禽传染性支气管炎（IB）是由传染性支气管炎病毒(IBV)引起的一种急性、高度接触性传染病。IBV在世界范围内流行，给养禽业造成了严重的经济损失。目前，许多商业化的IBV疫苗株（包括H120、M41、LDT3-A等）已广泛用于预防和控制禽传染性支气管炎，但由于IBV易于变异及重组导致疫苗免疫效果不够理想，IB疫情时有发生。

本研究从中国中部地区免疫过H120疫苗的鸡群中分离到两株IBV新毒株，分别命名为SX/2106和SX/2204，并对两株IBV的全基因组进行了序列测定及重组分析。基于S1基因的遗传演化分析结果显示，SX/2106属于GI-19基因型，SX/2204则属于GVI-1基因型。重组分析表明，SX/2106可能来源于GI-19基因型毒株、GI-7基因型毒株与类LDT3-A疫苗株的重组事件；SX/2204可能来源于GVI-13基因型毒株、GVI-1基因型毒株与类H120疫苗株的重组事件。病毒交叉中和试验表明，SX/2106及SX/2204的抗原性与H120疫苗株存在显著差异。动物实验表明，SX/2106和SX/2204均能在鸡的肺脏和肾脏中有效复制并引起发病和死亡；通过观察感染鸡后气管上皮细胞的纤毛运动情况，发现SX/2106和SX/2204感染均能显著抑制纤毛活性，对气管上皮细胞黏膜造成严重损伤。病毒交叉中和试验及免疫后攻毒保护试验结果表明，H120疫苗免疫并不能对这两株IBV感染提供有效保护。值得注意的是，与之前分离的GVI-1毒株相比，SX/2204的致病性有增强趋势，感染雏鸡死亡率高达60%，对于GVI-1基因型IBV毒株的监测与防控需引起高度重视。

IBV在自然界中通过重组和突变不断进化，产生新的变异株。目前鸡传染性支气管炎在我国鸡群中发病率居高不下，严重影响鸡产业的健康发展，持续加强IBV的流行病学监测及时发现新的变异毒株，对于预防和控制IBV流行具有重要意义。

本研究鉴定了一个新的lncRNA，命名为干旱诱导型lncRNA（DIR，DROUGHT-INDUCED INTERGENIC lncRNA)。基因表达分析表明，干旱胁迫显著诱导了DIR的表达，而植物激素脱落酸和茉莉酸处理不影响DIR的表达。此外，过表达DIR基因可增强转基因木薯脯氨酸的积累从而提升抗旱性。RNA测序分析发现，DIR优先影响与干旱相关的转录基因和代谢相关基因。利用RNA下拉技术（RNA pull-down）联合质谱分析发现DIR与325个蛋白存在相互作用。蛋白-蛋白互作分析（Protein-protein interaction analysis，PPI）发现，mRNA胞质运输和蛋白质翻译质控通路相关的蛋白质被显著富集。这些结果表明，DIR与其互作蛋白可通过调控mRNAs或蛋白质的代谢来响应干旱胁迫。因此，干旱胁迫下通过调节DIR的表达有提高木薯产量的潜力。

Litter uniformity, which is usually represented by within-litter weight coefficient of variation at birth (CVB), could influence litter performance of sows and the profitability of pig enterprises. The objective of this study was to characterize CVB and its effect on other reproductive traits in Large White sows. Genetic parameters and genetic correlation of the reproductive traits, including CVB, within-litter weight coefficient of variation at three weeks (CVT), total number born (TNB), number born alive (NBA), number born dead (NBD), gestation length (GL), piglet mortality at birth (M₀), piglet mortality at three weeks (M₃), total litter weight at birth (TLW0), and total litter weight at three weeks (TLW₃) were estimated for 2 032 Large White litters. The effects of parity and classified litter size on CVB, CVT, TNB, NBA, NBD, GL, M₀, M₃, TLW₀, and TLW₃ were also estimated. The heritabilities of these reproductive traits ranged from 0.06 to 0.17, with the lowest heritability for CVB and the highest heritability for TLW0. Phenotypic and genetic correlations between these reproductive traits were low to highly positive and negative (ranging from −0.03 to 0.93, and −0.53 to 0.93, respectively). The genetic correlations between TNB and CVB, and between M₀ and CVB were 0.32 and 0.29, respectively. In addition, CVB was significantly influenced by parity and litter size class (P<0.05). All the results suggest that piglet uniformity should be maintained in pig production practices and pig breeding programs.

   Ear size exhibits remarkable diversity in pig breeds. LEM domain-containing 3 (LEMD3) on chromosome 5 is considered as an important candidate for porcine ear size. This is the first study on cloning and characterization of LEMD3 cDNA. The complete cDNA contains 4 843 bp, including a 2 736-bp open reading frame (ORF), a 37-bp 5´-untranslated region (UTR) and a 2 070-bp 3´-UTR. The complete LEMD3 gene is 126 241-bp and contains 13 exons and 12 introns. The ORF encodes a deduced LEMD3 protein of 911 amino acids, which shares 82–94% nucleic acid and 51–96% amino acid identity with other species. A phylogenetic tree constructed based on the amino acid sequences revealed that the porcine LEMD3 protein was closely related with cattle LEMD3. Resequencing of the ORF and promoter of LEMD3 from Minzhu pig and Large White revealed three single nucleotide polymorphisms (SNPs): L964C>A in the complete coding region, L4625A>G in the 3´ UTR, and L-394T>C in the promoter region. Genome-wide association study (GWAS) revealed that all of SNPs were shown significant association with ear size in Large White×Minzhu pig intercross population. With conditional GWAS, –log₁₀(P-value) decreased by more than 80% when each of three SNPs was included as a fixed effect. These results suggested direct involvement of LEMD3 or close linkage to the causative mutation for ear size. The findings of this study might form the basis for understanding the genetic mechanism of ear size variation in pigs and provide potential molecular markers for screening ear size diversity in pig breeds.

Although quantitative trait loci (QTLs) for number of thoracic-lumbar vertebrae have been identified on Sus scrofa chromosomes (SSCs) 1 and 7, the influence of these QTLs on the thoracic and lumbar vertebrae is not clear. The aim of this study was to identify single nucleotide polymorphisms (SNPs) associated with total number of thoracic-lumbar vertebrae and for each trait (number of thoracic and lumbar vertebrae) separately. A total of 581 individuals from an F2 Large White×Minzhu population were genotyped using an SNP60K chip. Performing a genome-wide association study (GWAS) for total number of thoracic-lumbar vertebrae, 38 significant SNPs were identified in two QTL regions located on SSC1 and SSC7. Performing a GWAS for number of thoracic vertebrae only, 72 significant SNPs were located on SSC7. While performing a GWAS for number of lumbar vertebrae only, 17 significant SNPs were identified on SSC1. Gene mining suggested that the gene encoding orphan nuclear receptor, germ cell nuclear factor (NR6A1) on SSC1 was a strong candidate affecting the number of lumbar vertebrae in pigs. Additionally, genes encoding vertnin (VRTN), prospero homeobox 2 (PROX2), Finkel-Biskis-Jinkins murine osteosarcoma viral oncogene homolog (FOS), and transforming growth factor beta 3 (TGFB3) may be important candidates affecting the number of thoracic vertebrae in pigs. QTLs on SSC1 and SSC7 independently influenced the numbers of thoracic and lumbar vertebrae. These results shed light on the complex genetic background of vertebrae development in pigs.

Porcine carcass traits and organ weights have important economic roles in the swine industry. A total of 576 animals from a Large White×Minzhu intercross population were genotyped using the Illumina PorcineSNP60K Beadchip and were phenotyped for 10 traits, specifically, backfat thickness (6-7 libs), carcass length, carcass weight, foot weight, head weight, heart weight, leaf fat weight, liver weight, lung weight and slaughter body weight. The genome-wide association study (GWAS) was assessed by Genome Wide Rapid Association using the mixed model and regression-genomic control approach. A total of 31 single nucleotide polymorphisms (SNPs) (with the most significant SNP being MARC0033464, P value=6.80×10-13) were located in a 9.76-Mb (31.24-41.00 Mb) region on SSC7 and were found to be significantly associated with one or more carcass traits and organ weights. High percentage of phenotypic variance explanation was observed for each trait ranging from 31.21 to 67.42%. Linkage analysis revealed one haplotype block of 495 kb, in which the most significant SNP being MARC0033464 was contained, on SSC7 at complete linkage disequilibrium. Annotation of the pig reference genome suggested 6 genes (GRM4, HMGA1, NUDT3, RPS10, SPDEF and PACSIN1) in this candidate linkage disequilibrium (LD) interval. Functional analysis indicated that the HMGA1 gene presents the prime biological candidate for carcass traits and organ weights in pig, with potential application in breeding programs.

The erythropoietin receptor (EPOR) has shown to play an important role in fetal survival by promoting the maturation of red blood cells in many studies of uterine capacity and litter size in swine. In this study, we screened the porcine EPOR gene for mutations and identified five single nucleotide polymorphisms (SNPs): g.705G>T in intron 1, g.2 373C>T in intron 4, and g.2 882C>T, g.3 035A>G, and g.3 132A>T in intron 6. We then genotyped 247 Beijing Black (BB) sows and compared the polymorphism data with the litter sizes of 1 375 parities among the sows. At first parity, there was no association of g.2 882C>T and g.3 132A>T with litter sizes. However, the CT sows in g.2 882C>T had 2.13 higher total number born (TNB) (PT had the highest litter size when compared to the two homozygotes for the later parities (PG SNP,for the later parities, the TNB of the sows with the GG genotype was 3.81 higher (PT SNP was associated with a greater litter size at both the first parity (PT SNP was significantly more common in the more prolific Chinese breeds. These results indicated that the EPOR could be an important candidate gene for litter size and g.705G>T can serve as a useful genetic marker for improving litter size in both first and later parities in swine.