Fusarium head blight (FHB), mainly caused by the fungal pathogen Fusarium graminearum, is one of the most destructive wheat diseases.  Besides directly affecting the yield, the mycotoxin residing in the kernel greatly threatens the health of humans and livestock.  Xinong 979 (XN979) is a widely cultivated wheat elite with high yield and FHB resistance.  However, its resistance mechanism remains unclear.  In this study, we studied the expression of genes involved in plant defense in XN979 by comparative transcriptomics.  We found that the FHB resistance in XN979 consists of two lines of defense.  The first line of defense, which is constitutive, is knitted via the enhanced basal expression of lignin and jasmonic acid (JA) biosynthesis genes.  The second line of defense, which is induced upon F. graminearum infection, is contributed by the limited suppression of photosynthesis and the struggle of biotic stress-responding genes.  Meanwhile, the effective defense in XN979 leads to an inhibition of fungal gene expression, especially in the early infection stage.  The formation of the FHB resistance in XN979 may coincide with the breeding strategies, such as selecting high grain yield and lodging resistance traits.  This study will facilitate our understanding of wheat–F. graminearum interaction and is insightful for breeding FHB-resistant wheat.

Growth traits are among the most important economic traits in pigs and are regulated by polygenes with complex regulatory mechanisms.  As the major indicators of growth performance, the backfat thickness (BFT), loin eye area (LEA), and days to 100 kg (D100) traits are commonly used to the genetics improvement in pigs.  However, the available genetic markers for these traits are limited.  To uncover novel loci and candidate genes associated with growth performance, we collected the phenotypic information of BFT, LEA, and D100 in 1,186 pigs and genotyped all these individuals using the Neogen GGP porcine 80K BeadChip.  We performed a genome-wide association study (GWAS) using 4 statistical models, including mixed linear models (MLM), fixed and random model circulating probability unification (FarmCPU), settlement of MLM under progressively exclusive relationships (SUPER), Bayesian-information and linkage-disequilibrium Iteratively nested keyway (Blink), and identified 5, 3, and 6 high-confidence single nucleotide polymorphisms (SNPs) associated with BFT, LEA, and D100, respectively.  Variant annotation and quantitative trait locus (QTL) mapping analysis suggested that 6 genes (SKAP2, SATB1, PDE7B, PPP1R16B, WNT3, and WNT9B) were potentially associated with growth performance in pigs.  Transcriptome analysis suggested that the expression of Src Kinase Associated Phosphoprotein 2 (SKAP2) was higher in prenatal muscles than in postnatal muscles, and the expression of Phosphodiesterase 7B (PDE7B) continuously increased during the prenatal stages and gradually decreased after birth, implying their potential roles in prenatal skeletal muscle development.  Overall, this study provides new candidate loci and genes for the genetic improvement of pigs.

Light deficiency is a growing abiotic stress in rice production. However, few studies focus on shading effects on grain yield and quality of rice in East China. It is also essential to investigate proper nitrogen (N) application strategies that can effectively alleviate the negative impacts of light deficiency on grain yield and quality in rice. A two-year field experiment was conducted to explore the effects of shading (non-shading and shading from heading to maturity) and panicle N application (N_DP, decreased panicle N rate; N_MP, medium panicle N rate; N_IP, increased panicle N rate) treatments on rice yield- and quality-related characteristics. Compared with non-shading, shading resulted in a 9.5–14.8% yield loss (P<0.05), mainly due to lower filled-grain percentage and grain weight. N_MP and N_IP had higher (P<0.05) grain yield than N_DP under non-shading, and no significant difference was observed in rice grain yield among N_DP, N_MP, and N_IP under shading. Compared with N_MP and N_IP, N_DP achieved less yield loss under shading because of the increased filled-grain percentage and grain weight. Shading reduced leaf photosynthetic rate after heading, as well as shoot biomass weight at maturity, shoot biomass accumulation from heading to maturity, and nonstructural carbohydrate (NSC) content in the stem at maturity (P<0.05). The harvest index and NSC remobilization reserve of N_DP were increased under shading. Shading decreased (P<0.05) percentages of brown rice, milled rice, head rice, and amylose content while increasing (P<0.05) chalky rice percentage, chalky area, chalky degree, and grain protein. N_MP demonstrated a better milling quality under non-shading, while N_DP demonstrated under shading. N_DP exhibited both lower chalky rice percentage, chalky area, and chalky degree under non-shading and shading, compared with N_MP and N_IP. N_DP under shading decreased amylose content and breakdown but increased grain protein content and setback, contributing to similar overall palatability to nonshading. Our results suggested severe grain yield and quality penalty of rice when subjected to shading after heading. N_DP improved NSC remobilization, harvest index, and sink-filling efficiency and alleviated yield loss under shading. Besides, N_DP would maintain rice’s milling, appearance, and cooking and eating qualities under shading. Proper N management with a decreased panicle N rate could be adopted to mitigate the negative effects of shading on rice grain yield and quality.

Simultaneously enhancing plant growth and disease resistance is an ideal goal in Agriculture. Significant efforts have been made to promote plant growth or immunity through the use of biological reagents, such as the application of beneficial microbes and plant immunity inducers. However, balancing plant immunity and growth remains a challenging task. In this study, we engineered the plant growth-promoting bacterium Bacillus subtilis OKB105 to express a secreted microbial pattern, flg22, and accessed its activity in enhancing both plant growth and disease resistance. The OKB105 (flg22) strain exhibited plant growth-promoting activity similar to the OKB105 strain containing an empty vector, OKB105 (EV). Furthermore, the OKB105 (flg22) strain significantly enhanced plant resistance against two distinct pathogens, Pseudomonas syringae DC3000 ΔhopQ1-1 and Phytophthora parasitica, compared to OKB105 (EV), confirming that the engineered OKB105 (flg22) effectively enhances plant disease resistance. Interestingly, root irrigation with OKB105 (flg22) also markedly boosted the plant’s aboveground resistance to pathogens compared to OKB105 (EV). We further demonstrated that OKB105 (flg22) can be applied to confer resistance to pathogens in other plants that recognize flg22. Finally, RNA-Seq and qRT-PCR analyses illustrated that OKB105 (flg22) effectively induced the expression of defense-related genes in pattern-triggered immunity. Our results prove that employing an engineered beneficial microbe expressing a microbial pattern is a promising strategy for simultaneously enhancing plant growth and immunity. 

Kernel length (KL) is one of the components determining grain weight (GW) in wheat.  In this study, we firstly detected a putative locus on chromosome arm 2BL from a mutant BLS2 with long kernels using a Bulked Segregant Analysis (BSA) combined with a 60 K SNP array.  This putative locus was then confirmed as a major and stable QTL based on linkage mapping.  The locus, Qkl.sau-BC-2B.1, was mapped in an interval of 0.4 cM, and phenotypic variance explained by it varied from 17.01 to 30.53% across different environments.  Effects of this locus was further verified in a second population.  The positive allele of the locus could significantly increase hundred-kernel weight and prolong anthesis date, but it did not affect plant height, tiller number, spike length, and spikelet number per spike.  Expression and sequencing analyses identified TraesCS2B02G478100, possessing a G to C transition variation leading to an amino acid change, as the likely candidate gene underlying the locus.  Further, a new model for analyzing the genetic basis of yield-related traits was proposed. Taken together, our results provide a foundation for subsequent gene mining and breeding utilization of this promising QTL for KL.

Spike development is a key factor in determining wheat yield, and cold tolerance during the spike’s vulnerable stages is essential for preserving both fertility and productivity.  This study presents a comprehensive characterization of the apical spike aberrance mutant lwasa-B1, which was generated through ethyl methanesulfonate mutagenesis of the wheat cultivar Chuannong 16, and its response to low-temperature stress.  The mutant lwasa-B1 exhibited reduced cold tolerance, with a critical temperature threshold identified between 13-15°C.  Under low-temperature stress, lwasa-B1 showed delayed growth, increased tillering, and varying degrees of spike degradation.  Compared to the wild type, lwasa-B1 demonstrated significantly lower enzymatic activities of catalase, peroxidase, and auxin, while levels of malondialdehyde and gibberellin were markedly higher. Integrated metabolomic and transcriptome analyses suggest that lwasa-B1 may be implicated in plant hormone signal transduction and phenylpropanoid metabolic regulation pathways.  A target gene was mapped to the chromosome arm 4BS, within a 2.07 Mb region, bounded by the markers k_sau_4B_17478331 and k_sau_4B_19541181. The integrated analysis, encompassing BSE-Seq, transcriptomics, and metabolomics, has identified TraesCS4B02G023800 as a potentially key gene associated with lwasa-B1.  This research delineates the phenotypic and physiological responses of lwasa-B1 to low-temperature stress and nominates a candidate gene potentially responsible for spike degradation.  The study provides a preliminary dissection of the regulatory mechanisms underlying spike degradation in wheat under low-temperature stress, contributing significant insights for wheat breeding programs.