Gene Lineages Research Articles

Abstract 4141486: Site-Specific Transcriptomic Patterns and Cell Types Associated with Hypertension

Introduction: The biology of early human hypertensive heart disease (HHD) is largely unexplored due to limited cardiac tissue access. Site-specific transcriptomics of human cardiac tissue before development of overt HHD offers a unique vantage to understand the biology of HHD in human cardiac tissue. Hypothesis: We hypothesize that transcriptomic signatures and cell subtype proportions differ in human heart tissue from HTN donors compared to normotensive (NTN) donors in a site-specific manner. Methods: We performed bulk RNA-seq on rRNA-depleted libraries from left (LV) and right (RV) mid-ventricular-wall tissue (average depth 114 million reads/sample) collected postmortem from HTN (n=3, 67% Black/Latinx) and NTN (n=2, 50% Black/Latinx) donors. We performed single-nucleus RNA-seq (snRNA-Seq) on cardiac tissue from the same donors (average of 4,062 LV nuclei). Differential gene expression, lineage identification, and Gene Set Enrichment Analysis (GSEA) were performed with publicly available software. Results: All donors were female with matched postmortem intervals (time from death to tissue preservation; HTN 19±9 hours, NTN 18±6 hours). HTN donors were older (65±7 years) than NTN donors (36±16 years). A total of 416 genes were associated with HTN (Wald test, FDR q <0.05) across both ventricles (correcting for site). When tested separately, 72 (LV) or 83 (RV) genes were associated with HTN (FDR q <0.05), with 13 common genes, indicating site-specific differences. GSEA of genes ranked by Wald statistic computed across both ventricles showed that transcripts involved in single-stranded DNA helicase activity, branched-chain amino acid catabolism, and NAD-dependent deacetylase activity were coordinately associated with HTN (FDR q <0.05). snRNA-seq revealed 9 cell types in these samples, including immune cells and chamber-specific cardiomyocytes (CMs) with higher proportions of LV CMs and lymphocytes associated with HTN compared to NTN. MYH6 and MYL7 expression was unchanged with respect to HTN by RNA-seq but lower in LV HTN CMs compared to NTN by snRNA-seq, suggesting dysregulation of contractile programming in HTN LV CMs. Conclusion: HTN is associated with altered cardiomyocyte/lymphocyte ratios, and site-specific differential expression of cardiac contractile elements. Further study is required to validate these findings with additional samples and elucidate mechanisms driving transcriptional program differences in the hypertensive human heart.

BPDCN MYB fusions regulate cell cycle genes, impair differentiation and induce myeloid-dendritic cell leukemia.

MYB fusions are recurrently found in select cancers, including blastic plasmacytoid dendritic cell neoplasm (BPDCN), an acute leukemia with poor prognosis. They are markedly enriched in BPDCN compared to other blood cancers, and in some patients are the only obvious somatic mutation detected. This suggests they may alone be sufficient to drive dendritic cell transformation. MYB fusions are hypothesized to alter the normal transcription factor activity of MYB, but mechanistically how they promote leukemogenesis is poorly understood. Using CUT&RUN chromatin profiling, we found that in BPDCN leukemogenesis, MYB switches from being a regulator of dendritic cell lineage genes to aberrantly regulating G2/M cell cycle control genes. MYB fusions found in BPDCN patients increased the magnitude of DNA binding at these locations, and this was linked to BPDCN-associated gene expression changes. Furthermore, expression of MYB fusions in vivo impaired dendritic cell differentiation and induced transformation to generate a mouse model of myeloid-dendritic acute leukemia. Therapeutically, we present evidence that all-trans retinoic acid (ATRA) may cause loss of MYB protein and cell death in BPDCN.

Whole-Genome Analysis of Stress Resistance-Related Genes in Listeria monocytogenes

Listeria monocytogenes is a crucial foodborne pathogen with significant public health implications. This study analyzed whole-genome sequences (WGS) of L. monocytogenes strains from public databases, examining associations between resistance genes, lineage, strain type, isolation source, and geography. Results revealed that after eliminating duplicates and strains with incomplete WGS, a total of 316 strains were deemed suitable for subsequent analyses. Within these strains, lineages I and II were extensively distributed, predominantly isolated from clinical and food sources. 56.65% of these strains fell into seven major Clonal Complexes (CC), identified by Multilocus Sequence Typing (MLST), correlating significantly with isolation information. Analysis of 46 resistance-related genes showed a high consistency of resistance genes in the same type of strains, hinting at a potential causal chain of ‘food-food environment-evolution of L. monocytogenes’. Moreover, the standard strains exhibit similar gene carriage rates as the sample strains, with multiple variations observed in acid-resistance genes. In conclusion, through a comprehensive analysis of the L. monocytogenes genome sequences, this study deepens our understanding of the differences and associations between its lineage, strain typing, isolation sources, geographical distribution, and resistance genes, thereby providing a scientific basis for formulating more effective prevention and control strategies.

Distinct H3K9me3 heterochromatin maintenance dynamics govern different gene programmes and repeats in pluripotent cells.

H3K9me3 heterochromatin, established by lysine methyltransferases (KMTs) and compacted by heterochromatin protein 1 (HP1) isoforms, represses alternative lineage genes and DNA repeats. Our understanding of H3K9me3 heterochromatin stability is presently limited to individual domains and DNA repeats. Here we engineered Suv39h2-knockout mouse embryonic stem cells to degrade remaining two H3K9me3 KMTs within 1 hour and found that both passive dilution and active removal contribute to H3K9me3 decay within 12-24 hours. We discovered four different H3K9me3 decay rates across the genome and chromatin features and transcription factor binding patterns that predict the stability classes. A 'binary switch' governs heterochromatin compaction, with HP1 rapidly dissociating from heterochromatin upon KMT depletion and a particular threshold level of HP1 limiting pioneer factor binding, chromatin opening and exit from pluripotency within 12 h. Unexpectedly, receding H3K9me3 domains unearth residual HP1β peaks enriched with heterochromatin-inducing proteins. Our findings reveal distinct H3K9me3 heterochromatin maintenance dynamics governing gene networks and repeats that together safeguard pluripotency.

Genomes of Microtus rodents highlight the importance of olfactory and immune systems in their fast radiation.

The characterization of genes and biological functions underlying functional diversification and the formation of species is a major goal of evolutionary biology. In this study, we investigated the fast radiation of Microtus voles, one of the most speciose group of mammals, which shows strong genetic divergence despite few readily observable morphological differences. We produced an annotated reference genome for the common vole, Microtus arvalis, and resequenced the genomes of 10 different species and evolutionary lineages spanning the Microtus speciation continuum. Our full genome sequences illustrate the recent and fast diversification of this group, and we identified genes in highly divergent genomic windows that have likely particular roles in their radiation. We found three biological functions enriched for highly divergent genes in most Microtus species and lineages: olfaction, immunity and metabolism. In particular, olfaction-related genes (mostly olfactory receptors and vomeronasal receptors) are fast evolving in all Microtus species indicating the exceptional importance of the olfactory system in the evolution of these rodents. Of note is e.g. the shared signature among vole species on Olfr1019 which has been associated with fear responses against predator odours in rodents. Our analyses provide a genome-wide basis for the further characterization of the ecological factors and processes of natural and sexual selection that have contributed to the fast radiation of Microtus voles.

Mapping lineage-traced cells across time points with moslin

Simultaneous profiling of single-cell gene expression and lineage history holds enormous potential for studying cellular decision-making. Recent computational approaches combine both modalities into cellular trajectories; however, they cannot make use of all available lineage information in destructive time-series experiments. Here, we present moslin, a Gromov-Wasserstein-based model to couple cellular profiles across time points based on lineage and gene expression information. We validate our approach in simulations and demonstrate on Caenorhabditis elegans embryonic development how moslin predicts fate probabilities and putative decision driver genes. Finally, we use moslin to delineate lineage relationships among transiently activated fibroblast states during zebrafish heart regeneration.

Does time matter? Intraspecific diversity of ribosomal RNA genes in lineages of the allopolyploid model grass Brachypodium hybridum with different evolutionary ages

BackgroundPolyploidisation often results in genome rearrangements that may involve changes in both the single-copy sequences and the repetitive genome fraction. In this study, we performed a comprehensive comparative analysis of repetitive DNA, with a particular focus on ribosomal DNA (rDNA), in Brachypodium hybridum (2n = 4x = 30, subgenome composition DDSS), an allotetraploid resulting from a natural cross between two diploid species that resemble the modern B. distachyon (2n = 10; DD) and B. stacei (2n = 20; SS). Taking advantage of the recurrent origin of B. hybridum, we investigated two genotypes, Bhyb26 and ABR113, differing markedly in their evolutionary age (1.4 and 0.14 Mya, respectively) and which resulted from opposite cross directions. To identify the origin of rDNA loci we employed cytogenetic and molecular methods (FISH, gCAPS and Southern hybridisation), phylogenetic and genomic approaches.ResultsUnlike the general maintenance of doubled gene dosage in B. hybridum, the rRNA genes showed a remarkable tendency towards diploidisation at both locus and unit levels. While the partial elimination of 35S rDNA units occurred in the younger ABR113 lineage, unidirectional elimination of the entire locus was observed in the older Bhyb26 lineage. Additionally, a novel 5S rDNA family was amplified in Bhyb26 replacing the parental units. The 35S and 5S rDNA units were preferentially eliminated from the S- and D-subgenome, respectively. Thus, in the more ancient B. hybridum lineage, Bhyb26, 5S and 35S rRNA genes are likely expressed from different subgenomes, highlighting the complexity of polyploid regulatory networks.ConclusionComparative analyses between two B. hybridum lineages of distinct evolutionary ages revealed that although the recent lineage ABR113 exhibited an additive pattern of rDNA loci distribution, the ancient lineage Bhyb26 demonstrated a pronounced tendency toward diploidisation manifested by the reduction in the number of both 35S and 5S loci. In conclusion, the age of the allopolyploid appears to be a decisive factor in rDNA turnover in B. hybridum.

Myelination potential and injury susceptibility of grey versus white matter human oligodendrocytes.

Increasing evidence indicates heterogeneity in functional and molecular properties of oligodendrocyte lineage cells both during development and under pathologic conditions. In multiple sclerosis, remyelination of grey matter lesions exceeds that in white matter. Here we used cells derived from grey matter versus white matter regions of surgically resected human brain tissue samples, to compare the capacities of human A2B5-positive progenitor cells and mature oligodendrocytes to ensheath synthetic nanofibers, and relate differences to the molecular profiles of these cells. For both cell types, the percentage of ensheathing cells was greater for grey matter versus white matter cells. For both grey matter and white matter samples, the percentage of cells ensheathing nanofibers was greater for A2B5-positive cells versus mature oligodendrocytes. Grey matter A2B5-positive cells were more susceptible than white matter A2B5-positive cells to injury induced by metabolic insults. Bulk RNA sequencing indicated that separation by cell type (A2B5-positive vs mature oligodendrocytes) is more significant than by region but segregation for each cell type by region is apparent. Molecular features of grey matter versus white matter derived A2B5-positive and mature oligodendrocytes were lower expression of mature oligodendrocyte genes and increased expression of early oligodendrocyte lineage genes. Genes and pathways with increased expression in grey matter derived cells with relevance for myelination included those related to responses to external environment, cell-cell communication, cell migration, and cell adhesion. Immune and cell death related genes were up-regulated in grey matter derived cells. We observed a significant number of up-regulated genes shared between the stress/injury and myelination processes, providing a basis for these features. In contrast to oligodendrocyte lineage cells, no functional or molecular heterogeneity was detected in microglia maintained in vitro, likely reflecting the plasticity of these cells ex vivo. The combined functional and molecular data indicate that grey matter human oligodendrocytes have increased intrinsic capacity to myelinate but also increased injury susceptibility, in part reflecting their being at a stage earlier in the oligodendrocyte lineage.

Palaeognaths Reveal Evolutionary Ancestry of the Avian Major Histocompatibility Complex Class II.

The multigene family of the major histocompatibility complex (MHC) codes for the key antigen-presenting molecules of the vertebrate immune system. In birds, duplicated MHC class II (MHC-II) genes are highly homogenized by concerted evolution, and thus, identification of their orthologous relationships across long evolutionary timescales remains challenging. Relatively low evolutionary rate of avian MHC class IIA genes has been expected to provide a promising avenue to allow such inferences, but availability of MHC-IIA sequences in nonmodel bird species has been limited until recently. Here, taking advantage from accumulating genomic resources, we identified and analyzed MHC-IIA sequences from the most basal lineage of extant birds (Palaeognathae). Conserved region of the MHC-IIA membrane-proximal domain was used to search for orthologous relationships between palaeognath birds and nonavian reptiles. First, analyses of palaeognath sequences revealed the presence of a separate MHC-IIA gene lineage (DAA3) in kiwis, which did not cluster with previously described avian MHC-IIA lineages (DAA1 and DAA2). Next, phylogenetic reconstruction showed that kiwi DAA3 sequences form a single well-supported cluster with turtle MHC-IIA. High similarity of these sequences most likely reflects their remarkable evolutionary conservation and retention of ancient orthologous relationships, which can be traced back to basal archosauromorphs ca. 250 million years ago. Our analyses offer novel insights into macroevolutionary history of the MHC and reinforce the view that rapid accumulation of high-quality genome assemblies across divergent nonmodel species can substantially advance our understanding of gene evolution.

YY1 knockout in pro-B cells impairs lineage commitment, enabling unusual hematopoietic lineage plasticity.

During B-cell development, cells progress through multiple developmental stages, with the pro-B-cell stage defining commitment to the B-cell lineage. YY1 is a ubiquitous transcription factor that is capable of both activation and repression functions. We found here that knockout of YY1 at the pro-B-cell stage eliminates B lineage commitment. YY1 knockout pro-B cells can generate T lineage cells in vitro using the OP9-DL4 feeder system and in vivo after injection into sublethally irradiated Rag1-/- mice. These T lineage-like cells lose their B lineage transcript profile and gain a T-cell lineage profile. Single-cell RNA-seq experiments showed that as YY1 knockout pro-B cells transition into T lineage cells in vitro, various cell clusters adopt transcript profiles representing a multiplicity of hematopoietic lineages, indicating unusual lineage plasticity. In addition, YY1 KO pro-B cells in vivo can give rise to other hematopoietic lineages in vivo. Evaluation of RNA-seq, scRNA-seq, ChIP-seq, and scATAC-seq data indicates that YY1 controls numerous chromatin-modifying proteins leading to increased accessibility of alternative lineage genes in YY1 knockout pro-B cells. Given the ubiquitous nature of YY1 and its dual activation and repression functions, YY1 may regulate commitment in multiple cell lineages.

Identification of drug resistance-related virulence gene mutations in 667 clinical Mycobacterium tuberculosis isolates.

Drug-resistant tuberculosis is a severe global public health threat. Virulence factors and antibiotic resistance are generally considered to play a significant role in bacterial pathogenesis. However, the interaction between resistance and virulence in Mycobacterium tuberculosis (MTB) remains unclear. Here, we used whole genome sequences from 667 MTB isolates from 14 countries to complete an in silico evaluation of the correlations between virulence gene mutations, drug resistance, and lineage classification. The chi-square (χ2) test was used to determine whether specific virulence gene mutations and drug resistance were related. Our results showed that Mce1R_G171R and Pks15_V333A, were positively correlated with streptomycin and ethambutol resistance, respectively, and Pks15_T46I was correlated with isoniazid, rifampin, ethambutol, pyrazinamide and streptomycin resistance. We also identified an additional 24 and 40 single nucleotide polymorphisms as well as 6 and 2 insertions or deletions in various virulence genes that are likely to be associated with changes in drug susceptibility in L2 and L4, respectively. Taken together our data suggest that there may be some degree of co-selection between virulence and resistance factors, which may help MTB more easily adapt to new environments.

Untangling the colonization history of the Australo-Pacific reed warblers, one of the world's great island radiations.

Island radiations, such as those of the Australo-Pacific, offer unique insight into diversification, extinction, and early speciation processes. Yet, their speciation and colonization histories are often obscured by conflicting genomic signals from incomplete lineage sorting or hybridization. Here, we integrated mitogenomes and genome-wide SNPs to unravel the evolutionary history of one of the world's most geographically widespread island radiations. The Australo-Pacific reed warblers (Acrocephalus luscinius complex) are a speciose lineage including five species that have become extinct since the 19th century and ten additional species of conservation concern. The radiation spans over 10,000 km across Australo-Papua, Micronesia and Polynesia, including the Mariana, Hawaii and Pitcairn Island archipelagos. Earlier mtDNA studies suggested a stepping-stone colonization process, resulting in archipelago-level secondary sympatry of divergent mtDNA lineages in the Mariana Islands and Marquesas. These studies hypothesised that morphologically similar species on neighbouring islands arose from ecological convergence. Using hDNA from historical museum specimens and modern genetic samples, we show that incomplete lineage sorting and/or gene flow have shaped the radiation of Australo-Pacific reed warblers rather than secondary sympatry. The nuclear genome reconstructs a simpler biogeographic history than mtDNA, showing close relationships between species in the Mariana Islands and Marquesas despite their paraphyletic mtDNA lineages. Gene flow likely involved early and late colonizing waves of the radiation before the loss of ancestral dispersive ability. Our results highlight how collection genomics can elucidate evolutionary history and inform conservation efforts for threatened species.

Distinct H3K9me3 heterochromatin maintenance dynamics govern different gene programs and repeats in pluripotent cells.

H3K9me3-heterochromatin, established by lysine methyltransferases (KMTs) and compacted by HP1 isoforms, represses alternative lineage genes and DNA repeats. Our understanding of H3K9me3-heterochromatin stability is presently limited to individual domains and DNA repeats. We engineered Suv39h2 KO mouse embryonic stem cells to degrade remaining two H3K9me3-KMTs within one hour and found that both passive dilution and active removal contribute to H3K9me3 decay within 12-24 hours. We discovered four different H3K9me3 decay rates across the genome and chromatin features and transcription factor binding patterns that predict the stability classes. A "binary switch" governs heterochromatin compaction, with HP1 rapidly dissociating from heterochromatin upon KMTs' depletion and a particular threshold level of HP1 limiting pioneer factor binding, chromatin opening, and exit from pluripotency within 12 hr. Unexpectedly, receding H3K9me3 domains unearth residual HP1β peaks enriched with heterochromatin-inducing proteins. Our findings reveal distinct H3K9me3-heterochromatin maintenance dynamics governing gene networks and repeats that together safeguard pluripotency.

Distinct dynamics of parental 5-hydroxymethylcytosine during human preimplantation development regulate early lineage gene expression

The conversion of DNA 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) by TET enzymes represents a significant epigenetic modification, yet its role in early human embryos remains largely unknown. Here we showed that the early human embryo inherited a significant amount of 5hmCs from an oocyte, which unexpectedly underwent de novo hydroxymethylation during its growth. Furthermore, the generation of 5hmC in the paternal genome after fertilization roughly followed the maternal pattern, which was linked to DNA methylation dynamics and regions of sustained methylation. The 5hmCs persisted until the eight-cell stage and exhibited high enrichment at OTX2 binding sites, whereas knockdown of OTX2 in human embryos compromised the expression of early lineage genes. Specifically, the depletion of 5hmC affected the activation of embryonic genes, which was further evaluated by ectopically expressing mouse Tet3 in human early embryos. These findings revealed distinct dynamics of 5hmC and unravelled its multifaceted functions in early human embryonic development.

Genomic and Transcriptomic Insights into the Evolution of C4 Photosynthesis in Grasses.

C4 photosynthesis has independently evolved over 62 times within 19 angiosperm families. The recurrent evolution of C4 photosynthesis appears to contradict the complex anatomical and biochemical modifications required for the transition from C3 to C4 photosynthesis. In this study, we conducted an integrated analysis of genomics and transcriptomics to elucidate the molecular underpinnings of convergent C4 evolution in the grass family. Our genome-wide exploration of C4-related gene families suggests that the expansion of these gene families may have played an important role in facilitating C4 evolution in the grass family. A phylogenomic synteny network analysis uncovered the emergence of C4 genes in various C4 grass lineages from a common ancestral gene pool. Moreover, through a comparison between non-C4 and C4 PEPCs, we pinpointed 14 amino acid sites exhibiting parallel adaptations. These adaptations, occurring post the BEP-PACMAD divergence, shed light on why all C4 origins in grasses are confined to the PACMAD clade. Furthermore, our study revealed that the ancestor of Chloridoideae grasses possessed a more favorable molecular preadaptation for C4 functions compared to the ancestor of Panicoideae grasses. This molecular preadaptation potentially explains why C4 photosynthesis evolved earlier in Chloridoideae than in Panicoideae and why the C3-to-C4 transition occurred once in Chloridoideae but multiple times in Panicoideae. Additionally, we found that C4 genes share similar cis-elements across independent C4 lineages. Notably, NAD-ME subtype grasses may have retained the ancestral regulatory machinery of the C4 NADP-ME gene, while NADP-ME subtype grasses might have undergone unique cis-element modifications.

A Retinoic Acid:YAP1 signaling axis controls atrial lineage commitment.

Vitamin A/Retinoic Acid (Vit A/RA) signaling is essential for heart development. In cardiac progenitor cells (CPCs), RA signaling induces the expression of atrial lineage genes while repressing ventricular genes, thereby promoting the acquisition of an atrial cardiomyocyte cell fate. To achieve this, RA coordinates a complex regulatory network of downstream effectors that is not fully identified. To address this gap, we applied a functional genomics approach (i.e scRNAseq and snATACseq) to untreated and RA-treated human embryonic stem cells (hESCs)-derived CPCs. Unbiased analysis revealed that the Hippo effectors YAP1 and TEAD4 are integrated with the atrial transcription factor enhancer network, and that YAP1 is necessary for activation of RA-enhancers in CPCs. Furthermore, in vivo analysis of control and conditionally YAP1 KO mouse embryos (Sox2-cre) revealed that the expression of atrial lineage genes, such as NR2F2, is compromised by YAP1 deletion in the CPCs of the second heart field. Accordingly, we found that YAP1 is required for the formation of an atrial chamber but is dispensable for the formation of a ventricle, in hESC-derived patterned cardiac organoids. Overall, our findings revealed that YAP1 is a non-canonical effector of RA signaling essential for the acquisition of atrial lineages during cardiogenesis.

GATA6 regulates WNT and BMP programs to pattern precardiac mesoderm during the earliest stages of human cardiogenesis.

Haploinsufficiency for GATA6 is associated with congenital heart disease (CHD) with variable comorbidity of pancreatic or diaphragm defects, although the etiology of disease is not well understood. Here, we used cardiac directed differentiation from human embryonic stem cells (hESCs) as a platform to study GATA6 function during early cardiogenesis. GATA6 loss-of-function hESCs had a profound impairment in cardiac progenitor cell (CPC) specification and cardiomyocyte (CM) generation due to early defects during the mesendoderm and lateral mesoderm patterning stages. Profiling by RNA-seq and CUT&RUN identified genes of the WNT and BMP programs regulated by GATA6 during early mesoderm patterning. Furthermore, interactome analysis detected GATA6 binding with developmental transcription factors and chromatin remodelers suggesting cooperative regulation of cardiac lineage gene accessibility. We show that modulating WNT and BMP inputs during the first 48 hours of cardiac differentiation is sufficient to partially rescue CPC and CM defects in GATA6 heterozygous and homozygous mutant hESCs. This study provides evidence of the regulatory functions for GATA6 directing human precardiac mesoderm patterning during the earliest stages of cardiogenesis to further our understanding of haploinsufficiency causing CHD and the co-occurrence of cardiac and other organ defects caused by human GATA6 mutations.

Genetic Reassortment in a Child Coinfected with Two Influenza B Viruses, B/Yamagata Lineage and B/Victoria-Lineage Strains.

We identified a child coinfected with influenza B viruses of B/Yamagata and B/Victoria lineages, in whom we analyzed the occurrence of genetic reassortment. Plaque purification was performed using a throat swab specimen from a 9-year-old child, resulting in 34 well-isolated plaques. The genomic composition of eight gene segments (HA, NA, PB1, PB2, PA, NP, M, and NS genes) for each plaque was determined at the lineage level. Of the 34 plaques, 21 (61.8%) had B/Phuket/3073/2013 (B/Yamagata)-like sequences in all gene segments, while the other 13 (38.2%) were reassortants with B/Texas/02/2013 (B/Victoria)-like sequences in 1-5 of the 8 segments. The PB1 segment had the most B/Victoria lineage genes (23.5%; 8 of 34 plaques), while PB2 and PA had the least (2.9%; 1 of 34 plaques). Reassortants with B/Victoria lineage genes in 2-5 segments showed the same level of growth as viruses with B/Yamagata lineage genes in all segments. However, reassortants with B/Victoria lineage genes only in the NA, PB1, NP, or NS segments exhibited reduced or undetectable growth. We demonstrated that various gene reassortments occurred in a child. These results suggest that simultaneous outbreaks of two influenza B virus lineages increase genetic diversity and could promote the emergence of new epidemic strains.

The MYB family and their response to abiotic stress in ginger (Zingiber officinale Roscoe)

BackgroundZingiber officinale Roscoe, colloquially known as ginger, is a crop of significant medicinal and culinary value that frequently encounters adversity stemming from inhospitable environmental conditions. The MYB transcription factors have garnered recognition for their pivotal role in orchestrating a multitude of plant biological pathways. Nevertheless, the enumeration and characterization of the MYBs within Z. officinale Roscoe remains unknown. This study embarks on a genome-wide scrutiny of the MYB gene lineage in ginger, with the aim of cataloging all ZoMYB genes implicated in the biosynthesis of gingerols and curcuminoids, and elucidating their potential regulatory mechanisms in counteracting abiotic stress, thereby influencing ginger growth and development.ResultsIn this study, we identified an MYB gene family comprising 231 members in ginger genome. This ensemble comprises 74 singular-repeat MYBs (1R-MYB), 156 double-repeat MYBs (R2R3-MYB), and a solitary triple-repeat MYB (R1R2R3-MYB). Moreover, a comprehensive analysis encompassing the sequence features, conserved protein motifs, phylogenetic relationships, chromosome location, and gene duplication events of the ZoMYBs was conducted. We classified ZoMYBs into 37 groups, congruent with the number of conserved domains and gene structure analysis. Additionally, the expression profiles of ZoMYBs during development and under various stresses, including ABA, cold, drought, heat, and salt, were investigated in ginger utilizing both RNA-seq data and qRT-PCR analysis.ConclusionThis work provides a comprehensive understanding of the MYB family in ginger and lays the foundation for the future investigation of the potential functions of ZoMYB genes in ginger growth, development and abiotic stress tolerance of ginger.

Genome-wide characterization of the NBLRR gene family provides evolutionary and functional insights into blast resistance in pearl millet (Cenchrusamericanus (L.) Morrone).

The investigation is the first report on genome-wide identification and characterization of NBLRR genes in pearl millet. We have shown the role of gene loss and purifying selection in the divergence of NBLRRs in Poaceae lineage and candidate CaNBLRR genes for resistance to Magnaporthe grisea infection. Plants have evolved multiple integral mechanisms to counteract the pathogens' infection, among which plant immunity through NBLRR (nucleotide-binding site, leucine-rich repeat) genes is at the forefront. The genome-wide mining in pearl millet (Cenchrus americanus (L.) Morrone) revealed 146 CaNBLRRs. The variation in the branch length of NBLRRs showed the dynamic nature of NBLRRs in response to evolving pathogen races. The orthology of NBLRRs showed a predominance of many-to-one orthologs, indicating the divergence of NBLRRs in the pearl millet lineage mainly through gene loss events followed by gene gain through single-copy duplications. Further, the purifying selection (Ka/Ks < 1) shaped the expansion of NBLRRs within the lineage of pear millet and other members of Poaceae. Presence of cis-acting elements, viz. TCA element, G-box, MYB, SARE, ABRE and conserved motifs annotated with P-loop, kinase 2, RNBS-A, RNBS-D, GLPL, MHD, Rx-CC and LRR suggests their putative role in disease resistance and stress regulation. The qRT-PCR analysis in pearl millet lines showing contrasting responses to Magnaporthe grisea infection identified CaNBLRR20, CaNBLRR33, CaNBLRR46 CaNBLRR51, CaNBLRR78 and CaNBLRR146 as putative candidates. Molecular docking showed the involvement of three and two amino acid residues of LRR domains forming hydrogen bonds (histidine, arginine and threonine) and salt bridges (arginine and lysine) with effectors. Whereas 14 and 20 amino acid residues of CaNBLRR78 and CaNBLRR20 showed hydrophobic interactions with 11 and 9 amino acid residues of effectors, Mg.00g064570.m01 and Mg.00g006570.m01, respectively. The present investigation gives a comprehensive overview of CaNBLRRs and paves the foundation for their utility in pearl millet resistance breeding through understanding of host-pathogen interactions.