Rapid growth of Moso bamboo (Phyllostachys edulis): Cellular roadmaps, transcriptome dynamics, and environmental factors.

Moso bamboo (Phyllostachys edulis) shows remarkably rapid growth (114.5 cm/day), but the underlying biological mechanisms remain unclear. After examining more than 12,750 internodes from more than 510 culms from 17 Moso populations, we identified internode 18 as a representative internode for rapid growth. This internode includes a 2-cm cell division zone (DZ), a cell elongation zone up to 12 cm, and a secondary cell wall (SCW) thickening zone. These zones elongated 11.8 cm, produced approximately 570,000,000 cells, and deposited ∼28 mg g-1 dry weight (DW) lignin and ∼44 mg g-1 DW cellulose daily, far exceeding vegetative growth observed in other plants. We used anatomical, mathematical, physiological, and genomic data to characterize development and transcriptional networks during rapid growth in internode 18. Our results suggest that (1) gibberellin may directly trigger the rapid growth of Moso shoots, (2) decreased cytokinin and increased auxin accumulation may trigger cell DZ elongation, and (3) abscisic acid and mechanical pressure may stimulate rapid SCW thickening via MYB83L. We conclude that internode length involves a possible tradeoff mediated by mechanical pressure caused by rapid growth, possibly influenced by environmental temperature and regulated by genes related to cell division and elongation. Our results provide insight into the rapid growth of Moso bamboo.

Development of dual-visible reporter assays to determine the DNA-protein interaction.

The application of DNA-protein interaction reporter assays for relational or ratiometric measurements within an experimental system is popular in biological research. However, the existing reporter-based interaction assays always require special equipment, expensive chemicals, and a complicated operation. Here, we developed a DNA-protein interaction technology integrating two visible reporters, RUBY and UV-visible GFP (eYGFPuv), which allows the expression of the cassette reporter contained cis-acting DNA element (DE) fused upstream of TATA box and RUBY, and a constitutive promoter regulating eYGFPuv in the same construct. The interaction of transcription factor (TF) and the DE can be detected by co-expressed the cassette reporter and TF in tobacco leaves where the cassette reporter alone serves as a control. We also revealed that eight function-unknown bamboo AP2/ERFs interacted with the DE of ANT-AP2R1R2 (ABE), DRE (DBE), GCC-box (EBE), and RAV1 binding element (RBE), respectively, which are consistent with the results by dual-luciferase reporter assays. Thus, the dual-visible reporters offer a convenient, visible, and cost-saving alternative to other existing techniques for DNA-protein interaction in plants.

Evolutionary relationship of moso bamboo forms and a multihormone regulatory cascade involving culm shape variation.

Moso bamboo (Phyllostachys edulis) known as Mao Zhu (MZ) in Chinese exhibits various forms with distinct morphological characteristics. However, the evolutionary relationship among MZ forms and the mechanisms of culm shape variation are still lacking. Here, the main differences among MZ forms were identified as culm shape variation, which were confirmed by analysing MZ forms (799 bamboo culms) and MZ (458 bamboo culms) populations. To unravel the genetic basis underlying the morphological variations, 20 MZ forms were subjected to whole-genome resequencing. Further analysis yielded 3 230 107 high-quality SNPs and uncovered low genetic diversity and high genotype heterozygosity associated with MZ forms' formation. By integrating the SNP data of 427 MZ individuals representing 15 geographic regions, the origins of eight MZ forms were successfully traced using the phylogenetic tree and the identified common heterozygous loci. Meanwhile, transcriptomic analysis was performed using shoots from MZ and its two forms with culm shape variation. The results, combined with genomic analyses, demonstrated that hormone signalling related genes played crucial roles in culm variation. Co-expression network analysis uncovered genes associated with multiple plant hormone signal transduction, especially auxin and cytokinin were involved in culm shape variation. Furthermore, the regulatory relationships of a specific transcription factor and their target genes associated with auxin and ethylene signalling were validated by yeast one-hybrid, electrophoretic mobility shift assays, and dual-luciferase reporter. Overall, this study provides important insights into the culm shape variation formation in bamboo, which facilitates to breed new varieties with novel culms.

A bamboo 'PeSAPK4-PeMYB99-PeTIP4-3' regulatory model involved in water transport.

Water plays crucial roles in expeditious growth and osmotic stress of bamboo. Nevertheless, the molecular mechanism of water transport remains unclear. In this study, an aquaporin gene, PeTIP4-3, was identified through a joint analysis of root pressure and transcriptomic data in moso bamboo (Phyllostachys edulis). PeTIP4-3 was highly expressed in shoots, especially in the vascular bundle sheath cells. Overexpression of PeTIP4-3 could increase drought and salt tolerance in transgenic yeast and rice. A co-expression pattern of PeSAPK4, PeMYB99 and PeTIP4-3 was revealed by WGCNA. PeMYB99 exhibited an ability to independently bind to and activate PeTIP4-3, which augmented tolerance to drought and salt stress. PeSAPK4 could interact with and phosphorylate PeMYB99 in vivo and in vitro, wherein they synergistically accelerated PeTIP4-3 transcription. Overexpression of PeMYB99 and PeSAPK4 also conferred drought and salt tolerance in transgenic rice. Further ABA treatment analysis indicated that PeSAPK4 enhanced water transport in response to stress via ABA signaling. Collectively, an ABA-mediated cascade of PeSAPK4-PeMYB99-PeTIP4-3 is proposed, which governs water transport in moso bamboo.

A bamboo bHLH transcription factor PeRHL4 has dual functions in enhancing drought and phosphorus starvation tolerance.

ROOTHAIRLESS (RHL) is a typical type of basic helix-loop-helix (bHLH) transcription factor (TF), which has been reported to participate in various aspects of plant growth and in response to stress. However, the functions of RHL subfamily members in moso bamboo (Phyllostachys edulis) remain unknown. In this study, we identified 14 bHLH genes (PeRHL1-PeRHL14) in moso bamboo. Phylogenetic tree and conserved motif analyses showed that PeRHLs were clustered into three clades. The expression analysis suggested that PeRHL4 was co-expressed with PeTIP1-1 and PePHT1-1 in moso bamboo. Moreover, these three genes were all up-regulated in moso bamboo under drought stress and phosphate starvation. Y1H, DLR and EMSA assays demonstrated that PeRHL4 could activate the expression of PeTIP1-1 and PePHT1-1. Furthermore, overexpression of PeRHL4 could increase both drought and phosphate starvation tolerance in transgenic rice, in which the expression of OsTIPs and OsPHT1s was significantly improved, respectively. Overall, our results indicated that drought stress and phosphate starvation could induce the expression of PeRHL4, which in turn activated downstream genes involved in water and phosphate transport. Collectively, our findings reveal that PeRHL4 acting as a positive regulator contributes to enhancing the tolerance of moso bamboo under drought stress and phosphate starvation.

Regulatory networks of senescence-associated gene-transcription factors promote degradation in Moso bamboo shoots.

Bamboo cultivation, particularly Moso bamboo (Phyllostachys edulis), holds significant economic importance in various regions worldwide. Bamboo shoot degradation (BSD) severely affects productivity and economic viability. However, despite its agricultural consequences, the molecular mechanisms underlying BSD remain unclear. Consequently, we explored the dynamic changes of BSD through anatomy, physiology and the transcriptome. Our findings reveal ruptured protoxylem cells, reduced cell wall thickness and the accumulation of sucrose and reactive oxygen species (ROS) during BSD. Transcriptomic analysis underscored the importance of genes related to plant hormone signal transduction, sugar metabolism and ROS homoeostasis in this process. Furthermore, BSD appears to be driven by the coexpression regulatory network of senescence-associated gene transcription factors (SAG-TFs), specifically PeSAG39, PeWRKY22 and PeWRKY75, primarily located in the protoxylem of vascular bundles. Yeast one-hybrid and dual-luciferase assays demonstrated that PeWRKY22 and PeWRKY75 activate PeSAG39 expression by binding to its promoter. This study advanced our understanding of the molecular regulatory mechanisms governing BSD, offering a valuable reference for enhancing Moso bamboo forest productivity.

Sarcopenia is associated with leukopenia in urothelial carcinoma patients who receive tislelizumab combined with gemcitabine and cisplatin therapy.

BACKGROUND: In the era of combination therapy, there has been limited research on body composition. Specific body composition, such as sarcopenia, possesses the potential to serve as a predictive biomarker for toxic effects and clinical response in patients with urothelial carcinoma (UC) undergoing tislelizumab combined with gemcitabine and cisplatin (T + GC). MATERIALS AND METHODS: A total of 112 UC patients who received T + GC were selected at the Affiliated Hospital of Xuzhou Medical University from April 2020 to January 2023. Baseline patient characteristics and detailed hematological parameters were collected using the electronic medical system and laboratory examinations. The computed tomography images of patients were analyzed to calculate psoas muscle mass index (PMI). We evaluated the association between sarcopenia (PMI < 4.5 cm2/m2 in men; PMI < 3.3 cm2/m2 in women) and both hematological toxicity and tumor response. RESULTS: Overall, of the 112 patients (65.2% male, median age 56 years), 43 (38.4%) were defined as sarcopenia. Patients with sarcopenia were notably older (p = 0.037), more likely to have hypertension (p = 0.009), and had poorer ECOG-PS (p = 0.027). Patients with sarcopenia were more likely to develop leukopenia (OR 2.969, 95% CI 1.028-8.575, p = 0.044) after receiving at least two cycles of T + GC. However, these significant differences were not observed in thrombocytopenia and anemia. There were no significant differences in the tumor response and grade 3-4 hematological toxicity between patients with sarcopenia and those without sarcopenia. CONCLUSIONS: Patients with sarcopenia were more likely to develop leukopenia after receiving T + GC. There were no notable alterations observed in relation to anemia or thrombocytopenia. No significant difference was found between the sarcopenia group and non-sarcopenia group in terms of tumor response and grade 3-4 hematological toxicity.

Identification and characterization of CircRNA-associated CeRNA networks in moso bamboo under nitrogen stress.

BACKGROUND: Nitrogen is a macronutrient element for plant growth and development. Circular RNAs (circRNAs) serve as pivotal regulators for the coordination between nutrient supply and plant demand. Moso bamboo (Phyllostachys edulis) is an excellent plant with fast growth, and the mechanism of the circRNA-target module in response to nitrogen remains unclear. RESULTS: Deep small RNA sequencing results of moso bamboo seedlings under different concentrations of KNO3 (N0 = 0 mM, N6 = 6 mM, N18 = 18 mM) were used to identify circRNAs. A total of 549 circRNAs were obtained, of which 309 were generated from corresponding parental coding genes including 66 new ones. A total of 536 circRNA-parent genes were unevenly distributed in 24 scaffolds and were associated with root growth and development. Furthermore, 52 differentially expressed circRNAs (DECs) were obtained, including 24, 33 and 15 DECs from three comparisons of N0 vs. N6, N0 vs. N18 and N6 vs. N18, respectively. Based on integrative analyses of the identified DECs, differentially expressed mRNAs (DEGs), and miRNAs (DEMs), a competitive endogenous RNA (ceRNA) network was constructed, including five DECs, eight DEMs and 32 DEGs. A regulatory module of PeSca_6:12,316,320|12,372,905-novel_miR156-PH02Gene35622 was further verified by qPCR and dual-luciferase reporter assays. CONCLUSION: The results indicated that circRNAs could participate in multiple biological processes as miRNA sponges, including organ nitrogen compound biosynthesis and metabolic process regulation in moso bamboo. Our results provide valuable information for further study of circRNAs in moso bamboo under fluctuating nitrogen conditions.

Transcriptome and miRNAome analysis reveals components regulating tissue differentiation of bamboo shoots.

Primary thickening determines bamboo yield and wood property. However, little is known about the regulatory networks involved in this process. This study identified a total of 58,652 genes and 150 miRNAs via transcriptome and small RNA sequencing using the underground thickening shoot samples of wild-type (WT) Moso bamboo (Phyllostachys edulis) and a thick wall (TW) variant (P. edulis "Pachyloen") at five developmental stages (WTS1/TWS1-WTS5/TWS5). A total of 14,029 (65.17%) differentially expressed genes and 68 (45.33%) differentially expressed miRNAs were identified from the WT, TW, and WTTW groups. The first two groups were composed of four pairwise combinations, each between two successive stages (WTS2/TWS2_versus_WTS1/TWS1, WTS3/TWS3_versus_WTS2/TWS2, WTS4/TWS4_versus_WTS3/TWS3, and WTS5/TWS5_versus_WTS4/TWS4), and the WTTW group was composed of five combinations, each between two relative stages (TWS1-5_versus_WTS1-5). Additionally, among the phytohormones, zeatin showed more remarkable changes in concentrations than indole-3-acetic acid, gibberellic acid, and abscisic acid throughout the five stages in the WT and the TW groups. Moreover, 125 cleavage sites were identified for 387 miRNA-mRNA pairs via degradome sequencing (P < 0.05). The dual-luciferase reporter assay confirmed that 13 miRNAs bound to 12 targets. Fluorescence in situ hybridization localized miR166 and miR160 in the shoot apical meristem and the procambium of Moso bamboo shoots at the S1 stage. Thus, primary thickening is a complex process regulated by miRNA-gene-phytohormone networks, and the miRNAome and transcriptome dynamics regulate phenotypic plasticity. These findings provide insights into the molecular mechanisms underlying wood formation and properties and propose targets for bamboo breeding.

Urolithin A ameliorates obesity-induced metabolic cardiomyopathy in mice via mitophagy activation.

Metabolic cardiomyopathy (MC) is characterized by intracellular lipid accumulation and utilizing fatty acids as a foremost energy source, thereby leading to excess oxidative stress and mitochondrial dysfunction. There is no effective therapy available yet. In this study we investigated whether defective mitophagy contributed to MC and whether urolithin A (UA), a naturally occurring microflora-derived metabolite, could protect against MC in experimental obese mice. Mice were fed high fat diet for 20 weeks to establish a diet-induced obese model. We showed that mitochondrial autophagy or mitophagy was significantly downregulated in the heart of experimental obese mice. UA (50 mg·kg-1·d-1, for 4 weeks) markedly activated mitophagy and ameliorated MC in obese mice by gavage. In PA-challenged H9C2 cardiomyocytes, UA (5 µM) significantly increased autophagosomes and decreased autolysosomes. Furthermore, UA administration rescued PINK1/Parkin-dependent mitophagy and relieved mitochondrial defects in the heart of obese mice, which led to improving cardiac diastolic function and ameliorating cardiac remodelling. In PA-challenged primarily isolated cardiomyocytes, both application of mitophagy inhibitor Mdivi-1 (15 µM) and silencing of mitophagy gene Parkin blunted the myocardial protective effect of UA. In summary, our data suggest that restoration of mitophagy with UA ameliorates symptoms of MC, which highlights a therapeutic potential of UA in the treatment of MC.

A regulatory network driving shoot lignification in rapidly growing bamboo.

Woody bamboo is environmentally friendly, abundant, and an alternative to conventional timber. Degree of lignification and lignin content and deposition affect timber properties. However, the lignification regulatory network in monocots is poorly understood. To elucidate the regulatory mechanism of lignification in moso bamboo (Phyllostachys edulis), we conducted integrated analyses using transcriptome, small RNA, and degradome sequencing followed by experimental verification. The lignification degree and lignin content increased with increased bamboo shoot height, whereas phenylalanine ammonia-lyase and Laccase activities first increased and then decreased with shoot growth. Moreover, we identified 11,504 differentially expressed genes (DEGs) in different portions of the 13th internodes of different height shoots; most DEGs associated with cell wall and lignin biosynthesis were upregulated, whereas some DEGs related to cell growth were downregulated. We identified a total of 1,502 miRNAs, of which 687 were differentially expressed. Additionally, in silico and degradome analyses indicated that 5,756 genes were targeted by 691 miRNAs. We constructed a regulatory network of lignification, including 11 miRNAs, 22 transcription factors, and 36 enzyme genes, in moso bamboo. Furthermore, PeLAC20 overexpression increased lignin content in transgenic Arabidopsis (Arabidopsis thaliana) plants. Finally, we proposed a reliable miRNA-mediated "MYB-PeLAC20" module for lignin monomer polymerization. Our findings provide definite insights into the genetic regulation of bamboo lignification. In addition to providing a platform for understanding related mechanisms in other monocots, these insights could be used to develop strategies to improve bamboo timber properties.

Identification of the 14-3-3 Gene Family in Bamboo and Characterization of Pe14-3-3b Reveals Its Potential Role in Promoting Growth.

The 14-3-3 protein family plays an important role in regulating plant growth and development. The genes of the 14-3-3 family have been reported in multiple species. However, little is known about the 14-3-3 gene family in bamboo. In this study, a total of 58 genes belonging to the 14-3-3 family were identified in three representative bamboo species, i.e., Olyra latifolia, Phyllostachys edulis, and Bonia amplexicaulis, whose encoding proteins were grouped into ε and non-ε groups by phylogeny analysis with 14-3-3 proteins from Arabidopsis thaliana and Oryza sativa. The 14-3-3s had diverse gene structures and motif characteristics among the three bamboo species. Collinearity analysis suggested that the genes of the 14-3-3 family in bamboo had undergone a strong purification selection during evolution. Tissue-specific expression analysis showed the expression of Pe14-3-3s varied in different tissues of P. edulis, suggesting that they had functional diversity during growth and development. Co-expression analysis showed that four Pe14-3-3s co-expressed positively with eight ribosomal genes. Yeast two-hybrid (Y2H) assays showed that Pe14-3-3b/d could interact with Pe_ribosome-1/5/6, and qPCR results demonstrated that Pe14-3-3b/d and Pe_ribosome-1/5/6 had similar expression trends with the increase in shoot height, which further confirmed that they would work together to participate in the shoot growth and development of bamboo. Additionally, the transgenic Arabidopsis plants overexpressing Pe14-3-3b had longer roots, a larger stem diameter, an earlier bolting time and a faster growth rate than wild-type Arabidopsis, indicating that Pe14-3-3b acted as a growth promoter. Our results provide comprehensive information on 14-3-3 genes in bamboo and highlight Pe14-3-3b as a potential target for bamboo improvement.

Identification of KFB Family in Moso Bamboo Reveals the Potential Function of PeKFB9 Involved in Stress Response and Lignin Polymerization.

The Kelch repeat F-box (KFB) protein is an important E3 ubiquitin ligase that has been demonstrated to perform an important post-translational regulatory role in plants by mediating multiple biological processes. Despite their importance, KFBs have not yet been identified and characterized in bamboo. In this study, 19 PeKFBs were identified with F-box and Kelch domains; genes encoding these PeKFBs were unevenly distributed across 12 chromosomes of moso bamboo. Phylogenetic analysis indicated that the PeKFBs were divided into eight subclades based on similar gene structures and highly conserved motifs. A tissue-specific gene expression analysis showed that the PeKFBs were differentially expressed in various tissues of moso bamboo. All the promoters of the PeKFBs contained stress-related cis-elements, which was supported by the differentially expression of PeKFBs of moso bamboo under drought and cold stresses. Sixteen proteins were screened from the moso bamboo shoots' cDNA library using PeKFB9 as a bait through a yeast two-hybrid (Y2H) assay. Moreover, PeKFB9 physically interacted with PeSKP1-like-1 and PePRX72-1, which mediated the activity of peroxidase in proteolytic turnover. Taken together, these findings improved our understanding of PeKFBs, especially in response to stresses, and laid a foundation for revealing the molecular mechanism of PeKFB9 in regulating lignin polymerization by degrading peroxidase.

Identification and expression analysis of the glycosyltransferase GT43 family members in bamboo reveal their potential function in xylan biosynthesis during rapid growth.

BACKGROUND: Xylan is one of the most abundant hemicelluloses and can crosslink cellulose and lignin to increase the stability of cell walls. A number of genes encoding glycosyltransferases play vital roles in xylan biosynthesis in plants, such as those of the GT43 family. However, little is known about glycosyltransferases in bamboo, especially woody bamboo which is a good substitute for timber. RESULTS: A total of 17 GT43 genes (PeGT43-1 ~ PeGT43-17) were identified in the genome of moso bamboo (Phyllostachys edulis), which belong to three subfamilies with specific motifs. The phylogenetic and collinearity analyses showed that PeGT43s may have undergone gene duplication, as a result of collinearity found in 12 pairs of PeGT43s, and between 17 PeGT43s and 10 OsGT43s. A set of cis-acting elements such as hormones, abiotic stress response and MYB binding elements were found in the promoter of PeGT43s. PeGT43s were expressed differently in 26 tissues, among which the highest expression level was found in the shoots, especially in the rapid elongation zone and nodes. The genes coexpressed with PeGT43s were annotated as associated with polysaccharide metabolism and cell wall biosynthesis. qRT-PCR results showed that the coexpressed genes had similar expression patterns with a significant increase in 4.0 m shoots and a peak in 6.0 m shoots during fast growth. In addition, the xylan content and structural polysaccharide staining intensity in bamboo shoots showed a strong positive correlation with the expression of PeGT43s. Yeast one-hybrid assays demonstrated that PeMYB35 could recognize the 5' UTR/promoter of PeGT43-5 by binding to the SMRE cis-elements. CONCLUSIONS: PeGT43s were found to be adapted to the requirement of xylan biosynthesis during rapid cell elongation and cell wall accumulation, as evidenced by the expression profile of PeGT43s and the rate of xylan accumulation in bamboo shoots. Yeast one-hybrid analysis suggested that PeMYB35 might be involved in xylan biosynthesis by regulating the expression of PeGT43-5 by binding to its 5' UTR/promoter. Our study provides a comprehensive understanding of PeGT43s in moso bamboo and lays a foundation for further functional analysis of PeGT43s for xylan biosynthesis during rapid growth.

Targeted enrichment of novel chloroplast-based probes reveals a large-scale phylogeny of 412 bamboos.

BACKGROUND: The subfamily Bambusoideae belongs to the grass family Poaceae and has significant roles in culture, economy, and ecology. However, the phylogenetic relationships based on large-scale chloroplast genomes (CpGenomes) were elusive. Moreover, most of the chloroplast DNA sequencing methods cannot meet the requirements of large-scale CpGenome sequencing, which greatly limits and impedes the in-depth research of plant genetics and evolution. RESULTS: To develop a set of bamboo probes, we used 99 high-quality CpGenomes with 6 bamboo CpGenomes as representative species for the probe design, and assembled 15 M unique sequences as the final pan-chloroplast genome. A total of 180,519 probes for chloroplast DNA fragments were designed and synthesized by a novel hybridization-based targeted enrichment approach. Another 468 CpGenomes were selected as test data to verify the quality of the newly synthesized probes and the efficiency of the probes for chloroplast capture. We then successfully applied the probes to synthesize, enrich, and assemble 358 non-redundant CpGenomes of woody bamboo in China. Evaluation analysis showed the probes may be applicable to chloroplasts in Magnoliales, Pinales, Poales et al. Moreover, we reconstructed a phylogenetic tree of 412 bamboos (358 in-house and 54 published), supporting a non-monophyletic lineage of the genus Phyllostachys. Additionally, we shared our data by uploading a dataset of bamboo CpGenome into CNGB ( https://db.cngb.org/search/project/CNP0000502/ ) to enrich resources and promote the development of bamboo phylogenetics. CONCLUSIONS: The development of the CpGenome enrichment pipeline and its performance on bamboos recommended an inexpensive, high-throughput, time-saving and efficient CpGenome sequencing strategy, which can be applied to facilitate the phylogenetics analysis of most green plants.

A bamboo leaf-specific aquaporin gene PePIP2;7 is involved in abiotic stress response.

KEY MESSAGE: PePIP2;7, a leaf-specific aquaporin gene in bamboo, is upregulated under abiotic stresses. Overexpressing PePIP2;7 confers abiotic stresses tolerance in transgenic Arabidopsis plant and yeast. Aquaporins (AQPs) participate in the regulation of water balance in plants. However, the function of AQPs in bamboo remains unclear. Here, PePIP2;7 was identified as a leaf-specific aquaporin gene in moso bamboo based on the expression analysis of transcriptome data and PCR. In situ hybridization further indicated that PePIP2;7 was mainly expressed in mesophyll cells of mature leaves, while in immature leaves it was dominant in blade edge cells followed by mesophyll cells. Interestingly, PePIP2;7 was strongly expressed in the mesophyll cells near bulliform cells of immature leaves, suggesting that PePIP2;7 might function in water transport and contribute to leaf unfolding. The transient expression assay showed that PePIP2;7 was a plasma membrane intrinsic protein. Furthermore, PePIP2;7 was upregulated under abiotic stresses such as high light, drought, and NaCl. Compared with Col-0, transgenic Arabidopsis plants overexpressing PePIP2;7 had better seed germination rate, longer taproot length, higher SOD activity, and lower MDA content under abiotic stresses. Besides, yeasts expressing PePIP2;7 also had higher tolerance to stress compared to the control. Taken together, our results show that PePIP2;7 is leaf-specific and involved in stress response, which provides new insights into aquaporin function in bamboo.

Sea urchin-like CuO particles prepared using Cu3(PO4)2 flowers as precursor for high-performance ethanol sensing.

Cu3(PO4)2 flowers are reported for the first time as a solid precursor for the preparation of hierarchical CuO particles with sea urchin-like morphology in the absence of self-assembled templates or matrixes. In the alkaline condition, Cu3(PO4)2 transforms into Cu(OH)2 firstly, and then into CuO through dehydration at room temperature. Different from soluble Cu salt as precursor, the basic building blocks for CuO are continuously supplied in a controlled manner form Cu3(PO4)2 precursor, which ensures a nearly sustained supersaturated concentration that favors heterogeneous nucleation and progressive growth of sea urchin-like CuO particles. The gas sensing property of as-prepared sea urchin-like CuO particles to ethanol is investigated. The sea urchin-like CuO particles exhibit a good sensing performance in terms of high response, short response/recovery time, good selectivity, good reproducibility, and long-term stability. The facile strategy demonstrated here opens up a new strategy to fabricate hierarchical CuO particles with enormous potential from the perspective of practical application.

Genome-wide analysis of laccase genes in moso bamboo highlights PeLAC10 involved in lignin biosynthesis and in response to abiotic stresses.

KEY MESSAGE: Twenty-three PeLACs have been identified in moso bamboo, overexpression of PeLAC10 increases the lignin content and confers drought and phenolic acid tolerance in transgenic Arabidopsis. Laccases (LACs) have multifunction involved in the processes of cell elongation, lignification and stress response in plants. However, the function of laccases in bamboo remain unclear. Here, a total of 23 laccase genes (PeLAC1-PeLAC23) were identified in moso bamboo (Phyllostachys edulis). The diverse gene structure and expression pattern of PeLACs suggested that their function should be spatiotemporal and complicated, which was supported by the expression profiles in different tissues of moso bamboo. Eighteen PeLACs were identified as the targets of ped-miR397. The putative ped-miR397-binding site in the coding region of PeLAC10 was further confirmed by RLM-5' RACE, indicating that PeLAC10 was regulated by ped-miR397 after transcription. With the increasing shoot height, the expression abundance of PeLAC10 was up-regulated and reached the maximum in 15 cm shoots, while that of ped-miR397 was relative lower and showed the minimum in 15 cm shoots. PeLAC10 was up-regulated obviously under both ABA (100 µmol L-1) and NaCl (400 mmol L-1) treatments, and it was down-regulated under the GA3 (100 µmol L-1) treatment. The transgenic Arabidopsis plants over-expressing PeLAC10 became slightly smaller and their petioles were shorter than those of Col-0. However, they had a stronger capacity in resistance to phenolic acids and drought besides higher lignin content in stems. These results indicated that overexpression of PeLAC10 was helpful to increase the content of lignin in transgenic Arabidopsis and improve the adaptability to phenolic acid and drought stresses.

De novo sequencing of the transcriptome reveals regulators of the floral transition in Fargesia macclureana (Poaceae).

BACKGROUND: Fargesia macclureana (Poaceae) is a woody bamboo species found on the Qinghai-Tibet Plateau (QTP) approximately 2000 ~ 3800 m above sea level. It rarely blossoms in the QTP, but it flowered 20 days after growing in our lab, which is in a low-altitude area outside the QTP. To date, little is known regarding the molecular mechanism of bamboo flowering, and no studies of flowering have been conducted on wild bamboo plants growing in extreme environments. Here, we report the first de novo transcriptome sequence for F. macclureana to investigate the putative mechanisms underlying the flowering time control used by F. macclureana to adapt to its environment. RESULTS: Illumina deep sequencing of the F. macclureana transcriptome generated 140.94 Gb of data, assembled into 99,056 unigenes. A comprehensive analysis of the broadly, specifically and differentially expressed unigenes (BEUs, SEUs and DEUs) indicated that they were mostly involved in metabolism and signal transduction, as well as DNA repair and plant-pathogen interactions, which may be of adaptive importance. In addition, comparison analysis between non-flowering and flowering tissues revealed that expressions of FmFT and FmHd3a, two putative F. macclureana orthologs, were differently regulated in NF- vs F- leaves, and carbohydrate metabolism and signal transduction were two major KEGG pathways that DEUs were enriched in. Finally, we detected 9296 simple sequence repeats (SSRs) that may be useful for further molecular marker-assisted breeding. CONCLUSIONS: F. macclureana may have evolved specific reproductive strategies for flowering-related pathways in response to photoperiodic cues to ensure long vegetation growing period. Our findings will provide new insights to future investigations into the mechanisms of flowering time control and adaptive evolution in plants growing at high altitudes.

9-cis-Neoxanthin in Light Harvesting Complexes of Photosystem II Regulates the Binding of Violaxanthin and Xanthophyll Cycle.

The light-harvesting chlorophyll a/b complex of photosystem II (LHCII) is able to switch to multiple functions under different light conditions (i.e. harvesting solar energy for photosynthesis and dissipating excess excitation energy for photoprotection). The role of the different carotenoids bound to LHCII in regulating the structure and function of the complex is a long-lasting question in photosynthesis research. 9-cis-Neoxanthin (Nx) is one of the important carotenoids, which can only be found in the LHCIIs. High-resolution structural analysis of LHCII shows that Nx is located between different monomeric LHCIIs, with one side protruding into the lipid membrane. In this study, the various functional significances of this unique feature of Nx binding in LHCII are studied with the in vitro reconstituted LHCIIs both with and without Nx and the native complexes isolated either from wild-type Arabidopsis (Arabidopsis thaliana) or from its mutant aba4-3 lacking Nx Our results reveal that the binding of Nx affects the binding affinity of violaxanthin (Vx) to LHCII significantly. In the absence of Nx, Vx has a much higher binding affinity to trimeric LHCII. The strong coordination between Nx and Vx at the interfaces of adjacent monomers of LHCII plays an important role both in operating the xanthophyll cycle and in the transient modulation of nonphotochemical quenching.