Novel players in organogenesis and flavonoid biosynthesis in cucumber glandular trichomes

Abstract

Glandular trichomes (GTs) are outgrowths of plant epidermal cells that secrete and store specialized secondary metabolites that protect plants against biotic and abiotic stresses and have economic importance for human use. While extensive work has been done to understand the molecular mechanisms of trichome organogenesis in Arabidopsis (Arabidopsis thaliana), which forms unicellular, non-glandular trichomes (NGTs), little is known about the mechanisms of GT development or regulation of secondary metabolites in plants with multicellular GTs. Here, we identified and functionally characterized genes associated with GT organogenesis and secondary metabolism in GTs of cucumber (Cucumis sativus). We developed a method for effective separation and isolation of cucumber GTs and NGTs. Transcriptomic and metabolomic analyses showed that flavonoid accumulation in cucumber GTs is positively associated with increased expression of related biosynthesis genes. We identified 67 GT development-related genes, the functions of 7 of which were validated by virus-induced gene silencing. We further validated the role of cucumber ECERIFERUM1 (CsCER1) in GT organogenesis by overexpression and RNA interference transgenic approaches. We further show that the transcription factor TINY BRANCHED HAIR (CsTBH) serves as a central regulator of flavonoid biosynthesis in cucumber glandular trichomes. Work from this study provides insight into the development of secondary metabolite biosynthesis in multi-cellular glandular trichomes.

Advances in Endangered Plant Research: Ammopiptanthus’s Responses to Biotic and Abiotic Stressors

“…Researchers note that the dense trichomes on the leaves and stems of plants not only help them adapt to arid environments but also contribute to their defense against extreme temperatures and ultraviolet radiation. Additionally, these trichomes potentially serve as physical barriers against pests and pathogens [89,90]. Specifically, our current study has shown that the formation of trichomes is significantly increased in A. nanus plants subjected to salt stress (Unpublished data).…”

New insights into the evolution and local adaptation of the genus Castanea in east Asia

“…The rapid expansion of the CER1 family in the Chinese chestnut is related not only to the thickening of the wax layer to adapt to the arid environment in northern China, but possibly also to the development of chestnut glandular trichomes [ 58 ]. In cucumbers, CER1 can promote the formation of glandular trichomes [ 36 ]. Although we cannot confirm whether Chinese chestnut CER1 is also required in the glandular trichome development in addition to wax layer synthesis, it is highly likely that Chinese chestnut has adapted to cold and dry environments by promoting the development of leaf appendages through the expansion of the CER1 family.…”

Potential Regulatory Networks and Heterosis for Flavonoid and Terpenoid Contents in Pak Choi: Metabolomic and Transcriptome Analyses

“…Terpenoids are derived from one of two biosynthetic pathways: the mevalonic acid (MVA) and plastidial 2-C-methylerythritol 4-phosphate (MEP) pathways. Flavonoid and terpenoid metabolism have been studied in many species, including Cucumis sativus [4], Passiflora edulis [5], Cryptomeria fortunei [6], and Primula veris [7]. Metabolomic analysis targeting terpenoids has led to the identification of 50 terpenoid metabolites, including 27 triterpenoid saponins and 11 triterpenes [8].…”