Histological, metabolomic and transcriptomic analyses reveal mechanisms of cold acclimation of the Moso bamboo (Phyllostachys edulis) leaf

Abstract

Moso bamboo leaf copes well with the cold winter in southeastern China. However, until now, there has been almost no work reporting on its adaptation mechanisms to cold weather. Herein, we found that Moso bamboo leaf has evolved several anatomical structures that may play a role in enhancing its cold tolerance. These structures include fewer fusiform cells, smaller bulliform cells, lower stomata density, and many more trichomes, as well as lower relative water content than in the leaf of a cold-sensitive bamboo species, Bambusa ventricosa. Untargeted metabolomic analysis revealed that the winter leaf of Moso bamboo had ten- to thousand-fold higher stress-resistant metabolites such as glutathione, trehalose and ascorbic acid than the leaf of B. verntricosa on both warm and cold days. In contrast to the leaves that grew on a warm day, some metabolites such as glutathione and trehalose increased dramatically in the leaves of Moso bamboo that grew on a cold day. However, they unexpectedly decreased in the leaf of B. ventricosa growing at cold temperatures. Transcriptome analysis revealed a cold stress response network that includes trehalose, glutathione, flavonoid metabolism, DNA repair, reactive oxygen species degradation, stress-associated genes, and abiotic stress-related plant hormones such as jasmonic acid, abscisic acid, and ethylene. The potential mediator transcription factors such as EREBP, HSF, MYB, NAC, and WRYK were also found to be significantly upregulated in Moso bamboo leaves growing at cold temperatures. Interestingly, a large number of newly identified genes were found to be involved in the transcriptome of the winter leaf of Moso bamboo. Most of these new genes have not even been annotated yet. The above results indicate that the Moso bamboo leaf has evolved special histological structures, metabolic pathways, and a cold stress tolerant transcriptome to adapt to the cold weather in its distribution areas.

Characterization of anatomical features, developmental roadmaps, and key genes of bamboo leaf epidermis

“…As for the cell distribution pattern of the leaf epidermis, the stomata of the abaxial epidermis of P . japonica are distributed in 2–4 rows on both sides of the veins, and the arcuate, long, and thin papillae are densely distributed on the abaxial epidermis and completely cover the stomata in the lower epidermis (Figure 1), which has been observed in many other bamboo species such as Bambusa multiplex (Wang et al, 2022; Zhang et al, 2014). However, compared to other grasses, such as maize, the leaf epidermis of P .…”

“…For example, the leaf epidermis of P . japonica also consists of eight different cell types, such as stomata, silicon cells, cork cells, and papillae (Figure 1), just as in other bamboo species (Vieira et al, 2002; Wang et al, 2022). As for the cell distribution pattern of the leaf epidermis, the stomata of the abaxial epidermis of P .…”

“…Another interesting result was that epidermal appendages such as papillae and prickle hairs differentiated before the stomata and other epidermis cells, such as cork cells matured (Figures 3 and 4), which may improve the water storage capacity of P . japonica leaves (Wang et al, 2022).…”

“…Recent research also suggests that the epidermal structure of bamboo leaves, such as trichome and stomata density, is closely correlated with the cold stress tolerance of bamboo leaves (Wang et al, 2022). The deposition of silica in leaf epidermal cells, such as the silica cells of bamboo, has been reported to be important for mechanical stability, pathogen protection, drought resistance, and light absorption (Motomura et al, 2006).…”

The impact of genetic modified Ma bamboo on soil microbiome

“…1 Moreover, bamboo forestry has excellent carbon fixation ability ( Wang et al, 2021 ), and the demands for economically important bamboo species are increasing. Whereas, most giant bamboo species including Ma bamboo ( Dendrocalamus latiflorus Munro), which provides valuable natural construction materials and high quality young bamboo shoots as food and acts as one of the most important giant bamboo species in South Asia, are grown in the warm and moist tropical and subtropical area, and their distributions and development are largely affected by abiotic stresses, mainly cold and drought ( Liu et al, 2020 ; Wang et al, 2022 ). The question on how to improve their abiotic stress tolerance remains challenging for bamboo basic research and plantation.…”