肝脏是鸡最重要的器官之一，具有储存肝糖原、合成蛋白质、解毒和脱氧等生理功能。肝脏的代谢和生长是一个复杂过程，受到环境、饮食和遗传等因素的调控。microRNAs (miRNAs) 作为转录后调控因子可参与多种生理过程。越来越多的证据表明，miR-27b-5p在不同物种的肝脏发育和代谢中发挥着至关重要的调控作用。但是miR-27b-5p在鸡肝脏中的潜在作用尚未被探索。在本次试验中，我们首先发现脂肪肝鸡血清中TG和TC的含量显著高于正常鸡，而VLDL和血清激素(FSH、LH和E2)含量较正常组鸡显著降低。随后的研究发现miR-27b-5p在鸡脂肪肝中表达量较高，表明miR-27b-5p可能参与调节鸡肝脏的发育和代谢。接下来，我们探索了miR-27b-5p在鸡肝脏中的潜在功能，发现miR-27b-5p能促进脂肪合成、增加细胞内氧化应激水平和炎症反应，并最终导致肝细胞发生凋亡。之后，我们又构建了miR-27b-5p与其靶基因间的调控机制，发现miR-27b-5p通过吸附IRS2来调控PI3K/AKT信号通路。此外，我们又探索了IRS2在鸡肝脏细胞中的效应，结果表明干扰IRS2与外源性过表达miR-27b-5p具有相同的作用。最终，我们的研究揭示miR-27b-5p通过结合IRS2来抑制PI3K/AKT信号通路，从而导致鸡肝脏脂肪变性、氧化应激，炎症反应和细胞凋亡。

茶是世界上最受欢迎的非酒精饮料之一。游离氨基酸，尤其是茶氨酸，是茶汤鲜味的主要组成。然而，关于茶树氨基酸含量变异的遗传基础仍不清晰。因此，基于靶向代谢组学的方法，本研究连续两年检测了174份茶树种质嫩叶的游离氨基酸含量，并通过转录组分析获得了这些种质的基因型。基于代谢表型和基因型，通过全基因组关联研究研究影响茶树鲜叶游离氨基酸含量变异的位点。本研究鉴定到69个-log10 (P-value) 大于 5的位点。功能注释的结果分析显示，支链氨基酸转移酶、谷氨酰胺合成酶、硝酸盐转运蛋白和谷氨酸脱羧酶均可能在氨基酸代谢的过程中发挥重要作用。因此，本研究从中选择了两个显著的位点：谷氨酰胺合成酶（Glu1，P=3.71×10-4；Arg1，P=4.61×10-5）和支链氨基酸转移酶（Val1，P=4.67×10-5；I_Leu1，P=3.56×10-6）。对CsGS和CsBCAT进行基因型分析，选择CsGS的两个等位基因（CsGS-L、CsGS-H）和CsBCAT的两个等位基因（CsBCAT-L、CsBCAT-H）进行功能验证。CsGS-L和CsGS-H过表达提高了转基因植株中的谷氨酸和精氨酸含量；CsBCAT-L和CsBCAT-H过表达促进了缬氨酸、异亮氨酸和亮氨酸的积累。体外酶活性分析发现SNP₁₀₅₄对CsGS催化谷氨酸生成谷氨酰胺的酶活性具有重要影响。此外，CsGS-L和CsGS-H差异调控谷氨酰胺的积累，CsBCAT-L和CsBCAT-H差异调控支链氨基酸的积累。综上所述，本研究的结果将为茶树氨基酸含量变异的遗传基础解析提供新的认识，并为鉴定优质基因以提高茶树氨基酸含量提供理论依据。

随着居民收入的快速增长，中国牛肉消费量已从2000年的500万吨增长到了2019年的770万吨，但与猪肉和禽肉相比仍处于较低水平。在中国中等收入群体不断扩大的背景下，加深收入增长对牛肉消费影响的认识十分必要，这对于展望未来牛肉消费需求并为国内牛肉产业提供决策参考具有重要价值。本文基于国家统计局的32878户城镇居民家庭调查数据，运用反双曲正弦转换（IHS）的广义双栏模型估计了出城镇不同收入组家庭的牛肉需求收入弹性，并对未来牛肉消费的可能变动趋势进行了模拟分析。实证分析结果表明，在家牛肉消费需求的收入弹性从低收入组的0.169增长到高收入组0.671。不同收入增长情景的模拟分析结果表明，预计牛肉消费量在10年内将增长12.0％～38.8％，在15年内将增长18.6％～70.5％。本文的研究发现可以为决策者和其他利益相关者比如国内牛肉生产商和世界牛肉出口商提供有关未来牛肉需求变动趋势的定量依据，也说明了提高中国牛肉供给系统韧性的紧迫性。

The brown planthopper, Nilaparvata lugens is an economically important pest on rice plants. This species produces macropterous and brachypterous morphs in response to environmental cues, which makes it very difficult to control. The molecular basis of wing patterning in N. lugens is still unknown. It is necessary to identify wing patterning genes of N. lugens, and also to clarify the expression differences of wing patterning genes between macropterous and brachypterous morphs. High-throughput deep sequencing of transcriptome of N. lugens wing pad yielded 116 744 580 raw reads and 113 042 700 clean reads. All the reads were assembled into 55 963 unigenes with an average length of 804 bp. With the E-value cut-off of 1.0E–5,18 359 and 2 883 unigens had hits in NCBI-NR (NCBI non-redundant protein sequences) and NCBI-NT (NCBI nucleotide sequences) databases, respectively. A total of 16 502 unigenes were assigned to GO (gene ontology) classification, 9 709 ungenes were grouped into 26 COG (cluster of orthologous groups of proteins) classifications, and 6 724 unigenes were assigned to different KEGG (Kyoto encyclopedia of genes and genomes) pathways. In total, 56 unigenes which are homologous to wing patterning genes of Drosophila melanogaster or Tribolium castaneum were identified. Out of the 56 unigenes, 24 unigenes were selected, and their expression levels across the five nymphal stages between macropterous strain and brachypterous strain were examined by qRT-PCR. Two-way ANOVA analysis showed that development stage had significant effects on the expression level of all the 24 genes (P<0.05). The expression levels of 8 genes (Nlen, Nlhh, Nlsal, NlAbd-A, Nlwg, Nlvg, Nlexd and NlUbx) were significantly affected by wing morph. This is the first transcriptome analysis of wing pads of hemimetabolous insect, N. lugens. The identified wing patterning genes would be useful resource for future exploration of molecular basis of wing development. The 8 differentially expressed wing patterning genes between macropterous strain and brachypterous strain would contribute to explain molecular mechanism of wing-morph differentiation in N. lugens.

Seven important grain traits, including grain length (GL), grain width (GW), grain perimeter (GP), grain area (GA), grain length/width ratio (GLW), roundness (GR), and thousand-grain weight (TGW), were analyzed using a set of 139 simple sequence repeat (SSR) markers in 130 hexaploid wheat varieties and 193 Aegilops tauschii accessions worldwide. In total, 1 612 alleles in Ae. tauschii and 1 360 alleles in hexaploid wheat (Triticum aestivum L.) were detected throughout the D genome. 197 marker-trait associations in Ae. tauschii were identified with 58 different SSR loci in 3 environments, and the average phenotypic variation value (R2) ranged from 0.68 to 15.12%. In contrast, 208 marker-trait associations were identified in wheat with 66 different SSR markers in 4 environments and the average phenotypic R2 ranged from 0.90 to 19.92%. Further analysis indicated that there are 6 common SSR loci present in both Ae. tauschii and hexaploid wheat, which are significantly associated with the 5 investigated grain traits (i.e., GA, GP, GR, GL, and TGW) and in total, 16 alleles derived from the 6 aforementioned SSR loci were shared by Ae. tauschii and hexaploid wheat. These preliminary data suggest the existence of common alleles may explain the evolutionary process and the selection between Ae. tauschii and hexaploid wheat. Furthermore, the genetic differentiation of grain shape and thousand-grain weight were observed in the evolutionary developmental process from Ae. tauschii to hexaploid wheat.

Understanding the relationship between the timing of N fertilizer applications and crop primary production is crucial for achieving high yield and N use efficiency in agriculture. This study investigated the effects of starting-N plus topdressing N applications (as compared to the common practice of all basal application) on soybean photosynthetic capacity under different planting densities. A field experiment was conducted in two growing seasons (2011 and 2012), and the soybean (Glycine max L. Merrill) cultivar was Dongnong 52, three planting densities (20, 25 and 30 plants m-2), and four N fertilizer application patterns (all N fertilizer of 6 g N m-2 as basal fertilizer, all N fertilizer as topdressing at beginning pod stage (R3), 1.8 g N m-2 as basal fertilizer and 4.2 g N m-2 as topdressing at stage R3 and full pod stage (R4), respectively). The results indicated that under the same planting density, compared to applying all N as basal fertilizer, the application of starter-N plus topdressing N substantially reduced the rate of pod abscission, and enhanced leaf area index (LAI) significantly at beginning seed stage (R5) (P<0.05), net assimilation rate (NAR) during stages R4-full seed stage (R6) (P<0.05), contribution rate of post-seed filling assimilate to seed (CPA) (P<0.05), and yield (P<0.05). Applying topdressing N at stage R4 resulted in higher net primary production and yield than applying topdressing N at stage R3. When applying starter-N plus topdressing N at planting density of 25 plants m-2, LAI after stage R5 and NAR after stage R4 were increased by 5.92-16.3% (P<0.05) and 13.7-26.6% (P<0.05) with the planting density of 20 plants m-2, respectively, and yield was 8.46-14.0% (P<0.05) higher than that under 20 plants m-2. When planting density increased to 30 plants m-2, only LAI during stages R4-R5 and NAR during stages R4-R5 increased by applying starter-N plus topdressing N, while the other indexes declined. Overall, results of this study demonstrated that applying starter-N plus topdressing N could significantly enhance soybean photosynthetic capacity after stage R5 at planting density of 25 plants m-2.

Mitosis of mammary epithelial cell is foundation of mammal lactation. We developed a strategy of combined application of generation of longer cDNA fragments from the serial analysis of gene expression (SAGE) tags for gene identification (GLGI) to screen and identify genes influencing lactating ability of mammary epithelial cell in dairy goat. GLGI as a new tag identification technique was brought about with SAGE. Bzw2 was found as a candidate gene related to lactation by screening Long-SAGE library of mammary gland in dairy goat. Bzw2 cDNA was synthesized by switching mechanism at 5´-end of RNA transcript (SMART) technology. The mRNA level of Bzw2 was relatively higher in early lactation than in other development stages of mammary gland. The proliferation of mammary epithelial cell was inhibited by transfecting specific shRNA of Bzw2. The mRNA levels of Stat5, Csn2 and Prlr were also down-regulated, suggesting the lactating ability of mammary epithelial cell was attenuated after Bzw2 RNAi. The reduction of mammary epithelial cell growth and lactation by Bzw2 RNAi was rescued through over-expression of Bzw2. These results revealed that Bzw2 might play an important role in lactation though the molecular mechanism was still unclear.