SQUAMOSA promoter-binding protein-like (SPL), as plant specific transcription factors, is involved in many plant growth and development processes. However, there is less systematical study for SPL ...transcription factor in B. juncea (Cruciferae). Here, a total of 59 SPL genes classified into eight phylogenetic groups were identified in B. juncea, highly conserved within each ortholog were also found based on gene structure, conserved motif, as well as clustering level. In addition, clustering of SPL domain showed that two zinc finger-like structures and NLS segments were identified in almost of BjuSPLs. Analyzed of putative cis-elements for BjuSPLs demonstrated that SPL transcription factors were involved in adverse environmental changes, such as light, plant stresses and phytohormones response. Expression analysis showed that differentially expressed SPL genes were identified in flower and stem development of Cruciferae; such as BjuSPL3a-B, BjuSPL2b_B and BjuSPL2c_A were significantly expressed in flower; BjuSPL 3b_B and BjuSPL10a_A were significantly expressed in stem node (VP: vegetative period). Moreover, 28 of the 59 BjuSPLs were found involved in their posttranscriptional regulation targeted by miR156. We demonstrated that miR156 negatively regulated BjuSPL10a_A and BjuSPL3b_B to act for stem development in B. juncea.
Key message
RsMYB1a
was the crucial MYB, and
RsbHLH4
is the essential partner in regulating the anthocyanin biosynthesis in radish.
There are four color types of radish according to whether or not ...the anthocyanin accumulates in the skin and flesh of taproot. Red radishes accumulate a substantial amount of anthocyanins in both the skin and flesh. It is well known that the MYB-bHLH-WD40 transcription factor(s) complex regulates the biosynthesis of anthocyanin in plants. Here in, four candidate
MYB
and
bHLH
genes,
RsMYB1a
,
RsMYB1b
,
RsbHLH2
and
RsbHLH4
, were isolated from red radish ‘Hongxin 1’. The expression of
RsbHLH4
and the two structural genes
RsANS
and
RsUFGT
was significantly positively correlated with anthocyanin contents. The expression of
RsMYB1a
was also highly correlated with anthocyanin accumulation, particularly when the white flesh sample of ‘Hongxin 1-1’ was excluded. The transient expression of
RsMYB1a
in the radish cotyledon and leaf induced anthocyanin accumulation with even stronger promoting role when expression in combination with
RsbHLH4
. These results suggested that
RsMYB1a
was the crucial MYB, and that
RsbHLH4
is an essential partner in regulating the biosynthesis of anthocyanins in radish. The low or undetectable
RsbHLH4
expression paralleled the lack of anthocyanin accumulation in the white flesh of ‘Hongxin 1-1’ and ‘Shaguan 1’. Assays demonstrated that RsMYB1a interacted with RsbHLH4 and activated the expression of
RsbHLH4
. Notably, all the dark red radish cultivars have a longer
RsMYB1a
genomic DNA sequence, while the short and nonfunctional
RsMYB1a
is present in non-red cultivars. The length of the first intron and the presence of an early stop codon of
RsMYB1
might underlie the differential anthocyanin accumulation in the radish taproot.
Auxin signalling is vital for plant growth and development, from embryogenesis to senescence. Recent studies have shown that auxin regulates biological processes by mediating gene expression through ...a family of functionally original DNA-binding auxin response factors, which exist in a large multi-gene family in plants. However, to date, no information has been available about characteristics of the ARF gene family in Brassica juncea var. tumida. In this study, 65 B. juncea genes that encode ARF proteins were identified in the B. juncea whole-genome, classified into three phylogenetical groups and found to be widely and randomly distributed in the A-and B-genome. Highly conserved proteins were also found within each ortholog based on gene structure and conserved motifs, as well as clustering level. Furthermore, promoter cis-element analysis of BjARFs demonstrated that these genes affect the levels of plant hormones, such as auxin, salicylic, gibberellin acid, MeJA, abscisic acid, and ethylene. Expression analysis showed that differentially expressed BjARF genes were detected during the seedling stage, tumor stem development and the flowering period of B. juncea. Interestingly, we found that BjARF2b_A, BjARF3b_A, BjARF6b_A, and BjARF17a_B were significantly expressed in tumor stem, and an exogenous auxin assay indicated that these genes were sensitive to auxin and IAA signaling. Moreover, eight of the nine BjARF10/16/17 genes and all of the BjARF6/8 genes were involved in post-transcriptional regulation, targeted by Bj-miR160 and Bj-miR167c, respectively. This analysis provides deeper insight of diversification for ARFs and will facilitate further dissection of ARF gene function in B. juncea.
Red-fleshed radishes (RFRs) are economically important root vegetable in the Brassicaceae family that contain high concentrations of radish-red pigment in their fleshy root. However, the yield of the ...fleshy root is limited and germplasm resources for radish improvement are lacking. Genome doubling is an effective and efficient breeding tool for the rapid creation of new germplasm resources. Therefore, we aimed to induce tetraploidy in RFRs to improve pigment production. RFR seeds were immersed in aqueous colchicine (0, 0.01, 0.05, 0.10, 0.15, and 0.20% (w/v)) for 24 h followed by cultivation at 25℃ for 7 days, and those with uniform and distinctly swelled and short hypocotyls were selected as putative tetraploids. The putative tetraploids were identified by flow cytometry, and then we further examined the morphological and cytological characteristics of the diploid and tetraploid plants and measured gene expression via reverse transcription quantitative PCR. The results indicated that the most suitable concentration of colchicine (0.05% (w/v)) could induce tetraploidy in RFRs, with a tetraploid-induction rate as high as 34.50%. In addition, tetraploids exhibited a “gigantism” effect in both morphological and cytological traits, including swelled hypocotyls, thicker cotyledons, larger stoma, wider and longer leaves, taller plants, larger flowers, increased pollen size, larger seed pods and seeds, and a larger taproot. Moreover, compared with diploid plants, the pigment content and yield of pigment per plant of tetraploid plants were increased by 65.11% and 216.82%, respectively. Therefore, we present a simple and efficient method for tetraploid induction via soaking radish seeds in 0.05% (w/v) colchicine for 24 h. The results showed that tetraploid plants not only exhibited obvious “gigantism” effects but also significantly enhanced accumulation of anthocyanins, and represent a practical breeding material for improving pigment yield in RFRs.
Carmine radish produced in Chongqing is famous for containing a natural red pigment (red radish pigment). However, the anthocyanin biosynthesis transcriptome and the expression of anthocyanin ...biosynthesis-related genes in carmine radish have not been fully investigated. Uncovering the mechanism of anthocyanin biosynthesis in the 'Hongxin 1' carmine radish cultivar has become a dominant research topic in this field. In this study, a local carmine radish cultivar named 'Hongxin 1' containing a highly natural red pigment was used to analyze transcription factors (TFs) related to anthocyanin biosynthesis during the dynamic development of fleshy roots. Based on RNA sequencing data, a total of 1,747 TFs in 64 TF families were identified according to their DNA-binding domains. Of those, approximately 71 differentially expressed transcription factors (DETFs) were commonly detected in any one stage compared with roots in the seedling stage (SS_root). Moreover, 26 transcripts of DETFs targeted by 74 miRNAs belonging to 25 miRNA families were identified, including MYB, WRKY, bHLH, ERF, GRAS, NF-YA, C2H2-Dof, and HD-ZIP. Finally, eight DETF transcripts belonging to the C2C2-Dof, bHLH and ERF families and their eight corresponding miRNAs were selected for qRT-PCR to verify their functions related to anthocyanin biosynthesis during the development of carmine radish fleshy roots. Finally, we propose a putative miRNA-target regulatory model associated with anthocyanin biosynthesis in carmine radish. Our findings suggest that sucrose synthase might act as an important regulator to modulate anthocyanin biosynthesis in carmine radish by inducing several miRNAs (miR165a-5p, miR172b, miR827a, miR166g and miR1432-5p) targeting different ERFs than candidate miRNAs in the traditional WMBW complex in biological processes.
Vortex-Induced Vibration (VIV) is a major contributor to the fatigue damage of marine risers which are often arranged in an array configuration. In addition to helical strakes and fairings, studies ...have been strived in searching for possible VIV suppression techniques. Inspired by giant Saguaro Cacti, flexible cylinders of different cactus-shaped cross sections were tested in a water tunnel facility, and test results showed that cactus-like body shapes reduced VIV responses of a cylinder at no cost of significant increase of drag. A series of experiments were conducted on a pair of two tandem-arranged flexible cylinders and an array of four cylinders in a square configuration to investigate the effects of wake on the dynamic responses of cylinders and the VIV mitigation effectiveness of the cactus-like body shape. Results showed that the cylinders in a square configuration, either at the upstream or downstream positions, might have larger dynamic responses than those of a single cylinder. The cactus-like body shape could mitigate VIV responses of cylinders at upstream positions in an array configuration; however, similar to helical strakes, the mitigation efficiency was reduced on downstream cylinders. Note that the cactus-like cross-sectional shape investigated was not optimized for VIV suppression. The present study indicates that the modification of the cross-sectional shape of a cylinder to a well-designed cactus-like shape may be used as an alternative technique to mitigate the VIV of marine risers.
Flexible cylinders, such as marine risers, often experience sustained vortex-induced vibrations (VIVs). Installing helical strakes on a riser is the most widely used technique to mitigate VIVs. This ...study was inspired by the giant Saguaro Cacti which can withstand strong wind with a shallow root system. In this study, numerical simulations of flow past a stationary cylinder of a cactus-shaped cross-section in a two-dimensional flow field at a subcritical Reynolds number of 3900 were performed. Results show that cylinders of a cactus-shaped cross-section have a lower lift coefficient without increasing drag compared to those of a circular cylinder. VIV experiments on a single flexible pipe as well as on a set of two tandem-arranged flexible pipes were conducted at different reduced velocities to investigate the effects of the streamwise spacing and wake of the cactus-like body shape on VIV mitigation. Experimental results show that the cactus-like body shape can mitigate VIV responses of the cylinder at upstream position with no cost of increased drag; however, similar to helical strakes, the efficiency of VIV mitigation for the cylinder at downstream position is reduced. Although the cactus-like body shapes tested in this study were not optimized for oscillation suppression, still this study suggests that modification of the cross-sectional shape to a well-designed cactus-like shape has potentials to be used as an alternative technology to mitigate VIV of marine risers.
Fragrance is one of the most important quality traits in rice, and the phenotype is attributed to the loss-of-function betaine aldehyde dehydrogenase (BADH2) gene. At least 12 allelic variations of ...BADH2 have been identified, and some of these have been applied to rice fragrance breeding using traditional molecular markers and Sanger sequencing techniques. However, these traditional methods have several limitations, such as being very expensive, imprecise, inefficient, and having security issues. Thus, a new molecular marker technology must be developed to improve rice fragrance breeding.
In this study, more than 95% of the cultivated fragrant rice varieties belonged to a 7-bp deletion in exon 2 (badh2-E2) or an 8-bp deletion and 3-bp variation in exon 7 (badh2-E7). Both allelic variations resulted in the loss of function of the badh2 gene. We developed two novel SNP molecular markers, SNP_badh2-E2 and SNP_badh2-E7, related to the alleles. Their genotype and phenotype were highly cosegregated in the natural variation of rice accessions, with 160 of the 164 fragrant rice varieties detected with the two markers. These markers cosegregated with the fragrance phenotype in the F2 population.
Two functional SNP molecular markers of badh2-E2 and badh2-E7 allelic variations were developed. These functional SNP molecular markers can be used for genotype and genetic improvement of rice fragrance through marker-assisted selection and will significantly improve the efficiency of fragrant rice breeding and promote commercial molecular breeding of rice in the future.
How to cite: Li W, Zeng X, Li S, et al. Development and application of two novel functional molecular markers of BADH2 in rice. Electron J Biotechnol 2020;46. https://doi.org/10.1016/j.ejbt.2020.04.004.
An installation platform will disturb the natural seabed adjacent to a monopile and, consequently, affects the bearing capacity of the monopile foundation. Thus, consideration of the influence of ...installation disturbance is required in the monopile design, which can also save a fraction of the construction costs and avoid security risks. It was found in a sensitivity analysis, depending on the numerical simulations for an offshore monopile foundation installed using an installation platform, that the bearing capacities of the monopile were reduced by the penetration and extraction of the support legs of the installation platform, which were, a reduction of about 7% of the horizontal bearing capacity of the monopile (decreasing with a larger diameter of the monopile), about 2% of the ultimate bending moment, and almost no reduction of the vertical bearing capacity. For the monopile specifically subjected to the combined loads, it was found in SLS that horizontal displacement and rotation at the mudline increased by about 5.13% and 2.12%, respectively, and internal forces increased by about 3.29%–9.87%; and the horizontal displacement and the rotation at the mudline increased by about 4.56% and 2.79% in ULS, respectively, and the internal forces increased by about 3.49%–7.79% in the ULS. The study on the effects of the disturbance of the installation platform can be an important suggestion for the engineer in monopile design.
To determine the genetic diversity and evolutionary relationships among red radishes, 37 accessions with different flesh colors were analyzed in terms of the red pigment content, karyotypes, and ...simple sequence repeat markers. Red pigment content of red radish was 3.4 to 28.8% with an average of 15.62%. The karyotype formulas were 14 m (median) + 4 sm (submedian), 16 m + 2 sm, and 18 m for radishes with the same number of chromosomes. The number of alleles detected among the 86 simple sequence repeat primers was 2 to 15 in red-flesh radishes and 2 to 11 in white-flesh radishes. Clustering analysis separated the accessions into three clusters, with most accessions from the same region clustering together. The results indicated that (1) red radish is abundant in red radish, which is a valuable material in red pigment industry; (2) the white-flesh radish is an ancestor of the red-flesh radish, which should be considered a variety in Raphanussativus, and (3) a low level of genetic diversity exists among the 37 accessions. The available radish germplasms should be expanded by creating new hybrid or introducing genes from other crops.
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