Role of trichomes in plant defence - A crop specific review

Trichomes have long been investigated as an initial line of defence against insect herbivores. The structure, categorization and diversity of trichomes in flowering plants, as well as their mechanisms of action against abiotic and biotic stresses, are discussed. Plant-herbivore interactions are complicated interactions involving intricate networks of chemicals, signals and tactics to overcome each other's defences. To gain nutrients from host plants, herbivores employ a variety of feeding techniques. Plants respond by activating several defence mechanisms. Context of this review is based over the research on herbivore-trichome interactions and how trichomes are involved in both direct and indirect plant defences. Importance of trichome exudates like terpenes, acyl sugars, phenyl propanoid derivatives, methyl ketones, flavonoids and defensive proteins have been discussed. In our study, we emphasized on the relevance of trichomes as a reliable indicator of plant defence and how it is involved in defence responses of some economically important crops. Finally, we suggest several promising new study avenues for future work on trichomes and trichome-mediated responses.