Bin Han and colleagues report the draft genome of moso bamboo, an important non-timber forest product. RNA sequencing analysis of bamboo flowering tissues suggests a connection between drought-responsive genes and potential flowering genes. Bamboo represents the only major lineage of grasses that is native to forests and is one of the most important non-timber forest products in the world. However, no species in the Bambusoideae subfamily has been sequenced. Here, we report a high-quality draft genome sequence of moso bamboo (P. heterocycla var. pubescens). The 2.05-Gb assembly covers 95% of the genomic region. Gene prediction modeling identified 31,987 genes, most of which are supported by cDNA and deep RNA sequencing data. Analyses of clustered gene families and gene collinearity show that bamboo underwent whole-genome duplication 7–12 million years ago. Identification of gene families that are key in cell wall biosynthesis suggests that the whole-genome duplication event generated more gene duplicates involved in bamboo shoot development. RNA sequencing analysis of bamboo flowering tissues suggests a potential connection between drought-responsive and flowering genes.
Bamboo is one of the most important nontimber forestry products worldwide. However, a chromosome-level reference genome is lacking, and an evolutionary view of alternative splicing (AS) in bamboo remains unclear despite emerging omics data and improved technologies. Here, we provide a chromosome-level de novo genome assembly of moso bamboo (Phyllostachys edulis) using additional abundance sequencing data and a Hi-C scaffolding strategy. The significantly improved genome is a scaffold N50 of 79.90 Mb, approximately 243 times longer than the previous version. A total of 51,074 high-quality protein-coding loci with intact structures were identified using single-molecule real-time sequencing and manual verification. Moreover, we provide a comprehensive AS profile based on the identification of 266,711 unique AS events in 25,225 AS genes by large-scale transcriptomic sequencing of 26 representative bamboo tissues using both the Illumina and Pacific Biosciences sequencing platforms. Through comparisons with orthologous genes in related plant species, we observed that the AS genes are concentrated among more conserved genes that tend to accumulate higher transcript levels and share less tissue specificity. Furthermore, gene family expansion, abundant AS, and positive selection were identified in crucial genes involved in the lignin biosynthetic pathway of moso bamboo. These fundamental studies provide useful information for future in-depth analyses of comparative genome and AS features. Additionally, our results highlight a global perspective of AS during evolution and diversification in bamboo.
Moso bamboo (Phyllostachys edulis) is an economically and ecologically important nontimber forestry species. Further development of this species as a sustainable bamboo resource has been hindered by a lack of population genome information. Here, we report a moso bamboo genomic variation atlas of 5.45 million single-nucleotide polymorphisms (SNPs) from whole-genome resequencing of 427 individuals covering 15 representative geographic areas. We uncover low genetic diversity, high genotype heterozygosity, and genes under balancing selection underlying moso bamboo population adaptation. We infer its demographic history with one bottleneck and its recently small population without a rebound. We define five phylogenetic groups and infer that one group probably originated by a single-origin event from East China. Finally, we conduct genome-wide association analysis of nine important property-related traits to identify candidate genes, many of which are involved in cell wall, carbohydrate metabolism, and environmental adaptation. These results provide a foundation and resources for understanding moso bamboo evolution and the genetic mechanisms of agriculturally important traits.
Bamboo is a composite material reinforced axially by fibers called vascular bundles. In this paper, the mechanical stripping method was used to isolate vascular bundles from moso bamboo (Phyllostachys edulis), China’s most important commercial bamboo species. The paper focuses on analyzing the suitability of this method for measuring the mechanical properties of single vascular bundles with respect to their location within a bamboo culm. Using a confocal laser scanning microscope (CLSM) and video extensometry testing technique, we found that the tensile mechanical properties of vascular bundle can be determined with great accuracy. The method relies on mechanical stripping to prepare samples at a length scale from individual bamboo, which traditionally increases the difficulty of conducting tests. Therefore, to determine the elastic modulus of vascular bundle material, video extensometry was used for efficient strain detection in tensile experiments. This type of sample preparation minimizes the usual problems encountered when mounting samples. The cross-sectional area of the vascular bundle was determined by CLSM measurement using an ultramicrotome as a cutting tool. Applying this method, the elastic modulus and tensile strength of the vascular bundle of moso bamboo were measured to be ~44.67 GPa and ~709.96 MPa, respectively. It is noteworthy that the tensile mechanical properties of the fibrous sheath areas are higher than those observed over the whole area.
Plant-based natural biotemplates are increasingly gaining popularity for the development of catalytic filters in water treatment owing to their unique features, such as exquisite microstructures, renewable properties, and environmental friendliness. However, the development of catalytic filters, not limited to plant-based filters, to achieve both super-high water flux and excellent treatment efficiency, particularly under gravity-driven conditions, remains challenging. Therefore, herein, an efficient gravity-driven catalytic filter was fabricated using a naturally three-dimensional (3D) porous rattan biotemplate for water treatment. After reducing Ag(NH3)2+ ions via an in situ process that did not involve the addition of reductants or stabilizers, Ag nanoparticles (NPs) were immobilized in the inner microchannel of the porous rattan cane. The intrinsically aligned microchannels in the vascular bundles of rattan (diameter 24–420 μm) acted as reaction compartments for the immobilization and stabilization of Ag NPs. Furthermore, the 3D Ag/rattan filter exhibited excellent gravity-driven catalytic activity (up to 97.2% treatment efficiency for a high water flux of 7471 L m−2 h−1), good recyclability, high water permeability, and stability toward 4-nitrophenol reductions. These excellent properties were attributed to the synergistic effect of the evenly distributed nanosized Ag catalysts and microchannel structures of rattan. Rattan materials are abundantly available and naturally porous, and they can readily serve as cost-effective, nontoxic, biodegradable, and sustainable sources in numerous catalytic applications.