Expansion Of Gene Family Research Articles

Genome-wide identification and expression analysis of ZF-HD family in sunflower (Helianthus annuus L.) under drought and salt stresses

BackgroundSunflower (Helianthus annuus L.) is widely cultured in globally tropical and subtropical regions, with better resistance to various abiotic stresses as a model crop. Despite the fact that zinc finger-homeodomain (ZF-HD) genes play an important role in responding to plant growth, development and stress resistance across the multiple species, the evolutionary history and abiotic function of the ZF-HD gene family in sunflower remain largely unexplored.ResultsIn this study, we identified 15 HaZF-HD genes (designated as HaZF1–HaZF15) in the sunflower genome, and they were divided into MIF and ZHD subfamilies. The proteins from the same group were similar in conserved motifs and domains, such as motif 1 and motif 3, constituting the ZF domain, were almost existed in 15 HaZF-HD proteins. Motif 2 (HD domain) was specifically presented in the ZHD subfamily. Collinearity analysis revealed that 5 pairs of genes with fragment duplication contributed to the expansion of HaZF-HD gene family. The analysis of cis-acting element demonstrated that the response elements related the hormone response and abiotic/biotic stress were the most prevalent, followed by plant growth and development elements. In the tissue expression profile, HaZF-HD gene family had the highest expression in leaves and floral organs. Additionally, RNA-seq and RT-qPCR analysis revealed HaZF3 responded positively in the initial stage of drought stress, whereas a prompt and significant decrease of relative expression value in response to salt stress was showed in HaZF6 and HaZF9.ConclusionsOverall, this study enhances our comprehension of the function of ZF-HD genes in positive regulation of responsiveness to abiotic stress and provide key candidate genes for sunflower stress resistance breeding.

Genome-wide identification, phylogeny, evolutionary expansion, and expression analyses of ABC gene family in Castanea mollissima under temperature stress.

The ATP-binding cassette (ABC) gene family comprises some of the most critical transporter proteins in plants, playing vital roles in maintaining cellular homeostasis and adapting to environmental changes. While ABC transporters have been extensively characterized in various plant species, their profile in C. mollissima remains less understood. In this study, 164 ABC genes were identified and characterized within the C. mollissima genome, and subsequently classified into eight subfamilies. Collinear analysis suggested that dispersed duplication was the primary mechanism driving the expansion of the CmABC gene family. The study also examined morphological and physiological changes in C. mollissima under temperature stress, highlighting significant decreases in photosynthetic indicators and SOD enzyme activity, while other indicators varied. Transcriptome analysis revealed distinct expression patterns of various CmABC genes under temperature stress, identifying CmABCG29c and CmABCB11e as key candidates for responding to temperature stress. This was based on their expression patterns, correlation with physiological indicators, and WGCNA analysis. The expression levels of CmABC genes measured in RT-qPCR experiments were consistent with those observed in RNA-seq analysis. This research provides a theoretical foundation for understanding the physiological and gene expression responses of C. mollissima to temperature stress.

Genomes of the Caribbean reef-building corals Colpophyllia natans, Dendrogyra cylindrus, and Siderastrea siderea.

Coral populations worldwide are declining rapidly due to elevated ocean temperatures and other human impacts. The Caribbean harbors a high number of threatened, endangered, and critically endangered coral species compared to reefs of the larger Indo-Pacific. The reef corals of the Caribbean are also long diverged from their Pacific counterparts and may have evolved different survival strategies. Most genomic resources have been developed for Pacific coral species which may impede our ability to study the changes in genetic composition of Caribbean reef communities in response to global change. To help fill the gap in genomic resources, we used PacBio HiFi sequencing to generate the first genome assemblies for three Caribbean, reef-building corals, Colpophyllia natans, Dendrogyra cylindrus, and Siderastrea siderea. We also explore the genomic novelties that shape scleractinian genomes. Notably, we find abundant gene duplications of all classes (e.g., tandem and segmental), especially in S. siderea. This species has one of the largest genomes of any scleractinian coral (822Mb) which seems to be driven by repetitive content and gene family expansion and diversification. As the genome size of S. siderea was double the size expected of stony corals, we also evaluated the possibility of an ancient whole genome duplication using Ks tests and found no evidence of such an event in the species. By presenting these genome assemblies, we hope to develop a better understanding of coral evolution as a whole and to enable researchers to further investigate the population genetics and diversity of these three species.

Chromosome-level genome assembly of Pontederia cordata L. provides insights into its rapid adaptation and variation of flower colors.

Pontederia cordata L. is an aquatic ornamental plant native to the Americas, but has been widely distributed in South Asia, Australia, and Europe. The genetic mechanisms behind its rapid adaptation and spread have not yet been well understood. To understand the mechanisms for its rapid adaptation, this study assembled the first chromosome-level genome of P. cordata. The genome assembly, which spans 527.5Mb, is anchored on eight pseudochromosomes with a scaffold N50 of 48Mb and encompasses 29,389 protein-coding genes. Further analyses revealed that P. cordata had experienced three whole-genome duplications (WGDs) events. These WGDs are associated with gene family expansion and increased numbers of resistance gene analogs (RGAs) and transcription factors (TFs). Positive selection analysis indicated that genes derived from tandem duplication and proximal duplication were more likely to undergo positive selection, and were enriched in plant defense and disease resistance. These results implied that WGDs, tandem duplication, and positive selection enhanced the environmental adaptability of P. cordata. Additionally, we found that down-regulation of F3'5'H, DFR, ANS, and UFGT likely caused the flower color variation for P. cordata from violet to white. The first chromosome-level genome of P. cordata here provides a valuable genomic resource for investigating the rapid adaptation and flower color variation of the species.

Molecular and functional convergences associated with complex multicellularity in Eukarya.

A key trait of Eukarya is the independent evolution of complex multicellular (CM) in animals, plants, fungi, brown algae and red algae. This phenotype is characterized by the initial exaptation of cell-cell adhesion genes followed by the emergence of mechanisms for cell-cell communication, together with the expansion of transcription factor gene families responsible for cell and tissue identity. The number of cell types (NCT) is commonly used as a quantitative proxy for biological complexity in comparative genomics studies. While expansions of individual gene families have been associated with NCT variation within individual CM lineages, the molecular and functional roles responsible for the independent evolution of CM across Eukarya remain poorly understood. We employed a phylogeny-aware strategy to conduct a genomic-scale search for associations between NCT and the abundance of genomic components across a phylogenetically diverse set of 81 eukaryotic species, including species from all CM lineages. Our annotation schemas represent two complimentary aspects of genomic information: homology - represented by conserved sequences - and function - represented by Gene Ontology (GO) terms. We found many gene families sharing common biological themes that define CM to be independently expanded in two or more CM lineages, such as components of the extracellular matrix, cell-cell communication mechanisms, and developmental pathways. Additionally, we describe many previously unknown associations of biological themes and biological complexity, such as mechanisms for wound response, immunity, cell migration, regulatory processes, and response to natural rhythms. Together, our findings unveil a set of functional and molecular convergences independently expanded in CM lineages likely due to the common selective pressures in their lifestyles.

Evolutionary Dynamics and Expression Divergence of the MADS-Box Gene Family During Recent Speciation of AA-Genome Oryza Species

To investigate the evolutionary trajectory during the recent speciation of AA-genome Oryza species, we conducted a comprehensive analysis of the MADS-box gene family across eight Oryza species. We identified 1093 MADS-box genes in total and systematically examined their evolutionary history, gene family expansion, and expression divergence. Our results revealed that extensive lineage-specific expansions occurred in AA-genome Oryza species, which were primarily generated by proximal and tandem duplications, with a particularly notable episode in Type-I genes. Despite the significant expansion, Type-I genes were generally expressed at low levels or not expressed across various organs. In contrast, the expansion of Type-II genes was primarily observed in the AG, AGL12, SOC1, GGM13, and MIKC* subfamilies, which exhibited high levels of expression in reproductive organs such as panicles and stigmas. Additionally, we found species-specific gene expression in the two out-crossing wild rice species, Oryza rufipogon and Oryza longistaminata. Notably, a unique MADS-box gene in O. longistaminata exhibited high expression levels in rhizomes and stems, which may be associated with the species’ distinctive rhizomatous growth habit.

Genome-Wide Identification of the WD40 Gene Family in Walnut (Juglans regia L.) and Its Expression Profile in Different Colored Varieties

Abstract: The walnut (Juglans regia) is a woody oilseed crop with high economic and food value as its kernels are edible and its hulls can be widely used in oil extraction and plugging, chemical raw materials, and water purification. Currently, red walnut varieties have emerged, attracting consumer interest due to their high nutritional values as they are rich in anthocyanins. WD40 is a widespread superfamily in eukaryotes that play roles in plant color regulation and resistance to stresses. In order to screen for JrWD40 associated with walnut color, we identified 265 JrWD40s in walnuts by genome-wide identification, which were unevenly distributed on 16 chromosomes. According to the phylogenetic tree, all JrWD40s were classified into six clades. WGD (Whole genome duplication) is the main reason for the expansion of the JrWD40 gene family. JrWD40s were relatively conserved during evolution, but their gene structures were highly varied; lower sequence similarity may be the main reason for the functional diversity of JrWD40s. Some JrWD40s were highly expressed only in red or green walnuts. In addition, we screened 16 unique JrWD40s to walnuts based on collinearity analysis. By qRT-PCR, we found that JrWD40-133, JrWD40-150, JrWD40-155, and JrWD40-206 may regulate anthocyanin synthesis through positive regulation, whereas JrWD40-65, JrWD40-172, JrWD40-191, JrWD40-224, and JrWD40-254 may inhibit anthocyanin synthesis, suggesting that these JrWD40s are key genes affecting walnut color variation.

Whole-genome resequencing landscape of adaptive evolution in Relict gull (Larus relictus)

BackgroundThe relict gull (Larus relictus, Charadriiformes, Laridae) classified as vulnerable in the IUCN Red List is defined as a first-class national protected bird in China. However, our knowledge of the evolutionary history of L. relictus is limited. Here, we performed whole-genome resequencing of L. relictus (n = 14) and L. brunnicephalus (n = 3) to explore the genetic relationships and population structures and understand their adaptive evolution.ResultsThe whole genome resequencing generated 667.55 Gb clean reads with an average sequencing depth of ~ 29×. The genomic variant analysis identified 13,717,267 heterozygous SNPs in the samples obtained from 17 individuals. Population genetic diversity analysis revealed that low nucleotide diversity (0.00029) and no obvious population structure in L. relictus. Demographic history revealed that from 180 to 5 kya (thousand years ago), the effective population size (Ne) of L. relictus exhibited declines (24,000 to 5,000), with a very low range population size (2,200 to 5,000). In contrast, from 100 to 80 kya, L. brunnicephalus peaked in ancestral Ne, followed by distinct declines at ~ 70 kya (100,000 to 16,000). The findings identified several genes associated with the correlated changed life-history traits of L. relictus, including BMP4 involved in beak adaptation; HAND2, NEUROG1, COL11A2, and EDNRB involved in the evolution of the palate, soft palate, and tongue; PIGR and PLCB2 involved in an enhanced response to bitter taste by sensing chemical secretions released by staple food substrate insects to activate protective mechanisms. Furthermore, thirty-four genes related to sperm development and activity, including KLHL10 and TEKT3, were identified in the expanded gene family. In addition, MED1, CNOT9, NR5A1, and PATZ1 were involved in enhanced male hormone secretion and a high density of candidate genes associated with embryonic development were identified. The findings indicated that the L. relictus population was in a male-biased diffusion mode; the function of the TEKT3 gene showed that males played a dominant role in brooding, which enhanced their attraction to females. Our study revealed that significant enrichment of olfactory signaling pathway genes, including OR14C36, OR14J1, OR14I1, and OR14A16; inner ear development-related, including PTN, PTPN11, GATA2, ATP8B1, and MYO15A; and those related to hypoxic adaptation to high-altitude breeding and iris colour.ConclusionsBased on the results and the knowledge of this organism biology and habitat use, we infer that less adaptive evolutionary pressure on vision in L. relictus were related with their feeding behaviour and adaptation. In summary, this comprehensive analysis provides insights into the evolutionary features of L. relictus and a new perspective for scientific research on L. relictus to effectively determine its future survival viability.

Genome-Wide Identification of the Kinesin Gene Family in Soybean and Its Response to Salt Stress

The kinesin (KIN) gene family is a subgroup of motor proteins. It plays a critical role in plant development and responses to environmental stresses. However, their function in soybean salt tolerance has yet to be clearly defined. This study employed bioinformatics approaches and identified 139 kinesin family members in the soybean genome. These 139 genes were classified into 10 subgroups, unevenly distributed across the chromosomes. The promoter regions of GmKIN genes harbored several stress-responsive elements, and segmental duplication was the primary driver of the expansion of the GmKIN gene family. Based on publicly available RNA-seq data, we studied the response patterns of 139 GmKIN genes to salt stress and found that 20 KIN genes in soybeans were upregulated after salt stress, with GmKIN114, GmKIN102, GmKIN109, and GmKIN99 showing more than a threefold increase in their expression under salt stress. Using quantitative fluorescence PCR, transgenic yeast, and a transgenic hairy root system, we preliminarily validated the salt tolerance functions of the four KIN genes in soybeans. This study probed into the GmKIN gene family in soybean, offering valuable insights into the functional roles of these genes in stress adaptation.

De novo genome assembly and annotations of Bombus lapidarius and Bombus niveatus provide insights into the environmental adaptability

Bumblebees are ubiquitous, cold-adapted, primitively eusocial bees and important pollinators for crops and vegetation. However, many species are declining worldwide due to multiple factors, including human-induced habitat loss, agricultural chemicals, global warming, and climate change. In particular, future climate scenarios predict a shift in the spatial distribution of bumblebees under global warming, with some species declining and others potentially expanding. Here, we report a de novo genome assembly and annotation for Bombus lapidarius and Bombus niveatus to decipher species-specific potential genomic capacity against such environmental stressors. With harboring more than 23,000 protein-coding genes, the assembled genomes of B. lapidarius and B. niveatus are 244.44 Mb (scaffold N50 of 9.45 Mb) and 259.84 Mb (scaffold N50 of 10.94 Mb), respectively, which exhibit similar trends in terms of genome size and composition with other bumblebees. Gene family analysis reveals differences in species-specific expanded gene families. B. lapidarius exhibits expanded genes related to pre/postsynaptic organization, while B. niveatus shows a distinct expansion in gene families regulating cellular growth, aging, and responses to abiotic and biotic stressors, such as those containing SCAN domains, WD-repeats, and Ras-related proteins. Our genome-wide screens revealed positive selection on environmental stress-responsive genes such as dip2, yme1l, and spg7 in B. lapidarius, whereas positive selection signatures were found in genes such as myd88, mybbp1A, and rhau, which are involved in environmental stress resistance for B. niveatus. These high-quality genome assemblies and comparative genome analysis unveil potential drivers that underlie genome evolution in bumblebees, offering valuable insights into environmental adaptation and conservation efforts.

Genomic and Methylomic Signatures Associated With the Maintenance of Genome Stability and Adaptive Evolution in Two Closely Allied Wolf Spiders.

Pardosa spiders, belonging to the wolf spider family Lycosidae, play a vital role in maintaining the health of forest and agricultural ecosystems due to their function in pest control. This study presents chromosome-level genome assemblies for two allied Pardosa species, P. laura and P. agraria. Both species' genomes show a notable expansion of helitron transposable elements, which contributes to their large genome sizes. Methylome analysis indicates that P. laura has higher overall DNA methylation levels compared to P. agraria. DNA methylation may not only aids in transposable element-driven genome expansion but also positively affects the three-dimensional organisation of P. laura after transposon amplification, thereby potentially enhancing genome stability. Genes associated with hyper-differentially methylated regions in P. laura (compared to P. agraria) are enriched in functions related to mRNA processing and energy production. Furthermore, combined transcriptome and methylome profiling has uncovered a complex regulatory interplay between DNA methylation and gene expression, emphasising the important role of gene body methylation in the regulation of gene expression. Comparative genomic analysis shows a significant expansion of cuticle protein and detoxification-related gene families in P. laura, which may improve its adaptability to various habitats. This study provides essential genomic and methylomic insights, offering a deeper understanding of the relationship between transposable elements and genome stability, and illuminating the adaptive evolution and species differentiation among allied spiders.

Evidence for Multiple Independent Expansions of Fox Gene Families Within Flatworms.

Expansion and losses of gene families are important drivers of molecular evolution. A recent survey of Fox genes in flatworms revealed that this superfamily of multifunctional transcription factors, present in all animals, underwent extensive losses and expansions during platyhelminth evolution. In this paper, I analyzed Fox gene complement in four additional species of platyhelminths, that represent early-branching lineages in the flatworm phylogeny: catenulids (Stenostomum brevipharyngium and Stenostomum leucops) and macrostomorphs (Macrostomum hystrix and Macrostomum cliftonense). Phylogenetic analysis of Fox genes from this expanded set of species provided evidence for multiple independent expansions of Fox gene families within flatworms. Notably, FoxG, a panbilaterian brain-patterning gene, appears to be the least susceptible to duplication, while FoxJ1, a conserved ciliogenesis factor, has undergone extensive expansion in various flatworm lineages. Analysis of the single-cell atlas of S. brevipharyngium, combined with RNA in situ hybridization, elucidated the tissue-specific expression of the selected Fox genes: FoxG is expressed in the brain, three of the Fox genes (FoxN2/3-2, FoxO4 and FoxP1) are expressed in the pharyngeal cells of likely glandular function, while one of the FoxQD paralogs is specifically expressed in the protonephridium. Overall, the evolution of Fox genes in flatworms appears to be characterized by an early contraction of the gene complement, followed by lineage-specific expansions that have enabled the co-option of newly evolved paralogs into novel physiological and developmental functions.

Genome-Wide Identification and Characterization of the Homeodomain Leucine Zipper Protein (HD-Zip) Gene Family in Sea Buckthorn (Hippophae rhamnoides) Under Lead Stress

This study investigates the role of sea buckthorn HD-Zip genes in response to lead stress, identifying 28 genes distributed across 10 chromosomes, which are classified into four subfamilies. Each subfamily exhibits a similar gene structure and conserved protein motifs. The HD-Zip gene family is notably enriched in stress-responsive elements. Transcriptomic analysis revealed differential expression among the 28 members of the HD-Zip gene family in sea buckthorn, varying with different Pb ion concentrations. Upregulated genes were predominantly observed at stress concentrations of 1 g/kg and 5 g/kg, while downregulated genes were more prevalent at the 0.5 g/kg stress concentration. Covariance analysis indicated that large-scale gene duplication was the primary mechanism driving the expansion of the sea buckthorn HD-Zip gene family. Additionally, analysis of three-dimensional protein structures demonstrated high conservation within the HD-Zip gene, suggesting that certain sea buckthorn HD-Zip proteins may play significant regulatory roles in physiological functions. Scanning electron microscopy–energy-dispersive spectroscopy (SEM-EDS) analysis revealed that the majority of lead ions accumulated in the roots of the seedlings, with the lead concentration affecting the number, density, and function of leaf slits. These findings enhance our understanding of the complex regulatory mechanisms governing HD-Zip genes and will contribute to the genetic improvement of sea buckthorn for breeding under lead stress conditions.

Vanadium-Dependent Haloperoxidase Gene Evolution in Brown Algae: Evidence for Horizontal Gene Transfer.

Compared with green plants, brown algae are characterized by their ability to accumulate iodine, contributing to their ecological adaptability in high-iodide coastal environments. Vanadium-dependent haloperoxidase (V-HPO) is the key enzyme for iodine synthesis. Despite its significance, the evolutionary origin of V-HPO genes remains underexplored. This study investigates the genomic and evolutionary dynamics of V-HPOs in brown algae, focusing on Laminariales species, particularly Saccharina japonica. Genomic analyses revealed the extensive expansion of the V-HPO gene family in brown algae, with 88 V-HPOs identified in S. japonica, surpassing the number in red algae. Phylogenetic analysis demonstrated distinct evolutionary divergence between brown and red algal V-HPOs, with the brown algal clade closely related to bacterial V-HPOs. These findings suggest horizontal gene transfer (HGT) played a key role in acquiring V-HPO genes, particularly from Acidobacteriota, a bacterial phylum known for genomic plasticity. Additionally, enriched active transposable elements were identified around V-HPO genomic clusters, highlighting their role in tandem gene duplications and rapid HGT processes. Expression profiling further revealed dynamic regulation of V-HPOs in response to environmental conditions. This study provides new insights into how HGT has driven kelp genomic adaptations and enhances understanding of marine ecological success and evolutionary processes.

Redefining the spliceosomal introns of the sexually transmitted parasite Trichomonas vaginalis and its close relatives in columbid birds.

Trichomonas vaginalis infects the urogenital tract of men and women and causes the sexually transmitted infection trichomoniasis. Since the publication of its draft genome in 2007, the genome has drawn attention for several reasons, including its unusually large size, massive expansion of gene families, and high repeat content. The fragmented nature of the draft assembly made it challenging to obtain accurate metrics of features, such as spliceosomal introns. The number of introns identified varied over the years, ranging from 41 when first characterized in 2005, to 32 in 2018 when the repertoire was revised. In both cases, the results suggested that more introns could be present in the genome. In this study, we exploited our new T. vaginalis G3 chromosome-scale assembly and annotation and high-coverage transcriptome datasets to provide a definitive analysis of the complete repertoire of spliceosomal introns in the species. We developed a custom pipeline that distinguishes true splicing events from chimeric alignments by utilizing the extended motifs required by the splicing machinery and experimentally verified the results using transcript evidence. We identified a total of 63 active introns and 34 putative "inactive" intron sequences in T. vaginalis, enabling an analysis of their length distribution, extended consensus motifs, intron phase distribution (including an unexpected expansion of UTR introns), and functional annotation. Notably, we found that the shortest intron in T. vaginalis, at only 23 nucleotides in size, is one of the shortest introns known to date. We tested our pipeline on a chromosome-scale assembly of the bird parasite Trichomonas stableri, the closest known relative to T. vaginalis. Our results revealed some conservation of the main features (total intron count, sequence, length distribution, and motifs) of these two closely related species, although differences in their functional annotation and duplication suggest more specialized splicing machinery in T. vaginalis.

Genome-wide analyses of the NAC transcription factor gene family in Acer palmatum provide valuable insights into the natural process of leaf senescence.

Acer palmatum is a deciduous shrub or small tree. It is a popular ornamental plant because of its beautiful leaves, which change colour in autumn. This study revealed 116 ApNAC genes within the genome of A. palmatum. These genes are unevenly distributed on the 13 chromosomes of A. palmatum. An analysis of the phylogenetic tree of Arabidopsis thaliana NAC family members revealed that ApNAC proteins could be divided into 16 subgroups. A comparison of ApNAC proteins with NAC genes from other species suggested their potential involvement in evolutionary processes. Studies suggest that tandem and segmental duplications may be key drivers of the expansion of the ApNAC gene family. Analysis of the transcriptomic data and qRT‒PCR results revealed significant upregulation of most ApNAC genes during autumn leaf senescence compared with their expression levels in summer leaves. Coexpression network analysis revealed that the expression profiles of 10 ApNAC genes were significantly correlated with those of 200 other genes, most of which are involved in plant senescence processes. In conclusion, this study contributes to elucidating the theoretical foundation of the ApNAC gene family and provides a valuable basis for future investigations into the role of NAC genes in regulating leaf senescence in woody ornamental plants.

Degenerated vision, altered lipid metabolism, and expanded chemoreceptor repertoires enable Lindaspio polybranchiata to thrive in deep-sea cold seeps

BackgroundLindaspio polybranchiata, a member of the Spionidae family, has been reported at the Lingshui Cold Seep, where it formed a dense population around this nascent methane vent. We sequenced and assembled the genome of L. polybranchiata and performed comparative genomic analyses to investigate the genetic basis of adaptation to the deep sea. Supporting this, transcriptomic and fatty acid data further corroborate our findings.ResultsWe report the first genome of a deep-sea spionid, L. polybranchiata. Over long-term adaptive evolution, genes associated with vision and biological rhythmicity were lost, which may indirectly benefit oligotrophy by eliminating energetically costly processes. Compared to its shallow-sea relatives, L. polybranchiata has a significantly higher proportion of polyunsaturated fatty acids (PUFAs) and expanded gene families involved in the biosynthesis of unsaturated fatty acids and chromatin stabilization, possibly in response to high hydrostatic pressure. Additionally, L. polybranchiata has broad digestive scope, allowing it to fully utilize the limited food resources in the deep sea to sustain a large population. As a pioneer species, L. polybranchiata has an expanded repertoire of genes encoding potential chemoreceptor proteins, including ionotropic receptors (IRs) and gustatory receptor-like receptors (GRLs). These proteins, characterized by their conserved 3D structures, may enhance the organism’s ability to detect chemical cues in chemosynthetic ecosystems, facilitating rapid settlement in suitable environments.ConclusionsOur results shed light on the adaptation of Lindaspio to the darkness, high hydrostatic pressure, and food deprivation in the deep sea, providing insights into the molecular basis for L. polybranchiata becoming a pioneer species.

Genome-Wide Identification, Phylogenetic Evolution, and Abiotic Stress Response Analyses of the Late Embryogenesis Abundant Gene Family in the Alpine Cold-Tolerant Medicinal Notopterygium Species.

Late embryogenesis abundant (LEA) proteins are a class of proteins associated with osmotic regulation and plant tolerance to abiotic stress. However, studies on the LEA gene family in the alpine cold-tolerant herb are still limited, and the phylogenetic evolution and biological functions of its family members remain unclear. In this study, we conducted genome-wide identification, phylogenetic evolution, and abiotic stress response analyses of LEA family genes in Notopterygium species, alpine cold-tolerant medicinal herbs in the Qinghai-Tibet Plateau and adjacent regions. The gene family identification analysis showed that 23, 20, and 20 LEA genes were identified in three Notopterygium species, N. franchetii, N. incisum, and N. forrestii, respectively. All of these genes can be classified into six LEA subfamilies: LEA_1, LEA_2, LEA_5, LEA_6, DHN (Dehydrin), and SMP (seed maturation protein). The LEA proteins in the three Notopterygium species exhibited significant variations in the number of amino acids, physical and chemical properties, subcellular localization, and secondary structure characteristics, primarily demonstrating high hydrophilicity, different stability, and specific subcellular distribution patterns. Meanwhile, we found that the members of the same LEA subfamily shared similar exon-intron structures and conserved motifs. Interestingly, the chromosome distributions of LEA genes in Notopterygium species were scattered. The results of the collinearity analysis indicate that the expansion of the LEA gene family is primarily driven by gene duplication. A Ka/Ks analysis showed that paralogous gene pairs were under negative selection in Notopterygium species. A promoter cis-acting element analysis showed that most LEA genes possessed multiple cis-elements connected to plant growth and development, stress response, and plant hormone signal transduction. An expression pattern analysis demonstrated the species-specific and tissue-specific expression of NinLEAs. Experiments on abiotic stress responses indicated that the NinLEAs play a crucial role in the response to high-temperature and drought stresses in N. franchetii leaves and roots. These results provide novel insights for further understanding the functions of the LEA gene family in the alpine cold-tolerant Notopterygium species and also offer a scientific basis for in-depth research on the abiotic stress response mechanisms and stress-resistant breeding.

Genome-Wide Identification and Functional Characterization of SKP1-like Gene Family Reveal Its Involvement in Response to Stress in Cotton.

SKP1 constitutes the Skp1-Cullin-F-box ubiquitin E3 ligase (SCF), which plays a role in plant growth and development and biotic and abiotic stress in ubiquitination. However, the response of the SKP1-like gene family to abiotic and biotic stresses in cotton has not been well characterized. In this study, a total of 72 SKP1-like genes with the conserved domain of SKP1 were identified in four Gossypium species. Synteny and collinearity analyses revealed that segmental duplication played a major role in the expansion of the cotton SKP1-like gene family. All SKP1-like proteins were classified into three different subfamilies via phylogenetic analysis. Furthermore, we focused on a comprehensive analysis of SKP1-like genes in G. hirsutum. The cis-acting elements in the promoter site of the GhSKP1-like genes predict their involvement in multiple hormonal and defense stress responses. The expression patterns results indicated that 16 GhSKP1-like genes were expressed in response to biotic or abiotic stresses. To further validate the role of the GhSKP1-like genes in salt stress, four GhSKP1-like genes were randomly selected for gene silencing via VIGS. The results showed that the silencing of GhSKP1-like_7A resulted in the inhibition of plant growth under salt stress, suggesting that GhSKP1-like_7A was involved in the response to salt stress. In addition, yeast two-hybrid results revealed that GhSKP1-like proteins have different abilities to interact with F-box proteins. These results provide valuable information for elucidating the evolutionary relationships of the SKP1-like gene family and aiding further studies on the function of SKP1-like genes in cotton.

Chromosome Numbers and Reproductive Life Cycles in Green Plants: A Phylotranscriptomic Perspective.

The strong correlation between reproductive life cycle type and chromosome numbers in green plants has been a long-standing mystery in evolutionary biology. Within green plants, the derived condition of heterosporous reproduction has emerged from the ancestral condition of homospory in disparate locations on the phylogenetic tree at least 11 times, of which three lineages are extant. In all green plant lineages where heterospory has emerged, there has been a significant downsizing in chromosome numbers. This dynamic has been investigated without clear answers for many decades. In this study, we combine known ideas from existing literature with novel methods, tools, and data to generate fresh insights into an old question. Using gene family evolution models and selection analyses, we identified gene families that have undergone significant expansion, contraction, or selection in heterosporous lineages. Alongside lineage-specific genomic changes, our results revealed shared genomic changes/trends among heterosporous lineages. We found expansions in gene families related to developmental regulation, signaling pathways, and stress responses across heterosporous groups. Notably, the MATE efflux family showed consistent expansion and evidence of selection in heterosporous lineages, suggesting a potentially conserved role in heterospory evolution. These findings could provide novel avenues to investigate and probe the underlying mechanism that may underpin the association between heterospory and genomic changes. The general importance of chromosome numbers, structure, and sizes in cellular biology notwithstanding, the association between the emergence of heterosporous reproduction and chromosome number reduction/genome downsizing is not fully understood. It remains unclear why there exists an association between aspects of biology at such disparate levels as reproductive life cycles and chromosome numbers/genome size. Exploring and answering this conundrum of evolutionary biology can add to our broader understanding of life sciences and of biology at different levels. Applying the novel tools and methods emerging from ongoing progress in biotechnology and computational sciences presents an opportunity to make new inroads into this long-standing question.