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As an important physiological and reproductive organ, the silique is a determining factor of seed yield and a breeding target trait in rapeseed ( Brassica napus L.). Genetic studies of silique-related traits are helpful for rapeseed marker-assisted high-yield breeding. In this study, a recombinant inbred population containing 189 lines was used to perform a quantitative trait loci (QTLs) analysis for five silique-related traits in seven different environments. As a result, 120 consensus QTLs related to five silique-related traits were identified, including 23 for silique length, 25 for silique breadth, 29 for silique thickness, 22 for seed number per silique and 21 for silique volume, which covered all the chromosomes, except C5. Among them, 13 consensus QTLs, one, five, two, four and one for silique length, silique breadth, silique thickness, seed number per silique and silique volume, respectively, were repeatedly detected in multiple environments and explained 4.38–13.0% of the phenotypic variation. On the basis of the functional annotations of Arabidopsis homologous genes and previously reported silique-related genes, 12 potential candidate genes underlying these 13 QTLs were screened and found to be stable in multiple environments by analyzing the re-sequencing results of the two parental lines. These findings provide new insights into the gene networks affecting silique-related traits at the QTL level in rapeseed.

Oilseed–vegetable-dual-purpose (OVDP) rapeseed can effectively alleviate the land contradiction between crops and it supplements vegetable supplies in winter or spring. The soluble solids content (SSC) is an important index that is used to evaluate the quality and sugar content of fruits and vegetables. However, the genetic architecture underlying the SSC in Brassica napus shoots is still unclear. Here, quantitative trait loci (QTLs) for the SSC in B. napus shoots were investigated by performing linkage mapping using a recombinant inbred line population containing 189 lines. A germplasm set comprising 302 accessions was also used to conduct a genome-wide association study (GWAS). The QTL mapping revealed six QTLs located on chromosomes A01, A04, A08, and A09 in two experiments. Among them, two major QTLs, qSSC/21GY.A04-1 and qSSC/21NJ.A08-1, accounted for 12.92% and 10.18% of the phenotypic variance, respectively. In addition, eight single-nucleotide polymorphisms with phenotypic variances between 5.62% and 10.18% were identified by the GWAS method. However, no locus was simultaneously identified by QTL mapping and GWAS. We identified AH174 (7.55 °Brix and 7.9 °Brix), L166 (8.9 °Brix and 8.38 °Brix), and L380 (8.9 °Brix and 7.74 °Brix) accessions can be used as superior parents. These results provide valuable information that increases our understanding of the genetic control of SSC and will facilitate the breeding of high-SSC B. napus shoots.

Rapeseed (Brassica napus L.) is one of the main oil crops in the world, and increasing its yield is of great significance for ensuring the safety of edible oil. Presently, improving rapeseed plant architecture is an effective way to increase rapeseed yield with higher planting density. However, the regulatory mechanism of rapeseed plant architecture is poorly understood. In this study, a dwarf rapeseed mutant dwarf08 (df08) is obtained by ethyl methane sulfonate (EMS)-mutagenesis. The decrease in plant height of df08 is mainly caused by the reduction in main inflorescence length and first effective branch height and controlled by a single semi-dominant gene. The hybrid plants (F1) show a semi-dwarf phenotype. Through map-based cloning and transgenic assay, we confirm that the nonsynonymous single nucleotide variant (SNV) (C to T) in BnaC03.BIN2, which is homologous with Arabidopsis (Arabidopsis thaliana) BIN2, is responsible for the dwarfism of df08. BnaC03.BIN2 interacts with BnaBZR1/BES1 and involves in brassinosteroids (BRs) signal transduction. Proline to Leucine substitution in 284 (P284L) enhances the protein stability of BnaC03.bin2-D, disrupts BRs signal transduction and affects the expression of genes regulating cell division, leading to dwarfism of df08. This study provides a new insight for the mechanism of rapeseed plant height regulation and creates an elite germplasm that can be used for genetic improvement of rapeseed architecture.

Rapeseed (Brassica napus L.) is mainly used for oil production and industrial purposes. A high photosynthetic efficiency is the premise of a high yield capable of meeting people’s various demands. Chlorophyll-deficient mutants are ideal materials for studying chlorophyll biosynthesis and photosynthesis. In a previous study, we obtained the mutant yl1 for leaf yellowing throughout the growth period by ethyl methanesulfonate mutagenesis of B. napus. A genetic analysis showed that the yl1 chlorophyll-deficient phenotype was controlled by one incompletely dominant gene, which was mapped on chromosome A03 by a quantitative trait loci sequencing analysis and designated as BnA03.Chd in this study. We constructed an F2 population containing 5256 individuals to clone BnA03.Chd. Finally, BnA03.Chd was fine-mapped to a 304.7 kb interval of the B. napus ‘ZS11’ genome containing 58 annotated genes. Functional annotation, transcriptome, and sequence variation analyses confirmed that BnaA03g0054400ZS, a homolog of AT5G13630, was the most likely candidate gene. BnaA03g0054400ZS encodes the H subunit of Mg-chelatase. A sequence analysis revealed a single-nucleotide polymorphism (SNP), causing an amino-acid substitution from glutamic acid to lysine (Glu1349Lys). In addition, the molecular marker BnaYL1 was developed based on the SNP of BnA03.Chd, which perfectly cosegregated with the chlorophyll-deficient phenotype in two different F2 populations. Our results provide insight into the molecular mechanism underlying chlorophyll synthesis in B. napus.

Background: Brassica napus is one of the most important oil crops in the world, and B. napus shoots are nutrient-rich fresh vegetables. The crude fiber (CF) component is one of the most important factors affecting the taste quality of B. napus shoots, but the factors underlying the desirable low-CF trait remain poorly understood. Methods: In this study, a high-density single-nucleotide polymorphism (SNP) map was used to map quantitative trait loci (QTLs) for five CF-related traits in a recombinant inbred population. Results: A total of 49 QTLs were obtained in four environments, including eleven, twelve, eight, twelve and six QTLs for content of neutral detergent fiber, acid detergent fiber, acid detergent lignin, hemicellulose and cellulose, respectively. The phenotypic variation explained by single QTL ranged from 4.62% to 14.76%. Eight of these QTLs were further integrated into four unique QTLs, which controlled two different traits simultaneously. Five CF-component-related candidate genes were identified, among which BnaC03g07110D and BnaC07g21271D were considered to be the most likely candidate genes. In addition, five lines with low CF content were selected, which can be used as excellent germplasm resources in breeding. Conclusions: The QTLs identified in this study will contribute to our understanding of the genetic mechanism of CF and can be used as targets for reducing CF content in B. napus shoots. In addition, this study also provided excellent germplasm resources for low CF content breeding.

Purpose The aim of this study was to compare single posterior debridement, interbody fusion and instrumentation with one-stage anterior debridement, interbody fusion and posterior instrumentation for treating thoracic and lumbar spinal tuberculosis. Method From January 2006 to January 2010, we enrolled 115 spinal tuberculosis patients with obvious surgical indications. Overall, 55 patients had vertebral body destruction, accompanied by a flow injection abscess or a unilateral abscess volume greater than 500 ml. The patients underwent one-staged anterior debridement, bone grafting and posterior instrumentation (group A) or single posterior debridement, bone grafting and instrumentation (group B). Clinical and radiographic results for the two groups were analyzed and compared. Results Patients were followed 12–36 months (mean 21.3 months), Fusion occurred at 4–12 months (mean 7.8 months). There were significant differences between groups regarding the post-operative kyphosis angle, angle correction and angle correction rate, especially if pathology is present in thoracolumbar and lumbar regions. Operative complications affected five patients in group A, and one patient in group B. A unilateral psoas abscess was observed in three patients 12 months postoperatively. In one of them, interbody fusion did not occur, and there was fixation loosening and interbody absorption. All of them were cured by an anterior operation. Conclusion Anterior debridement and bone grafting with posterior instrumentation may not be the best choice for treating patients with spinal tuberculosis. Single posterior debridement/bone grafting/instrumentation for single-segment of thoracic or lumbar spine tuberculosis produced good clinical results, except in patients who had a psoas abscess.

Purpose The correction of severe post-tubercular kyphosis (PTK) is complex and has the disadvantage of being multistaged with a high morbidity. In this study, we evaluated the outcomes of children who underwent single-stage closing–opening wedge osteotomy as a surgical treatment of PTK of the thoracolumbar spine. Method Our study group included 12 children with thoracolumbar PTK (seven boys and five girls) with an average age of 9.4 years (range 6–12 years), who were treated at our institution from January 2004 to October 2009. The American Spinal Injury Association Impairment Scale and visual analog scale score were used to classify neurologic function. All patients underwent halo-pelvic traction before surgery and were treated with single-stage closing–opening wedge osteotomy. Result The duration of surgery averaged 99 min (range 70–150 min). Average blood loss was 782 ml (range 560–1,200 ml), and the average length of hospital stay was 12 days (range 8–16 days). The neurological function of all patients improved significantly after the procedure. The mean preoperative kyphotic angle was 83.3° (range 59–118°), which had reduced to 27.6° (range 20–38°) at the final follow-up visit. All patients had solid fusion, and no major complications were observed through the final follow-up visit. Conclusion Single-stage closing–opening wedge osteotomy is an effective method to correct severe thoracolumbar PTK. A main advantage of the procedure is that it is a posterior-only, single-staged surgery, allowing for significant correction with minimal complications.

The aim of this retrospective study was to analyze the results of two surgical treatments for thoracic and lumbar spinal tuberculosis. A total of 73 patients with monosegmental thoracic or lumbar spinal tuberculosis were enrolled from January 2006 to April 2011. The patients were divided into two groups. Patients in group A (n=34) underwent one-stage posterior debridement, limited decompression, bone grafting and internal fixation combined with lamina reconstruction, while those in group B (n=39) underwent one-stage posterior debridement, decompression, bone grafting and posterior instrumentation. Clinical and radiographic results were analyzed and compared between the groups. Patients were followed for a mean 31.3 months (range, 21-42 months). Fusion occurred at 4-12 months (mean, 7.7 months). Surgical complications affected one and five patients in groups A and B, respectively. There was extraction of internal fixation in two group B patients. Postoperatively, there was significant Cobb angle correction in the two groups. By the last follow-up, the Cobb angle and correction loss in group A were significantly better than that in group B; the group A Oswestry Disability Index and Frankel grade were better than that in group B. In conclusion, one-stage posterior limited decompression, bone grafting and internal fixation combined with lamina reconstruction enables rapid management of monosegmental thoracic and lumbar spinal tuberculosis with fewer complications and minimal invasion.