The secret Behind Bamboo’s explosive growth: a dynamic nitrogen-sharing network
image: PeHDZ23987 activated PeAAP29123 by binding to its promoter. (A) The distribution diagram of TF binding sites of proPeAAP29123. (B) Y1H assays were used to identify PeHDZ23987 binding to the promoter of PeAAP29123. (C) Dual-luciferase complementation imaging assays used to show that PeHDZ23987 activated the expression of PeAAP29123. (D) The firefly luciferase (LUC)/Renilla luciferase (REN) (LUC/REN) activity ratio was used to verify that PeHDZ23987 activated PeAAP29123. (E, G) PeHDZ23987 activating the transcription of HD-motifs of PeAAP29123 in tobacco leaves by dual-luciferase assays. pMotif1, pMotif2, pMutant1, and pMutant2 indicated pPeAAP29123-Motif1::LUC, pPeAAP29123-Motif2::LUC, pPeAAP29123-Mutant2::LUC, and pPeAAP29123-Mutant1::LUC, respectively. Representative photographs were taken using a chemiluminescence imaging system. (F, H) LUC/REN activity detection to verify PeHDZ23987 activating the transcription of HD-motifs of PeAAP29123. Data are shown as mean ± standard deviation (n ≥ 3). The asterisk indicates a significant difference (*P < 0.05, **P < 0.01). (I–J) PeHDZ23987 binds to two motifs (HDZ-motif1 5'-CAATCAAG-3′ and HDZ-motif2 5'-CAATTATT-3′) of the PeAAP29123 promoter by EMSA. Unlabelled probes were used as competitors. The 60× represent the concentrations of the competitor. Mut represents a mutated probe in which the motif is replaced by 5'-ACGGCTCC-3′.
Credit: Horticulture Research
Rapid shoot expansion is a hallmark of Moso bamboo, yet the nutrient-supply mechanisms that support this extraordinary growth remain unclear. This study uncovers how nitrogen—a core component of biomass accumulation—is dynamically allocated within clonal bamboo networks. Using ^15N isotope tracing and transcriptome profiling, the researchers reveal a developmental shift in nitrogen acquisition, moving from parent-derived nitrogen at early stages to root-absorbed nitrogen as shoots mature. The work also identifies PeAAP29123 as a central transporter controlling long-distance nitrogen movement, and demonstrates that its upstream regulator PeHDZ23987 enhances nitrogen uptake efficiency. Together, these findings illuminate how bamboo sustains its exceptional growth rate.
Moso bamboo is one of the world’s fastest-growing plants, capable of reaching full height within just 35–40 days. This explosive development requires a rapid and efficient nitrogen supply, yet tracking nutrient movement through its underground rhizome network has long been challenging. While previous studies have emphasized hormonal regulation, structural changes, and gene expression dynamics, the processes guiding nitrogen allocation—especially across connected ramets—remain poorly understood. Key questions include how parent culms fuel emerging shoots and which molecular regulators coordinate this long-distance transport. Based on these challenges, there is a need to conduct in-depth research on nitrogen transfer pathways and their regulatory mechanisms.
Researchers from Zhejiang A&F University and partner institutions reported (DOI: 10.1093/hr/uhaf062) new insights on February 25, 2025, in Horticulture Research. Using in-field ^15N labeling and transcriptome sequencing, the team mapped nitrogen movement between parent culms and developing shoots of Moso bamboo. Their study reveals a flexible nutrient-sharing system that shifts with developmental stage, while molecular analyses highlight PeAAP29123 as a key nitrogen transporter activated by the transcription factor PeHDZ23987. Together, these discoveries offer the most detailed molecular explanation to date of how bamboo maintains its rapid growth.
To investigate how nitrogen supports rapid shoot elongation, the team established clonal fragments consisting of a parent ramet, a young shoot, and the connecting rhizome. They applied ^15N tracers either to the parent culm or the rhizome soil and followed nitrogen allocation across four developmental stages: early, peak, branching, and leafing. The results showed a striking shift in nitrogen sources. At the early stage, 72.53% of shoot nitrogen originated from the parent culm, whereas during the leafing stage, 69.85% was absorbed through rhizome roots. During the peak and branching stages, parent and rhizome contributions were nearly equal, demonstrating a demand-driven, dynamic nutrient-sharing system.
Transcriptome analysis of 48 samples identified more than 58,000 expressed genes, with thousands showing stage-specific expression. Among these, PeAAP29123 displayed strong correlation with ^15N content and high expression in both parent culms and rapidly growing shoots. Functional assays demonstrated that PeHDZ23987, a homeodomain-leucine zipper transcription factor, binds directly to two HD-motifs in the PeAAP29123 promoter, activating its transcription. Overexpressing either PeAAP29123 or PeHDZ23987 in rice significantly enhanced nitrogen uptake and improved tolerance to nitrogen starvation, providing functional evidence that this regulatory module drives long-distance amino acid transport in bamboo.
“Our findings reveal a highly coordinated nutrient-sharing system that allows Moso bamboo to sustain one of the fastest growth rates in nature,” said the study’s senior author. “The discovery of the PeHDZ23987–PeAAP29123 regulatory module provides the first molecular evidence for long-distance nitrogen transport between interconnected bamboo culms. This mechanism demonstrates how clonal plants balance internal nutrient flows to maximize survival and productivity. Beyond fundamental biology, these insights open new opportunities for improving nitrogen-use efficiency in crops through targeted manipulation of transporter genes and their regulators.”
This study provides important implications for bamboo cultivation and broader agricultural practices. Understanding the dynamic nitrogen-sharing pattern between parent culms and rhizome roots offers a scientific basis for more precise fertilization strategies, potentially reducing nitrogen waste and improving bamboo forest productivity. The identification of PeAAP29123 and its regulator PeHDZ23987 also presents promising gene targets for breeding crops with enhanced nitrogen-use efficiency, as demonstrated by improved uptake in transgenic rice. Beyond bamboo, the work deepens understanding of nutrient integration in clonal plants and may guide the development of sustainable biomass production and afforestation systems to support carbon-sequestration goals.
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References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhaf062
Funding information
The authors are grateful for the financial support from the National Natural Science Foundation of China (31930075, 32125027, 32101493) and Scientific Research Foundation of Zhejiang A&F University (2022LFR006).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.