Genetica最新文献

In addition to their roles in developmental and metabolic processes, MYB transcription factors play crucial roles in plant defense mechanisms and stress responses. A comprehensive analysis of six pearl millet genomes revealed the presence of 1133 MYB genes, which can be classified into four phylogenetically distinct subgroups. The duplication pattern of MYB genes across the pearl millet genomes demonstrates their conserved and similar evolutionary history. Overall, MYB genes were observed to be involved in drought and heat stress responses, with stronger differential expressed observed in root tissues. Multiple analyses indicated that MYB genes mediate abiotic stress responses by modulating abscisic acid-related pathways, circadian rhythms, and histone modification processes. A substantial number of duplicated genes were determined to exhibit differential expression under abiotic stress. The consistent positive expression trend observed in duplicated gene pairs, such as PMA5G04432.1 and PMA2G00728.1, across various abiotic stresses suggests that duplicated MYB genes plays a key role in the evolution of adaptive responses of pearl millet to abiotic stresses.

The sterile insect technique (SIT) is a highly effective biologically-based method for the population suppression of highly invasive insect pests of medical and agricultural importance. The efficacy of SIT could be significantly enhanced, however, by improved methods of male sterilization that avoid the fitness costs of irradiation. An alternative sterilization method is possible by gene-editing that targets genes essential for sperm maturation and motility, rendering them nonfunctional, similar to the CRISPR-Cas9 targeting of β2-tubulin in the genetic model system, Drosophila melanogaster. However, since genetic strategies for sterility are susceptible to breakdown or resistance in mass-reared populations, alternative targets for sterility are important for redundancy or strain replacement. Here we have identified and characterized the sequence and transcriptional expression of two genes in a Florida strain of Drosophila suzukii, that are cognates of the D. melanogaster spermatocyte-specific genes wampa and Prosalpha6T. Wampa encodes a coiled-coil dynein subunit required for axonemal assembly, and the proteasome subunit gene, Prosalpha6T, is required for spermatid individualization and nuclear maturation. The reading frames of these genes differed from their NCBI database entries derived from a D. suzukii California strain by 44 and 8 nucleotide substitutions/polymorphisms, respectively, though all substitutions were synonymous resulting in identical peptide sequences. Expression of both genes is predominant in the male testis, and they share similar transcriptional profiles in adult males with β2-tubulin. Their amino acid sequences are highly conserved in dipteran species, including pest species subject to SIT control, supporting their potential use in targeted male sterilization strategies.

Adaptation to various altitudes and oxygen levels is a major aspect of vertebrate evolution. Hemoglobin is an erythrocyte protein belonging to the globin superfamily, and the α-, β-globin genes of jawed vertebrates encode tetrameric ((α₂β₂) hemoglobin, which contributes to aerobic metabolism by delivering oxygen from the respiratory exchange surfaces into cells. However, there are various gaps in knowledge regarding hemoglobin gene evolution, including patterns in cartilaginous fish and the roles of gene conversion in various taxa. Hence, we evaluated the evolutionary history of the vertebrate hemoglobin gene family by analyses of 97 species representing all classes of vertebrates. By genome-wide analyses, we extracted 879 hemoglobin sequences. Members of the hemoglobin gene family were conserved in birds and reptiles but variable in mammals, amphibians, and teleosts. Gene motifs, structures, and synteny were relatively well-conserved among vertebrates. Our results revealed that purifying selection contributed substantially to the evolution of all vertebrate hemoglobin genes, with mean d_N/d_S (ω) values ranging from 0.057 in teleosts to 0.359 in reptiles. In general, after the fish-specific genome duplication, the teleost hemoglobin genes showed variation in rates of evolution, and the β-globin genes showed relatively high ω values after a gene transposition event in amniotes. We also observed that the frequency of gene conversion was high in amniotes, with fewer hemoglobin genes and higher rates of evolution. Collectively, our findings provide detail insight into complex evolutionary processes shaping the vertebrate hemoglobin gene family, involving gene duplication, gene loss, purifying selection, and gene conversion.

Retrotransposon families in the rodent family Cricetidae have been understudied in contrast to Muridae, both taxa classified within the superfamily Muroidea. Therefore, we carried out a study to advance our knowledge of the unique mys LTR-retroelement identified in Peromyscus leucopus, by incorporating intra-ORF PCR, quantitative dot blots, DNA and protein library screens, the generation of molecular phylogenies, and analyses of orthologous LTR-retroelement loci. These analyses led to the discovery of three additional related families of LTR-retroelements, which include a 2900 bp full-length element of mys-related sequences (mysRS), an 8000 bp element containing the mys ORF1 sequence (mORF1) with ERV-related sequences downstream in the reverse orientation, as well as an 1800 bp element primarily consisting of mys ORF2 (mORF2) related sequences flanked by LTRs. Our data revealed only a few full-length mys elements among genera of the Neotominae subfamily of cricetid rodents, most existing as partial copies. The mysRS and mORF1 elements are also limited to the genomes of the Neotominae subfamily, whereas mORF2 appears to be restricted to the Peromyscus genus. Molecular phylogenies demonstrating concerted evolution along with an assessment of orthologous loci in Peromyscus for the presence or absence of elements are consistent with activity of these novel LTR-retroelement families within this genus. Together with known activity of various families of non-LTR retroelements in Peromyscus species, we propose that retrotransposons have been continually contributing to the dynamics of Peromyscus genomes promoting genomic diversity and may be correlated with the evolution of more than 50 identified Peromyscus species.

Multidrug and Toxic Compound Extrusion (MATE) proteins are essential transporters that extrude metabolites and participate in plant development and cellular detoxification. MATE transporters, which play crucial roles in the survival of mangrove plants under highly challenged environments, by specialized salt extrusion mechanisms, are mined from their genomes and reported here for the first time. Through homology search and domain prediction in the genome assemblies of Avicennia marina, Bruguiera sexangula, Ceriops zippeliana, Kandelia obovata, Rhizophora apiculata and Ceriops tagal, 74, 68, 66, 66, 63 and 64 MATE proteins, respectively were identified. The phylogenetic analysis divided the identified proteins into five major clusters and following the clustering pattern of the functionally characterized proteins, functions of the transporters in each cluster were predicted. Amino acid sequences, exon-intron structure, motif details and subcellular localization pattern for all the 401 proteins are described. The custom designed repeat masking libraries generated for each of these genomes, which will be of extensive use for the researchers worldwide, are also provided in this paper. This is the first study on the MATE genes in mangroves and the results provide comprehensive information on the molecular mechanisms enabling the survival of mangroves under hostile conditions.

Plant hormone abscisic acid (ABA) plays an important role in plant growth, development and response to biotic / abiotic stressors. Thus, it is necessary to investigate the crucial genes associated with ABA synthesis. Currently, the carotenoid cleavage oxygenases (CCOs) family that function as the key step for ABA synthesis are not well understood in banana. In this study, 13 MaCCO genes and 12 MbCCO genes, divided into NCED subgroup and CCD subgroup, were identified from the banana genome, and their evolutionary relationship, protein motifs, and gene structures were also determined. Transcriptomic analysis suggested the involvement of CCO genes in banana development, ripening, and response to abiotic and biotic stressors, and homologous gene pairs showed homoeologue expression bias in the A or B subgenome. Our results identified MaNCED3A, MaCCD1, and MbNCED3B as the genes with the highest expression during fruit development and ripening. MaNCED5 / MbNCED5 and MaNCED9A might respond to abiotic stress, and MaNCED3A, 3B, 6 A, 9 A, and MbNCED9A showed transcriptional changes that could be a response to Foc4 infection. These findings may contribute to the characterization of key enzymes involved in ABA biosynthesis, as well as to identify potential targets for the genetic improvement of banana.

Nucleotide Binding Site - Leucine Rich Repeat (NBS-LRR) genes play a significant role in plant defense against biotic stresses and are an integral part of signal transduction pathways. Vat gene has been well reported for their role in resistance to Aphis gossypii and viruses transmitted by them. Despite their importance, Vat like NBS-LRR resistance genes have not yet been identified and studied in cotton species. This study report hundreds of orthologous Vat like NBS-LRR genes from the genomes of 18 cotton species through homology searches and the distribution of those identified genes were tend to be clustered on different chromosome. Especially, in a majority of the cases, Vat like genes were located on chromosome number 13 and they all shared two conserved NBS-LRR domains, one disease resistant domain and several repeats of LRR on the investigated cotton Vat like proteins. Gene ontology study on Vat like NBS-LRR genes revealed the molecular functions viz., ADP and protein binding. Phylogenetic analysis also revealed that Vat like sequences of two diploid species, viz., G. arboreum and G. anomalum, were closely related to the sequences of the tetraploids than all other diploids. The Vat like genes of G. aridum and G. schwendimanii were distantly related among diploids and tetraploids species. Various hormones and defense related cis-acting regulatory elements were identified from the 2 kb upstream sequences of the Vat like genes implying their defensive response towards the biotic stresses. Interestingly, G. arboreum and G. trilobum were found to have more regulatory elements than larger genomes of tetraploid cotton species. Thus, the present study provides the evidence for the evolution of Vat like genes in defense mechanisms against aphids infestation in cotton genomes and allows further characterization of candidate genes for developing aphid and aphid transmitted viruses resistant crops through cotton breeding.

Weeping forsythia is a wide-spread shrub in China with important ornamental, medicinal and ecological values. It is widely distributed in China's warm temperate zone. In plants, WRKY transcription factors play important regulatory roles in seed germination, flower development, fruit ripening and coloring, and biotic and abiotic stress response. To date, WRKY transcription factors have not been systematically studied in weeping forsythia. In this study, we identified 79 WRKY genes in weeping forsythia and classified them according to their naming rules in Arabidopsis thaliana. Phylogenetic tree analysis showed that, except for IIe subfamily, whose clustering was inconsistent with A. thaliana clustering, other subfamily clustering groups were consistent. Cis-element analysis showed that WRKY genes related to pathogen resistance in weeping forsythia might be related to methyl jasmonate and salicylic acid-mediated signaling pathways. Combining cis-element and expression pattern analyses of WRKY genes showed that more than half of WRKY genes were involved in light-dependent development and morphogenesis in different tissues. The gene expression results showed that 13 WRKY genes were involved in drought response, most of which might be related to the abscisic acid signaling pathway, and a few of which might be regulated by MYB transcription factors. The gene expression results under cold stress showed that 17 WRKY genes were involved in low temperature response, and 9 of them had low temperature responsiveness cis-elements. Our study of WRKY family in weeping forsythia provided useful resources for molecular breeding and important clues for their functional verification.

We sequenced the mitogenomes of two Erebid species, namely Ischyja manlia (Cramer, 1776) and Rusicada privata (Walker, 1865) to analyse the phylogenetic relationship and to establish the taxonomic position of incertae sedis members of the family Erebidae. The two circular genomes of I. manlia and R. privata were 15,879 bp and 15,563 bp long, respectively. The gene order was identical, containing 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and an A + T-rich region. The nucleotide compositions of the A + T-rich region of both mitogenomes were similar: 80.65% for R. privata, and 81.09% for I. manlia. The AT skew and GC skew were slightly positive in I. manlia and negative in R. privata. In I. manlia and R. privata, except for cox1 which started with CGA and TTG codons, all the other 12 PCGs started with ATN codon. The A + T-rich regions of I. manlia and R. privata were 433 and 476 bp long, respectively, and contained common characteristics of Noctuoidea moths. At present, Ischyja is treated as Erebinae incertae sedis. However, phylogenetic analysis conducted in the present study reveals that the genus Ischyja is most likely to be a member of the subfamily Erebinae.