Improving plant resistance to Verticillium wilt (VW), which causes massive losses in Gossypium hirsutum, is a global challenge.  Crop plants need to efficiently allocate their limited energy resources to maintain a balance between growth and defense.  However, few transcriptional regulators specifically respond to Verticillium dahliae and the underlying mechanism has not been identified in cotton.  In this study, we found that the that expression of most R2R3-MYB members in cotton is significantly changed by V. dahliae infection relative to the other MYB types.  One novel R2R3-MYB transcription factor (TF) that specifically responds to V. dahliae, GhMYB3D5, was identified.  GhMYB3D5 was not expressed in 15 cotton tissues under normal conditions, but it was dramatically induced by V. dahliae stress.  We functionally characterized its positive role and underlying mechanism in VW resistance.  Upon V. dahliae infection, the up-regulated GhMYB3D5 bound to the GhADH1 promoter and activated GhADH1 expression.  In addition, GhMYB3D5 physically interacted with GhADH1 and further enhanced the transcriptional activation of GhADH1.  Consequently, the transcriptional regulatory module GhMYB3D5-GhADH1 then promoted lignin accumulation by improving the transcriptional levels of genes related to lignin biosynthesis (GhPAL, GhC4H, Gh4CL, and GhPOD/GhLAC) in cotton, thereby enhancing cotton VW resistance.  Our results demonstrated that the GhMYB3D5 promotes defense-induced lignin accumulation, which can be regarded as an effective way to orchestrate plant immunity and growth. 

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.

Excessive cadmium (GrCdc) and deficiencies of copper (GrCuc) and magnesium (GrMgc) in grains pose serious human health risks.  Common wheat breeding has reduced genetic diversity within elite germplasm resources, negatively impacting future wheat production.  Thus, identifying loci controlling GrCdc, GrCuc, and GrMgc from tetraploid wheat and introducing them into common wheat is essential for genetic improvement.  In this study, we identified quantitative trait loci (QTL) for GrCdc, GrCuc, and GrMgc using the Wheat 55K single nucleotide polymorphism (SNP) array-based linkage map and phenotypic data across multiple environments in recombinant inbred lines derived from a cross between a wild emmer accession (LM001) and an endemic tetraploid wheat in Sichuan (Ailanmai).  Four major, stably expressed QTL were identified.  Three of these, including QGrCdc.sau-AM-5A for GrCdc, QGrCuc.sau-AM-4A for GrCuc, and QGrMgc.sau-AM-4A for GrMgc, were novel. These loci were validated using tightly linked Kompetitive Allele Specific PCR (KASP) markers in various genetic backgrounds. Several candidate genes (TRIDC5AG052690, TRIDC5BG060070, and TRIDC4AG008520) with sequence variations were predicted to influence Cd, Cu, or Mg absorption and transport within these QTL intervals.  Correlation analysis revealed that GrCdc was not correlated with GrCuc or GrMgc, although GrCuc was significantly correlated with GrMgc.  Furthermore, no significant effects of GrCdc, GrCuc, or GrMgc on agronomic traits were detected, as no correlation between them and any of the eleven agronomic traits investigated was observed.  Additionally, QGrCuc.sau-AM-4A colocalized with QGrMgc.sau-AM-4A, suggesting potential shared physiological and/or genetic control.  Altogether, these stably expressed QTL across environments provide theoretical guidance for further germplasm improvement and fine mapping.

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.

Efficient nitrogen management is crucial in developing sustainable strategies aimed at enhancing yield while mitigating negative environmental impacts.  However, limited research has focused on this aspect in the production of fresh maize.  Therefore, this study analyzed nitrogen application rates and yield for 40 sweet and 44 waxy maize varieties in Zhejiang Province, China from 2015 to 2019 across five sites.  Nitrogen application rates were categorized as relatively high (RHN: >300 kg ha^-1 for sweet maize, >320 kg ha^-1 for waxy maize) or relatively low (RLN).  An increase in nitrogen application rates for both sweet and waxy maize significantly reduced nitrogen fertilizer partial productivity (R²=0.616, P<0.01; R²=0.643, P<0.01), indicating that the optimum nitrogen application rate in this study might be the lowest values (160 kg ha^-1 for sweet maize and 180 kg ha^-1 for waxy maize).  The kernel number per ear of sweet maize had a potentially more significant impact on fresh grain yield compared to the 1,000-fresh kernel weight both under RLN and RHN.  In waxy maize, 1,000-kernel weight contributed more to fresh grain yield under RLN, and kernel number ear^-1 and 1,000-kernel weight cooperatively affected yield under RHN.  In this study, it was observed that sweet maize required taller plant and ear height, along with an optimal ear-plant height ratio, to enhance dry matter accumulation and increase source size, particularly under RLN, to achieve a higher fresh grain yield.  In contrast, a lower ear height and ear-plant height ratio of waxy maize probably contributed more to increased kernel number and weight under RLN, likely due to a lower ear height can reduce the distance between sink and source, enabling more efficient photoassimilate allocation to the ear.