H9N2禽流感病毒（AIV）已在全球家禽中广泛流行，并在人类和哺乳动物中引起零星的感染。本研究旨在了解H9N2AIV的遗传进化和流行病学特征。2019-2021年，从中国山东省采集136份疑似AI感染的鸡的组织样品，共分离出11株H9N2AIV。遗传进化分析表明，分离出的11株H9N2AIV的8个基因片段与欧亚谱系的几个亚谱系密切相关：BJ/94-like分支（HA和NA基因）、G1-like分支（PB2和M基因）、SH/F/98-like分支（PB1、PA、NP和NS基因）。所有分离病毒HA蛋白的裂解位点仅含有一个碱性氨基酸，表明它们都属于低致病性AIV。分离株表现出优先与类人受体 (HA) 结合和哺乳动物适应性（PB2、PB1和PA）的突变位点，从而增加了它们跨越物种屏障并引起人类感染的风险。此外，11株H9N2AIV还存在抗原位点和耐药性位点的突变，说明应及时评估疫苗的有效性，加强抗流感药物的研发。小鼠感染显示，4株H9N2AIV的致病性水平不同。从中国山东省采集的7237份鸡血清样品中，HI抗体平均滴度为8.49 log₂，离散度为23.56%，抗体合格率为98.52%（≥4 1og2），表明山东省规模化养鸡场对H9N2AI的整体免疫效果较好。基于我们的结果，应该加强对H9N2AIV的流行病学监测。

茄科劳尔氏菌，简称青枯菌(Ralstonia solanacearum)，是一种分布广泛的土传细菌病原菌，该病原菌从根部侵染植物，最终引发青枯病(Bacterial wilt disease)。青枯菌寄主范围广泛，可在200多种植物包括马铃薯、番茄、辣椒、烟草、花生等重要作物上引起毁灭性的植物病害，被列为世界上第二大细菌性植物病原菌，给全世界的农作物生产带来巨大威胁。研究并解析青枯菌与植物互作的分子机制可为青枯病防控策略的建立奠定基础。然而，目前科研中主要采用的青枯菌土壤灌根法接种方法存在实验周期长、所需植物培养空间大、且条件不容易控制等问题，限制了青枯菌与植物互作研究的开展。因此，亟需一种快速、操作简易、且结果稳定的青枯菌接种方法。为此，本文建立了一种培养皿内青枯菌接种方法(Petri-dish inoculation method)，该方法具备接种后发病稳定、操作简易和实验周期短等特点，可广泛用于青枯菌与植物互作研究。为了证明该方法在青枯菌与植物互作研究中的有效性，本文利用引发植物防御作用的分子模式Pep1，拟南芥感病突变体npr1，以及具有不同毒力水平的青枯菌突变体ΔhrcV和ΔRipAC，研究了青枯菌皿内接种方法在评估植物抗病性和青枯菌致病性中的适用性和高效性。同时，我们利用皿内接种方法再现了前人对4个烟草品种的抗性评估结果，表明该方法可用于不同植物种质材料的抗性评估和筛选。鉴于此方法具有快速、操作简单、节省空间，人力和财力，以及所需接种量少的优点，该方法可用于快速大规模青枯菌突变体致病性分析以及植物对青枯菌抗性种质材料的筛选和鉴定。青枯菌皿内接种方法也可为其他土传病原菌的接种提供参考。

    Lead (Pb) contamination has often been recorded in Chinese field soils. In recent years, efforts have been made to investigate Pb toxicity thresholds in soils with plant growth and microbial assays. However, the influence of soil properties on Pb toxicity impacts on soil microbial processes is poorly understood. In this study ten soils with different properties were collected in China to investigate the relationships between thresholds of Pb toxicity to soil microbes and soil properties. The effect of soil leaching on Pb toxicity was also investigated to determine the possible influence of added anions on Pb toxicity during dose-response tests. Toxicity was inferred by measuring substrate-induced nitrification in leached and non-leached soils after Pb addition. We found that soil microbe Pb toxicity thresholds (EC_x, x=10, 50) differed significantly between the soils; the 10% inhibition ratio values (EC₁₀) ranged from 86 to 218 mg kg^–1 in non-leached soils and from 101 to 313 mg kg^–1 in leached soils. The 50% inhibition ratio values (EC₅₀) ranged from 403 to 969 mg kg^–1 in non-leached soils and from 494 to 1 603 mg kg^–1 in leached soils. Soil leaching increased EC10 and EC50 values by an average leaching factor (LF) of 1.46 and 1.33, respectively. Stepwise multiple regression models predicting Pb toxicity to soil microbes were developed based on EC_x and soil properties. Based on these models, soil pH and organic carbon are the most important soil properties affecting Pb toxicity thresholds (R₂>0.60). The quantitative relationship between Pb toxicity and soil properties will be helpful for developing soil-specific guidance on Pb toxicity thresholds in Chinese field soils.

   The variations of grain cadmiun (Cd) concentrations, translocation factors (TFs) of Cd from roots to shoots/grains of six rice cultivars, characterized with different Cd-sensitivities in polluted soil were studied, the selected rice cultivars were Xiangzao 17 (R1), Jiayu 211 (R2), Xiangzao 42 (R3), Zhuliangyou 312 (R4), Zhuliangyou 611 (R5), and Jinyou 463 (R6), respectively. The Cd subcellular distribution and Cd binding characteristics on subcellular fractions of rice root cell wall (CW) were further investigated. The results showed that the rice grain Cd contents varied significantly, with a maximum variation of 47.0% among the cultivars, the largest grain Cd content was observed with cultivar R1 (Cd-sensitivity cultivar) and the smallest with R5 (Cd-tolerance cultivar). The translocation factors of Cd from roots to shoots (TF_shoot) and roots to grains (TF_grain) varied greatly among the cultivars. In general, the TF_grain of the cultivars followed the order of R1>R2>R3>R4> R6-R5. The Cd concentration (mg kg^–1 FW) in the fraction of root CW, the fraction of cell wall removing pectin (CW-P) and the fraction of cell wall removing pectin and hemicellulose (CW-P-HC) of the cultivars generally followed the order of CW-P>CW>CW-P-HC; the ratios of Cd concentration (mg kg^–1 FW) in the fraction of CW-P to that of CW were mostly more than 1.10, while the ratios of Cd concentration in the fraction of CW-P-HC to that of CW were mostly less than 0.60, indicating that Cd was mainly stored in the hemicellulose of the root CW. The ratios of Cd of CW-P-HC to CW generally followed the descending order of R1~R2>R3>R4>R5~R6 for the cultivars, which implied that hemicellulose is probably the main subcellular pool for transferring Cd into rice grain, and it restrains the translocation of Cd from shoot to the grain, especially for the Cd-tolerance cultivars (R5 and R6), the compartmentation of more Cd in hemicellulose in root CW is probably one of the main mechanisms for Cd tolerance of rice cultivars.

Apple (Malus×domestica) has been proposed as an important woody plant and the major cultivated fruit trees in temperate regions. Apple whole genome sequencing has been completed, which provided an excellent opportunity for genome-wide analysis of the synonymous codon usage patterns. In this study, a multivariate bioinformatics analysis was performed to reveal the characteristics of synonymous codon usage and the main factors affecting codon bias in apple. The neutrality, correspondence, and correlation analyses were performed by CodonW and SPSS (Statistical Product and Service Solutions) programs, indicating that the apple genome codon usage patterns were affected by mutational pressure and selective constraint. Meanwhile, coding sequence length and the hydrophobicity of proteins could also influence the codon usage patterns. In short, codon usage pattern analysis and determination of optimal codons has laid an important theoretical basis for genetic engineering, gene prediction and molecular evolution studies in apple.

It is imperative to derive an appropriate cadmium (Cd) health risk toxicity threshold for paddy soils to ensure the Cd concentration of rice grains meet the food safety standard. In this study, 20 rice cultivars from the main rice producing areas in China were selected, and a pot-experiment was conducted to investigate transformation of Cd in paddy soil-rice system with 0 (CK), 0.3 mg kg–1 (T1) and 0.6 mg kg–1 (T2) Cd treatments in greenhouse. The results showed that Cd concentrations of rice grains existed significant difference (P<0.05) in 20 rice cultivars under the same Cd level in soil. The Cd concentrations of rice grains of the CK, T1 and T2 treatments were in the range of 0.143–0.202, 0.128–0.458 and 0.332–0.806 mg kg–1, respectively. Marked differences of the ratios of Cd concentration for soil to rice grain (BCFs) and transfer factors (TFs, root to grain and straw to grain) among the tested cultivars were observed in this study. The bioconcentration factors (BCFgrain) and TFs of the 20 rice cultivars were 0.300–1.112 and 0.342–0.817, respectively. The TFs of Cd from straw to grain ranged from 0.366 to 1.71, with significant differences among these 20 rice cultivars. The bioconcentration factors (BCFgrain) and TFs among the 20 rice cultivars ranged from 0.300–1.112 and 0.342–0.817, respectively. The species-sensitivity distribution (SSD) of Cd sensitivity of the rice species could be fitted well with Burr-III (R2=0.987) based on the data of BCFs. The toxicity threshold of Cd derived from SSD for the paddy soil was 0.507 mg kg–1 in the present study.

Mixtures composed of five wheat cultivars, Jingshuang 16, Jing 411, Jingdong 8, Lunxuan 987, and Baofeng 104, with different levels of resistance against powdery mildew were tested for their potential containment of the disease development in the field and for the influence on grain yield and the content of crude protein in the years 2007 and 2010. The plots were inoculated artificially with mixed isolates collected in the fields and propagated in the greenhouse and the disease was scored in 7 d interval during the two growing seasons. It was indicated that certain combinations, e.g., Jingdong 8: Lunxuan 987, Jingdong 8:Baofeng 104, and Jing 411:Jingdong 8:Baofeng 104, showed positive efficacy on the mildew. The cultivar combinations tested in 2007 showed increase of grain yield, while most of the combinations tested in 2010 did not show the increase. The differences of the increases or decreases were not statistically significant except combinations Jing 411:Jingdong 8:Baofeng104, Jingshuang16:Jingdong8:Lunxuang 987 and Jingshuang 16:Jingdong 8:Lunxuan 987: Baofeng 104, which showed the decrease of the grain yield. The mixtures did not show influence on the content of crude protein in grain. More cultivar combinations need to be tested.

Pig (Sus scrofa) fat accumulation can be reduced by feeding with high dosages of clenbuterol, but the molecular mechanism has not yet been explained. In our study, a porcine cDNA microarray representing 3 358 pig genes was successfully developed. This microarray is the first porcine DNA microarray in China and its false positive rate is 0.98%, which means the microarray platform is reliable. The microarray can be used to study gene expression profiles in multiple pig tissues because the present genes percentage of adipose, skeletal muscle, heart, liver, lung, kidney, and spleen were all more than 60%. This microarray was used to identify the genes responding to clenbuterol stimulation in pig internal organs, including heart, liver, lung, spleen, and kidney. Many genes were identified including enzymes involved in lipids metabolism (lipoprotein lipase up-regulated in liver, heart and lung, ATP-citrate lyase and carnitine palmitoyltransferase II precursor up-regulated in liver, succinyl-CoA up-regulated in lung, mitochondrial malate dehydrogenase down-regulated in spleen), and signaling pathway genes (cAMP-protein kinase A signaling pathway was found up-regulated in liver, heart, lung, and kidney as reported previously, while transforming growth factor was found down-regulated in heart and lung). However, no common gene responding to clenbuterol administration was found in all tissues. The expression levels of 14 genes were analyzed using real-time PCR with 82.1% of them induced to express similar magnitudes as in the microarray analyses. This work offers some understanding of how clenbuterol so effectively reduces pig adipose accumulation on the molecular level.