Molecular Evolution and Nucleotide Sequences of the Maize Plastid Genes for the α Subunit of CF1 (atpA) and the Proteolipid Subunit of CF0 (atpH)

Genetics ◽  
1987 ◽  
Vol 116 (1) ◽  
pp. 127-139
Author(s):  
Steven R Rodermel ◽  
Lawrence Bogorad

ABSTRACT The nucleotide sequences of the maize plastid genes for the α subunit of CF1 (atpA) and the proteolipid subunit of CF 0 (atpH) are presented. The evolution of these genes among higher plants is characterized by a transition mutation bias of about 2:1 and by rates of synonymous and nonsynonymous substitution which are much lower than similar rates for genes from other sources. This is consistent with the notion that the plastid genome is evolving conservatively in primary sequence. Yet, the mode and tempo of sequence evolution of these and other plastid-encoded coupling factor genes are not the same. In particular, higher rates of nonsynonymous substitution in atpE (the gene for the ∊ subunit of CF1) and higher rates of synonymous substitution in atpH in the dicot vs. monocot lineages of higher plants indicate that these sequences are likely subject to different evolutionary constraints in these two lineages. The 5′- and 3′ transcribed flanking regions of atpA and atpH from maize, wheat and tobacco are conserved in size, but contain few putative regulatory elements which are conserved either in their spatial arrangement or sequence complexity. However, these regions likely contain variable numbers of "species-specific" regulatory elements. The present studies thus suggest that the plastid genome is not a passive participant in an evolutionary process governed by a more rapidly changing, readily adaptive, nuclear compartment, but that novel strategies for the coordinate expression of genes in the plastid genome may arise through rapid evolution of the flanking sequences of these genes.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Zihan Cheng ◽  
Xuemei Zhang ◽  
Wenjing Yao ◽  
Kai Zhao ◽  
Lin Liu ◽  
...  

Abstract Background The Late Embryogenesis-Abundant (LEA) gene families, which play significant roles in regulation of tolerance to abiotic stresses, widely exist in higher plants. Poplar is a tree species that has important ecological and economic values. But systematic studies on the gene family have not been reported yet in poplar. Results On the basis of genome-wide search, we identified 88 LEA genes from Populus trichocarpa and renamed them as PtrLEA. The PtrLEA genes have fewer introns, and their promoters contain more cis-regulatory elements related to abiotic stress tolerance. Our results from comparative genomics indicated that the PtrLEA genes are conserved and homologous to related genes in other species, such as Eucalyptus robusta, Solanum lycopersicum and Arabidopsis. Using RNA-Seq data collected from poplar under two conditions (with and without salt treatment), we detected 24, 22 and 19 differentially expressed genes (DEGs) in roots, stems and leaves, respectively. Then we performed spatiotemporal expression analysis of the four up-regulated DEGs shared by the tissues, constructed gene co-expression-based networks, and investigated gene function annotations. Conclusion Lines of evidence indicated that the PtrLEA genes play significant roles in poplar growth and development, as well as in responses to salt stress.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1456
Author(s):  
Xin Jin ◽  
Can Baysal ◽  
Margit Drapal ◽  
Yanmin Sheng ◽  
Xin Huang ◽  
...  

Light is an essential regulator of many developmental processes in higher plants. We investigated the effect of 4-hydroxy-3-methylbut-2-enyl diphosphate reductase 1/2 genes (OsHDR1/2) and isopentenyl diphosphate isomerase 1/2 genes (OsIPPI1/2) on the biosynthesis of chlorophylls, carotenoids, and phytosterols in 14-day-old etiolated rice (Oyza sativa L.) leaves during de-etiolation. However, little is known about the effect of isoprenoid biosynthesis genes on the corresponding metabolites during the de-etiolation of etiolated rice leaves. The results showed that the levels of α-tocopherol were significantly increased in de-etiolated rice leaves. Similar to 1-deoxy-D-xylulose-5-phosphate synthase 3 gene (OsDXS3), both OsDXS1 and OsDXS2 genes encode functional 1-deoxy-D-xylulose-5-phosphate synthase (DXS) activities. Their expression patterns and the synthesis of chlorophyll, carotenoid, and tocopherol metabolites suggested that OsDXS1 is responsible for the biosynthesis of plastidial isoprenoids in de-etiolated rice leaves. The expression analysis of isoprenoid biosynthesis genes revealed that the coordinated expression of the MEP (2-C-methyl-D-erythritol 4-phosphate) pathway, chlorophyll, carotenoid, and tocopherol pathway genes mirrored the changes in the levels of the corresponding metabolites during de-etiolation. The underpinning mechanistic basis of coordinated light-upregulated gene expression was elucidated during the de-etiolation process, specifically the role of light-responsive cis-regulatory motifs in the promoter region of these genes. In silico promoter analysis showed that the light-responsive cis-regulatory elements presented in all the promoter regions of each light-upregulated gene, providing an important link between observed phenotype during de-etiolation and the molecular machinery controlling expression of these genes.


2018 ◽  
Vol 19 (11) ◽  
pp. 3591 ◽  
Author(s):  
Aki Nishiyama ◽  
Sakura Matsuta ◽  
Genki Chaya ◽  
Takafumi Itoh ◽  
Kotaro Miura ◽  
...  

Heterotrimeric G proteins are important molecules for regulating plant architecture and transmitting external signals to intracellular target proteins in higher plants and mammals. The rice genome contains one canonical α subunit gene (RGA1), four extra-large GTP-binding protein genes (XLGs), one canonical β subunit gene (RGB1), and five γ subunit genes (tentatively named RGG1, RGG2, RGG3/GS3/Mi/OsGGC1, RGG4/DEP1/DN1/OsGGC3, and RGG5/OsGGC2). RGG1 encodes the canonical γ subunit; RGG2 encodes the plant-specific type of γ subunit with additional amino acid residues at the N-terminus; and the remaining three γ subunit genes encode the atypical γ subunits with cysteine abundance at the C-terminus. We aimed to identify the RGG3/GS3/Mi/OsGGC1 gene product, Gγ3, in rice tissues using the anti-Gγ3 domain antibody. We also analyzed the truncated protein, Gγ3∆Cys, in the RGG3/GS3/Mi/OsGGC1 mutant, Mi, using the anti-Gγ3 domain antibody. Based on nano-liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, the immunoprecipitated Gγ3 candidates were confirmed to be Gγ3. Similar to α (Gα) and β subunits (Gβ), Gγ3 was enriched in the plasma membrane fraction, and accumulated in the flower tissues. As RGG3/GS3/Mi/OsGGC1 mutants show the characteristic phenotype in flowers and consequently in seeds, the tissues that accumulated Gγ3 corresponded to the abnormal tissues observed in RGG3/GS3/Mi/OsGGC1 mutants.


Author(s):  
William Rice

Centromeres are among the fastest evolving genomic regions in a diverse array of organisms. The evolutionary process driving this rapid evolution has not been unambiguously established. Here I integrate diverse information to motivate a model in which centromeres evolve rapidly because of their intrinsic molecular phenotype: they tightly bind centromeric proteins throughout the cell cycle. DNA-bound proteins have been shown to cause stalling and collapse of DNA replication forks in many genomic regions, including centromeres. Collapsed replication forks generate one-sided double strand breaks (DSBs) that are repaired by the Break-Induced Repair (BIR) pathway. Here I show why this repair is expected to generate tandem repeat structure and three key features at centromeres: i) increased nucleotide substitution mutation rates, ii) out-of- register re-initiation of replication that leads to indels spanning one or more repeat units, and iii) elevated rates of large and small transpositions within centromeres and between genomic regions. These phenotypes lead to: i) a rapid rate of nucleotide substitutions within a clade of centromeric sequences, ii) continual turnover of monomers within centromeres that fosters molecular-drift and molecular-drive, and iii) recurrent quantum leaps in centromere sequence due to the formation of mosaic monomers and new sequences transposed into non-homologous centromeres. These features are plausibly the major reason centromeres evolve so rapidly. I also speculate on how the DNA sequence of centromeres might perpetually coevolve with the protein sequence of histone CENH3 –the major epigenetic mark of centromeres.


1991 ◽  
Vol 39 (11) ◽  
pp. 1495-1506 ◽  
Author(s):  
P M Motte ◽  
R Loppes ◽  
M Menager ◽  
R Deltour

We report the 3-D arrangement of DNA within the nucleolar subcomponents from two evolutionary distant higher plants, Zea mays and Sinapis alba. These species are particularly convenient to study the spatial organization of plant intranucleolar DNA, since their nucleoli have been previously reconstructed in 3-D from serial ultra-thin sections. We used the osmium ammine-B complex (a specific DNA stain) on thick sections of Lowicryl-embedded root fragments. Immunocytochemical techniques using anti-DNA antibodies and rDNA/rDNA in situ hybridization were also applied on ultra-thin sections. We showed on tilted images that the OA-B stains DNA throughout the whole thickness of the section. In addition, very low quantities of cytoplasmic DNA were stained by this complex, which is now the best DNA stain used in electron microscopy. Within the nucleoli the DNA was localized in the fibrillar centers, where large clumps of dense chromatin were also visible. In the two plant species intranucleolar chromatin forms a complex network with strands partially linked to chromosomal nucleolar-organizing regions identified by in situ hybridization. This study describes for the first time the spatial arrangement of the intranucleolar chromatin in nucleoli of higher plants using high-resolution techniques.


2009 ◽  
Vol 70 (5) ◽  
pp. 487-498 ◽  
Author(s):  
Sugey Ramona Sinagawa-García ◽  
Tarinee Tungsuchat-Huang ◽  
Octavio Paredes-López ◽  
Pal Maliga

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1711-1720 ◽  
Author(s):  
Bryant F McAllister ◽  
Gilean A T McVean

Abstract The amino acid sequence of the transformer (tra) gene exhibits an extremely rapid rate of evolution among Drosophila species, although the gene performs a critical step in sex determination. These changes in amino acid sequence are the result of either natural selection or neutral evolution. To differentiate between selective and neutral causes of this evolutionary change, analyses of both intraspecific and interspecific patterns of molecular evolution of tra gene sequences are presented. Sequences of 31 tra alleles were obtained from Drosophila americana. Many replacement and silent nucleotide variants are present among the alleles; however, the distribution of this sequence variation is consistent with neutral evolution. Sequence evolution was also examined among six species representative of the genus Drosophila. For most lineages and most regions of the gene, both silent and replacement substitutions have accumulated in a constant, clock-like manner. In exon 3 of D. virilis and D. americana we find evidence for an elevated rate of nonsynonymous substitution, but no statistical support for a greater rate of nonsynonymous relative to synonymous substitutions. Both levels of analysis of the tra sequence suggest that, although the gene is evolving at a rapid pace, these changes are neutral in function.


2020 ◽  
Vol 12 (8) ◽  
pp. 1277-1301
Author(s):  
Mark J Nolte ◽  
Peicheng Jing ◽  
Colin N Dewey ◽  
Bret A Payseur

Abstract Island populations repeatedly evolve extreme body sizes, but the genomic basis of this pattern remains largely unknown. To understand how organisms on islands evolve gigantism, we compared genome-wide patterns of gene expression in Gough Island mice, the largest wild house mice in the world, and mainland mice from the WSB/EiJ wild-derived inbred strain. We used RNA-seq to quantify differential gene expression in three key metabolic organs: gonadal adipose depot, hypothalamus, and liver. Between 4,000 and 8,800 genes were significantly differentially expressed across the evaluated organs, representing between 20% and 50% of detected transcripts, with 20% or more of differentially expressed transcripts in each organ exhibiting expression fold changes of at least 2×. A minimum of 73 candidate genes for extreme size evolution, including Irs1 and Lrp1, were identified by considering differential expression jointly with other data sets: 1) genomic positions of published quantitative trait loci for body weight and growth rate, 2) whole-genome sequencing of 16 wild-caught Gough Island mice that revealed fixed single-nucleotide differences between the strains, and 3) publicly available tissue-specific regulatory elements. Additionally, patterns of differential expression across three time points in the liver revealed that Arid5b potentially regulates hundreds of genes. Functional enrichment analyses pointed to cell cycling, mitochondrial function, signaling pathways, inflammatory response, and nutrient metabolism as potential causes of weight accumulation in Gough Island mice. Collectively, our results indicate that extensive gene regulatory evolution in metabolic organs accompanied the rapid evolution of gigantism during the short time house mice have inhabited Gough Island.


2020 ◽  
Vol 21 (8) ◽  
pp. 2659
Author(s):  
Hong Zhang ◽  
Huan Guo ◽  
Weiguo Hu ◽  
Wanquan Ji

Growing interest and recent evidence have identified long non-coding RNA (lncRNA) as the potential regulatory elements for eukaryotes. LncRNAs can activate various transcriptional and post-transcriptional events that impact cellular functions though multiple regulatory functions. Recently, a large number of lncRNAs have also been identified in higher plants, and an understanding of their functional role in plant resistance to infection is just emerging. Here, we focus on their identification in crop plant, and discuss their potential regulatory functions and lncRNA-miRNA-mRNA network in plant pathogen stress responses, referring to possible examples in a model plant. The knowledge gained from a deeper understanding of this colossal special group of plant lncRNAs will help in the biotechnological improvement of crops.


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