Salicylic acid and salicylic acid glucoside in xylem sap of <Emphasis Type="Italic">Brassica napus</Emphasis> infected with <Emphasis Type="Italic">Verticillium longisporum</Emphasis>

Salicylic acid (SA) and its glucoside (SAG) were detected in xylem sap of Brassica napus by HPLC–MS. Concentrations of SA and SAG in xylem sap from the root and hypocotyl of the plant, and in extracts of shoots above the hypocotyl, increased after infection with the vascular pathogen Verticillium longisporum. Both concentrations were correlated with disease severity assessed as the reduction in shoot length. Furthermore, SAG levels in shoot extracts were correlated with the amount of V. longisporum DNA in the hypocotyls. Although the concentration of SAG (but not SA) in xylem sap of infected plants gradually declined from 14 to 35 days post infection, SAG levels remained significantly higher than in uninfected plants during the whole experiment. Jasmonic acid (JA) and abscisic acid (ABA) levels in xylem sap were not affected by infection with V. longisporum. SA and SAG extend the list of phytohormones potentially transported from root to shoot with the transpiration stream. The physiological relevance of this transport and its contribution to the distribution of SA in plants remain to be elucidated.     

The effect of <Emphasis Type="Italic">INDEHISCENT</Emphasis> point mutations on silique shatter resistance in oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis>)

Key message

This study elucidates the influence of indehiscent mutations on rapeseed silique shatter resistance. A phenotype with enlarged replum-valve joint area and altered cell dimensions in the dehiscence zone is described.

Abstract

Silique shattering is a major factor reducing the yield stability of oilseed rape (Brassica napus). Attempts to improve shatter resistance often include the use of mutations in target genes identified from Arabidopsis (Arabidopsis thaliana). A variety of phenotyping methods assessing the level of shatter resistance were previously described. However, a comparative and comprehensive evaluation of the methods has not yet been undertaken. We verified the increase of shatter resistance in indehiscent double knock-down mutants obtained by TILLING with a systematic approach comparing three independent phenotyping methods. A positive correlation of silique length and shatter resistance was observed and accounted for in the analyses. Microscopic studies ruled out the influence of different lignification patterns. Instead, we propose a model to explain increased shattering resistance of indehiscent rapeseed mutants by altered cell shapes and sizes within the contact surfaces of replum and valves.

     

Association mapping of quantitative resistance for <Emphasis Type="Italic">Leptosphaeria maculans</Emphasis> in oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis> L.)

Stem canker caused by the fungus Leptosphaeria maculans is a major disease of Brassica napus. Quantitative resistance factors appear to be important components for effective and durable control of this pathogen. Quantitative trait loci (QTL) for stem canker resistance have previously been identified in the Darmor variety. However, before these QTL can be used in marker-assisted selection (MAS) to breed resistant varieties, they must be validated in a wide range of genetic backgrounds. We used an association mapping approach to confirm the markers located within the QTL previously identified in Darmor and establish their usefulness in MAS. For this, we characterized the molecular diversity of an oilseed rape collection of 128 lines showing a large spectrum of responses to infection by L. maculans, using 72 pairs of primers for simple sequence repeat and other markers. We used different association mapping models which either do or do not take into account the population structure and/or family relatedness. In all, 61 marker alleles were found to be associated with resistance to stem canker. Some of these markers were associated with previously identified QTL, which confirms their usefulness in MAS. Markers located in regions not harbouring previously identified QTL were also associated with resistance, suggesting that new QTL or allelic variants are present in the collection. All of these markers associated with stem canker resistance will help identify accessions carrying desirable alleles and facilitate QTL introgression.     

Antioxidant defense system in leaves of Indian mustard (<Emphasis Type="Italic">Brassica juncea</Emphasis>) and rape (<Emphasis Type="Italic">Brassica napus</Emphasis>) under cadmium stress

Plant species capable of hyper-accumulating heavy metals are of considerable interest for phytoremediation, and differ in their ability to accumulate metals from environment. Using two brassica species (Brassica juncea and Brassica napus), nutrient solution experiments were conducted to study variation in tolerance to cadmium (Cd) toxicity based on (1) lipid peroxidation and (2) changes in antioxidative defense system in leaves of both plants (i.e., superoxide dismutase (SOD EC 1.15.1.1), catalase (CAT EC 1.11.1.6), ascorbate peroxidase (APX EC 1.11.1.11), guaiacol peroxidase (GPX EC 1.11.1.7), glutathione reductase (GR EC 1.6.4.2), levels of phytochelatins (PCs), non-protein thiols (NP-SH), and glutathione. Plants were grown in nutrient solution under controlled environmental conditions, and subjected to increasing concentrations of Cd (0, 10, 25 and 50 μM) for 15 days. Results showed marked differences between both species. Brassica napus under Cd stress exhibited increased level of lipid peroxidation, as was evidenced by the increased malondialdehyde (MDA) content in leaves. However, in Brassica juncea treated plants, MDA content remained unchanged. In Brassica napus, with the exception of GPX, activity levels of some antioxidant enzymes involved in detoxification of reactive oxygen species (ROS), including SOD, CAT, GR, and APX, decreased drastically at high Cd concentrations. By contrast, in leaves of Brassica juncea treated plants, there was either only slight or no change in the activities of the antioxidative enzymes. Analysis of the profile of anionic isoenzymes of GPX revealed qualitative changes occurring during Cd exposure for both species. Moreover, levels of NP-SH and PCs, monitored as metal detoxifying responses, were much increased in leaves of Brassica juncea by increasing Cd supply, but did not change in Brassica napus. These results indicate that Brassica juncea plants possess the greater potential for Cd accumulation and tolerance than Brassica napus.     

Pollen-mediated intraspecific gene flow from herbicide resistant oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis> L.)

The cultivation of genetically modified (GM) herbicide resistant oilseed rape (Brassica napus) has increased over the past few years. The transfer of herbicide resistance genes via pollen (gene flow) from GM crops to non-GM crops is of relevance for the realisation of co-existence of different agricultural cultivation forms as well as for weed management. Therefore the likelihood of pollen-mediated gene flow has been investigated in numerous studies. Despite the difficulty to compare different experiments with varying levels of outcrossing, we performed a literature search for world-wide studies on cross-fertilisation in fully fertile oilseed rape. The occurrence and frequency of pollen-mediated intraspecific gene flow (outcrossing rate) can vary according to cultivar, experimental design, local topography and environmental conditions. The outcrossing rate from one field to another depends also on the size and arrangement of donor and recipient populations and on the ratio between donor and recipient plot size. The outcrossing levels specified in the presented studies are derived mostly from experiments where the recipient field is either surrounding the donor field (continuous design) or is located as a patch at different distances from the donor field (discontinuous design). Reports of gene flow in Brassica napus generally show that the amount of cross-fertilisation decreases as the distance from the pollen source increases. The evidence given in various studies reveals that the bulk of GM cross-fertilisation occurs within the first 10 m of the recipient field. The removal of the first 10 m of a non-transgenic field facing a GM crop might therefore be more efficient for reducing the total level of cross-fertilisation in a recipient sink population than to recommend separation distances. Future experiments should investigate cross-fertilisation with multiple adjacent donor fields at the landscape level under different spatial distributions of rapeseed cultivars and different cropping systems. The level of cross-fertilisation occurring over the whole field is mainly important for co-existence and has not been investigated in agricultural scale experiments until now. Potential problems with herbicide resistant oilseed rape volunteers arising from intraspecific gene flow can be largely solved by the choice of suitable cultivars and herbicides as well as by soil management.     

Phosphinothricin-resistant <Emphasis Type="Italic">Brassica napus</Emphasis> + <Emphasis Type="Italic">Orychophragmus violaceus</Emphasis> somatic hybrids

Hybrid plants resistant to phosphinothricin (PPT) are obtained as a result of experiments with somatic hybridization between Brassica napus L. cv. Kalinins’kyy and Orychophragmus violaceus L. O.E. Shulz. The hybrids inherited PPT resistance from O. violaceus plants that had been previously transformed by a vector containing the maize transposon system Spm/dSPm with bar gene located within the nonautonomous transposon. The morphologically obtained plants occupy an intermediate position between the initial forms, which is in agreement with the results of isoenzyme analyses (analysis of multiple forms of amylase and esterase) and PCR analysis (presence of the genes bar, gus, and SpmTPase). Inheritance of the plastome occurs from oilseed rape, while that of the mitochondrion, from O. violaceus, which is proved by means of PCR-RFLP analysis. The plant hybrids may be utilized for further selection research with oilseed rape following determination of the edible quality of its oil as well as in experiments with chloroplast transformation, a topic which is of critical importance for oilseed rape.     

Interaction of silicon and cadmium in <Emphasis Type="Italic">Brassica juncea</Emphasis> and <Emphasis Type="Italic">Brassica napus</Emphasis>

The objective of this study was to determine the effect of silicon (Si) and cadmium (Cd) on root and shoot growth and Cd uptake in two hydroponically cultivated Brassica species (B. juncea (L.) Czern. cv. Vitasso and B. napus L. cv. Atlantic). Both species are potentially usable for phytoextraction. Inhibitory effects of Cd on root elongation were diminished by the impact of Si. Primary roots elongation in the presence of Cd + Si compared with Cd was stronger and the number of lateral roots was lower in B. juncea than in B. napus. Cd content per plant was higher in B. napus roots and shoots compared with B. juncea. Suberin lamellae were formed closer to the root apex in Cd + Si than in Cd treated plants and this effect was stronger in B. napus than in B. juncea. Accelerated maturation of endodermis was associated with reduced Cd uptake. Cd decreased the content of chlorophylls and carotenoids in both species, but Si addition positively influenced the content of photosynthetic pigments which was higher in B. napus than in B. juncea. Si enhanced more substantially translocation of Cd into the shoot of B. napus than of B. juncea. Based on our results B. napus seems to be more suitable for Cd phytoextraction than B. juncea because these plants produce more biomass and accumulate higher amount of Cd. The protective effect of Si on Cd treated Brassica plants could be attributed to more extensive development of suberin lamellae in endodermis.     

Development of INDELs markers in oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis> L.) using re-sequencing data

Insertions/deletions (INDELs), a type of abundant length polymorphisms in the plant genomes, combine the characteristics of both simple sequence repeats (SSRs) and single-nucleotide polymorphisms (SNP), and thus can be developed as desired molecular markers for genetic studies and crop breeding. There has been no large-scale characterization of INDELs variations in Brassica napus yet. In this study, we identified a total of 538,691 INDELs in size range of 1–10 bp by aligning whole-genome re-sequencing data of 23 B. napus inbred lines (ILs) to the B. napus genome sequence of ‘Darmor-bzh.’ Of these, 104,190 INDELs were uniquely mapped on the pseudochromosomes of the reference genome. A set of 595 unique INDELs of 2–5 bp in length was selected for experimental validation in the 23 ILs. Of these INDELs, 530 (89.01 %) produced a single PCR product and were single locus. A total of 523 (87.9 %) INDELs were found polymorphic among the 23 ILs. A genetic linkage map containing 108 single-locus INDELs and 89 anchor SSR markers was constructed using 188 recombinant ILs. The majority of INDELs markers on the linkage map showed consistency with the pseudochromosomes of the B. napus cultivar ‘Darmor-bzh.’ The INDELs variations and markers reported here will be valuable resources in future for genetic studies and molecular breeding in oilseed rape.     

Genetic characterization of a new cytoplasmic male sterility system (<Emphasis Type="Italic">hau</Emphasis>) in <Emphasis Type="Italic">Brassica </Emphasis><Emphasis Type="Italic">juncea</Emphasis> and its transfer to <Emphasis Type="Italic">B. napus</Emphasis>

A novel cytoplasmic male sterility (CMS) was identified in Brassica juncea, named as hau CMS (00-6-102A). Subsequently, the male sterility was transferred to B. napus by interspecific hybridization. The hau CMS has stable male sterility. Flowers on the A line are absolutely male sterile, and seeds harvested from the line following pollinations with the maintainer gave rise to 100% sterile progeny. The anthers in CMS plants are replaced by thickened petal-like structures and pollen grains were not detected. In contrast, in other CMS systems viz. pol, nap, tour, and ogu, anthers are formed but do not produce viable pollen. The sterility of hau CMS initiates at the stage of stamen primordium polarization, which is much earlier compared with the other four CMS systems. We have successfully transferred hau CMS from B. juncea to B. napus. Restorer lines for pol, ogu, nap, and tour CMS systems were found to be ineffective to restore fertility in hau CMS. Sixteen out of 40 combinations of mitochondrial probe/enzyme used for RFLP analysis distinguished the hau CMS system from the other four systems. Among these sixteen combinations, five ones alone could distinguish the five CMS systems from each other. The evidence from genetic, morphological, cytological and molecular studies confirmed that the hau CMS system is a novel CMS system. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Characterization of Defense Signaling Pathways of <Emphasis Type="Italic">Brassica napus</Emphasis> and <Emphasis Type="Italic">Brassica carinata</Emphasis> in Response to <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis> Challenge

Canola (Brassica napus L.) is an agriculturally and economically important crop in Canada, and its growth and yield are frequently influenced by fungal pathogens. Sclerotinia sclerotiorum is among those fungal pathogens and causes stem rot disease in B. napus whereas it has been reported that Brassica carinata is moderately tolerant to S. sclerotiorum. Jasmonic acid/ethylene (JA/ET) and salicylic acid (SA) are phytohormones that are known to be involved in plant disease responses. To investigate the defense signaling cascades involved in the interaction of B. napus and B. carinata with S. sclerotiorum, we examined the expression of five orthologs of B. napus genes involved in JA/ET or SA signaling pathways using quantitative RT-PCR. Our results indicated that there are differences in the timing of JA/ET and SA signaling pathways between B. napus and B. carinata. Our results in these two Brassica species also support previous observations that necrotrophic pathogens trigger JA/ET signaling in response to infection. Finally, we observed that transgenic canola expressing 1-aminocyclopropane-1-carboxylate-deaminase producing low levels of ET was relatively more susceptible to S. sclerotiorum than its wild-type counterpart, suggesting that ET inhibits S. sclerotiorum-induced symptom development.     

Phosphite accelerates programmed cell death in phosphate-starved oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis>) suspension cell cultures

Phosphite (H₂PO₃^–, Phi) prevents the acclimation of plants and yeast to orthophosphate (Pi, HPO₄^2–) deprivation by specifically obstructing the derepression of genes encoding proteins characteristic of their Pi-starvation response. In this study, we report that prolonged (i.e., 3–4 weeks) culture of Brassica napus L. suspension cells in Pi-deficient (–Pi) media leads to programmed cell death (PCD). However, when the B. napus cells were subcultured into –Pi media containing 2 mM Phi, they initiated PCD within 5 days, with 95% cell death observed by day 9. Dying cells exhibited several morphological and biochemical features characteristic of PCD, including protoplast shrinkage, chromatin condensation, and fragmentation of nuclear DNA. Immunoblotting indicated that B. napus cells undergoing PCD upregulated a 30-kDa cysteine endoprotease that is induced during PCD in the inner integument cells of developing B. napus seeds. It is concluded that PCD in B. napus suspension cells is triggered by extended Pi starvation, and that Phi treatment greatly accelerates this process. Our results also infer that the adaptive value of acclimating at the molecular level to Pi-stress is to extend the viability of –Pi B. napus cell cultures by about 3 weeks.Abbreviations APase acid phosphatase (EC 3.1.3.2) - BnCysP B. napus cysteine proteinase - DAPI 4,6-diamidino-2-phenylindole - FDA fluorescein diacetate - PCD programmed cell death - Phi phosphite - +Pi and –Pi Pi-sufficient and -deficient, respectively - PI propidium iodide - PSI Pi-starvation inducible     

Protection of Oilseed Rape (<Emphasis Type="Italic">Brassica napus</Emphasis>) Toward Fungal Pathogens by Strains of Plant-associated <Emphasis Type="Italic">Bacillus amyloliquefaciens</Emphasis>

In this report, four Bacillus strains were tested for effects on plant fitness and disease protection of oilseed rape (Brassica napus). The strains belonged to newly discovered plant-associated Bacillus amyloliquefaciens and a recently proposed species, Bacillus endophyticus. The fungal pathogens tested represented different infection strategies and included Alternaria brassicae, Botrytis cinerea, Leptosphaeria maculans, and Verticillium longisporum. The B. amyloliquefaciens strains showed no or a weak plant growth promoting activity, whereas the B. endophyticus strain had negative effects on the plant as revealed by phenological analysis. On the other hand, two of the B. amyloliquefaciens strains conferred protection of oilseed rape toward all pathogens tested. In vitro experiments studying the effects of Bacillus exudates on fungal growth showed clear growth inhibition in several but not all cases. The protective effects of Bacillus can therefore, at least in part, be explained by production of antibiotic substances, but other mechanisms must also be involved probably as a result of intricate plant–bacteria interaction. The protective effects observed for certain Bacillus strains make them highly interesting for further studies as biocontrol agents in Brassica cultivation.     

Small RNA changes in synthetic <Emphasis Type="Italic">Brassica napus</Emphasis>

Main conclusion

Small RNAs and microRNAs were found to vary extensively in synthetic Brassica napus and subsequent generations, accompanied by the activation of transposable elements in response to hybridization and polyploidization.

Abstract

Resynthesizing B. napus by hybridization and chromosome doubling provides an approach to create novel polyploids and increases the usable genetic variability in oilseed rape. Although many studies have shown that small RNAs (sRNAs) act as important factor during hybridization and polyploidization in plants, much less is known on how sRNAs change in synthetic B. napus, particularly in subsequent generations after formation. We performed high-throughput sequencing of sRNAs in S₁–S₄ generations of synthetic B. napus and in the homozygous B. oleracea and B. rapa parent lines. We found that the number of small RNAs (sRNAs) and microRNAs (miRNAs) doubled in synthetic B. napus relative to the parents. The proportions of common sRNAs detected varied from the S₁ to S₄ generations, suggesting sRNAs are unstable in synthetic B. napus. The majority of miRNAs (67.2 %) were non-additively expressed in the synthesized Brassica allotetraploid, and 33.3 % of miRNAs were novel in the resynthesized B. napus. The percentage of miRNAs derived from transposable elements (TEs) also increased, indicating transposon activation and increased transposon-associated miRNA production in response to hybridization and polyploidization. The number of target genes for each miRNA in the synthesized Brassica allotetraploid was doubled relative to the parents, enhancing the complexity of gene expression regulation. The potential roles of miRNAs and their targets are discussed. Our data demonstrate generational changes in sRNAs and miRNAs in synthesized B. napus.

     

Mapping of days to flower and seed yield in spring oilseed <Emphasis Type="Italic">Brassica napus</Emphasis> carrying genome content introgressed from <Emphasis Type="Italic">Brassica oleracea</Emphasis>

Earliness of flowering and maturity and high seed yield are important objectives of breeding spring Brassica napus canola. Previously, we have introgressed earliness of flowering from Brassica oleracea into spring B. napus canola through interspecific crossing between these two species. In this paper, we report quantitative trait locus (QTL) mapping of days to flower and seed yield by use of publicly available markers and markers designed based on flowering time genes and a doubled haploid population, derived from crossing of the spring canola parent and an early flowering line developed from a B. napus × B. oleracea cross, tested in nine field trials for over 5 years. Five genomic regions associated with days to flower were identified on C1, C2, C3, and C6 of which the single QTL of C1 was detected in all trials; in all cases, the allele introgressed from B. oleracea reduced the number of days to flower. BLASTn search in the Brassica genomes located the physical position of the QTL markers and identified putative flowering time genes in these regions. In the case of seed yield, ten QTL from eight linkage groups were detected; however, none could be consistently detected in all trials. The QTL region of C1 associated with days to flower did not show significant association with seed yield in more than 80% of the field trials; however, in a single trial, the allele introgressed from B. oleracea exerted a negative effect on seed yield. Thus, the genomic regions and molecular markers identified in this research could potentially be used in breeding for the development of early flowering B. napus canola cultivars without affecting seed yield in a majority of the environments.     

Cadmium distribution and microlocalization in oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis>) after long-term growth on cadmium-contaminated soil

Brassica napus (L.) was grown from seeds on a reconstituted soil contaminated with 100 mg Cd kg(-1). Compared with roots and stems, leaves accumulated high amounts of Cd. Although the Cd concentration in the leaves remained high throughout plant growth and no appreciable change was noticed in the total, extractable or soluble Cd in the soil adhering to the roots, the symptoms of Cd toxicity (leaf chlorosis, growth retardation) decreased with time. Cd induced a noticeable accumulation of phytochelatins in young plants (aged 22 days), which decreased in parallel to the disappearance of the symptoms of Cd intoxication. The subcellular distribution of Cd in leaves of Cd-acclimated plants was determined using biochemical, microscopic and metal-imaging techniques. Leaf fractionation by differential centrifugations showed that Cd was present predominantly in the 'soluble' fraction corresponding to the vacuoles and the cytoplasm. Transmission electron microscopic analyses revealed that those cell compartments contained electron-dense granules associated with needle-like structures. Cd, and also high amounts of sulfur, was detected in those structures by electron-spectroscopic imaging. This technique also showed Cd binding to cell walls by a mechanism that does not involve sulfur atoms. In contrast, very little Cd was found in chloroplasts, and this is consistent with the preservation of photosynthesis in plants grown on Cd-polluted soil. The microanalytical results presented here confirm that long-term growth of B. napus on Cd-contaminated soil is accompanied by preferential storage of Cd in the vacuoles and the cell walls. This phenomenon diverted Cd ions from metabolically active compartments (cytosol, chloroplasts, mitochondria), resulting in a reduction of Cd toxicity in the leaves.     

Effect of a turnip rape <Emphasis Type="Italic">(Brassica rapa)</Emphasis> trap crop on stem-mining pests and their parasitoids in winter oilseed rape <Emphasis Type="Italic">(Brassica napus)</Emphasis>

Concerns about the negative effects of chemical control of oilseed rape (Brassica napus L.) pests on non-target species, human safety, and development of insecticide resistance, require alternative control strategies such as the use of trap crops and biocontrol to be developed. Psylliodes chrysocephala(L.) (Coleoptera: Chrysomelidae) (cabbage stem flea beetle) and Ceutorhynchus pallidactylus (Marsh.) (Coleoptera: Curculionidae) (cabbage stem weevil) are two major stem-mining pests of oilseed rape. This study investigated the phenology of these pests and their main parasitoids in the UK, the potential use of turnip rape (Brassica rapa L.) as a trap crop to reduce oilseed rape infestation, and the effects of insecticide treatment on pest incidence and larval parasitism. Water trap samples, plant dissections and pest larval dissections were done to determine: the incidence of adult pests and their parasitoids, the level of plant infestation by the pests and percentage larval parasitism, respectively. The turnip rape trap crop borders reduced P. chrysocephalabut not C. pallidactylus infestation of oilseed rape plots. Treatment of the trap crop with insecticide had little effect on either pest or parasitoid incidence in the oilseed rape. TersilochusmicrogasterSzép. andT. obscurator Aub. (Hymenoptera: Ichneumonidae) were the main larval parasitoids of P. chrysocephalaand C. pallidactylus, respectively. Tersilochus microgasteris reported for the first time in the UK. The implications for integrated pest management are discussed.     

Genetics and fine mapping of a yellow-green leaf gene (<Emphasis Type="Italic">ygl</Emphasis>-<Emphasis Type="Italic">1</Emphasis>) in cabbage (<Emphasis Type="Italic">Brassica oleracea</Emphasis> var. <Emphasis Type="Italic">capitata</Emphasis> L.)

Cabbage (Brassica oleracea var. capitata L.) is one of the most popular cultivated vegetables worldwide. Cabbage has rich phenotypic diversity, including plant height, head shape, head color, leaf shape and leaf color. Leaf color plays an important role in cabbage growth and development. At present, there are few reports on fine mapping of leaf color mutants in B. oleracea. In this study, a naturally occurring yellow-green leaf cabbage mutant (YL-1), derived from the self-pollinated progenies of the hybrid ‘Hosom’, was used for inheritance analysis and gene mapping. Segregation populations including F₂ and BC₁ were generated from the cross of two inbred lines, YL-1 and 01–20. Genetic analysis with the F₂ and BC₁ populations demonstrated that the yellow-green leaf color was controlled by a single recessive nuclear gene, ygl-1. Insertion–deletion (InDel) markers, designed based on the parental re-sequencing data, were used for the preliminary mapping with BSA (bulked segregant analysis) method. A genetic map constructed with 15 InDels indicated that ygl-1 was located on chromosome C01. The ygl-1 gene is flanked by InDel markers ID2 and M8, with genetic distances of 0.4 cM and 0.35 cM, respectively. The interval distance between two markers is 167 kb. Thus, it enables us to locate the ygl-1 gene for the first time in B. oleracea. This study lays the foundation for candidate gene prediction and ygl-1gene cloning.     

<Emphasis Type="Italic">LMI1</Emphasis>-like genes involved in leaf margin development of <Emphasis Type="Italic">Brassica napus</Emphasis>

In rapeseed (Brassica napus L.), leaf margins are variable and can be entire, serrate, or lobed. In our previous study, the lobed-leaf gene (LOBED-LEAF 1, BnLL1) was mapped to a 32.1 kb section of B. napus A10. Two LMI1-like genes, BnaA10g26320D and BnaA10g26330D, were considered the potential genes that controlled the lobed-leaf trait in rapeseed. In the present study, these two genes and another homologous gene (BnaC04g00850D) were transformed into Arabidopsis thaliana (L.) Heynh. plants to identify their functions. All three LMI1-like genes of B. napus produced serrate leaf margins. The expression analysis indicated that the expression level of BnaA10g26320D determined the difference between lobed- and entire-leaved lines in rapeseed. Therefore, it is likely that BnaA10g26320D corresponds to BnLL1.