The inhibition of nitrification by mixing nitrification inhibitors (NI) with fertilizers is emerging as an effective method to reduce fertilizer-induced nitrous oxide (N₂O) emissions.  The additive 3,4-dimethylpyrazole phosphate (DMPP) apparently inhibits ammonia oxidizing bacteria (AOB) more than ammonia oxidizing archaea (AOA), which dominate the nitrification in alkaline and acid soil, respectively.  However, the efficacy of DMPP in terms of nitrogen sources interacting with soil properties remains unclear.  We therefore conducted a microcosm experiment using three typical Chinese agricultural soils with contrasting pH values (fluvo-aquic soil, black soil and red soil), which were fertilized with either digestate or urea in conjunction with a range of DMPP concentrations.  In the alkaline fluvo-aquic soil, fertilization with either urea or digestate induced a peak in N₂O emission (60 μg N kg^–1 d^–1) coinciding with the rapid nitrification within 3 d following fertilization.  DMPP almost eliminated this peak in N₂O emission, reducing it by nearly 90%, despite the fact that the nitrification rate was only reduced by 50%.  In the acid black soil, only the digestate induced an N₂O emission that increased gradually, reaching its maximum (20 μg N kg^–1 d^–1) after 5–7 d.  The nitrification rate and N₂O emission were both marginally reduced by DMPP in the black soil, and the N₂O yield (N₂O-N per NO₂^–+NO₃^–-N produced) was exceptionally high at 3.5%, suggesting that the digestate induced heterotrophic denitrification.  In the acid red soil, the N₂O emission spiked in the digestate and urea treatments at 50 and 10 μg N kg^–1 d^–1, respectively, and DMPP reduced the rates substantially by nearly 70%.  Compared with 0.5% DMPP, the higher concentrations of DMPP (1.0 to 1.5%) did not exert a significantly (P<0.05) better inhibition effect on the N₂O emissions in these soils (either with digestate or urea).  This study highlights the importance of matching the nitrogen sources, soil properties and NIs to achieve a high efficiency of N₂O emission reduction.

Wheat grain yield is generally sink-limited during grain filling.  The grain-filling rate (GFR) plays a vital role but is poorly studied due to the difficulty of phenotype surveys.  This study explored the grain-filling traits in a recombinant inbred population and wheat collection using two highly saturated genetic maps for linkage analysis and genome-wide association study (GWAS).  Seventeen stable additive quantitative trait loci (QTLs) were identified on chromosomes 1B, 4B, and 5A.  The linkage interval between IWB19555 and IWB56078 showed pleiotropic effects on GFR₁, GFR_max, kernel length (KL), kernel width (KW), kernel thickness (KT), and thousand kernel weight (TKW), with the phenotypic variation explained (PVE) ranging from 13.38% (KW) to 33.69% (TKW).  198 significant marker-trait associations (MTAs) were distributed across most chromosomes except for 3D and 4D.  The major associated sites for GFR included IWB44469 (11.27%), IWB8156 (12.56%) and IWB24812 (14.46%).  Linkage analysis suggested that IWB35850, identified through GWAS, was located in approximately the same region as QGFRmax2B.3-11, where two high-confidence candidate genes were present.  Two important grain weight (GW)-related QTLs colocalized with grain-filling QTLs.  The findings contribute to understanding the genetic architecture of the GFR and provide a basic approach to predict candidate genes for grain yield trait QTLs.

CRISPR/Cas9-based gene editing research has advanced greatly and shows broad potential for practical application in life sciences, but the Cas9 system is often constrained by the requirement of a protospacer adjacent motif (PAM) at the target site. While xCas9, a variant derived from Streptococcus pyogenes Cas9 (SpCas9), can recognize a broader range of PAMs, its application in non-model insects is lacking. In this study, we explored xCas9 activity in gene editing by selecting corazonin (Crz) and the target sites with various PAMs in Locusta migratoria, a destructive insect pest worldwide. We found that xCas9 could cleave the target site with AG PAM while SpCas9 could not, although xCas9 appeared to have lower activity than SpCas9 at the canonical NGG PAMs. The heritable homozygous Crz^-/- locust strain was generated by the application of xCas9. The Crz^-/- strain showed an albino body color, with significantly downregulated expression of several body color-related genes including Pale, Vermilion, Cinnabar, White and β-carotene-binding protein. In addition, Crz^-/- mutants exhibited significantly reduced expression of Chitin synthase 1, along with a markedly lower chitin content as well as compact and rigid cuticles. Furthermore, Crz^-/- mutants displayed impaired performance under low-temperature stress, including prolonged lifespan, reduced body weight and smaller body size. Our results suggest that xCas9 is effective for insect genome editing, and Crz plays essential roles in insect body color, cuticle development and adaptation to low-temperature stress. The findings of this study extend the application of xCas9 in non-model insects and provide new insights into our understanding of the regulation of insect cuticle development and environmental adaptation.