互联网被认为能够给弱势农户的绿色生产转型带来更多技术红利，但这却与偏向性技术进步理论相悖。从理性忽略的视角，基于山东省1015份农户调查数据，利用内生转换probit模型分析了互联网对农户病虫害综合治理（IPM）技术采纳的影响及其原因。研究表明：（1）互联网虽有效促进了农户IPM采纳，但并未真正给弱势农户带来更多影响，较大的选择偏差导致弱势农户的技术红利被高估；（2）技术信息获取渠道差异导致农户对互联网信息的理性忽略程度存在差别，这是互联网影响异质性的重要原因；（3）对强关系网络信息渠道的过度依赖使弱势农户容易陷入信息茧房，对互联网信息产生理性忽略，因而难以被互联网信息所影响。要更好地发挥互联网对弱势农户IPM采纳甚至绿色生产转型的促进作用，不仅需要推动互联网农业技术信息服务的适老化，还应激励善于利用互联网的农户积极分享外部信息，引导弱势农户走出信息茧房。

传染性法氏囊病（Infectious bursal disease, IBD）是一种严重危害养禽业健康发展的传染病，该病的病原是传染性法氏囊病病毒（Infectious bursal disease virus, IBDV）。IBDV的基因组由双节段双股RNA组成，即A节段和B节段。传统上，依据致病性和抗原性，IBDV可分为经典株、变异株、超强毒株和弱毒株。近年来，随着IBDV的不断变异，具有新的基因特征的IBDV毒株不断出现。传统的IBDV分类方法已不能涵盖这些新出现的毒株。因此，亟需建立一种新的IBDV基因型分类方法用于IBDV的流行病学研究。近年来，A节段基因序列常被用于IBDV的基因分类。然而，对于基因组分节段的IBDV来讲，A节段和B节段在病毒的遗传演化中都很重要，仅基于A节段基因序列的基因分类方法是不全面的。而且，原有的分类方法已经不能涵盖不断出现的IBDV节段重配病毒和最新出现的IBDV新型变异株。因此，本研究率先建立了一种兼顾IBDV基因组双节段特征的新的IBDV基因分型方法。在该分型系统中，基于A节段编码的VP2高变区核苷酸序列特征，IBDV被分为9个基因群（A1、A2、A3、A4、A5、A6、A7、A8和AII）；基于B节段编码的B-maker的核苷酸序列特征，IBDV被分为5个基因群（B1、B2、B3、B4和BII）；A2又被进一步分为4个亚群（A2a、A2b、A2c和A2d）。利用新的基因分型方法，传统的经典株、变异株、超强毒株和弱毒株分别被归类于基因群A1B1、A2B1、A3B2和A8B1。本研究中鉴定的IBDV新型变异株被归类为基因群A2dB1。本研究建立的IBDV基因分型方法，是一个灵活多样的开元系统，可用于现有毒株和新出现毒株的明确鉴定，将极大地方便IBDV的分子流行病学研究。

传染性法氏囊病（Infectious bursal disease，IBD）是由传染性法氏囊病病毒（Infectious bursal disease virus，IBDV）引起的。IBD是危害养禽业的最重要的免疫抑制病之一，是影响全球养禽业可持续发展的重要限制因素。IBD在巴基斯坦也是危害养禽业的重要疫病，然而该国IBDV优势流行毒株尚不明确。本研究针对巴基斯坦主要养禽地区（旁遮普省、信德省、俾路支省和首都伊斯兰堡），开展了IBDV的流行病学研究。之前报道的巴基斯坦IBDV毒株仅显示了A节段编码的VP2基因，在GenBank上未见到过其B节段编码的VP1基因。然而，IBDV的基因组分为A、B两个节段，单独的VP2基因是无法科学地反映IBDV的真实特征的。在本研究中，运用RT-PCR技术，对覆盖29个肉鸡场的36株IBDV进行了VP1和VP2基因代表区段的扩增、测序和分析。基因遗传进化树和同源率比较研究结果显示，本研究的全部36株巴基斯坦IBDV毒株的VP2基因属于IBDV超强毒（very virulent IBDV，IBDV），而VP1基因则独立于超强毒和非超强毒之外形成了独特分支，这类毒株属于独特型节段重组IBDV毒株（vv-A/Uniq-B）。与流行于中国、印度等国家的vv-A/Uniq-B型IBDV相比，巴基斯坦IBDV毒株形成一个独立的亚群，具有明显的地域特点。本研究首次证明，具有地域特点的独特的节段重组毒株（vv-A/Uniq-B）是巴基斯坦IBDV的重要流行毒株。本研究揭示了巴基斯坦IBDV毒株的分子特征，这对于IBD疫苗的科学选择和该病的有效防控具有重要意义。

Soybean mosaic virus (SMV) is one of the major viral pathogens affecting soybean crops worldwide.  Three SMV resistance genes, R_SC4, R_SC8, and R_SC14Q , have been identified and mapped on soybean chromosomes 14, 2, and 13 from Dabaima, Kefeng 1, and Qihuang 1 cultivars, respectively.  Soybean cultivar Nannong 1138-2 is widely grown in the Yangtze River Valley of China.  In this study, crosses were made between Qihuang 1×Kefeng 1 and Dabaima×Nannong 1138-2.  Ten simple sequence repeat (SSR) markers linked to three resistance loci (R_SC4, R_SC8, and R_SC14Q ) were used to assist pyramided breeding.  Pyramided families containing three resistance loci (R_SC4, R_SC8, and R_SC14Q ) were evaluated by inoculating them with 21 SMV strains from China.  Results indicated that the 10 markers can be used effectively to assist the selection of resistant individuals containing R_SC4, R_SC8, and R_SC14Q .  A total of 53 F6 plants were confirmed to contain three homozygous alleles conferring resistance to SMV.  Five F₇ homozygous pyramided families exhibited resistance to 21 strains of SMV and showed desirable agronomic traits using dual selection.  The strategy of pyramiding resistance gene derived from different varieties has practical breeding value in providing broad-spectrum resistance against the existing strains of SMV in China.  

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.

Infectious bursal disease virus (IBDV) is responsible for the highly contagious infectious bursal disease of chickens. Further understanding the gene-function is necessary to design the tailored vaccine. The amino acid residue 279, located on strand PF of VP2, is one of the three residues that have been reported to be involved in cell-tropism but with some inconsistency. In this study, to further clarify the amino acids involved in the cell tropism of IBDV, a series of mutations about residue 279 were introduced into the VP2 of vvIBDV Gx strain. With the reverse genetic system, we found single mutation of D279N, double mutations of D279N/A284T or Q253H/D279N were not enough to adapt IBDV to chicken embryo fibroblast (CEF) cell. To evaluate whether residue 279 could influence the replication and virulence of IBDV, the virus rGxHT-279 with three mutations (Q253H/D279N/A284T) was rescued and evaluated. Results showed that the mutation of residue 279 in VP2 had no efficient effects on both the replication efficiency in vitro and the virulence to SPF chickens of IBDV. In summary, the results demonstrated that residue 279 of VP2 did not contribute efficiently to cell tropism, replication efficiency, and virulence of IBDV at least in some strains. These findings provided further information for understanding the gene function of IBDV.

Food safety issues constitute an international topic discussed by many scholars. Although there is an extensive body of literature on comparisons of food safety control practices across different governance structures, these studies have been conducted mainly in terms of qualitative and descriptive analysis. In addition, little attention has been given to family farms. This study addresses the food safety control practices adopted by firms with different governance structures in China. Food safety control is expressed by the following aspects, i.e., pollution-free, green, organic, and/or geographical indication products certification, establishment of production records, and pesticide residue testing. Three types of governance structures that engage in agricultural production are distinguished: farmer cooperatives, agricultural companies, and family farms. The food safety control practices of various governance structures are investigated based on a database that comprises 600 vegetable and fruit enterprises in Zhejiang, China. The results show that (1) pesticide residue testing is adopted by the most firms, followed by products certification, and production records are adopted by the fewest firms, and (2) agricultural companies adopt more food safety control practices than family farms, while farmer cooperatives adopt the fewest food safety control practices. Governance structure features of a cooperative in terms of ownership, decision-making, and income distribution are the main reasons for the low level of food safety control in the cooperative.

Soybean mosaic virus (SMV), a member of the genus Potyvirus, is a major pathogen of soybean plants in China, and 16 SMV strains have been identified nationwide based on a former detailed SMV classification system. As the P3 gene is thought to be involved in viral replication, systemic infection, pathogenicity, and overcoming resistance, knowledge of the P3 gene sequences of SMV and other potyviruses would be useful in efforts to know the genetic relationships among them and control the disease. P3 gene sequences were obtained from representative isolates of the above-mentioned 16 SMV strains and were compared with other SMV strains and 16 Potyvirus species from the National Center for Biotechnology GenBank database. The P3 genes from the 16 SMV isolates are composed of 1 041 nucleotides, encoding 347 amino acids, and share 90.7-100% nucleotide (NT) sequence identities and 95.1-100% amino acid (AA) sequence identities. The P3 coding regions of the 16 SMV isolates share high identities (92.4-98.9% NT and 96.0-100% AA) with the reported Korean isolates, followed by the USA isolates (88.5-97.9% NT and 91.4-98.6% AA), and share low identities (80.5-85.2% NT and 82.1-84.7% AA) with the reported HZ1 and P isolates from Pinellia ternata. The sequence identities of the P3 genes between SMV and the 16 potyviruses varied from 44.4 to 81.9% in the NT sequences and from 21.4 to 85.3% in the AA sequences, respectively. Among them, SMV was closely related to Watermelon mosaic virus (WMV), with 76.0-81.9% NT and 77.5-85.3% AA identities. In addition, the SMV isolates and potyvirus species were clustered into six distinct groups. All the SMV strains isolated from soybean were clustered in Group I, and the remaining species were clustered in other groups. A multiple sequence alignment analysis of the C-terminal regions indicated that the P3 genes within a species were highly conserved, whereas those among species were relatively variable.