Search Results (756)

Since the molecular mechanisms underlying sex determination in Procambarus clarkii are still unclear, it is important to investigate the genetic basis of sex determination in crustaceans. Currently, the molecular mechanisms of sex determination and the gender-specific markers in this species remain poorly understood. In this study, a total of 14,046,984 SNPs and 2,160,652 InDels were identified through genome-wide resequencing of 89 individuals (45 females and 44 males). Further analysis confirmed that the candidate chromosome was Chr38, the sex determination system was identified as XY, and the sex determination region was located at Chr38: 6,000,000–21,100,000 bp. A pair of sex-specific molecular markers has been identified based on a 21 bp female-specific insertion within the candidate sex-determining region. Additionally, SOAT, NPC1, PTGS2, FANCD1, and VAlRS were identified as candidate sex-determining genes through the screening of candidate genes and RT-qPCR validation analysis. These findings provide a robust foundation for investigating sex-determining mechanisms in crustaceans. Through the integration of genome-wide association studies (GWAS), selection signals, and transcriptome analysis, we identified, for the first time, genes associated with sex determination, growth, and immunity. These genes represent promising candidates for further functional studies and genetic improvement in Procambarus clarkii. Full article

The basic/helix-loop-helix (bHLH) transcription factors are crucial regulators of plant development and stress responses. In this study, we conducted a genome-wide analysis of the bHLH family in Rosa roxburghii, an economically important fruit crop. A total of 89 non-redundant RrbHLHs were identified and unevenly distributed across the seven chromosomes. Phylogenetic analysis classified them into 23 subfamilies and 7 Arabidopsis subfamilies were absent, indicating lineage-specific evolutionary trajectories. Conserved motif and gene structure analyses showed that members within the same subfamily generally shared similar architectures, yet subfamily-specific variations were evident, suggesting potential functional diversification. Notably, key residues involved in DNA-binding and dimerization were highly conserved within the bHLH domain. Promoter analysis identified multiple cis-acting elements related to hormone response, stress adaptation, and tissue-specific regulation, hinting at broad regulatory roles. Expression profiling across fruit developmental stages and in response to GA₃ treatment revealed dynamic expression patterns. Furthermore, 21 duplicated gene pairs (17 segmental and 4 tandem duplicated pairs) were identified, with most evolving under purifying selection. Detailed analysis of these pairs revealed that segmental duplication, coupled with structural variations such as exon indels, dissolution/joining, and exonization/pseudoexonization, substantially contributed to their functional divergence during evolution. Our results provide a basis for understanding the evolution and potential functions of the RrbHLHs. Full article

Chromosome dynamics, recombination, and nucleolar organization intersect during meiotic prophase I, yet how the recombination context influences nucleolar architecture remains unclear. We analyzed the nucleolar pool of Cdc14 in Saccharomyces cerevisiae under matched prophase I gating and a uniform, frame-based operational definition of transient two-focus episodes. In a prophase-arrest reference, Cdc14–mCherry formed a predominant single nucleolar focus with occasional, reversible two-focus episodes that Nop56–GFP placed within the nucleolar compartment (nucleolar splitting). Splitting rose sharply when interhomolog recombination was compromised and remained elevated when Spo11 catalytic activity was abolished, indicating that increased DSB formation is not required and pointing instead to the homolog engagement state as a key variable. Population checkpoint readouts did not map onto the phenotype: Hop1 phosphorylation differed strongly across genotypes, yet splitting remained high in recombination-defective and DSB-free contexts and low in the reference. Timing analyses showed that events concentrated early and declined in the reference, whereas recombination-defective and DSB-free backgrounds retained activity into later windows across thresholds. We propose that nucleolar splitting reflects a rheological response of the nucleolus to chromosome-scale forces that vary with homolog engagement, consistent with contributions from DSB-independent chromosome dynamics such as telomere clustering, telomere-led rapid prophase movements, and centromere coupling/pairing. Together, these data support the nucleolus as a mesoscale, mechanically sensitive readout of meiotic chromosome dynamics. Full article

Tartary buckwheat has increasingly become the focus of people’s attention due to its powerful health benefits. Golden buckwheat is a traditional Chinese medicine. People have begun to utilize it through wide hybridization to further enhance the health benefits of Tartary buckwheat. To study the genetic stability of the interspecific hybrids of Tartary buckwheat with golden buckwheat, and to provide scientific basis for the interspecific cross breeding of buckwheat, the mitotic chromosomes of two buckwheat double lines and their interspecific hybrids with golden buckwheat were subjected to observe the karyotypes. The results showed as follows: (1) The two autotetraploid Tartary buckwheat lines (Long Black-4T and Daku-1) have chromosome number 2n = 32. The karyotype formula of 2n = 4x = 32 consisted of 16 pairs of metacentric chromosomes for Long Black-4T (TTTT) while Daku-1 (TTTT) has 1sm + 7m Gui Jinqiao 4 with 2n = 32 has a karyotype formula of 2n = 4x = 32 that consisted 1sm + 6m + 1M (genome M) and 2sm + 5m + 1M (genome M’). The normal fertile tetraploid hybrid F1 plants between Long Black-4T and Gui Jinqiao 4 has 2n = 4x = [1sm + 7m (M), 1sm + 7m (M’), 14m + 2M (TT)]. The normal fertile variety Gui Jinku 1 from the above hybrid progenies shows 2n = 4x = [3sm + 5m (M), 2sm + 6m (M’), 16m (TT)], indicating an increment of sm chromosomes by rearrangements of chromosome structure in the M and M’ genomes. The above parents and their hybrids with the MM’TT genome show fertility. A plant from F2 of the above cross, showing highly infertility, has 2n = 3x= [1sm + 7m (M), 1sm + 7m (M’), 8m (T)]; and back cross progeny plant from Daku 1/Gui Jinqiao 4 F2//Gui Jinqiao 2 golden buckwheat has 2n = 4x = [16m (MM), 5sm + 3m (M’), 1sm + 7m (T)], showed high infertility, which is caused by genome aneuploidy and non-even ploidy. The above shows that there are obvious variations of genome karyotypes from the same parent, indicated by certain chromosome structural rearrangements in genomes T, M, and M’. Full article

Bacillus velezensis strain G2T39 is an endophytic bacterium previously isolated from Crotalaria retusa L., with evidenced biocontrol activity against Fusarium oxysporum f. sp. Cubense and Fusarium graminearum. In this study, it was shown that this strain also exhibited biocontrol activity against Colletotrichum gloeosporioides and Fusarium oxysporum f. sp. Vasinfectum, two important crop pathogens in tropical zones. Comprehensive phylogenetic and genomic analyses were performed to further characterize this strain. The genome of B. velezensis G2T39 consists of a single circular chromosome of 4,040,830 base pairs, with an average guanine–cytosine (GC) content of 46.35%. Both whole-genome-based phylogeny and average nucleotide identity (ANI) confirmed its identity as B. velezensis, being closely related to biocontrol and plant growth promotion Gram-positive model strains such as B. velezensis FZB42. Whole-genome annotation revealed 216 carbohydrate-active enzymes and 14 gene clusters responsible for secondary metabolite production, including surfactin, macrolactin, bacillaene, fengycin, bacillibactin, bacilysin, and difficidin. Genes involved in plant defense mechanisms were also identified. Additionally, G2T39 genome harbors multiple plant growth-promoting traits, such as genes associated with nitrogen metabolism (nifU, nifS, nifB, fixB, glnK) and a putative phosphate metabolism system (phyC, pst glpQA, ugpB, ugpC). Additional genes linked to biofilm formation, zinc solubilization, stress tolerance, siderophore production and regulation, nitrate reduction, riboflavin and nicotinamide synthesis, lactate metabolism, and homeostasis of potassium and magnesium were also identified. These findings highlight the genetic basis underlying the biocontrol capacity and plant growth-promoting properties of B. velezensis G2T39 and support its potential application as a sustainable bioinoculant in agriculture. Full article

Distant hybridization between bread wheat (Triticum aestivum L.) and wild Aegilops species is a valuable approach to take to broaden genetic diversity, but it is frequently impeded by reproductive barriers. This study evaluated crossability, pollen tube dynamics, meiotic behavior, somatic chromosome numbers, and pollen fertility in twelve Kazakh wheat cultivars crossed with Ae. triaristata Willd., Ae. cylindrica Host, Ae. triuncialis L., and Ae. squarrosa L. under field-based controlled pollination. Hybridization success varied significantly among combinations, with Ae. triaristata showing the highest compatibility (26.0% in Bezostaya 1 × Ae. triaristata), while Ae. squarrosa produced the lowest seed set. In compatible crosses, pollen tubes reached the ovary within 20–30 min, whereas delayed elongation (>60 min) was associated with fertilization failure. Meiotic analysis revealed incomplete homologous pairing (3–7 bivalents per PMC) and high abnormality rates (>90%). Somatic chromosome counts (2n) of selected F₁ hybrids confirmed extensive aneuploidy and partial chromosome elimination. Pollen fertility was generally below 20%. These results identify Ae. triaristata as a promising donor species for pre-breeding in Kazakhstan and underscores the importance of integrating classical cytology with molecular approaches to overcome hybridization barriers. Full article

The Gretchen Hagen 3 (GH3) gene family, a key component of the early auxin-responsive gene family, plays a pivotal role in regulating plant growth, development, and stress responses. However, to date, a comprehensive genome-wide analysis of the GH3 gene family and its potential role in plant defense against viruses, such as tomato yellow leaf curl virus (TYLCV), has not been conducted in Nicotiana benthamiana. Here, the GH3 gene family was thoroughly examined in N. benthamiana using a comprehensive genome-wide bioinformatic approach. A total of 25 potential GH3 genes were discovered in N. benthamiana. Phylogenetic analysis classified these NbGH3s into three different clades. Chromosomal distribution and synteny analyses revealed that NbGH3s are unevenly distributed across 14 chromosomes, with 20 segmental and one tandem duplication pairs. Promoter analysis suggested their involvement in phytohormone signaling and stress responses. Quantitative PCR showed that several NbGH3s are transcriptionally responsive to TYLCV infection, with five of them significantly upregulated in infected leaves. Furthermore, virus-induced gene silencing revealed that the suppression of NbGH3-3 and NbGH3-9 markedly increased host susceptibility to TYLCV, underscoring their critical roles in plant antiviral defense mechanisms. This research establishes a framework for understanding the functions of NbGH3s in plant growth and their response to TYLCV infection. Full article

Cytochrome P450 (CYP450) monooxygenases are a class of enzymes containing conserved heme-binding functional domain. They contribute to a wide range of biosynthetic processes, serving a pivotal function in plant resistance to abiotic stress. To date, little is known about the CYP450s of Chlamydomonas reinhardtii. In our study, a total of 37 crP450 genes were identified from C. reinhardtii based on domain and sequence alignment, unevenly distributed on 12 chromosomes with 4 pairs of tandem replications shared among family members. Most of these genes contained 10 or more introns and encoded CYP450 proteins with an average of 593 amino acids and 3–9 conserved motifs. CYP450 enzymes were mainly distributed in the chloroplasts, cytoplasms, mitochondria, and cytoplasmic membranes. There were numerous light, jasmonic acid, abscisic acid, and salicylic acid response elements located in the upstream of gene coding sequences, suggesting that these genes could be modulated by plant hormones. Transcriptome analysis uncovered distinct expression patterns of crP450 genes under various stress conditions, with the 37 crP450 genes grouped into 9 clusters. In summary, this study presented a genome-wide characterization of CYP450 genes in C. reinhardtii, providing a strong foundation for further exploration into their biological functions. Full article

Background: Emerging evidence suggests that biological sex shapes glioma biology and therapeutic response. Methods: We performed a sex-stratified analysis of CGGA (Chinese Glioma Genome Atlas) RNA sequencing data comparing low-grade glioma (LGG) with high-grade glioma (HGG) and glioblastoma (GBM). Using the 3PodR framework, we integrated differential expression analysis with Gene Set Enrichment Analysis (GSEA), EnrichR, leading-edge analysis, and iLINCS drug repurposing. Results: These comparisons provide a proxy for biological processes underlying malignant transformation. In LGG vs. HGG, 973 significantly differentially expressed genes (DEGs) were identified in females and 1236 in males, with 15.5% and 33.5% unique to each sex, respectively. In LGG vs. GBM, 2011 DEGs were identified in females and 2537 in males, with 12.6% and 30.7% being unique. Gene-level contrasts included GLI1 upregulation in males and downregulation in females, GCGR upregulation in males, MYOD1 upregulation in females, and HIST1H2BH downregulation in males. Additional top DEGs included PRLHR, DGKK, DNMBP-AS1, HOXA9, CTB-1I21.1, RP11-47I22.1, HPSE2, SAA1, DLK1, H19, PLA2G2A, and PI3. In both sexes, LGG–HGG and LGG–GBM grade comparisons converged on neuronal and synaptic programs, with enrichment of glutamatergic receptor genes and postsynaptic modules, including GRIN2B, GRIN2A, GRIN2C, GRIN1, and CHRNA7. In contrast, collateral pathways diverged by sex: females showed downregulation of mitotic and chromosome-segregation programs, whereas males showed reduction of extracellular matrix and immune-interaction pathways. Perturbagen analysis nominated signature-reversing compounds across sexes, including histone deacetylase inhibitors, Aurora kinase inhibitors, microtubule-targeting agents such as vindesine, and multi-kinase inhibitors targeting VEGFR, PDGFR, FLT3, PI3K, and MTOR. Conclusions: Glioma grade comparisons reveal a shared neuronal–synaptic program accompanied by sex-specific transcriptional remodeling. These findings support sex-aware therapeutic strategies that pair modulation of neuron–glioma coupling with chromatin- or receptor tyrosine kinase/angiogenic-targeted agents, and they nominate biomarkers such as GLI1, MYOD1, GCGR, PRLHR, and HIST1H2BH for near-term validation. Full article

Gene conversion contributes to gene copy number changes, DNA mutations, and functional innovation and has been widely reported in three domains of life. However, it has hardly been described in Aspergillus, including industrially and commercially important or pathogenic fungi. Here, we revealed multiple sets of homologous genes located in a region of chromosome 1 of A. flavus, and its orthologous counterpart of A. oryzae. Phylogenetic analysis showed evidence of frequent gene (DNA) conversion between ectopic paralogs in each species, accompanied by prominent point mutations and DNA deletion (from several to hundreds of base pairs). At least two independent cases showed that the converted genes in A. oryzae have been repeatedly split into shorter genes by the introduction of stop codons, and then ectopic conversion rendered paralogous genes (regions) to have the same configuration of tandemly located new genes. Inference of nucleotide substitution and ancestral gene content showed that the conversion-affected regions have seen 3.48 times as many substitutions and 4–6 times as many gene losses compared to the non-affected regions. We predicted that a DNA loop between proximal regions, in the common ancestor and inherited by each species, facilitates ectopic gene (DNA) conversion and elevated rates of mutations and losses. Overall, we found that gene conversion proves to be a key factor resulting in genome instability, elevated gene evolutionary rates, and an effective avenue to produce new genes, likely leading to the speciation of two Aspergillus lineages. Full article

Protein phosphatase 2Cs (PP2Cs) constitute a widespread family of signaling regulators in plants and play central roles in abscisic acid (ABA)-mediated stress signaling; however, the PP2C gene family has not yet been systematically identified and characterized in pea (Pisum sativum), a salt-sensitive legume crop. In this study, we identified 89 PsPP2C genes based on domain features and sequence homology. These genes are unevenly distributed across seven chromosomes and classified into ten subfamilies, providing a comparative framework for evaluating structural and regulatory diversification within the PsPP2C family. The encoded proteins vary substantially in length, physicochemical properties, and predicted subcellular localization, while most members contain the conserved PP2Cc catalytic domain. Intra- and interspecies homology analyses identified 19 duplicated gene pairs in pea and numerous orthologous relationships with several model plants; all reliable gene pairs exhibited Ka/Ks < 1, indicating pervasive purifying selection. PsPP2C genes also showed broad variation in exon number and intron phase, and their promoter regions contained diverse light-, hormone-, and stress-related cis-elements with heterogeneous positional patterns. Expression profiling across 11 tissues revealed pronounced tissue-specific differences, with generally higher transcript abundance in roots and seeds than in other tissues. Under salt treatment, approximately 20% of PsPP2C genes displayed concentration- or time-dependent transcriptional changes. Among them, PsPP2C67 and PsPP2C82—both belonging to the clade A PP2C subfamily—exhibited the most pronounced induction under high salinity and at early stress stages. Functional annotation indicated that these two genes are involved in ABA-related processes, including regulation of abscisic acid-activated signaling pathway, plant hormone signal transduction, and MAPK signaling pathway-plant. Collectively, this study provides a systematic characterization of the PsPP2C gene family, including its structural features, evolutionary patterns, and transcriptional responses to salt stress, thereby establishing a foundation for future functional investigations. Full article

Background/Objectives: Sites of ribosomal RNA genes are the most widely documented regions of chromosomes in various groups of eukaryotes, including insects. Data on the number and chromosomal location of 45S rDNAs (25S, 5.8S, and 18S rDNA) are actively used to study the diversity of karyotypes, the organization of individual chromosomes, and the evolution of entire genomes. In true bugs (suborder Heteroptera), the number and chromosomal distribution of 18S rDNA loci are currently known for less than 0.5% of described species. Although some patterns of rDNA distribution can already be identified both in individual taxa of true bugs and in the suborder as a whole, there are still negligible data. In order to expand our understanding of the diversity of rDNA distribution in Heteroptera, we studied for the first time the location of 18S rDNA in 13 species from 13 genera (seven families) of the infraorders Cimicomorpha and Pentatomomorpha (=Terheteroptera, the terminal group of Heteroptera). Methods: Fluorescence in situ hybridization (FISH) with an 18S rDNA probe was used in our study. Results: In total, we have identified three main types of rDNA arrangement: (1) on autosomes, (2) on the X chromosome, and (3) on autosomes and on the X chromosome simultaneously. In most of the studied species, 18S rDNA loci were detected in the terminal position on one pair of autosomes. Conclusions: This study contributed to the understanding of the chromosomal distribution of rDNA loci in the infraorders Cimicomorpha and Pentatomomorpha and confirmed the importance of rDNA in the reorganization of the genomes of Heteroptera as a whole. Full article

The AGC kinase family is crucial for regulating plant disease resistance, integrating hormone signals, managing reactive oxygen species (ROS) metabolism, and maintaining redox balance. However, research on AGC kinases in Solanaceae plants is limited, and the functions of most AGC kinases remain unidentified. Using the tetraploid potato (Solanum tuberosum L.) cultivar ‘Tingsha No. 9’, we conducted a genome-wide identification of the AGC gene family and profiled transcript responses to late-blight (Phytophthora infestans) stress. Additionally, we examined the subcellular localization and characterized the phenotypic responses of overexpression lines of the late-blight–responsive kinase StD6PK under late-blight stress. A total of 141 AGC family members were identified in ‘Qingshu No. 9’, categorized into eight subfamilies. This classification includes one cultivar-specific subfamily that was previously unrecognized, as well as 50 AGC family members within subfamily 1. AGC family members had significant differences in physicochemical characteristics and most of which were located in the nucleus. AGC family members are distributed on 46 chromosomes, with the largest number of chromosome 11 and the least number of chromosome 7. Gene duplication is dominated by whole-genome duplication (WGD) and segmental duplication. Ka/Ks values of all collinear pairs are less than 1. Purification selection drives family evolution in a long evolutionary process. Its promoter is rich in light-responsive, hormone-responsive, and stress-responsive elements, and its expression varies significantly in tissues; and some genes are highly expressed in specific organs. RNA-seq analysis revealed that 78.1% of the members responded to late-blight stress, and the expression levels of the selected eight subfamily members all showed significant increases or decreases after inoculation with late blight. StD6PK (Soltu.Q9.Chr04_A40011450.g) was strongly induced at 48~72 h, and its expression level at 72 h was 5.7 times higher than that at 0 h. Stable transformation of potato demonstrated that overexpression of StD6PK could enhance the resistance of potato to late blight, with subcellular localization revealing its nuclear localization characteristic. This study was the first time to complete the identification of AGC family genome of tetraploid potato ‘Qingshu No. 9’, reveal its evolution and expression characteristics, clarify the response characteristics of StD6PK to late blight, and provide insights into the evolutionary and functional basis of the AGC kinase gene family in potato late blight resistance mechanisms, while supplying genetic resources to accelerate the development of late blight-resistant germplasm. Full article

The genus Dasypyrum represents a valuable source of beneficial traits for wheat improvement, yet the cytogenetic organization of its genomes, particularly of the satellite repeats, remains poorly understood. This study aimed through comparative analysis of satellite DNA in diploid D. villosum (W6 21717, V genome) and tetraploid D. breviaristatum (PI 516547, VV^b genomes) to reveal the evolutionary dynamics of their subgenomes and to identify species-specific chromosomal markers. We performed whole-genome sequencing, bioinformatic analysis, and fluorescence in situ hybridization (FISH). Bioinformatic screening identified 14 satellite repeats in the D. breviaristatum genome (CL9, CL95, CL100, CL110, CL127, CL133, CL134, CL135, CL147, CL153, CL165, CL169, CL173, and CL197), which were classified by copy number: one as high-copy (CL9, ≥0.6%) and the rest as low-copy (<0.29%). Their monomer sizes ranged broadly from 118 to 1118 base pairs. Most repeats showed varying degrees of homology with known sequences from the Triticeae family, and one repeat, CL165, had no detectable homologs in existing databases. FISH analysis subdivided repeats into three groups: predominantly terminal (CL100, CL110, CL134, CL135, CL147, CL165, CL169, CL173, and CL197), pericentromeric (CL127 and CL133), and mixed localization (CL9). Significant species-specific differences were revealed, including emergence of tetraploid-specific repeats (CL110, CL134, CL135, CL147, CL165, and CL173) and the reorganization of conserved sequence distribution. Notably, the repeat CL135 was identified as a specific marker for the V subgenome within the allopolyploid D. breviaristatum. The obtained data support the allopolyploid origin of D. breviaristatum and demonstrate that these two species are genetically distinct but evolutionarily closely related. Chromosomal markers developed based on newly discovered satellite repeats open new avenues for investigating genomic architecture and evolutionary relationships within the genus Dasypyrum, as well as for identifying its chromatin in distant hybrids. Full article

The family Sisyridae, the Spongilla-flies, is notable for its phylogenetic position as a basal group within Neuroptera. Using the improved Schiff-Giemsa method, we analyzed the behavior of the sex chromosomes X and Y during male meiosis in Sisyra nigra (Retzius 1738). The diploid chromosome number in males was 2n = 12 + XY. In pachytene, X and Y chromosomes appeared positively heteropycnotic and loosely paired. In early diakinetic nuclei, autosomal bivalents typically exhibited one distally located chiasma, although bivalents with two chiasmata were occasionally observed. The X and Y univalents were isopycnotic with the autosomes, with the X considerably larger than the Y. During the first meiotic division, metaphase plates were radial, with autosomal bivalents forming a ring and X and Y univalents positioned centrally, well separated from each other. In metaphase cells, X and Y were located at the equator, strongly indicating their amphitelic orientation. However, they later formed a pseudobivalent from which X and Y segregated simultaneously with autosomal half bivalents at anaphase I. This achiasmatic segregation mechanism, touch-and-go pairing, has now been observed for the first time in a species carrying chromosomes with a localized centromere. At the second metaphase, two cell types were observed: one with the X chromosome and the other with the Y chromosome. The behavior of the sex chromosomes in S. nigra is notably different from that in other Neuroptera, where sex chromosomes exhibit syntelic orientation and distance pairing at metaphase I. The unusual mechanism of sex chromosome segregation in the family Sisyridae aligns well with molecular phylogenetic findings concerning the family’s basal position within the order Neuroptera. Full article