Effect of rape flower on benign prostatic hyperplasia in rats

We were carried out to investigate the efficacy of Rape (Rapeseed, Brassica napus L.) flower on BPH (benign prostatic hyperplasia) in rats. We found that the extract from Rape flower prevented hyperplasia in testosterone-induced BPH model, the relevant animal model of human BPH. Extract reduced the weight of prostate and induced significantly cell apoptosis in prostate in BPH model. In addition, the extract controlled expression of TGF-ß1 in prostate gland and promoted urinary output in dose-dependence in BPH model. Our data provide that Rape flower may be useful for treatment of BPH

Live Imaging of embryogenic structures in Brassica napus microspore embryo cultures highlights the developmental plasticity of induced totipotent cells.

KEY MESSAGE: In vitro embryo development is highly plastic; embryo cell fate can be re-established in tissue culture through different pathways. In most angiosperms, embryo development from the single-celled zygote follows a defined pattern of cell divisions in which apical (embryo proper) and basal (root and suspensor) cell fates are established within the first cell divisions. By contrast, embryos that are induced in vitro in the absence of fertilization show a less regular initial cell division pattern yet develop into histodifferentiated embryos that can be converted into seedlings. We used the Brassica napus microspore embryogenesis system, in which the male gametophyte is reprogrammed in vitro to form haploid embryos, to identify the developmental fates of the different types of embryogenic structures found in culture. Using time-lapse imaging of LEAFY COTYLEDON1-expressing cells, we show that embryogenic cell clusters with very different morphologies are able to form haploid embryos. The timing of surrounding pollen wall (exine) rupture is a major determinant of cell fate in these clusters, with early exine rupture leading to the formation of suspensor-bearing embryos and late rupture to suspensorless embryos. In addition, we show that embryogenic callus, which develops into suspensor-bearing embryos, initially expresses transcripts associated with both basal- and apical-embryo cell fates, suggesting that these two cell fates are fixed later in development. This study reveals the inherent plasticity of in vitro embryo development and identifies new pathways by which embryo cell fate can be established.

Cytological observation of anther structure and genetic investigation of a thermo-sensitive genic male sterile line 373S in Brassica napus L.

BACKGROUND: Photoperiod and/or thermo-sensitive male sterility is an effective pollination control system in crop two-line hybrid breeding. We previously discovered the spontaneous mutation of a partially male sterile plant and developed a thermo-sensitive genic male sterile (TGMS) line 373S in Brassica napus L. The present study characterized this TGMS line through cytological observation, photoperiod/ temperature treatments, and genetic investigation. RESULTS: Microscopic observation revealed that the condensed cytoplasm and irregular exine of microspores and the abnormal degradation of tapetum are related to pollen abortion. Different temperature and photoperiod treatments in field and growth cabinet conditions indicated that the fertility alteration of 373S was mainly caused by temperature changes. The effects of photoperiod and interaction between temperature and photoperiod were insignificant. The critical temperature leading to fertility alteration ranged from 10 °C (15 °C/5 °C) to 12 °C (17 °C/7 °C), and the temperature-responding stage was coincident with anther development from pollen mother cell formation to meiosis stages. Genetic analysis indicated that the TGMS trait in 373S was controlled by one pair of genes, with male sterility as the recessive. Multiplex PCR analysis revealed that the cytoplasm of 373S is pol type. CONCLUSIONS: Our study suggested that the 373S line in B. napus has a novel thermo-sensitive gene Bnmst1 in Pol CMS cytoplasm background, and its fertility alteration is mainly caused by temperature changes. Our results will broaden the TGMS resources and lay the foundation for two-line hybrid breeding in B. napus.

Phenotypic, biochemical and genomic variability in generations of the rapeseed (Brassica napus L.) mutant lines obtained via chemical mutagenesis.

The phenotypic, biochemical and genetic variability was studied in M2-M5 generations of ethyl methansulfonat (EMS, 0.2%) mutagenized rapeseed lines generated from canola, '00', B. napus cv. Vikros. EMS mutagenesis induced extensive diversity in morphological and agronomic traits among mutant progeny resulted in selection of EMS populations of B. napus- and B. rapa-morphotypes. The seeds of the obtained mutant lines were high-protein, low in oil and stabilized in contents of main fatty acids which make them useful for feed production. Despite the increased level of various meiotic abnormalities revealed in EMS populations, comparative karyotype analysis and FISH-based visualization of 45S and 5S rDNA indicated a high level of karyotypic stability in M2-M5 plants, and therefore, the obtained mutant lines could be useful in further rapeseed improvement. The revealed structural chromosomal reorganizations in karyotypes of several plants of B. rapa-type indicate that rapeseed breeding by chemical mutagenesis can result in cytogenetic instability in the mutant progeny, and therefore, it should include the karyotype examination. Our findings demonstrate that EMS at low concentrations has great potential in rapeseed improvement.

Dissection of the genetic architecture of three seed-quality traits and consequences for breeding in Brassica napus.

Genome-wide association studies (GWASs) combining high-throughput genome resequencing and phenotyping can accelerate the dissection of genetic architecture and identification of genes for plant complex traits. In this study, we developed a rapeseed genomic variation map consisting of 4 542 011 SNPs and 628 666 INDELs. GWAS was performed for three seed-quality traits, including erucic acid content (EAC), glucosinolate content (GSC) and seed oil content (SOC) using 3.82 million polymorphisms in an association panel. Six, 49 and 17 loci were detected to be associated with EAC, GSC and SOC in multiple environments, respectively. The mean total contribution of these loci in each environment was 94.1% for EAC and 87.9% for GSC, notably higher than that for SOC (40.1%). A high correlation was observed between phenotypic variance and number of favourable alleles for associated loci, which will contribute to breeding improvement by pyramiding these loci. Furthermore, candidate genes were detected underlying associated loci, based on functional polymorphisms in gene regions where sequence variation was found to correlate with phenotypic variation. Our approach was validated by detection of well-characterized FAE1 genes at each of two major loci for EAC on chromosomes A8 and C3, along with MYB28 genes at each of three major loci for GSC on chromosomes A9, C2 and C9. Four novel candidate genes were detected by correlation between GSC and SOC and observed sequence variation, respectively. This study provides insights into the genetic architecture of three seed-quality traits, which would be useful for genetic improvement of B. napus.

A novel Brassica-rhizotron system to unravel the dynamic changes in root system architecture of oilseed rape under phosphorus deficiency.

BACKGROUND AND AIMS: An important adaptation of plants to phosphorus (P) deficiency is to alter root system architecture (RSA) to increase P acquisition from the soil, but soil-based observations of RSA are technically challenging, especially in mature plants. The aim of this study was to investigate the root development and RSA of oilseed rape (Brassica napus L.) under low and high soil P conditions during an entire growth cycle. METHODS: A new large Brassica-rhizotron system (approx. 118-litre volume) was developed to study the RSA dynamics of B. napus 'Zhongshuang11' in soils, using top-soils supplemented with low P (LP) or high P (HP) for a full plant growth period. Total root length (TRL), root tip number (RTN), root length density (RLD), biomass and seed yield traits were measured. KEY RESULTS: TRL and RTN increased more rapidly in HP than LP plants from seedling to flowering stages. Both traits declined from flowering to silique stages, and then increased slightly in HP plants; in contrast, root senescence was observed in LP plants. RSA parameters measured from the polycarbonate plates were empirically consistent with analyses of excavated roots. Seed yield and shoot dry weights were closely associated positively with root dry weights, TRL, RLD and RTN at both HP and LP. CONCLUSIONS: The Brassica-rhizotron system is an effective method for soil-based root phenotyping across an entire growth cycle. Given that root senescence is likely to occur earlier under low P conditions, crop P deficiency is likely to affect late water and nitrogen uptake, which is critical for efficient resource use and optimal crop yields.

High-throughput root phenotyping screens identify genetic loci associated with root architectural traits in Brassica napus under contrasting phosphate availabilities.

BACKGROUND AND AIMS: Phosphate (Pi) deficiency in soils is a major limiting factor for crop growth worldwide. Plant growth under low Pi conditions correlates with root architectural traits and it may therefore be possible to select these traits for crop improvement. The aim of this study was to characterize root architectural traits, and to test quantitative trait loci (QTL) associated with these traits, under low Pi (LP) and high Pi (HP) availability in Brassica napus. METHODS: Root architectural traits were characterized in seedlings of a double haploid (DH) mapping population (n = 190) of B. napus ['Tapidor' × 'Ningyou 7' (TNDH)] using high-throughput phenotyping methods. Primary root length (PRL), lateral root length (LRL), lateral root number (LRN), lateral root density (LRD) and biomass traits were measured 12 d post-germination in agar at LP and HP. KEY RESULTS: In general, root and biomass traits were highly correlated under LP and HP conditions. 'Ningyou 7' had greater LRL, LRN and LRD than 'Tapidor', at both LP and HP availability, but smaller PRL. A cluster of highly significant QTL for LRN, LRD and biomass traits at LP availability were identified on chromosome A03; QTL for PRL were identified on chromosomes A07 and C06. CONCLUSIONS: High-throughput phenotyping of Brassica can be used to identify root architectural traits which correlate with shoot biomass. It is feasible that these traits could be used in crop improvement strategies. The identification of QTL linked to root traits under LP and HP conditions provides further insights on the genetic basis of plant tolerance to P deficiency, and these QTL warrant further dissection.

Phenotypic characterization and genetic analysis of a partially female-sterile mutant in Brassica napus.

mfs is a partially female-sterile Brassica napus mutant derived from a spontaneous mutation. When the mutant is crossed as a female, very poor seed set is obtained, whereas it is fertile as a pollen donor. The floret of the mutant consisted of almost equal-length stamens, a short pistil, a flat style and ovary, and the stigma was chapped. Measures of pollen viability and pollen tube growth in vitro indicated that the mutation enhanced pollen viability. The papillae of mfs consisted of two conjoint bilobed domes, and the papillar cells were sparse, oblate and large at anthesis, but become withered and senesced quickly afterward. Pollen grains could germinate over the papillar cells, but pollen tubes could not penetrate into it. After flower opening, the number of organelles in mfs papillar cell decreased, the structure of it distinctly degenerated, and vacuolization was abnormally high. Genetic analysis of 3 F2 populations and 3 BC1F1 populations suggested that the mutant trait was controlled by two recessive genes.

Quantitative trait loci for root morphology in response to low phosphorus stress in Brassica napus.

Phosphorus (P) deficiency in soils is a major limiting factor for crop growth worldwide. Changes in root morphology and architecture represent as an important mechanism of adaptation of plants to low P (LP) stress. To elucidate the genetic control of tolerance to P deficiency in Brassica napus, quantitative trait loci (QTL) for root morphology in response to LP were identified in three independent paper culture experiments, and dissected through QTL meta-analysis. In total, 62 significant QTL for total root length, root surface area, root volume, total dry weight, and plant P uptake under high and low P conditions were detected in the three experiments. Forty-five of these QTL were clustered within four linkage groups and were integrated into eight unique QTL by two rounds of QTL meta-analysis. Three of the unique QTL, uq.A1, uq.C3a and uq.C3b, were specific for LP condition. uq.C3a and uq.C3b were identified specifically for root traits and P uptake under LP stress, and may contribute to the adaptability of B. napus to P deficiency. Two functional markers, BnIPS2-C3 and BnGPT1-C3, which were developed from the genes AtIPS2 and AtGPT1 in Arabidopsis, were located in the confidence intervals of uq.C3a and uq.C3b, respectively. And AtGPT1 that corresponded to the interval of uq.C3b by in silico mapping was a possible candidate gene of uq.C3b. These results confirmed the importance of root traits for the adaptability of B. napus to LP and partially revealed the genetic basis of tolerance to P deficiency. These findings should be valuable for further study of the mechanism of P efficiency and the breeding of P-efficient cultivars by marker-assisted selection.