SignificanceA high-quality genome assembly of Camellia sinensis var. sinensis facilitates genomic, transcriptomic, and metabolomic analyses of the quality traits that make tea one of the world’s most-consumed beverages. The specific gene family members critical for biosynthesis of key tea metabolites, monomeric galloylated catechins and theanine, are indicated and found to have evolved specifically for these functions in the tea plant lineage. Two whole-genome duplications, critical to gene family evolution for these two metabolites, are identified and dated, but are shown to account for less amplification than subsequent paralogous duplications. These studies lay the foundation for future research to understand and utilize the genes that determine tea quality and its diversity within tea germplasm.

Acyl-CoA: diacylglycerol acyltransferase (DGAT) is a key enzyme responsible for triacylglycerol (TAG) synthesis in eukaryotic organisms. The present work reported DGAT genes in the green alga Myrmecia incisa, a promising candidate for arachidonic acid (ArA) production. According to the results of homology search against a transcriptome database, we cloned three cDNAs encoding putative DGAT1 and DGAT2. The 2238-bp, 1056-bp and 1068-bp of open reading frame (ORF) of these three cDNAs, designated as MiDGAT1, MiDGAT2A and MiDGAT2B, were predicted to encode proteins composed of 745, 351 and 355 amino acids. They were separated by 14, 6 and 6 introns, respectively, as revealed by comparing their corresponding cDNA and DNA sequences. Multiple sequence alignment of amino acids indicated that MiDGAT1 had a pleckstrin homology (PH) domain, whilst MiDGAT2s contained a highly conserved HPHG, a characteristic motif of DGAT2 family. To determine the function, they were expressed heterologously in a Saccharomyces cerevisiae mutant strain with impaired TAG metabolism. Results of thin-layer chromatography and BODIPY staining indicated that both MiDGAT1 and MiDGAT2s were able to restore TAG synthesis and lipid body formation. GC-MS analysis indicated that palmitic acid and stearic acid were the major components of TAGs in yeast cells, and their ratio between wild type and the transformed yeasts was not significantly different. Quantitative RT-PCR results showed that the transcript level of MiDGAT2A was regulated by nitrogen starvation, which was consistent with TAG accumulation in M. incisa.

Tea is a globally consumed non-alcohol beverage with great economic importance. However, lack of the reference genome has largely hampered the utilization of precious tea plant genetic resources towards breeding. To address this issue, we previously generated a high-quality reference genome of tea plant using Illumina and PacBio sequencing technology, which produced a total of 2,124 Gb short and 125 Gb long read data, respectively. A hybrid strategy was employed to assemble the tea genome that has been publicly released. We here described the data framework used to generate, annotate and validate the genome assembly. Besides, we re-predicted the protein-coding genes and annotated their putative functions using more comprehensive omics datasets with improved training models. We reassessed the assembly and annotation quality using the latest version of BUSCO. These data can be utilized to develop new methodologies/tools for better assembly of complex genomes, aid in finding of novel genes, variations and evolutionary clues associated with tea quality, thus help to breed new varieties with high yield and better quality in the future.

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GeoGauge is a portable instrument for rapid determination of the stiffness and modulus of compacted soil, which can quickly, safely, and nondestructively evaluate the quality of each compacted layer. In order to deeply study the effectiveness of the detection instrument and equipment used in the soil-rock mixed subgrade, based on the construction project of Beijing-Qinhuangdao Expressway, the influence of water content and compaction degree on the test results and the correlation between GeoGauge detection stiffness and settlement difference were studied and analyzed by indoor model test and field test. Finally, the subgrade compaction uniformity is evaluated according to the measured data of the test section and the predicted value obtained by the ordinary Kriging interpolation method. The results show that: The GeoGauge detection stiffness value shows a trend of first increasing and then decreasing as the water content increases. When the water content is 8%, the detection stiffness value of the earth rock mixture reaches the maximum value. There is a good exponential relationship between the compactness of soil-rock mixture and the stiffness value of GeoGauge detection, and the correlation coefficient is 0.9231, which indicates that the stability of GeoGauge detection results is high. The GeoGauge detection stiffness value increases with the increase of the number of rolling passes. When the number of rolling passes is greater than five, the increase in the detection stiffness of subgrade soil decreases, indicating that the subgrade filler has approached the compaction standard after five passes of rolling. The regression equation between GeoGauge detection stiffness value and settlement difference is established, and the specific index of subgrade stiffness is calculated according to the regression equation when the compactness meets the design conditions, which provides reference for practical engineering.