Trichome

Types and Functions of Trichomes

• Algal trichomes in filamentous algae and cyanobacteria like Spirulina and Oscillatoria.
• Plant trichomes with varied features like epidermal outgrowths, glandular or non-glandular, and different types such as hairs, scales, and peltate hairs.
• Functions of trichomes include preventing soil erosion, deterring herbivores, reducing transpiration, reflecting sunlight, and enhancing water droplet accumulation.
• Glandular trichomes found on around 30% of plants secrete metabolites like terpenoids, phenylpropanoids, flavonoids, and acylsugars.
• Non-glandular trichomes provide structural protection, synthesize polyphenols, flavonoids, ellagitannins, and glycosides for stress resistance.

Development and Regulation of Trichomes

• Trichomes and root hairs are lateral outgrowths of epidermal cells.
• Genetic control of trichome and root hair patterning involves transcription factors like GL1, GL3, and TTG1.
• Phytohormones like gibberellic acid, cytokinins, and jasmonic acids influence trichome formation.
• Enzymes play a role in regulating trichome and root hair development.
• Arabidopsis thaliana trichomes are classified as aerial, epidermal, unicellular, tubular structures.

Significance in Taxonomy and Molecular Biology

• Trichomes aid in plant identification and taxonomy based on type, presence, absence, and location.
• Trichomes are used in forensic examination to identify plants like Cannabis sativa.
• GLABROUS1 protein initiates trichome formation in Arabidopsis thaliana, serving as a model for cell differentiation and pattern formation.
• Knockouts of the gene lead to glabrous plants used in genome editing experiments.

Uses and Defense Mechanisms of Trichomes

• Bean leaves historically trap bedbugs by impaling their feet with trichomes.
• European wool carder bees use trichomes for nest building.
• Trichomes are used by plants to deter herbivores physically or chemically.
• Stinging trichomes induce pain upon contact, with higher densities in herbivory-prone areas.
• Some organisms have developed mechanisms to resist trichome effects.

Influence on Insects and Genetics Studies

• Plant secretions prevent wasp parasitism in nests of wool-carder bees.
• Trichomes play a role in herbivore handling and defense mechanisms.
• Studies on trichomes in various plant species highlight their diverse functions.
• Genetics studies focus on trichome development and CRISPR/Cas9-based gene targeting in Arabidopsis thaliana.

Trichome Data Sources