Characterization of the complete chloroplast genome of an annual halophyte, Chenopodium glaucum (Amaranthaceae)

Bacillus amyloliquefaciens 11B91 inoculation enhances the growth of quinoa (Chenopodium quinoa Willd.) under salt stress

Quinoa (Chenopodium quinoa Willd.) is a highly nutritious food product with a comprehensive development prospect. Here, we discussed the effect of Bacillus amyloliquefaciens 11B91 on the growth, development and salt tolerance (salt concentrations: 0, 150, 300 mmol·L-1) of quinoa and highlighted a positive role for the application of plant growth-promoting rhizobacteria bacteria in quinoa. In this artical, the growth-promoting effect of Bacillus amyloliquefaciens 11B91 on quinoa (Longli No.1) and the changes in biomass, chlorophyll content, root activity and total phosphorus content under salt stress were measured. The results revealed that plants inoculated with 11B91 exhibited increased maximum shoot fresh weight (73.95%), root fresh weight (75.36%), root dry weight (136%), chlorophyll a (65.32%) contents and chlorophyll b (58.5%) contents, root activity (54.44%) and total phosphorus content (16.66%). Additionally, plants inoculated with 11B91 under salt stress plants showed significantly improved, fresh weight (107%), dry weight (133%), chlorophyll a (162%) contents and chlorophyll b (76.37%) contents, root activity (33.07%), and total phosphorus content (42.73%).

CgMYB1, an R2R3-MYB transcription factor, can alleviate abiotic stress in an annual halophyte Chenopodium glaucum

MYB transcription factors (TFs) are important regulators of the stress response in plants. In the present study, we characterized the CgMYB1 gene in Chenopodium glaucum, a member of the R2R3-MYB TF family. CgMYB1 was located in the nucleus with an activating domain at the C terminus. The CgMYB1 gene could be induced by salt and cold stress in C. glaucum. Overexpressing CgMYB1 in Arabidopsis significantly enhanced salt and cold tolerance, probably by improving physiological performance and stress-related gene expression. Further analysis suggests that the positive response of CgMYB1 to abiotic stress may partially be attributed to the interaction between CgMYB1 and the CgbHLH001 promoter followed by activation of downstream stress-responsive genes, which mediates stress tolerance. Our findings should contribute to further understanding of the function of R2R3 MYB TF in response to abiotic stress.

Promoter activity and transcriptome analyses decipher functions of CgbHLH001 gene (Chenopodium glaucum L.) in response to abiotic stress

BACKGROUND

Our previous studies revealed that CgbHLH001 transcription factor (TF) played an important role in abiotic stress tolerance, suggesting that its promoter was a potential target in response to stress signals. In addition, the regulatory mechanism of CgbHLH001 TF is still limited.

RESULTS

In the present study, a 1512 bp of 5'-flanking sequence of CgbHLH001 gene was identified, and the sequence carried quite a few of cis-acting elements. The gene promoter displayed strong activity and was induced by multiple abiotic stress. A series of 5'-deletions of the promoter sequence resulted in a gradual decrease in its activity, especially, the 5' untranslated region (UTR) was necessary to drive promoter activity. Further, CgbHLH001 promoter drove its own gene overexpression ectopically at the transcriptional and translational levels, which in turn conferred the stress tolerance to transgenic Arabidopsis. Transcriptome analysis showed that salt stress induced a large number of genes involved in multiple biological regulatory processes. Differentially expressed genes (DEGs) that mediate phytohormone signal transduction and mitogen-activated protein kinase (MAPK) signaling pathway were widely induced and mostly upregulated under salt stress, and the transcription levels in P_bHLH::bHLH-overexpressing transgenic lines were higher than that of 35S::bHLH overexpression.

CONCLUSIONS

The CgbHLH001 promoter exhibited a positive response to abiotic stress and its 5' UTR sequence enhanced the regulation of gene expression to stress. A few important pathways and putative key genes involved in salt tolerance were identified, which can be used to elucidate the mechanism of salt tolerance and decipher the regulatory mechanism of promoters to develop an adaptation strategy for desert halophytes.

Characterization of the complete chloroplast genome of an annual herb, Chenopodium album (Amaranthaceae)

Chenopodium album is an annual herb from Amaranthaceae with worldwide distribution. It is a leafy vegetable as well as an important subsidiary grain crop with high nutritional value and medicinal value. In this study, we reported the complete chloroplast genome of C. album. The total chloroplast genome was 152,167 bp in length, containing a large single-copy region (LSC, 83,676 bp), a small single-copy region (SSC, 18,105 bp), and a pair of inverted repeat regions (IRs, 25,193 bp). The complete chloroplast genome contains 110 genes, including 78 protein-coding genes, 28 transfer RNA (tRNA) genes, and 4 ribosomal RNA (rRNA) genes with an overall GC content of 37.3%. Phylogenetic analysis showed that C. album was sister to C. acuminatum within Chenopodioideae. The complete chloroplast genome of C. album will provide useful resources for the development and utilization of this species and the phylogenetic study of Amaranthaceae.

The complete chloroplast genome of Chenopodium acuminatum Willd. (Amaranthaceae)

The complete chloroplast genome (plastome) of the Chenopodium acuminatum was assembled and annotated in this study. The complete plastome was composed of circular DNA molecules with a total length of 152,200 bp, comprising a large single-copy region (83,683 bp), a small single-copy region (18,131 bp), and two inverted repeat regions (25,193 bp). GC content of this complete plastome was 37.2%. In total, 113 unique genes were annotated, including 79 protein-coding genes (PCGs), 30 transfer RNAs, and 4 ribosomal RNAs. Phylogenomic analysis showed that C. acuminatum was closely related to C. album.

Complete chloroplast genome of the grain Chenopodium quinoa Willd., an important economical and dietary plant

The grain Chenopodium quinoa Willd. is the main traditional food of Inca aboriginal, which was a native grain in South American Andes Mountains, the edible and cultivation history of which has been more than five thousand years. In this study, we sequenced the complete chloroplast genome of C. quinoa on the Illumina platform by shotgun genome skimming method. The complete chloroplast genome of C. quinoa was 152,087 bp in length with the GC content 37.2%, which was comprised of a large single copy (LSC) region of 83,570 bp, a small single copy (SSC) region of 18,107 bp, and a pair of inverted repeats (IRA/IRB) of 25,205 bp. The chloroplast genome encoded 133 genes including 88 protein-coding genes, 37 tRNA genes and eight rRNA genes. Phylogenetic analysis constructed using the maximum likelihood (ML) method strongly supported the monophyly of each genus in the family Chenopodiaceae, and the genus Chenopodium is sister to Spinacia as a cluster, which closely grouped to Dysphania.