterized by the production of 14:1A9 which is efficiently elongated, as in E. coli, to the two unique fatty acids 16:1A1" and 18:1A'3 ( Fig.…”

“…Thus the novel 16:1A11 and 18:1A13 fatty acids are direct precursors to the 22:1co5 and 24:1w5 anacardic acids, respectively, which are associated with pest resistance (6,7). Consistent with this, the 16:1A11 and 18:1A13 fatty acids and corresponding c5 anacardic acids are specifically localized in the trichomes of the resistant genotype (3,4,10).…”