Advances in the regulatory mechanisms of multicellular trichome formation and its secondary metabolite synthesis in vegetable crops

Trichomes are specialized epidermal appendages, which can be divided into glandular or non-glandular types based on their diverse morphology. The glands of glandular trichomes are responsible for the biosynthesis and storage of many natural metabolites. Recent progress has been made in characterizing the regulatory mechanisms of trichome formation and metabolite biosynthesis in the trichome. In this paper, we describe the structural and morphological features of glandular trichomes in vegetable crops, mainly focusing on tomato and cucumber. We discuss the developmental processes and regulatory mechanisms involved in trichome formation, including the roles of regulatory factors, phytohormones and environmental influences. We also highlight recent advances in the regulatory mechanisms underlying glandular trichome-related metabolites. This review provides a basis for understanding the formation of multicellular trichome and their secondary metabolites.