Photosynthesis serves as the primary source of nutrients synthesized in higher plants, and improving photosynthetic efficiency can significantly increase crop yield and fruit quality. Leaf color mutants represent ideal materials for studying chloroplast development and photosynthesis mechanisms and have been widely characterized in field crops. However, relevant research on watermelon leaf color mutants remains scarce. In this study, we isolated a yellow-green phenotype mutant, PKH352, from an EMS-mutagenized watermelon mutant library. The chlorophyll content and maximal photochemical efficiency in PKH352 were significantly decreased. Genetic analysis showed that the mutated trait was controlled by a single nuclear gene, which was named Clygp (Citrullus lanatus yellow-green plant). Through MutMap and linkage analysis in an F₂ population of 440 plants, we identified a single nucleotide polymorphism (SNP) mutation within ClG42_04g0106300, which encoded a signal recognition particle 54 kDa protein, as the causal variant for the yellow-green phenotype. Further validation using a CRISPR/Cas9-mediated system confirmed that knockout of ClG42_04g0106300 results in the yellow-green phenotype in watermelon. In addition, comparative transcriptomic analysis revealed that mutations in ClG42_04g0106300 greatly affected the expression of key genes associated with chloroplast development and photosynthesis, providing strong evidence that this gene plays a critical role in these biological pathways. Taken together, these findings provide insights into the molecular mechanisms underlying chloroplast development and photosynthetic efficiency, offering a theoretical basis for breeding watermelon varieties with high photosynthetic efficiency.

A novel variegated tea cultivar exhibiting a stable variegated phenotype was recently identified, demonstrating significantly elevated amino acid content concomitantly with reduced polyphenolic compound levels compared to conventional green-leaf varieties. Nevertheless, the underlying mechanism remains unclear. Here, variegated leaves and normal leaves of ‘Huangshanzhong’ tea plant were used to perform pigment content analysis and comparative transcriptome analysis. The chlorophyll content in variegated leaves significantly decreased compared to normal leaves, while the ratio of Chl a to Chl b was enhanced. Multiple genes (CsrpiA, CsGAPDH, CsPGAM, CsPK and CsOGDH) involved in sugar metabolism exhibited downregulated expression in variegated leaves. Key genes involved in the photosynthetic pathway were down-regulated in variegated leaves, including those encoding light-harvesting protein complex chlorophyll a/b binding proteins (CsLhca1, CsLhca4, CsLhcb1 and CsLhcb3) and photosystem II complex proteins (CspsbP and CspsbW). Meanwhile, genes involved in chlorophyll degradation metabolism (CsSGR and CsCLH1) were upregulated in variegated leaves. Compared to the wild type, transgenic plants overexpressing CsCLH1 and CsCLH2 exhibited no significant changes in chlorophyll content. Enzyme activity assays showed that CsCLH1 could degrade chlorophyll in vitro. Subcellular localization results revealed that CsCLH1 and CsCLH2 were localized in the cytoplasm and nucleus. These findings suggest that impaired photosynthetic system function, suppressed carbohydrate synthesis, and accelerated degradation of photosynthetic pigments collectively contribute to the variegated phenotype in tea leaves. This study advances our understanding of mechanisms underlying leaf variegation in plants.

Plant pathogenic fungi release cell wall-degrading enzymes (CWDEs), which are significant weapons for breaking down plant cell walls, although only a few reports focus on their pathogenesis. The current study demonstrates that MoFco1, a conserved α-L-fucosidase in several pathogenic fungi, degrades the hemicellulose component XXFG and contributes to the pathogenicity of Magnaporthe oryzae. In addition, MoFco1 enzyme activity is essential for its pathogenic function, as the enzyme activity mutation induced pathogenesis defects identical to the ΔMofco1 mutant. We further performed a structure-based virtual screening targeting MoFco1 and discovered 0989, which binds to MoFco1 and effectively inhibits M. oryzae pathogenesis. In brief, our study reveals the pathogenic mechanism of MoFco1 and explored the application of structure-based virtual screening in plant protection.

Drought stress is a significant environmental stressor that can have detrimental effects on crop yields, especially during stem elongation. Drought priming has emerged as a promising technique for enhancing plant drought tolerance. However, the effects of drought priming on the spike differentiation process and its physiological basis in wheat are not clear. In this study, we investigated the effects of drought priming on spike development under drought stress by applying drought priming at the three-leaf stage and drought stress during stem elongation. This study demonstrated that drought priming significantly increased the photosynthetic rate of flag leaves by approximately 25.7% and improved leaf water potential by 17.4% during drought stress. Moreover, it mitigated oxidative damage by reducing the hydrogen peroxide and malondialdehyde levels by 30.6 and 11.1%, respectively, during stem elongation. Drought priming also markedly enhanced the activities of two key carbon metabolism enzymes, hexokinase and fructokinase, by 170.0 and 236.0%, respectively. This improved carbon metabolism and stabilized spike differentiation, leading to increased spikelet and floret primordia formation. Ultimately, drought priming achieved a 13.8% increase in kernel number per spike, demonstrating its potential for improving grain yield under drought conditions. This study innovatively revealed the “carbon homeostasis-spike development” coordination mechanism underlying drought priming-enhanced reproductive stress tolerance. The findings advance our understanding of stress memory as it relates to spatiotemporal regulation in crops and offer transformative solutions for stabilizing wheat production under climate change scenarios.

Uneven crop stands arise from natural variations in emergence time, which are influenced by different irrigation measures applied post-sowing. In the pursuit of high-yielding maize populations, the emergence rate and uniformity of maize stands are critical factors. This study investigates the effects of different irrigation methods and drip irrigation at various days after sowing on the emergence uniformity and yield of summer maize. The experiment consisted of six treatments: drip irrigation on the 0th, 3rd, 6th, 9th, and 12th days after sowing (DAS0, DAS3, DAS6, DAS9, and DAS12), and sprinkling irrigation on the 0th day after sowing (SI0). Agronomic traits, ear characteristics, harvest yield, and indices of population uniformity were evaluated at critical growth stages. Results indicated that timely drip irrigation (DAS0-3) significantly increased the emergence rate and number of harvestable ears by 9.57% (8621.61 plants ha^-1) and 10.54% (8017.05 ears ha^-1) compared to the SI treatment. Treatment with DAS0-3 resulted in a significant increase of 13.50% in ear length and 24.85% in kernel weight per ear compared to the SI treatment. Maize populations subjected to delayed drip irrigation (DAS6-12) demonstrated a progressive decline in quality throughout the growth period. At the silk stage, the uniformity of plant height and ear height decreased by 47.19 and 44.85%, respectively, compared to the DAS0-3 treatment. Furthermore, at harvest, the uniformity of dry matter accumulation and leaf area index (LAI) was reduced by 28.24 and 41.83%, respectively, relative to the DAS0-3 treatment. Correlation analysis reveals that the uniformity of kernel weight per ear is most significantly associated with yield, as indicated by a correlation coefficient of 0.90^**. The yield in the DAS0-3 treatment was significantly higher than that in the SI treatment by 23.71%. The yields of the DAS6-12 treatments were notably lower than those of the DAS0-3 treatment, ranging from 13.18 to 23.97% lower, and were comparable to the yields observed in the SI treatment. The suboptimal implementation of drip irrigation technology has prevented it from realizing its potential for increasing crop yields. Each day’s delay in initiating drip irrigation after the third day post-sowing reduces yield by an average of 0.32 Mg ha^-1. Timely drip irrigation following maize seeding significantly enhances emergence rate and population uniformity, increases the number of harvestable ears and kernel weight per ear, ultimately leading to higher final yields. Drip irrigation for seedling emergence within three days after sowing can better bring out the yield-increasing potential of drip irrigation.

Soil compaction has become a serious limitation for further increasing the grain yield of maize (Zea mays L.) in the North China Plain (NCP). However, considerable variability exists among maize hybrids in their grain yield responses to soil compaction. To understand the physiological processes related to the variation of responses among maize hybrids to different soil compaction levels, a two-year field experiment was conducted with 17 maize hybrids and three soil compaction treatments (NC, no compaction with soil bulk density (SBD) of 1.0–1.3 g cm^–3; MC, moderate compaction with SBD of 1.4–1.5 g cm^–3, and HC, heavy compaction with SBD>1.6 g cm^–3) to examine the root and shoot morphological traits, dry matter accumulation, and grain yield. Compared to NC, MC and HC significantly reduced the maize yield by 0.9–26.7% and 5.9–41.1% across the hybrids and years, respectively. Hybrids with high compaction tolerance (H) had greater grain yield than those with middle compaction tolerance (M) and low compaction tolerance (L), particularly under HC. The yield benefits obtained from the H hybrid were enhanced due to better root and shoot growth under HC conditions. Greater root length, root surface area, and root weight, as well as root activity, absorption capacity, and antioxidant capacity for H hybrid was found under HC conditions, and it also showed increased leaf area index and dry matter accumulation. Moreover, the increases in root growth indices for the H hybrid were greater than that of shoot growth, particularly under HC conditions, leading to a greater root/shoot ratio. We conclude that soil compaction impacts maize root and shoot growth differently depending on genotype, and the root growth advantages of the H hybrid were more obvious than shoot growth, which enhanced the yield benefits from the H hybrid under heavy compaction conditions.

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.

Maize (Zea mays L.) is a crucial global crop that serves as a primary source of food and feed. However, its kernels are susceptible to infection by Aspergillus flavus, a fungus known for producing aflatoxins - which are highly carcinogenic compounds harmful to human and animal health. Identifying quantitative trait loci (QTLs) for aflatoxin resistance and developing aflatoxin-resistant maize varieties are essential for mitigating aflatoxin contamination. In this study, a genome-wide association study (GWAS) using an enlarged genotypic panel of 311 maize inbred lines was used to identify genetic loci associated with A. flavus resistance. Phenotypic data on A. flavus resistance were collected through controlled inoculation experiments conducted under controlled conditions. The results revealed that the resistance to A. flavus follows a normal distribution. In addition, temperate inbreds exhibited stronger resistance to A. flavus than tropical/subtropical materials. This study identified 13 novel QTLs encompassing 47 highly expressed genes, with each QTL explaining 8.22–27.71% of the phenotypic variation, indicating that the higher marker density improved statistical power. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that these genes are related to fatty acid synthesis, glycoside decomposition, and root growth and development. One specific gene located on ZmAFR16, ZmFUC1, displayed clustered peaks and accounted for an average of 10.21% of the phenotypic variation. This gene was found to play a role in cell membrane formation and possess alpha-L-fucosidase activity, so it promotes glycoside metabolism and contributes to polysaccharide degradation. Haplotype analysis showed significant differences in resistance to A. flavus among the different haplotypes of elo1 and ZmFUC1. Inbreds carrying the favorable haplotype combination of these two genes exhibited strong resistance to A. flavus. A select sweep analysis indicated that ZmFUC1 was selected during the domestication of teosinte (Zea mays ssp. mexicana) to modern maize, as well as during the adaptation from tropical/subtropical maize to temperate maize. Importantly, this study developed molecular markers in the promoter region of ZmFUC1 to efficiently identify maize germplasm with beneficial haplotypes for resistance to A. flavus. These findings not only enhance our understanding of the genetic factors influencing maize kernel resistance to A. flavus but also offer valuable insights for improving existing germplasm and developing new maize varieties with enhanced resistance to this pathogen

Lysophosphatidic acid acyltransferase (LPAT) enzymes are widely expressed in various plant species, and they contribute to growth, development, and stress responses. Currently, information regarding the LPAT gene family in soybeans is limited. In this study, genome-wide analyses identified 15 soybean LPATs, which were then evaluated for their conserved protein motifs. These genes were grouped into three clusters based on their phylogenetic relationships. Confocal microscopy was used to visualize the localization of six GmLPATs within Arabidopsis mesophyll protoplasts. cis-Acting regulatory element analyses and qRT-PCR experiments revealed that these GmLPATs were upregulated in response to hormonal stimulation or exposure to abiotic stressors, including drought, alkaline conditions, and salt stress. The expression patterns of these GmLPATs varied among different soybean tissue types. One member of the solLPAT1 subtype (GmLPAT11) was found to be upregulated in response to a range of treatments, highlighting its role in soybean salt stress responses. GmLPAT11 expression in Escherichia coli confirmed the LPAT activity of this recombinant enzyme, and overexpressing this LPAT reduced reactive oxygen species production in transgenic soybean plants, thereby enhancing their salt stress tolerance. Gene association analyses indicated that GmLPAT11 variants are closely associated with seedling salt tolerance, and a polymorphism in the GmLPAT11 CDS region was potentially associated with salt tolerance. These results provide new insights into the nature of the LPAT gene family in soybeans while also identifying promising candidate genes for future research efforts to enhance the overall salt tolerance of soybean crops.

Rapeseed (Brassica napus L.) is one of the most important oilseed crops worldwide, and the development of rapeseed varieties with high-quality oil is a long-term breeding goal. Reducing the content of palmitic acid, the main saturated fatty acid in rapeseed oil, can greatly improve oil quality. Here, a genome-wide association study (GWAS) and transcriptome-wide association study (TWAS) of seed palmitic acid content (SPAC) were performed using 393 diverse B. napus accessions. Four genes (BnaA08.DAP, BnaA08.PAA1, BnaA08.DUF106, and BnaC03.DAP) were identified by both GWAS and TWAS. The transcripts per million (TPM) values of these candidate genes at 20 and 40 days after flowering (DAF) were significantly correlated with SPAC in this association panel. Based on genetic variation in the candidate genes, four low-SPAC haplotypes were identified by combining candidate gene association analysis and haplotype analysis. Brassica napus accessions carrying low-SPAC haplotypes had lower SPAC than those carrying high-SPAC haplotypes without affecting seed oil content, seed protein content, or seed yield. Based on the functional single-nucleotide polymorphism (SNP) chrA08_9529850 (C/A) in the promoter of BnaA08.DUF106, a molecular marker (Bn_A8_SPAC_Marker) was developed that can be used to facilitate breeding for low SPAC in B. napus. Our findings provide valuable information for studying the genetic control of SPAC in B. napus. Moreover, the candidate genes, favorable haplotypes, and molecular marker identified in this study will be useful for breeding low-SPAC B. napus varieties.