Premature senescence of flag leaf severely affects wheat yield and quality. Chlorophyll (Chl) degradation is the most obvious symptom during leaf senescence and catalyzed by a series of enzymes. Pheophytin pheophorbide hydrolase (Pheophytinase, PPH) gene encodes a Chl degradation hydrolase. In this study, the coding, genomic and promoter sequences of wheat TaPPH-A gene were cloned. The corresponding lengths were 1467 bp, 4479 bp and 3666 bp, respectively. Sequence structure analysis showed that TaPPH-A contained five exons and four introns. After the multiple sequences alignment of TaPPH-A genome from 36 accessions in a wheat diversity panel, four SNPs and one 2-bp InDel were observed, which formed two haplotypes, TaPPH-7A-1 and TaPPH-7A-2. Based on the SNP at 1299 bp (A/G), a molecular marker TaPPH-7A-dCAPS was developed to distinguish allelic variation (A/G). Using the molecular markers, 13 SSR, and 116 SNP markers, a linkage map of chromosome 7A were integrated. TaPPH-A was mapped on the chromosome region flanked by Xwmc9 (0.94 cM) and AX-95634545 (1.04 cM) on 7A in a DH population. Association analysis between TaPPH-7A allelic variation and agronomic traits found that TaPPH-7A was associated with TGW in 11 of 12 environments and Chl content at grain-filling stage under drought stress using Population 1 consisted of 323 accessions. The accessions possessed TaPPH-7A-1 (A) had higher TGW and Chl content than those possessed TaPPH-7A-2 (G), thus TaPPH-7A-1 (A) was a favorable allelic variation. By analyzing the frequency of favorable allelic variation TaPPH-7A-1 (A) in Population 2 with 157 landraces and Population 3 with 348 modern cultivars, we found it increased from pre-1950 (0) to 1960s (54.5%), then maintained a relatively stable level about 56% from 1960s to 1990s. These results suggested the favorable allelic variation TaPPH-7A-1 (A) should be valuable in enhancing grain yield by improving the source (chlorophyll content) and sink (the developing grain) simultaneously. Furthermore, the newly developed molecular marker TaPPH-7A-dCAPS could be integrated into a breeding kit of screening high TGW wheat for marker-assisted selection.

Sorghum bicolor (L.) is one of the oldest crops cultivated by human beings which has been used in food and wine making. To understand the genetic diversity of sorghum breeding resources and further guide molecular-marker-assisted breeding, six yield-related traits were analyzed for 214 sorghum germplasm from all over the world, and 2,811,016 single-nucleotide polymorphisms (SNPs) markers were produced by resequencing these germplasms. After controlling Q and K, QTLs were found to be related to the traits using three algorisms. Interestingly, an important QTL was found which may affect multiple traits in this study. It was the most likely candidate gene for the gene SORBI_3008G116500, which was a homolog of Arabidopsis thaliana gene-VIP5 found by analyzing the annotation of the gene in the LD block. The haplotype analysis showed that the SORBI_3008G116500^hap3 was the elite haplotype, and it only existed in Chinese germplasms. The traits were proven to be more associated with the SNPs of the SORBI_3008G116500 promoter through gene association studies. Overall, the QTLs and the genes identified in this study would benefit molecular-assisted yield breeding in sorghum.

Chloramphenicol antibiotics (CAs) are broad-spectrum antibiotics which are widely used in the prevention and treatment of infectious diseases in livestock and poultry breeding. However, overused CAs can enter the watershed and eventually enter the sediment. Antibiotics in sediment can cause secondary pollution through disturbance and suspension. In this study, taking the Fenhe River Basin as the research area, the risk of CAs in sediment were assessed by collecting sediment samples. The results showed that CAs were detected in all sediment samples of the Fenhe River Basin. The mean concentration of CAs was 79.1 μg/kg, and the concentration of thiamphenicol (THI) was dominant, which was up to 58.3 μg/kg. Temporally, there are great differences in different seasons; the concentration of CAs was higher in winter than that in summer, up to 4.79–174 times. Spatially, the mean concentration of CAs in midstream was 83.5 μg/kg, which was higher than that in the upstream and downstream. The concentration of CAs in tributaries were generally higher than that in the main stream, and the mean concentration of tributaries was 1.1 times that of the main stream. CAs in S2 (Lanhe River) was the most prominent among all sample sites; the concentration of CAs was 190.8 μg/kg. The risk threshold of CAs in the sediment was calculated using the Equilibrium Partitioning approach (EqP), based on the distribution coefficient (Kp) and the predicted no-effect concentration (PNEC) in the water, and the values were 0.091–1.44 mg/kg. Based on the risk threshold, the ecological risk of the CAs in sediment was assessed using risk quotients (RQ). The results showed that the Chloramphenicol (CHL) was the most prominent in the Fenhe River Basin, and the proportion of medium-risk areas reached 21.7%, while all the other areas showed low risk. Secondly, the proportion of medium-risk areas was 17.4% for THI, and all the other areas showed low risk. The risk for Florfenicol (FF) was least among all CAs, and the proportion of low-risk areas was only 8.7%, while all the other areas were of insignificant risk.

The fall armyworm (FAW), Spodoptera frugiperda, is one of the major agricultural pests that has invaded China. The FAW is a polyphagous insect with the gramineous crop sorghum being a key host plant. However, the basis of sorghum’s chemical defense against FAW feeding is still unclear. In this study, we investigated the potential defensive mechanism of sorghum against this insect species. It was found that FAW larvae preferred maize over sorghum, the selection and damage rates for sorghum plants by larvae were significantly lower than those of maize plants, and feeding on sorghum restricted larval weight. The non-target metabolomics revealed that the feeding of FAW larvae altered the plant secondary metabolite spectra in maize and sorghum, resulting in species-specific differential secondary metabolites (DSMs). Of these, 19 DSMs were specific in maize, and 51 in sorghum, and only 6 were found in both species. Two-choice and no-choice feeding assays found that gambogenic acid and chimonanthine, two DSMs unique to sorghum, were found to deter larval feeding and decrease the larval weight. These findings reveal that the defense of sorghum against FAW is regulated by changing the response spectra of secondary metabolites and that the induced metabolites have a defensive function by acting as antifeedants, which provides new insights into employing bioactive plant compounds against polyphagous insects.

The Pheophorbide a oxygenase (PaO) is a key enzyme in chlorophyll degradation and plays an important role in plant senescence. However, the PaO gene’s function in sorghum remains underexplored. In this study, we identified five SbPaO gene family members in the sorghum genome through bioinformatics analysis. Analyses of gene structure, phylogeny, and collinearity revealed high conservation of this gene family among grass crops, suggesting similar functions. Subcellular localization and protein network predictions indicated that SbPaOs may participate in chlorophyll catabolism and regulate leaf senescence. Expression pattern analysis showed that SbPaO1, SbPaO3, SbPaO4, and SbPaO5 were highly expressed in leaves and significantly upregulated during senescence. Haplotype analysis found three SbPaO genes significantly linked to thousand-grain weight (TGW); superior haplotypes SbPaO1-hap4, SbPaO3-hap5, and SbPaO4-hap4 notably increased this trait. Single-gene improvements increased TGW by 10.57–17.20%, dual-gene aggregation by 18.78–24.75%, and three-gene aggregation by 29.09%. The study also developed Kompetitive Allele-Specific PCR (KASP) markers that identify superior haplotypes with 100% accuracy. In summary, this study’s results provide a theoretical basis and genetic resources for further exploration of haplotype pyramiding strategies to breed new high-yielding sorghum varieties and delineate a clear research direction for subsequent functional validation and breeding practices.