Aerobic polychlorinated biphenyl-degrading bacteria isolated from the Tohoku region of Japan are not regionally endemic

In the Tohoku region of Japan, 72% of the land comprises mountain forest zones. During winter, severe climatic conditions include heavy snowfall. In such an environment, which is considered high in biodiversity, we assumed that aerobic bacteria would be diverse and would possess the ability to degrade polychlorinated biphenyls (PCBs). In this study, 78 environmental samples were collected from the Tohoku region and 56 aerobic PCB-degrading bacterial strains were isolated. They belonged to the genera Achromobacter, Rhodococcus, Pseudomonas, Stenotrophomonas, Comamonas, Pigmentiphaga, Xenophilus, Acinetobacter, and Pandoraea. Previously reported aerobic PCB-degrading bacterial strains isolated in Japan belonged to the same genera, except that the genera Acidovorax and Bacillus were not identified in the present study. In particular, the isolated Comamonas testosteroni strains YAZ2 and YU14-111 had high PCB-degrading abilities. Analysis of the sequences of the YAZ2 and YU14-111 strains showed that the gene structures of the bph operon, which encode enzymes associated with PCB degradation, were the same as those of the Acidovorax sp. KKS102 strain. Moreover, 2,3-biphenyl dioxygenase activity was responsible for the degradation characteristics of all the isolated strains. Overall, this study suggests that aerobic PCB-degrading bacteria are not specifically endemic to the Tohoku region but distributed across Japan.

Genome-wide sequence identification and expression analysis of N6-methyladenosine demethylase in sugar beet (Beta vulgaris L.) under salt stress

In eukaryotes, N6-methyladenosine (m6A) is the most abundant and highly conserved RNA modification. In vivo, m6A demethylase dynamically regulates the m6A level by removing the m6A marker where it plays an important role in plant growth, development and response to abiotic stress. The confirmed m6A demethylases in Arabidopsis thaliana include ALKBH9B and ALKBH10B, both belonging to the ALKB family. In this study, BvALKB family members were identified in sugar beet genome-wide database, and their conserved domains, gene structures, chromosomal locations, phylogeny, conserved motifs and expression of BvALKB genes were analyzed. Almost all BvALKB proteins contained the conserved domain of 2OG-Fe II-Oxy. Phylogenetic analysis suggested that the ten proteins were clustered into five groups, each of which had similar motifs and gene structures. Three Arabidopsis m6A demethylase-homologous proteins (BvALKBH6B, BvALKBH8B and BvALKBH10B) were of particular interest in our study. Expression profile analysis showed that almost all genes were up-regulated or down-regulated to varying degrees under salt stress. More specifically, BvALKBH10B homologous to AtALKBH10B was significantly up-regulated, suggesting that the transcriptional activity of this gene is responsive to salt stress. This study provides a theoretical basis for further screening of m6A demethylase in sugar beet, and also lays a foundation for studying the role of ALKB family proteins in growth, development and response to salinity stress.

Genome-Wide Identification and Co-Expression Analysis of ARF and IAA Family Genes in Euscaphis konishii: Potential Regulators of Triterpenoids and Anthocyanin Biosynthesis

Euscaphis konishii is an evergreen plant that is widely planted as an industrial crop in Southern China. It produces red fruits with abundant secondary metabolites, giving E. konishii high medicinal and ornamental value. Auxin signaling mediated by members of the AUXIN RESPONSE FACTOR (ARF) and auxin/indole-3-acetic acid (Aux/IAA) protein families plays important roles during plant growth and development. Aux/IAA and ARF genes have been described in many plants but have not yet been described in E. konishii. In this study, we identified 34 EkIAA and 29 EkARF proteins encoded by the E. konishii genome through database searching using HMMER. We also performed a bioinformatic characterization of EkIAA and EkARF genes, including their phylogenetic relationships, gene structures, chromosomal distribution, and cis-element analysis, as well as conserved motifs in the proteins. Our results suggest that EkIAA and EkARF genes have been relatively conserved over evolutionary history. Furthermore, we conducted expression and co-expression analyses of EkIAA and EkARF genes in leaves, branches, and fruits, which identified a subset of seven EkARF genes as potential regulators of triterpenoids and anthocyanin biosynthesis. RT-qPCR, yeast one-hybrid, and transient expression analyses showed that EkARF5.1 can directly interact with auxin response elements and regulate downstream gene expression. Our results may pave the way to elucidating the function of EkIAA and EkARF gene families in E. konishii, laying a foundation for further research on high-yielding industrial products and E. konishii breeding.

Genome-wide identification and expression profile of YABBY genes in Averrhoa carambola

Background Members of the plant-specific YABBY gene family are thought to play an important role in the development of leaf, flower, and fruit. The YABBY genes have been characterized and regarded as vital contributors to fruit development in Arabidopsis thaliana and tomato, in contrast to that in the important tropical economic fruit star fruit (Averrhoa carambola), even though its genome is available. Methods In the present study, a total of eight YABBY family genes (named from AcYABBY1 to AcYABBY8) were identified from the genome of star fruit, and their phylogenetic relationships, functional domains and motif compositions, physicochemical properties, chromosome locations, gene structures, protomer elements, collinear analysis, selective pressure, and expression profiles were further analyzed. Results Eight AcYABBY genes (AcYABBYs) were clustered into five clades and were distributed on five chromosomes, and all of them had undergone negative selection. Tandem and fragment duplications rather than WGD contributed to YABBY gene number in the star fruit. Expression profiles of AcYABBYs from different organs and developmental stages of fleshy fruit indicated that AcYABBY4 may play a specific role in regulating fruit size. These results emphasize the need for further studies on the functions of AcYABBYs in fruit development.

Comprehensive Genome-wide Identification, Characterization, and Expression Analysis of CCHC Zinc Finger Gene Family in Wheat (Triticum aestivum L.)

Background: The CCHC zinc finger proteins (CCHC-ZFPs) are transcription factors that play versatile roles in plant growth, development, and responses to biotic/abiotic stress. However, little is known about the CCHC-ZF genes in bread wheat (Triticum aestivum), an important food crop.Results: In this study, 50 TaCCHC-ZF genes were identified and distributed unevenly on 21 wheat chromosomes. According to the phylogenetic features, the 50 TaCCHC-ZF genes were classified into eight groups with specific motifs and gene structures. 43 TaCCHC-ZF genes were identified as segmentally duplicated genes that formed 36 segmental duplication gene pairs. Additionally, the collinearity analyses between wheat and eight other representative plant species showed that wheat had closer phylogenetic relationships with monocots compared to dicots. A total of 636 cis-elements related to environmental stress and phytohormone responsiveness were identified in the promoter of TaCCHC-ZF genes. Moreover, GO enrichment results revealed that all 50 TaCCHC-ZF genes were annotated under metal ion binding and nucleic acid binding. 91 miRNA binding sites within the 34 TaCCHC-ZF genes were identified by miRNA targets analyses, indicating that the expression of TaCCHC-ZF genes could be regulated by the miRNAs. Based on published transcriptome data, 38 TaCCHC-ZF genes were identified as DEGs, and 15 TaCCHC-ZF genes among them were verified by qRT-PCR assays, which showed response to drought, heat, or simultaneous response of them.Conclusions: This study systematically explored the gene structures, evolutionary characteristics, and potential roles during environmental responses of TaCCHC-ZF genes, providing a foundation for further investigation and application of TaCCHC-ZF genes in the molecular breeding of T. aestivum.

Genome-Wide Characterization and Abiotic Stresses Expression Analysis of Annexin Family Genes in Poplar

Poplar is an illustrious industrial woody plant with rapid growth, providing a range of materials, and having simple post-treatment. Various kinds of environmental stresses limit its output. Plant annexin (ANN) is a calcium-dependent phospholipid-binding protein involved in plant metabolism, growth and development, and cooperatively regulating drought resistance, salt tolerance, and various stress responses. However, the features of the PtANN gene family and different stress responses remain unknown in poplar. This study identified 12 PtANN genes in the P. trichocarpa whole-genome and PtANNs divided into three subfamilies based on the phylogenetic tree. The PtANNs clustered into the same clade shared similar gene structures and conserved motifs. The 12 PtANN genes were located in ten chromosomes, and segmental duplication events were illustrated as the main duplication method. Additionally, the PtANN4 homogenous with AtANN1 was detected localized in the cytoplasm and plasma membrane. In addition, expression levels of PtANNs were induced by multiple abiotic stresses, which indicated that PtANNs could widely participate in response to abiotic stress. These results revealed the molecular evolution of PtANNs and their profiles in response to abiotic stress.

Genome-Wide Identification and Expression Profile of OSCA Gene Family Members in Triticum aestivum L.

Hyperosmolality and various other stimuli can trigger an increase in cytoplasmic-free calcium concentration ([Ca2+]cyt). Members of the Arabidopsis thaliana (L.) reduced hyperosmolality-gated calcium-permeable channels (OSCA) gene family are reported to be involved in sensing extracellular changes to trigger hyperosmolality-induced [Ca2+]cyt increases and controlling stomatal closure during immune signaling. Wheat (Triticum aestivum L.) is a very important food crop, but there are few studies of its OSCA gene family members. In this study, 42 OSCA members were identified in the wheat genome, and phylogenetic analysis can divide them into four clades. The members of each clade have similar gene structures, conserved motifs, and domains. TaOSCA genes were predicted to be regulated by cis-acting elements such as STRE, MBS, DRE1, ABRE, etc. Quantitative PCR results showed that they have different expression patterns in different tissues. The expression profiles of 15 selected TaOSCAs were examined after PEG (polyethylene glycol), NaCl, and ABA (abscisic acid) treatment. All 15 TaOSCA members responded to PEG treatment, while TaOSCA12/-39 responded simultaneously to PEG and ABA. This study informs research into the biological function and evolution of TaOSCA and lays the foundation for the breeding and genetic improvement of wheat.

Genome-wide Identification of the GRAS Gene Family of Actinidia Arguta

GRAS transcription factors play important roles in plant growth, development, and abiotic and biotic stress responses. In this study, the genome-wide identification of the transcription factor family of Actinidia arguta was carried out including an analysis of the physical and chemical properties, phylogenetic development, gene structure, collinearity between genes, and protein interactions. A total of 88 GRAS genes were identified in the genome of Actinidia arguta with protein lengths of 103-510 aa, a molecular mass of 11,603.25-22,457.96 kDa, and isoelectric points in the hydrophilic range between 4.45 and 6.50 From these genes, 67 were located in the nucleus and 21 in the chloroplast. The identified genes were further divided into eight subfamilies: SCR, HAM, DELLA, PAT1, SHR, SCL4/7, and GIGR. Members of the same subfamily had similar gene structures and conserved motifs. Motif 5 was highly conserved in the GRAS family. On the chromosomes of LG3, LG15, LG22, LG24, LG26 and LG28, there was a large number of tandem duplications of GRAS genes, with 64 pairs of genes orthologous with Arabidopsis thaliana. The analysis of protein interactions found that there were interactive relationships between SCL28 in the DLT subfamily and SCL14 in the LISCL subfamily and between SCL13 in the PAT1 subfamily and proteins of the LAS subfamily. Interactions were also observed between the SCL30, SCL33, and HAM4 proteins in the LISCL subfamily. This study, therefore, provides a reference for mining and verification within the GRAS genes in the Actinidia arguta genome.

Genome-Wide Identification and Characterization of HSP70 Gene Family in Aquilaria sinensis (Lour.) Gilg

The heat shock protein 70 (HSP70) gene family perform a fundamental role in protecting plants against biotic and abiotic stresses. Aquilaria sinensis is a classic stress-induced medicinal plant, producing a valuable dark resin in a wood matrix, known as agarwood, in response to environmental stresses. The HSP70 gene family has been systematic identified in many plants, but there is no comprehensive analysis at the genomic level in A. sinensis. In this study, 15 putative HSP70 genes were identified in A. sinensis through genome-wide bioinformatics analysis. Based on their phylogenetic relationships, the 15 AsHSP70 were grouped into six sub-families that with the conserved motifs and gene structures, and the genes were mapped onto six separate linkage groups. A qRT-PCR analysis showed that the relative expression levels of all the AsHSP70 genes were up-regulated by heat stress. Subcellular localization of all HSP70s was predicted, and three were verified by transiently expressed in Arabidopsis protoplasts. Based on the expression profiles in different tissues and different layers treated with Agar-Wit, we predict AsHSP70 genes are involved in different stages of agarwood formation. The systematic identification and expression analysis of HSP70s gene family imply some of them may play important roles in the formation of agarwood. Our findings not only provide a foundation for further study their biological function in the later research in A. sinensis, but also provides a reference for the analysis of HSPs in other species.

Brassica napus genes Rlm4 and Rlm7, conferring resistance to Leptosphaeria maculans, are alleles of the Rlm9 wall-associated kinase-like resistance locus

Brassica napus (canola/rapeseed) race specific resistance genes against blackleg disease, caused by the ascomycete fungus Leptosphaeria maculans, have been commonly used in canola breeding. To date, LepR3, Rlm2 and Rlm9 R genes against L. maculans have been cloned from B. napus. LepR3 and Rlm2 are Receptor Like Proteins (RLP) and the recently reported Rlm9 is a Wall Associated Kinase-Like (WAKL) protein. Rlm9 located on chromosome A07 is closely linked with Rlm3, Rlm4, RLm7 genes. Recognition of AvrLm5-9 and AvrLm3 by their corresponding Rlm9 and Rlm3 proteins is masked in the presence of AvrLm4-7. Here we report cloning of Rlm4 and Rlm7 by generating genome sequence of the doubled haploid (DH) B. napus cv Topas DH16516 introgression lines Topas-Rlm4 and Topas-Rlm7. Candidate Rlm4 and Rlm7 genes were identified form the genome sequence and gene structures were determined by mapping RNA-sequence reads, generated from infected cotyledon tissues, to the genome of Topas-Rlm4 and Topas-Rlm7. Rlm4 and Rlm7 genomic constructs with their native promoters were transferred into the blackleg susceptible B. napus cv Westar. Complementation of resistance response in the transgenic Westar-Rlm4 and Westar-Rlm7 that were inoculated with L. maculans transgenic isolates 2367-AvrRlm4-7 or 2367-AvrLm7 confirmed the function of Rlm4 and Rlm7 genes. Wild type L. maculans isolate 2367 that does not contain AvrLm4-7 or AvrLm7, and transgenic 2367-AvrLm3 and 2367-AvrLm5-9 did not induce resistance proving the specificity of Rlm4 and Rlm7 response. Rlm4 and Rlm7 alleles are also allelic to Rlm9. Rlm4 and Rlm7 genes encode WAKL proteins. Comparison of highly-homologous sequences of Rlm4 and Rlm7 with each other and with the sequence of additional alleles identified a limited number of point mutation located within the predicted extracellular receptor domains.