Morphological Structures of Bamboo (Bambusa emeiensis) Shoot Shells and Trichomes and Functions in Response to Herbivory

Abstract

Bamboo (Bambusa emeiensis) shoot, a nutritious food, easily attracts herbivores, including the bamboo weevil, Cyrtotrachelus buqueti. Scanning electron microscopy revealed that bamboo shoot shells (BSSs), the protective layers encasing bamboo shoots, are composed of closely packed fibers and bamboo shoot trichomes (BSTs) are divided into three types, including glandular trichome I, and non-glandular types II and III. To elucidate the underlying molecular defense mechanisms, 50 transcription factors (TFs) were chosen for qRT-PCR analyses of BSS and BST based on bamboo shoot transcriptome data. Among these, 8 and 23 genes were significantly differentially expressed in BSS and BST, respectively, indicating that BSS and BST responded to herbivory. BSS and non-glandular BST functioned as physical barriers and glandular BST released volatile compounds in defense against herbivory. Some TFs might act as mediators and participate in defense responses by BSS and BST.