As the main component of plant cell walls, lignin can not only provide mechanical strength and physical defense for plants, but can also be an important indicator affecting the properties and quality of wood and bamboo. Dendrocalamus farinosus is an important economic bamboo species for both shoots and timber in southwest China, with the advantages of fast growth, high yield and slender fiber. Caffeoyl-coenzyme A-O-methyltransferase (CCoAOMT) is a key rate-limiting enzyme in the lignin biosynthesis pathway, but little is known about it in D. farinosus. Here, a total of 17 DfCCoAOMT genes were identified based on the D. farinosus whole genome. DfCCoAOMT1/14/15/16 were homologs of AtCCoAOMT1. DfCCoAOMT6/9/14/15/16 were highly expressed in stems of D. farinosus; this is consistent with the trend of lignin accumulation during bamboo shoot elongation, especially DfCCoAOMT14. The analysis of promoter cis-acting elements suggested that DfCCoAOMTs might be important for photosynthesis, ABA/MeJA responses, drought stress and lignin synthesis. We then confirmed that the expression levels of DfCCoAOMT2/5/6/8/9/14/15 were regulated by ABA/MeJA signaling. In addition, overexpression of DfCCoAOMT14 in transgenic plants significantly increased the lignin content, xylem thickness and drought resistance of plants. Our findings revealed that DfCCoAOMT14 can be a candidate gene that is involved in the drought response and lignin synthesis pathway in plants, which could contribute to the genetic improvement of many important traits in D. farinosus and other species.

Dendrocalamus farinosus bamboo shoots, a species with rich nutritional value, are important in Southwest China. Lignin is an important factor affecting the postharvest flavor quality of bamboo shoots; however, the underlying mechanism of lignin deposition in D. farinosus bamboo shoots during cold storage is still not fully understood. In this study, the mutant D. farinosus XK4 with low lignin content at 3.11% and the cultivated variety ZPX at 4.47% were used as experimental materials. The lignin content of D. farinosus XK4 and ZPX, as well as the gene expression differences between them, were compared and analyzed during cold storage using transcriptomic and physiological methods. Our analysis revealed several key genes and found that D. farinosus CCoAOMT1 plays a key role in the regulatory network of bamboo shoots during cold storage. Tobacco heterologous transformation experiments demonstrated that overexpression of DfCCoAOMT1 significantly increases lignin content. This study provides a novel foundation for future research aimed at improving the postharvest quality and flavor of D. farinosus bamboo shoots through targeted genetic manipulation during cold storage.

Fargesia rufa, one of the main food bamboo species for giant pandas, exhibits significant changes in nutritional composition with altitudinal gradient. However, the molecular mechanisms underlying this adaptation and its impact on the foraging behavior of giant pandas remain unclear. In this study, metabolomic and transcriptomic analyses were integrated to compare gene expression and metabolite profiles in leaves and rhizomes of F. rufa collected from 1000 m and 2000 m altitudes. With increasing altitude, 710 metabolites were up-regulated and 1032 were down-regulated in the leaves of F. rufa, whereas 684 metabolites were up-regulated and 1342 were down-regulated in the rhizomes; only 629 differential metabolites were shared between the two organs. Further analyses revealed that F. rufa responds to altitudinal changes through organ-specific metabolic reprogramming: leaves adopt a “metabolic conservation” strategy, downregulating the majority of flavonoid and phenylpropanoid metabolites, while rhizomes take an “active storage” strategy, significantly enhancing secondary metabolite synthesis and starch accumulation. This functional differentiation is consistent with the biological roles of the organs: the metabolic simplification of leaves may enhance the palatability of high-altitude leaves, while the nutritional reserves in rhizomes support bamboo shoot emergence. This study reveals the molecular mechanisms of bamboo’s altitudinal adaptation at the organ level, clarifies the intrinsic link between plant metabolism and animal diet, and provides a theoretical basis for giant panda habitat conservation.

Background/Objectives: Moso bamboo (Phyllostachys edulis), the most widely distributed bamboo species in China, is valued for both its shoots and timber. This species often faces challenges from high-temperature stress. To cope with this stress, Moso bamboo has evolved various adaptive mechanisms at the physiological and molecular levels. Although numerous studies have revealed that a large number of transcription factors (TFs) and genes play important roles in the regulatory network of plant heat stress responses, the regulatory network involved in heat responses remains incompletely understood. Methods: In this study, Moso bamboo was placed in a high-temperature environment of 42 °C for 1 h and 24 h, and transcriptome sequencing was carried out to accurately identify key molecules affected by high temperature and their related biological pathways. Results: Through a differential expression analysis, we successfully identified a series of key candidate genes and transcription factors involved in heat stress responses, including members of the ethylene response factor, HSF, WRKY, MYB, and bHLH families. Notably, in addition to traditional heat shock proteins/factors, multiple genes related to lipid metabolism, antioxidant enzymes, dehydration responses, and hormone signal transduction were found to play significant roles in heat stress responses. To further verify the changes in the expression of these genes, we used qRT-PCR technology for detection, and the results strongly supported their key roles in cellular physiological processes and heat stress responses. Conclusions: This study not only deepens our understanding of plant strategies for coping with and defending against extreme abiotic stresses but also provides valuable insights for future research on heat tolerance in Moso bamboo and other plants.

GDSL esterases/lipases constitute a large and functionally versatile gene family in plants, yet their systematic characterization in bamboo—perennial woody grasses with exceptionally rapid shoot elongation—remains scarce. Here, we performed a genome-wide identification of the GDSL family in allohexaploid Dendrocalamus farinosus and characterized the function of a candidate gene in secondary wall synthesis. A total of 265 DfGDSL genes were identified and classified into nine clades; rice xylan deacetylases BS1 and DARX1 fell within Clade VIII, which harbors 75 members. Chromosomal distribution, exon–intron organization, conserved motifs, and collinearity analyses indicated that whole-genome and tandem duplications drove family expansion, with purifying selection as the predominant evolutionary force. Expression profiling across tissues and shoot developmental stages pinpointed DfGDSL58 as the sole highly expressed OsDARX1 homolog in D. farinosus, showing specific upregulation during rapid elongation (50–400 cm). Its promoter contains auxin-responsive elements, and exogenous NAA treatment significantly induced its expression, with a peak at 6 h. Heterologous overexpression of DfGDSL58 (designated DfDACX1) in tobacco increased plant height and basal diameter while reducing lignin and hemicellulose deposition, xylem width, and transcript levels of xylan synthase (NtIRX9) and lignin biosynthetic genes (NtC4H, NtCOMT, NtCAD), whereas cellulose content and cellulose synthase genes (NtCESA4, NtCESA7) remained largely unchanged. Collectively, these findings demonstrate that DfDACX1 negatively regulates secondary wall thickening and promotes longitudinal growth, likely via modulating xylan deacetylation and downstream lignin biosynthesis. This study presents the first systematic characterization of the GDSL family in D. farinosus and identifies DfDACX1 as a key modulator of the trade-off between cell wall deposition and rapid shoot elongation, offering mechanistic insights into bamboo’s extraordinary growth and a potential target for engineering plant architecture.

Bamboo shoots, as the most nutritionally valuable food source for giant pandas during key reproductive seasons, are critical for conservation because their availability and timing directly influence panda foraging and habitat use. However, the molecular mechanisms through which altitudinal temperature variation governs rhizome shooting in staple food bamboos remain largely unknown. Here, we performed integrated metabolomic and transcriptomic analyses of Fargesia rufa rhizomes collected along an elevational gradient (1000 m, 1500 m, and 2000 m), with a critical paired comparison at 2000 m between a non-shooting cold gully-edge site (16.4 °C) and a shooting warm gully-center site (21.1 °C), where soil temperature is elevated by approximately 4 °C due to prolonged solar exposure. Our results demonstrate that soil temperature, rather than elevation per se, acts as the primary driver of rhizome shooting, with an apparent threshold near 20 °C. A core shooting metabolome (CSM) comprising 843 metabolites was consistently accumulated across all shooting conditions, which featured gibberellin/auxin precursors, TCA cycle intermediates, and phenylpropanoid compounds. Correspondingly, a core shooting transcriptome (Rh_shooting) of 10,970 genes was identified, which resolved into three functionally distinct temporal clusters: “shooting-on” (activated upon threshold crossing, enriched in hormone signaling and cell wall metabolism), “temperature-dose” (progressively upregulated with rising temperature, enriched in energy metabolism and defense), and “microenvironment-enhanced” (specifically upregulated in the high-elevation warm gully, enriched in photosynthesis and antioxidant pathways). Integrative network analysis further revealed zeatin riboside and multiple hub genes as central coordinators linking hormone signaling, energy metabolism, and cell wall remodeling. Collectively, these findings establish a molecular framework linking altitudinal temperature variation to bamboo rhizome regeneration—a process that directly determines the spatiotemporal availability of bamboo shoots for giant pandas. This work provides mechanistic insights into giant panda foraging ecology and has direct implications for predicting habitat quality under climate change and informing evidence-based conservation strategies for this flagship species and its critical food resource.