BackgroundBamboo 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.ResultsHere, 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.ConclusionsThese 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.

The MYB family, one of the largest transcription factor (TF) families in the plant kingdom, plays vital roles in cell formation, morphogenesis and signal transduction, as well as responses to biotic and abiotic stresses. However, the underlying function of bamboo MYB TFs remains unclear. To gain insight into the status of these proteins, a total of 85 PeMYBs, which were further divided into 11 subgroups, were identified in moso bamboo (Phyllostachys edulis) by using a genome-wide search strategy. Gene structure analysis showed that PeMYBs were significantly different, with exon numbers varying from 4 to 13. Phylogenetic analysis indicated that PeMYBs clustered into 27 clades, of which the function of 18 clades has been predicted. In addition, almost all of the PeMYBs were differently expressed in leaves, panicles, rhizomes and shoots based on RNA-seq data. Furthermore, qRT-PCR analysis showed that 12 PeMYBs related to the biosynthesis and deposition of the secondary cell wall (SCW) were constitutively expressed, and their transcript abundance levels have changed significantly with increasing height of the bamboo shoots, for which the degree of lignification continuously increased. This result indicated that these PeMYBs might play fundamental roles in SCW thickening and bamboo shoot lignification. The present comprehensive and systematic study on the members of the MYB family provided a reference and solid foundation for further functional analysis of MYB TFs in moso bamboo.

A high average ZT value (ZTave) of ~ 1.13 in n-type PbSe-based thermoelectric material at 300-873 K have been achieved in this work. Its high thermoelectric performance originates from ultrahigh...

To achieve high-performance n-type PbTe-based thermoelectric materials, this work provides a synergetic strategy to improve electrical transport property with indium (In) element doping and reduces thermal conductivity with sulfur (S) element alloying. In n-type PbTe, In doping can tune the carrier density in the whole working temperature range, causing the carrier density to increase from 2.18 × 10 19 cm −3 at 300 K to 4.84 × 10 19 cm −3 at 823 K in Pb 0.98 In 0.005 Sb 0.015 Te. The optimized carrier density can further modulate electrical conductivity and Seebeck coefficient, finally contributing to a substantial increase of power factor, and a maximum power factor increase from 19.7 µW cm −1 K −2 in Pb 0.985 Sb 0.015 Te to 28.2 µW cm −1 K −2 in Pb 0.9775 In 0.0075 Sb 0.015 Te. Based on the optimally In-doped PbTe, S alloying is introduced to suppress phonon propagation by forming a complete solid solution, which could effectively reduce lattice thermal conductivity and simultaneously benefit carrier mobility to maintain high power factor. With S alloying, the minimum lattice thermal conductivity decreases from 0.76 Wm −1 K −1 in Pb 0.985 Sb 0.015 Te to 0.42 Wm −1 K −1 in Pb 0.98 In 0.005 Sb 0.015 Te 0.88 S 0.12. Combining the advantages of both In doping and S alloying, the peak ZT value and averaged ZT (ZT ave) (300-873 K) are boosted from 1.0 and 0.60 in Pb 0.985 Sb 0.015 Te to 1.4 and 0.87 in Pb 0.98 In 0.005 Sb 0.015 Te 0.94 S 0.06 .

Lead sulfide (PbS) presents large potential in thermoelectric application due to its earth‐abundant S element. However, its inferior average ZT (ZTave) value makes PbS less competitive with its analogs PbTe and PbSe. To promote its thermoelectric performance, this study implements strategies of continuous Se alloying and Cu interstitial doping to synergistically tune thermal and electrical transport properties in n‐type PbS. First, the lattice parameter of 5.93 Å in PbS is linearly expanded to 6.03 Å in PbS0.5Se0.5 with increasing Se alloying content. This expanded lattice in Se‐alloyed PbS not only intensifies phonon scattering but also facilitates the formation of Cu interstitials. Based on the PbS0.6Se0.4 content with the minimal lattice thermal conductivity, Cu interstitials are introduced to improve the electron density, thus boosting the peak power factor, from 3.88 μW cm−1 K−2 in PbS0.6Se0.4 to 20.58 μW cm−1 K−2 in PbS0.6Se0.4−1%Cu. Meanwhile, the lattice thermal conductivity in PbS0.6Se0.4−x%Cu (x = 0–2) is further suppressed due to the strong strain field caused by Cu interstitials. Finally, with the lowered thermal conductivity and high electrical transport properties, a peak ZT ~1.1 and ZTave ~0.82 can be achieved in PbS0.6Se0.4 − 1%Cu at 300–773K, which outperforms previously reported n‐type PbS.

coefficient, σ represents electrical conductivity, T represents working temperature in Kelvin, κ ele denotes electronic thermal conductivity, and κ lat denotes lattice thermal conductivity. [4,5] Extensive efforts are devoted to decoupling these correlative parameters. [6] Electrically, the strategies of band convergence, [2] band alignment, [4,7] densityof-states (DOS) distortion, [8,9] modulation doping, [10] enhancing the symmetry of crystal [11] and quantum confinement [12] are successfully established to equilibrate the Seebeck coefficient (S) and the electrical conductivity (σ) in favor of a superior power factor (PF). [13] It is well known that the enhanced band degeneracy due to band convergence could increase the effective mass a bit without degrading the carrier mobility. And DOS distortion, which improves the band effective mass, is a feasible strategy with risks for deteriorating the carrier mobility. [14] It is clear that the optimal balance between the effective mass and the carrier mobility is beneficial for the electrical performance of TE materials. This relationship primarily depends on the weighted mobility, µW = μ H (m * /m e ) 3/2 , where μ H represents the carrier mobility, m * represents the DOS effective mass, and m e represents the unit electron mass.Thermally, intensifying the phonon scattering is considered to be an effective method to decrease the thermal conductivity (κ lat ), which is generally classified into incorporating extra phonon scattering centers [15] and seeking inherent low lattice thermal conductivity materials. [16,17] The latter representing materials might have a complex crystal structure, [1] heavy constituent elements, [18] intense lattice anharmonicity, [19] and soft chemical bonding. [20] And the extra phonon scattering sources include point defects, nanoprecipitates, grain boundaries, and so on. [21] To date, state-of-the-art TE materials, including Zintl phase, [22] half-Heusler, [23] skutterudite, [24] SiGe, [25] chalcogenides, [8,26] and Bi 2 Te 3 -based compounds, [27] etc., exhibit prominent thermoelectric performance.GeTe is proven to be an eminent mid-temperature thermoelectric material. [28,29] The well-recognized characters of GeTe are multiple valance bands, phase transition, ultrahigh carrier concentration, and high thermal conductivity, which diversify the degrees of freedom to tailor its TE performance. [30][31][32] Counter-doping using aliovalent elements, such as Bi, Sb, and In, [33,34] is a common method to achieve the optimal carrier Thermoelectric materials can achieve the direct conversion between electricity and heat, which has drawn extensive attention in recent decades. Understanding the chemical nature of band structure and microstructure is essential to boost the thermoelectric performance of given materials. Herein, CdSe alloying promotes the evolution of multiple valence bands in GeTe, resulting in the contemporaneous appearance of band convergence and density of state distortion, which benefits the sharply enhanced effective mass from ...

Irrigation regime and fertilizer nitrogen (N) are considered as the most effective agricultural management systems to mitigate greenhouse gas (GHG) emissions from crop fields, but few studies have involved saline-alkaline paddy soil. Gas emitted from saline-alkaline paddy fields (1-year-old and 57-year-old) was collected during rice growing seasons by the closed chamber method. Compared to continuous flooding irrigation, lower average CH 4 flux (by 22.81% and 23.62%), but higher CO 2 flux (by 24.84% and 32.39%) was observed from intermittent irrigation fields. No significant differences of N 2 O flux were detected. Application rates of N fertilizer were as follows: (1) No N (N0); (2) 60 kg ha −1 (N60); (3) 150 kg ha −1 (N150); and (4) 250 kg ha −1 (N250). The cumulative emissions of GHG and N fertilizer additions have positive correlation, and the largest emission was detected at the rate of 250 kg N ha −1 (N250). Global warming potential (GWP, CH 4 + N 2 O + CO 2 ) of the 57-year-old field under the N250 treatment was up to 4549 ± 296 g CO 2 -eq m −2 , approximately 1.5-fold that of N0 (no N application). In summary, the results suggest that intermittent irrigation would be a better regime to weaken the combined GWP of CH 4 and N 2 O, but N fertilizer contributed positively to the GWP.

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