Genome-Wide Analysis of Long Intergenic Noncoding RNAs Responding to Low-Nutrient Conditions in Arabidopsis thaliana: Possible Involvement of Trans-Acting siRNA3 in Response to Low Nitrogen

2019 ◽  
Vol 60 (9) ◽  
pp. 1961-1973 ◽  
Author(s):  
Makiha Fukuda ◽  
Sho Nishida ◽  
Yusuke Kakei ◽  
Yukihisa Shimada ◽  
Toru Fujiwara

Abstract Long intergenic noncoding RNAs (lincRNAs) play critical roles in transcriptional and post-transcriptional regulation of gene expression in a wide variety of organisms. Thousands of lincRNAs have been identified in plant genomes, although their functions remain mostly uncharacterized. Here, we report a genome-wide survey of lincRNAs involved in the response to low-nutrient conditions in Arabidopsis thaliana. We used RNA sequencing data derived from A. thaliana roots exposed to low levels of 12 different nutrients. Using bioinformatics approaches, 60 differentially expressed lincRNAs were identified that were significantly upregulated or downregulated under deficiency of at least one nutrient. To clarify their roles in nutrient response, correlations of expression patterns between lincRNAs and reference genes were examined across the 13 conditions (12 low-nutrient conditions and control). This analysis allowed us to identify lincRNA-RNA pairs with highly positive or negative correlations. In addition, calculating interaction energies of those pairs showed lincRNAs that may act as regulatory interactors; e.g. small interfering RNAs (siRNAs). Among them, trans-acting siRNA3 (TAS3), which is known to promote lateral root development by producing siRNA against Auxin response factor 2, 3, and 4, was revealed as a nitrogen (N)-responsive lincRNA. Furthermore, nitrate transporter 2 was identified as a potential target of TAS3-derived siRNA, suggesting that TAS3 participates in multiple pathways by regulating N transport and root development under low-N conditions. This study provides the first resource for candidate lincRNAs involved in multiple nutrient responses in plants.

2020 ◽  
Author(s):  
Rhonda C. Meyer ◽  
Kathleen Weigelt-Fischer ◽  
Dominic Knoch ◽  
Marc Heuermann ◽  
Yusheng Zhao ◽  
...  

ABSTRACTWe assessed early vegetative growth in a population of 382 accessions of Arabidopsis thaliana using automated non-invasive high-throughput phenotyping. All accessions were imaged daily from seven to 18 days after sowing in three independent experiments and genotyped using the Affymetrix 250k SNP array. Projected leaf area (PLA) was derived from image analysis and used to calculate relative growth rates (RGR). In addition, initial seed size was determined. The generated data sets were used jointly for a genome-wide association study that identified 238 marker-trait associations (MTAs) individually explaining up to 8 % of the total phenotypic variation. Co-localisation of MTAs occurred at 33 genomic positions. At 21 of these positions, sequential co-localisation of MTAs for two to nine consecutive days was observed. The detected MTAs for PLA and RGR could be grouped according to their temporal expression patterns, emphasising that temporal variation of MTA action can be observed even during the vegetative growth phase, a period of continuous formation and enlargement of seemingly similar rosette leaves. This indicates that causal genes may be differentially expressed in successive periods. Analyses of the temporal dynamics of biological processes are needed to gain important insight into the molecular mechanisms of growth-controlling processes in plants.HighlightA genome-wide association study including the factor time highlighted that early plant growth in Arabidopsis is governed by several medium and many small effect loci, most of which act only during short phases of two to nine days.


2021 ◽  
Author(s):  
◽  
Noémie Valenza-Troubat

<p><b>Understanding the relationship between DNA sequence variation and the diversity of observable traits across the tree of life is a central research theme in biology. In all organisms, most traits vary continuously between individuals. Explaining the genetic basis of this quantitative variation requires disentangling genetic from non-genetic factors, as well as their interactions. The identification of causal genetic variants yields fundamental insights into how evolution creates diversity across the tree of life. Ultimately, this information can be used for medical, environmental and agricultural applications. Aquaculture is an industry that is experiencing significant global growth and is benefiting from the advances of genomic research. Genomic information helps to improve complex commercial phenotypes such as growth traits, which are easily quantified visually, but influenced by polygenes and multiple environmental factors, such as temperature. In the context of a global food crisis and environmental change, there is an urgent need not only to understand which genetic variants are potential candidates for selection gains, but also how the architecture of these traits are composed (e.g. monogenes, polygenes) and how they are influenced by and interact with the environment. The overall goal of this thesis research was to generate a genome-wide multi-omics dataset matched with exhaustive phenotypic information derived from a F0-F1 pedigree to investigate the quantitative genetic basis of growth in the New Zealand silver trevally (Pseudocaranx georgianus). These data were used to identify genomic regions that co-segregate with growth traits, and to describe the regulation of the genes involved in response to temperature fluctuations. The findings of this research helped gain fundamental insights into the genotype–phenotype map in an important teleost species and understand its ability to dynamically respond to temperature variations. This will ultimately support the establishment of a genomics-informed New Zealand aquaculture breeding programme. </b></p> <p>Chapter 1 of this thesis provides an overview of how genes interact with the environment to produce various growth phenotypes and how an understanding of this is important in aquaculture. This first chapter provides the deeper context for the research in subsequent data chapters. </p> <p>Chapter 2 describes the study population, the collection of phenotypic and genotypic data, and a first description of the genetic parameters of growth traits in trevally. A combination of Whole Genome Sequencing (WGS) and Genotyping-By-Sequencing (GBS) techniques were used to generate 60 thousand Single Nucleotide Polymorphism (SNP) markers for individuals in a two-generation pedigree. Together with phenotypic data, the genotyping data were used to reconstruct the pedigree, measure inbreeding levels, and estimate heritability for 10 growth traits. Parents were identified for 63% of the offspring and successful pedigree reconstruction indicated highly uneven contributions of each parent, and between the sexes, to the subsequent generation. The average inbreeding levels did not change between generations, but were significantly different between families. Growth patterns were found to be similar to that of other carangids and subject to seasonal variations. Heritability as well as genetic and phenotypic correlations were estimated using both a pedigree and a genomic relatedness matrix. All growth trait heritability estimates and correlations were found to be consistently high and positively correlated to each other. </p> <p>In Chapter 3, genotypic and phenotypic data were used to carry out linkage mapping and a genome-wide association study (GWAS) to map quantitative trait loci (QTLs) associated with growth differences in the F1 population. A linkage map was generated using the largest family, which allowed to scan for rare variants associated with the traits. The linkage map reported in this thesis is the first one for the Pseudocaranx genus and one of the densest for the carangid family. It included 19,861 SNPs contained in 24 linkage groups, which correspond to the 24 trevally chromosomes. Eight significant QTLs associated with height, length and weight were discovered on three linkage groups. Using GWAS, 113 SNPs associated with nine traits were identified and 29 genetic growth hot spots were uncovered. Two of the GWAS markers co-located with the QTLs discovered with the linkage mapping analysis. This demonstrates that combining QTL mapping and GWAS represents a powerful approach for the identification and validation of loci controlling complex phenotypes, such as growth, and provides important insights into the genetic architecture of these traits. </p> <p>Chapter 4, the last data chapter, investigates plasticity in gene expression patterns and growth of juvenile trevally, in response to different temperatures. Temperature conditions were experimentally manipulated for 1 month to mimic seasonal extremes. Phenotypic differences in growth were measured in 400 individuals, and the gene expression patterns of the pituitary gland and the liver were compared across treatments in a subset of 100 individuals, using RNA sequencing. Results showed that growth increased 50% more in the warmer compared with the colder condition, suggesting that temperature has a large impact on the metabolic activity associated with growth. We were able to annotate 27,887 gene models and found 39 differentially expressed genes (DEGs) in the pituitary, and 238 in the liver. Of these, 6 DEGs showed a common expression pattern between the tissues. Annotated blast matches of all DEGs revealed genes linked to major pathways affecting metabolism and reproduction. Our results indicate that native New Zealand trevally exhibit predictable plastic regulatory responses to temperature stress and the genes identified provide excellent for selective breeding objectives and studied how populations may adapt to increasing temperatures.</p> <p>Finally, Chapter 5 discusses the implications, future directions, and application of this research for trevally and other breeding programmes. It more broadly highlights the insights that were gained on the genetic architecture of growth, and the role of temperature in interacting and modulating genes involved in plastic growth responses.</p>


Author(s):  
Bo Shu ◽  
YaChao Xie ◽  
Fei Zhang ◽  
Dejian Zhang ◽  
Chunyan Liu ◽  
...  

Calmodulin-like (CML) proteins represent a diverse family of protein in plants, and play significant roles in biotic and abiotic stress responses. However, the involvement of citrus CMLs in plant responses to drought stress (abiotic stress) and arbuscular mycorrhizal fungi (AMF) colonization remain relatively unknown. We characterized the citrus CML genes by analyzing the EF-hand domains and a genome-wide search, and identified a total of 38 such genes, distributed across at least nine chromosomes. Six tandem duplication clusters were observed in the CsCMLs, and 12 CsCMLs exhibited syntenic relationships with Arabidopsis thaliana CMLs. Gene expression analysis showed that 29 CsCMLs were expressed in the roots, and exhibited differential expression patterns. The regulation of CsCMLs expression was not consistent with the cis-elements identified in their promoters. CsCML2, 3, and 5 were upregulated in response to drought stress, and AMF colonization repressed the expression of CsCML7, 9, 12, 13,20, 27, 28, and 35,and induced that of CsCML1, 2, 3, 5, 8, 10, 11, 14, 15, 16, 18, 25, 30, 33, and 37. Furthermore, AMF colonization and drought stress exerted a synergistic effect, evident from the enhanced repression of CsCML7, 9, 12, 13, 27, 28, and 35 and enhanced expression of CsCML2, 3, and 5 under AMF colonization and drought stress. The present study provides valuable insights into the CsCML gene family and its responses to AMF colonization and drought stress.


BMC Genetics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Liping Guan ◽  
Ke Cao ◽  
Yong Li ◽  
Jian Guo ◽  
Qiang Xu ◽  
...  

Abstract Background Peach (Prunus persica L.) is a diploid species and model plant of the Rosaceae family. In the past decade, significant progress has been made in peach genetic research via DNA markers, but the number of these markers remains limited. Results In this study, we performed a genome-wide DNA markers detection based on sequencing data of six distantly related peach accessions. A total of 650,693~1,053,547 single nucleotide polymorphisms (SNPs), 114,227~178,968 small insertion/deletions (InDels), 8386~12,298 structure variants (SVs), 2111~2581 copy number variants (CNVs) and 229,357~346,940 simple sequence repeats (SSRs) were detected and annotated. To demonstrate the application of DNA markers, 944 SNPs were filtered for association study of fruit ripening time and 15 highly polymorphic SSRs were selected to analyze the genetic relationship among 221 accessions. Conclusions The results showed that the use of high-throughput sequencing to develop DNA markers is fast and effective. Comprehensive identification of DNA markers, including SVs and SSRs, would be of benefit to genetic diversity evaluation, genetic mapping, and molecular breeding of peach.


2019 ◽  
Vol 20 (21) ◽  
pp. 5419 ◽  
Author(s):  
Gao-Feng Zhou ◽  
Li-Ping Zhang ◽  
Bi-Xian Li ◽  
Ou Sheng ◽  
Qing-Jiang Wei ◽  
...  

Long non-coding RNAs (lncRNAs) play important roles in plant growth and stress responses. As a dominant abiotic stress factor in soil, boron (B) deficiency stress has impacted the growth and development of citrus in the red soil region of southern China. In the present work, we performed a genome-wide identification and characterization of lncRNAs in response to B deficiency stress in the leaves of trifoliate orange (Poncirus trifoliata), an important rootstock of citrus. A total of 2101 unique lncRNAs and 24,534 mRNAs were predicted. Quantitative real-time polymerase chain reaction (qRT-PCR) experiments were performed for a total of 16 random mRNAs and lncRNAs to validate their existence and expression patterns. Expression profiling of the leaves of trifoliate orange under B deficiency stress identified 729 up-regulated and 721 down-regulated lncRNAs, and 8419 up-regulated and 8395 down-regulated mRNAs. Further analysis showed that a total of 84 differentially expressed lncRNAs (DELs) were up-regulated and 31 were down-regulated, where the number of up-regulated DELs was 2.71-fold that of down-regulated. A similar trend was also observed in differentially expressed mRNAs (DEMs, 4.21-fold). Functional annotation of these DEMs was performed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, and the results demonstrated an enrichment of the categories of the biosynthesis of secondary metabolites (including phenylpropanoid biosynthesis/lignin biosynthesis), plant hormone signal transduction and the calcium signaling pathway. LncRNA target gene enrichment identified several target genes that were involved in plant hormones, and the expression of lncRNAs and their target genes was significantly influenced. Therefore, our results suggest that lncRNAs can regulate the metabolism and signal transduction of plant hormones, which play an important role in the responses of citrus plants to B deficiency stress. Co-expression network analysis indicated that 468 significantly differentially expressed genes may be potential targets of 90 lncRNAs, and a total of 838 matched lncRNA-mRNA pairs were identified. In summary, our data provides a rich resource of candidate lncRNAs and mRNAs, as well as their related pathways, thereby improving our understanding of the role of lncRNAs in response to B deficiency stress, and in symptom formation caused by B deficiency in the leaves of trifoliate orange.


2019 ◽  
Vol 116 (12) ◽  
pp. 5653-5658 ◽  
Author(s):  
Lin Shao ◽  
Feng Xing ◽  
Conghao Xu ◽  
Qinghua Zhang ◽  
Jian Che ◽  
...  

Utilization of heterosis has greatly increased the productivity of many crops worldwide. Although tremendous progress has been made in characterizing the genetic basis of heterosis using genomic technologies, molecular mechanisms underlying the genetic components are much less understood. Allele-specific expression (ASE), or imbalance between the expression levels of two parental alleles in the hybrid, has been suggested as a mechanism of heterosis. Here, we performed a genome-wide analysis of ASE by comparing the read ratios of the parental alleles in RNA-sequencing data of an elite rice hybrid and its parents using three tissues from plants grown under four conditions. The analysis identified a total of 3,270 genes showing ASE (ASEGs) in various ways, which can be classified into two patterns: consistent ASEGs such that the ASE was biased toward one parental allele in all tissues/conditions, and inconsistent ASEGs such that ASE was found in some but not all tissues/conditions, including direction-shifting ASEGs in which the ASE was biased toward one parental allele in some tissues/conditions while toward the other parental allele in other tissues/conditions. The results suggested that these patterns may have distinct implications in the genetic basis of heterosis: The consistent ASEGs may cause partial to full dominance effects on the traits that they regulate, and direction-shifting ASEGs may cause overdominance. We also showed that ASEGs were significantly enriched in genomic regions that were differentially selected during rice breeding. These ASEGs provide an index of the genes for future pursuit of the genetic and molecular mechanism of heterosis.


Genome ◽  
2020 ◽  
Author(s):  
Jiawen Wu ◽  
Huimin Liu ◽  
Shan Lu ◽  
Jian Hua ◽  
Baohong Zou

Chloroplast ribonucleoproteins (cpRNPs) are implicated in splicing, editing and stability control of chloroplast RNAs as well as in regulating development and stress tolerance. To facilitate a comprehensive understanding of their functions, we carried out a genome-wide identification, curation, and phylogenetic analysis of cpRNP genes in Oryza sativa (rice) and Arabidopsis thaliana (Arabidopsis). Ten cpRNP genes were identified in each of Arabidopsis and rice genomes based on the presence of two RRM (RNA recognition motif) domains and an N-terminal chloroplast targeting signal peptide in the predicted proteins. These proteins are localized to chloroplasts. Gene expression analysis revealed that cpRNPs have differential tissue expression patterns and some cpRNPs are induced by abiotic stresses such as cold, heat and drought. Taken together, our study provides a comprehensive annotation of the cpRNP gene family and their expression patterns in Arabidopsis and rice which will facilitate further studies on their roles in plant growth and stress responses.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Weizhuo Zhu ◽  
Yiyi Guo ◽  
Yeke Chen ◽  
Dezhi Wu ◽  
Lixi Jiang

Abstract Background Transcription factors GATAs are involved in plant developmental processes and respond to environmental stresses through binding DNA regulatory regions to regulate their downstream genes. However, little information on the GATA genes in Brassica napus is available. The release of the reference genome of B. napus provides a good opportunity to perform a genome-wide characterization of GATA family genes in rapeseed. Results In this study, 96 GATA genes randomly distributing on 19 chromosomes were identified in B. napus, which were classified into four subfamilies based on phylogenetic analysis and their domain structures. The amino acids of BnGATAs were obvious divergence among four subfamilies in terms of their GATA domains, structures and motif compositions. Gene duplication and synteny between the genomes of B. napus and A. thaliana were also analyzed to provide insights into evolutionary characteristics. Moreover, BnGATAs showed different expression patterns in various tissues and under diverse abiotic stresses. Single nucleotide polymorphisms (SNPs) distributions of BnGATAs in a core collection germplasm are probably associated with functional disparity under environmental stress condition in different genotypes of B. napus. Conclusion The present study was investigated genomic structures, evolution features, expression patterns and SNP distributions of 96 BnGATAs. The results enrich our understanding of the GATA genes in rapeseed.


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