The lateral transport of labile organic carbon represents a critical pathway for soil organic carbon (SOC) loss, reducing organic carbon sequestration and increasing the risk of waterbody pollution.  Livestock manure application on croplands serves as a common fertilizer reduction practice to sustain crop yields, enhance SOC sequestration, and reduce water erosion.  However, limited quantitative assessments have examined the effects of livestock manure substitution on labile organic carbon lateral loss and fluxes in long-term experiments.  This study conducted a three-year field investigation on subtropical sloping croplands to assess the impact of livestock manure substitution on dissolved organic carbon (DOC) and particulate organic carbon (POC) loss via surface runoff, interflow and eroded sediments.  There are four treatments: no fertilization (CK); chemical nitrogen fertilizer (SF), 40% nitrogen substitution with pig manure (PMF), and 100% nitrogen substitution from pig manure (PM).  Compared to SF treatment, long-term livestock manure substitution in PMF and PM treatments significantly (P<0.05) reduced annual cumulative surface runoff fluxes by 13.5 and 21.6%, respectively.  Manure applications decreased annual sediment fluxes by 12.9 and 19.1%, respectively.  Soil water stable aggregates for mean weight diameter (MWD) increased significantly by 37.7 and 73.6%.  Annual cumulative POC loss flux via eroded sediment under PMF and PM treatments increased significantly (P<0.05) by 61.1 and 47.9%, respectively.  The labile organic carbon loss fluxes, including DOC and POC losses, under PMF and PM treatments increased significantly (P<0.05) by 11.9 and 31.4%, respectively.  These results demonstrate that while water erosion intensity decreases due to enhanced soil aggregate stability, the risk of labile organic carbon loss increases after long-term livestock manure substitution in subtropical sloping croplands.  Future research should examine labile organic carbon lateral migration under various soil types and slope gradients for livestock manure application in subtropical agricultural ecosystem croplands to better understand extreme rainfall effects.

Avian infectious bronchitis (IB) is a highly contagious infectious disease caused by infectious bronchitis virus (IBV), which is prevalent in many countries worldwide and causes serious harm to the poultry industry.  At present, many commercial IBV vaccines have been used for the prevention and control of IB; however, IB outbreaks occur frequently.  In this study, two new strains of IBV, SX/2106 and SX/2204, were isolated from two flocks which were immunized with IBV H120 vaccine in central China.  Phylogenetic and recombination analysis indicated that SX/2106, which was clustered into the GI-19 lineage, may be derived from recombination events of the GI-19 and GI-7 strains and the LDT3-A vaccine.  Genetic analysis showed that SX/2204 belongs to the GVI-1 lineage, which may have originated from the recombination of the GI-13 and GVI-1 strains and the H120 vaccine.  The virus cross-neutralization test showed that the antigenicity of SX/2106 and SX/2204 was different from H120.  Animal experiments found that both SX/2106 and SX/2204 could replicate effectively in the lungs and kidneys of chickens and cause disease and death, and H120 immunization could not provide effective protection against the two IBV isolates.  It is noteworthy that the pathogenicity of SX/2204 has significantly increased compared to the GVI-1 strains isolated previously, with a mortality rate up to 60%.  Considering the continuous mutation and recombination of the IBV genome to produce new variant strains, it is important to continuously monitor epidemic strains and develop new vaccines for the prevention and control of IBV epidemics.

Early defoliation, which usually occurs during summer in pear trees, is gradually becoming a major problem that poses a serious threat to the pear industry in southern China.  However, there is no system for evaluating the responses of different cultivars to early defoliation, and our knowledge of the potential molecular regulation of the genes underlying this phenomenon is still limited.  In this study, we conducted field investigations of 155 pear accessions to assess their resistance or susceptibility to early defoliation.  A total of 126 accessions were found to be susceptible to early defoliation, and only 29 accessions were resistant.  Among them, 19 resistant accessions belong to the sand pear species (Pyrus pyrifolia).  To identify the resistance genes related to early defoliation, the healthy and diseased samples of two sand pear accessions, namely, the resistant early defoliation accession ‘Whasan’ and the susceptible early defoliation accession ‘Cuiguan’, were used to perform RNA sequencing.  Compared with ‘Cuiguan’, a total of 444 genes were uniquely differentially expressed in ‘Whasan’.  Combined with GO and KEGG enrichment analyses, we found that early defoliation was closely related to the stress response.  Furthermore, a weighted gene co-expression network analysis revealed a high correlation of WRKY and ethylene responsive factor (ERF) transcription factors with early defoliation resistance.  This study provides useful resistant germplasm resources and new insights into potentially essential genes that respond to early defoliation in pears, which may facilitate a better understanding of the resistance mechanism and molecular breeding of resistant pear cultivars

MicroRNAs (miRNAs) are endogenous non-protein-coding small RNAs that play crucial and versatile regulatory roles in plants.  Using a computational identification method, we identified 55 conserved miRNAs in tea (Camellia sinensis) by aligning miRNA sequences of different plant species with the transcriptome library of tea strain 1005.  We then used quantitative real-time PCR (qRT-PCR) to analyze the expression of 31 identified miRNAs in tea leaves of different ages, thereby verifying the existence of these miRNAs and confirming the reliability of the computational identification method.  We predicted which miRNAs were involved in catechin synthesis using psRNAtarget Software based on conserved miRNAs and catechin synthesis pathway-related genes.  Then, we used RNA ligase-mediated rapid amplification of cDNA ends (RLM-RACE) to obtain seven miRNAs cleaving eight catechin synthesis pathway-related genes including chalcone synthase (CHS), chalcone isomerase (CHI), dihydroflavonol 4-reductase (DFR), anthocyanidin reductase (ANR), leucoanthocyanidin reductase (LAR), and flavanone 3-hydroxylase (F3H).  An expression analysis of miRNAs and target genes revealed that miR529d and miR156g-3p were negatively correlated with their targets CHI and F3H, respectively.  The expression of other miRNAs was not significantly related to their target genes in the catechin synthesis pathway.  The RLM-RACE results suggest that catechin synthesis is regulated by miRNAs that can cleave genes involved in catechin synthesis.