H9N2 avian influenza virus (AIV) has widely circulated in poultry worldwide and sporadic infections in humans and mammals.  During our surveillance of chicken from 2019 to 2021 in Shandong Province, China, we isolated 11 H9N2 AIVs.  Phylogenetic analyses showed that the eight gene segments of the 11 isolates were closely related to several sublineages of Eurasian lineage: BJ/94-like clades (HA and NA genes), G1-like clades (PB2 and M genes), and SH/F/98-like clades (PB1, PA, NP and NS genes).  The isolates showed mutation sites that preferentially bind to human-like receptors (HA) and mammalian fitness sites (PB2, PB1 and PA), as well as mutations in antigen and drug resistance sites.  Moreover, studies with mice revealed four isolates with varying levels of pathogenicity.  The average antibody titer of the H9N2 AIVs was 8.60 log2.  Based on our results, the epidemiological surveillance of H9N2 AIVs should be strengthened.

Ralstonia solanacearum causes a lethal bacterial wilt disease in many crops, leading to huge losses in crop production every year.  Understanding of plant–R. solanacearum interactions will aid to develop efficient strategies to control the disease.  As a soilborne pathogen, R. solanacearum naturally infects plants via roots.  A huge limitation in studying plant–R. solanacearum interactions is the large variation of R. solanacearum infection assay due to the variable soil conditions and uneven inoculum exposure.  Here, we developed a robust and reliable Petri-dish inoculation method which allows consistent and stable infection in young plant seedlings.  This method is easy to use, takes about only 10 days from seed germination to the completion of inoculation assay, and requires less inoculum of bacteria as well as growth chamber space.  We proved the efficacy of the seedling Petri-dish inoculation method by analyzing plant defense primed by molecular patterns, resistance of defense-related plant mutants, and virulence of R. solanacearum mutants.  Furthermore, we demonstrated that the seedling Petri-dish inoculation method can be applied to other host plants such as tobacco and has great potential for high-throughput screening of resistant plant germplasms to bacterial wilt in the future.

    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.

Plants experience dynamic light environments in the field, and the mechanisms for physiological and biochemical acclimation to fluctuating light (FL) vary among species.  How soybean (Glycine max (L.) Merr.) integrates multiple physiological changes to acclimate to FL remains unclear.  This study evaluated the impact of FL conditions on soybean morphology and photosynthetic characteristics by analyzing changes in photosynthetic gas exchange parameters and chlorophyll (Chl) a fluorescence parameters under alternating high and low light conditions.  Results showed that soybeans subjected to FL conditions had low dry matter mass, small and thin leaves, and a low Chl a to Chl b ratio, resembling the traits of soybeans grown in low-light environments.  However, their photosynthetic gas exchange rates and photosynthetic capacity remained constant, which was not the case under consistent low-light conditions.  The adaptation processes for fluctuating and lowlight conditions are distinct.  Correlation analyses indicated that the drop in carbon assimilation under FL primarily resulted from two aspects: the speed of recovery in stomatal conductance when transitioning to bright light and the slow relief of nonphotochemical quenching as light levels decreased.  Thus, the decrease in carbon assimilation under FL conditions cannot be ascribed to adjustments during low-light phases but is due to a lag in photosynthetic response.