Development of a rapid and efficient system for CR genes identification based on hairy root transformation in Brassicaceae

Many economically important crops and vegetables belonging to the cruciferous family are heavily endangered by clubroot disease caused by Plasmodiophora brassicae infection.Breeding of clubroot resistant cultivars based on mapping and cloning of resistant genes is commonly regarded as the most cost-effective and efficient way to fight against this disease.The traditional way of R gene functional validation requires stable transformation that is both time-and labor-consuming.In this study,a rapid and efficient hairy-root transgenic protocol mediated by Agrobacterium rhizogenes was developed.The transformation positive rate was over 80%in Brassica napus showed by GUS reporter gene and this transformation only took 1/6 of the time compared with stable transformation.The system was applicable to different B.napus varieties and other cruciferous crops including Brassica rapa and Brassica oleracea.In particular,two known CR genes,CRA3.7.1 and CRA8.2.4 were used respectively,as example to show that the system works well for CR gene study combined with subsequent P.brassicae infection in B.napus.Most importantly,it works both in over-expression that led to disease resistance,as well as in RNAi which led to disease susceptible phenotype.Therefore,this system can be used in batch-wise identification of CR genes,and also offered the possibility of manipulating key genes within the P.brassicae genome that could improve our knowledge on host-pathogen interaction.

Diversity of glucosinolates among common Brassicaceae vegetables in China

Brassicaceae vegetables are an important traditional daily food in China and around the world, which provide nutrients and phytochemicals that are beneficial for human health. Among them, Brassica and Raphanus are widely cultivated and eaten, have been evolved and/or bred for special characteristics during the long history of cultivation. Epidemiological studies suggest that the health benefits of Brassicaceae vegetables are mainly associated with glucosinolates(GSLs) and their hydrolytic products. In this review, we discuss the diversity of common consumed Brassicaceae vegetables and their GSL composition in edible parts. We also discuss the diversity factors affecting GSL content, and the diversity roles and functions of GSL. The information in this review provides guidance for consumers to select vegetables with a high GSL content,optimum edible stages, suitable edible methods, and provides a theoretical basis for crop molecular breeding and market development of GSL products.

Molecular phylogeny of Solms-laubachia(Brassicaceae) s.l.,based on multiple nuclear and plastid DNA sequences,and its biogeographic implications

The Hengduan Mountains region of south-west China is a noted biodiversity,hotspot, but the geographic origins and historical assembly of its rich endemic flora, including the sky-island species ofSolms-laubachia Muschl. （Brassicaceae）, have been little studied. Previous molecular studies on the phylogeny of Solms-laubachia showed it to be paraphyletic, leading to considerable expansion not only of its taxonomic limits, but also its geographic range, with the inclusion of taxa from outside the Hengduan region. However, these studies provided little resolution of interspecific relationships, preventing inferences about historical biogeography within the clade. In the present study, new sequence data from two nuclear genes （LEAFY and G3pdh） and two chloroplast intergenic spacers （petN-psbM and psbM-trnD） were combined with existing markers to increase phylogenetic signals. Phaeonychium villosum （Maxim.） Al-Shehbaz was found to be nested within Solms-laubachia s.l. In general, phylogenetic relationships appear to be a good predictor of geography, with the Hengduan Mountain endemics embedded in a paraphyletic grade of species from the western Himalayas and central Asia, but they also imply morphological homoplasy, lncongruence was detected between the nuclear and chloroplast gene trees, perhaps resulting from incomplete lineage sorting of ancestral polymorphisms. The crown age ofSolms-laubachia s.l. was estimated to be approximately 1.42-3.68 mya, using Bayesian relaxed molecular clock analysis. Historical biogeographic analysis using a parametric dispersalextinction-cladogenesis model inferred central Asia and the western Himalayas as most probable ancestral range of Solms-laubachia s.l., and estimated higher rates of eastward expansion than westward during the diversification of descendant lineages. In summary, our results suggest that Solms-laubachia s.l. originated during the Pliocene in central Asia, and subsequently migrated eastward into the Hengduan Mountains, colonizing sky-island, alpine scree-slope habitats that may have provided novel ecological opportunity and accelerated speciation, ultimately establishing this region as the present center of diversity of the genus.

Notes on the family Brassicaceae in China

A critical revision of the collections of Brassicaceae in some Chinese （PE, XJA, XJBI, XJFA, XJNM, XJU） and foreign （LE, P） herbaria is made. One genus, Neurotropis （DC.） E K. Mey., and 11 species, Alyssum szarabiacum Nyar., Barbarea stricta Andrz., Erysimum czernjajevii N. Busch, Erysimum kotuchovii D. German, Erysimum mongolicum D. German, Lepidium karelinianum Al-Shehbaz, Matthiola superba Conti, Neurotropis platycarpa （Fisch. ＆ Mey.） E K. Mey., Ptilotrichum dahuricum Peschkova, Sisymbrium subspinescens Bunge, and Smelowskia micrantha （Botsch. ＆ Vved.） Al-Shehbaz ＆ S. I. Warwick, are reported from China for the first time. Six species, Aphragmus involucratus （Bunge） O. E. Schulz, Dontostemonperennis C. A. Mey., Goldbachia torulosa DC., Lepidium amplexicaule Willd., Neotorularia brevipes （Kar. ＆ Kir.） Hedge ＆ J. Leonard, and Parrya stenocarpa Kar. ＆ Kir., are confirmed to occurr in China. Five species, Dontostemon integrifolius （L.） C. A. Mey., Draba zangbeiensis L. L. Lou, Lepidium alashanicum H. L. Yang, Sinapis arvensis L., and Strigosella brevipes （Bunge） Botsch., are reported as novelties for some provinces in China, and Strigosella hispida （Litv.） Botsch. occurs in Xinjiang, China. However, the occurrence of one genus, Pseudoarabidopsis Al-Shehbaz, O＇Kane ＆ Price, and four species, Draba huetii Boiss., Eutrema halophilum （C. A. Mey.） Al-Shehbaz ＆ S. I. Warwick, Galitzkya spathulata （Steph. ex Willd.） V. Bocz., and Pseudoarabidopsis toxophylla （Bieb.） Al-Shehbaz, O＇Kane ＆ Price, could not be confirmed in China. The occurrence of six species, Aphragmus bouffordii Al-Shehbaz, Barbarea orthoceras Ledeb., Lepidium latifolium L., Ptilotrichum canescens （DC.） C. A. Mey., Strigosella hispida （Litv.） Botsch., and Strigosella scorpioides （Bunge） Botsch., is not confirmed in certain provinces of China. All names follow the latest taxonomic treatment for relevant groups; detailed morphological descriptions of the newly recorded taxa are provided; and distinguishing characters from related species already known in China are discussed. Other comments are provided where needed.

Polyphenol Composition and Antioxidant Activity of Two Autochthonous Brassicaceae of the Campania Region, Southern Italy

Torzella (Brassica oleracea acephala) is one of the most ancient kinds of cauliflower developed in the Mediterranean area. Broccolo (Brassica oleracea botrytis cimosa), var. “San Pasquale” is a leafy vegetable cultivated in Campania too, mainly in the province of Naples. We evaluated the polyphenols content and the antioxidant activity of these two Brassicaceae, provided by the same experimental plant of the Campania region. Both vegetables showed high content of total polyphenols (6.37 mM GAE/g and 2.24 mM GAE/g of Torzella and Broccolo, respectively), and a remarkable antioxidant activity (EC50 1.53 mg and EC50 6.51 mg, in Torzella and Broccolo, respectively). Polyphenol composition, determined by ultra performance liquid chromatography (UPLC), allowed us to detect a certain number of compounds (gallic, ferulic, chlorogenic, p-coumaric and caffeic acids, catechin, luteolin, naringenin) common to both species. Therefore, epicatechin was found only in the extract of san Pasquale broccoli;on the contrary, rutin and apigenin were detected only in the extracts of torzella broccoli. Hence, such products can be considered therapeutic functional foods due to their extraordinary reserve of secondary metabolites and bioactive constituents that are beneficial for managing and preventing several chronic illnesses in humans.

Structural Features of the Leaf of Ephemeral Species of Representatives of the Brassicaceae Burnett Family in Southwestern Kyzylkum (Uzbekistan)

The results of a study conducted by light microscopy of the anatomical structure of the leaf in ephemeral species from the family Brassicaceae growing under the conditions of Kyzylkum (Uzbekistan) are presented. The following diagnostic, structural adaptive features were revealed: a leaf lamellar, dentate (Diptychocarpus strictus), in Leptaleum filifolium—valky. It is pubescent with various types of trichomes: stellate, dendroid (Meniocus linifolius), equilateral (Streptoloma desertorum) and unequal (Strigosella, Leptaleum filifolium species), unicellular hooked (Leptaleum filifolium). Epidermal cells flattened with wavy or winding walls. The stomata are numerous, not submerged, anomocytic, hemiparacytic, anisocytic types are noted. In all species, the isolate-palisade type of leaf mesophyll predominates. Vascular bundles of all species are sclerified. The main protective features of the leaf of species of the family Brassicaceae are pubescence and sclerification of vascular bundles. We consider the mesomorphic and xeromorphic lines of development ancient and independent. Identified and described signs that can be used in taxonomy and ecology.

The Current Situation of Coenopopulation of <i>Lepidium subcordatum</i>Botsch. et Vved. (<i>Brassicaceae</i>) in Relict Mountains Kyzylkum (Uzbekistan)

Lepidium subcordatum Botsch. et Vved. (Brassicaceae) is a rare endemic species of relict mountains of the Kyzylkum desert. The plant is listed in the “Red Data Book of Uzbekistan”. It grows on stony and rocky slopes of relict mountains. The ontogenetic structure of five coenotypical populations of this taxa growing in the Kuldzhuktau and Auminzatau mountains had been revealed. The ontogenesis duration is more than 20 years in natural habitats. All investigated coenopopulations can be assessed as normal and incomplete. The typical spectrum of coenopopulations is centralized with a peak in the middle-generative individuals. The ontogenetic spectrum of the most studied coenopopulations coincides with the characteristic ontogenetic structure that indicates a favorable environmental condition in region for self-maintenance of L. subcordatum coenopopulations.

Community Structure and Value Evaluation of Local Brassicaceae Potherbs in Shiyan City

[Objectives]This study was conducted to evaluate the value of local Brassicaceae potherb resources in Shiyan City.[Methods]Seven species of local Brassicaceae edible plants resources in Shiyan City,including Cardamine hirsuta L.,Cardamine flexuosa,Cardamine impatiens L.,Capsella bursa-pastoris(Linn.),Orychophragmus violaceus(L.)O.E.Schulz,Draba nemorosa L.,Rorippa indica(L.)Hiern.,were investigated using sampling method,and their value was evaluated.[Results]①Shiyan City was rich in resources of local Brassicaceae potherbs,mostly of which grew in humid areas.②In the communities of target species,there were 20 species of plants in 19 genera of 15 families in the arbor layer,19 species of plants in 16 genera from 15 families in the shrub layer,and 58 species of plants in 51 genera from 23 families in the herbaceous layer.The tree,shrub and herb species with the highest dominance Populus simonii var.przewalskii,Robinia pseudoacacia and Chrysanthemum indicum.Local Brassicaceae potherbs in Shiyan City have high edible and medicinal value,especially Cardamine,which has strong selenium-rich ability and is worthy of vigorous development.[Conclusions]This study provides scientific basis and reference for the development and utilization of local potherbs of Brassicaceae in this area.

Genome assembly of the Brassicaceae diploid Orychophragmus violaceus reveals complex whole-genome duplication and evolution of dihydroxy fatty acid metabolism

Orychophragmus violaceus is a Brassicaceae species widely cultivated in China,particularly as a winter cover crop in northern China because of its low-temperature tolerance and low water demand.Recently,O.violaceus has also been cultivated as a potential industrial oilseed crop because of its abundant 24-carbon dihydroxy fatty acids(diOH-FAs),which contribute to superior high-temperature lubricant properties.In this study,we performed de novo assembly of the O.violaceus genome.Whole-genome synteny analysis of the genomes of its relatives demonstrated that O.violaceus is a diploid that has undergone an extrawhole-genome duplication(WGD)after the Brassicaceae-specific a-WGD event,with a basic chromosome number of x=12.Formation of diOH-FAs is hypothesized to have occurred after the WGD event.Based on the genome and the transcriptome data from multiple stages of seed development,we predicted that OvDGAT1-1 and OvDGAT1-2 are candidate genes for the regulation of diOH-FA storage in O.violaceus seeds.These results may greatly facilitate the development of heat-tolerant and eco-friendly plant-based lubricants using O.violaceus seed oil and improve our understanding of the genomic evolution of Brassicaceae.

Developing multifunctional crops by engineering Brassicaceae glucosinolate pathways

Glucosinolates(GSLs),found mainly in species of the Brassicaceae family,are one of the most well-studied classes of secondary metabolites.Produced by the action of myrosinase on GSLs,GSL-derived hydrolysis products(GHPs)primarily defend against biotic stress in planta.They also significantly affect the quality of crop products,with a subset of GHPs contributing unique food flavors and multiple therapeutic benefits or causing disagreeable food odors and health risks.Here,we explore the potential of these bioactive functions,which could be exploited for future sustainable agriculture.We first summarize our accumulated understanding of GSL diversity and distribution across representative Brassicaceae species.We then systematically discuss and evaluate the potential of exploited and unutilized genes involved in GSL biosynthesis,transport,and hydrolysis as candidate GSL engineering targets.Benefiting from available information on GSL and GHP functions,we explore options for multifunctional Brassicaceae crop ideotypes to meet future demand for food diversification and sustainable crop production.An integrated roadmap is subsequently proposed to guide ideotype development,in which maximization of beneficial effects and minimization of detrimental effects of GHPs could be combined and associated with various end uses.Based on several use-case examples,we discuss advantages and limitations of available biotechnological approaches that may contribute to effective deployment and could provide novel insights for optimization of future GSL engineering.

Temperature Modulates Tissue-Specification Program to Control Fruit Dehiscence in Brassicaceae

Plants respond to diurnal and seasonal changes in temperature by reprogramming vital developmental pathways. Understanding the molecular mechanisms that define environmental modulation of plant growth and reproduction is critical in the context of climate change that threatens crop yield worldwide. Here, we report that elevated temperature accelerates fruit dehiscence in members of the Brassicaceae family including the model plant Arabidopsis thaliana and important crop species. Arabidopsis fruit development is controlled by a network of interacting regulatory genes. Among them, the INDEHISCENT （IND） gene is a key regulator of the valve-margin tissue that mediates fruit opening, hence facilitating fruit dehiscence. We demonstrated that the valve-margin development is accelerated at higher temperature and that IND is tar- geted for thermosensory control. Our results reveal that IND upregulation is facilitated via temperature- induced chromatin dynamics leading to accelerated valve-margin specification and dispersal of the seed. Specifically, we show that temperature-induced changes in IND expression are associated with ther- mosensory H2A.Z nucleosome dynamics. These findings establish a molecular framework connecting tis- sue identity with thermal sensing and set out directions for the production of temperature-resilient crops.

Evolution and protein interactions of AP2 proteins in Brassicaceae： Evidence linking development and environmental responses

Plants have evolved a large number of transcription factors（TF）, which are enriched among duplicate genes,highlighting their roles in complex regulatory networks. The APETALA2/EREBP-like genes constitute a large plant TF family and participate in development and stress responses. To probe the conservation and divergence of AP2/EREBP genes,we analyzed the duplication patterns of this family in Brassicaceae and identified interacting proteins of representative Arabidopsis AP2/EREBP proteins. We found that many AP2/EREBP duplicates generated early in Brassicaceae history were quickly lost, but many others were retained in all tested Brassicaceae species, suggesting early functional divergence followed by persistent conservation. In addition,the sequences of the AP2 domain and exon numbers were highly conserved in rosids. Furthermore, we used 16 A.thaliana AP2/EREBP proteins as baits in yeast screens and identified 1,970 potential AP2/EREBP-interacting proteins,with a small subset of interactions verified in planta. Many AP2 genes also exhibit reduced expression in an antherdefective mutant, providing a possible link to developmental regulation. The putative AP2-interacting proteins participate in many functions in development and stress responses,including photomorphogenesis, flower development, pathogenesis, drought and cold responses, abscisic acid and auxin signaling. Our results present the AP2/EREBP evolution patterns in Brassicaceae, and support a proposed interaction network of AP2/EREBP proteins and their putative interacting proteins for further study.

Genome Size Evolution Mediated by Gypsy Retrotransposons in Brassicaceae

The dynamic activity of transposable elements(TEs)contributes to the vast diversity of genome size and architecture among plants.Here,we examined the genomic distribution and transposition activity of long terminal repeat retrotransposons(LTR-RTs)in Arabidopsis thaliana(Ath)and three of its relatives,Arabidopsis lyrata(Aly),Eutrema salsugineum(Esa),and Schrenkiella parvula(Spa),in Brassicaceae.Our analyses revealed the distinct evolutionary dynamics of Gypsy retrotransposons,which reflects the different patterns of genome size changes of the four species over the past million years.The rate of Gypsy transposition in Aly is approximately five times more rapid than that of Ath and Esa,suggesting an expanding Aly genome.Gypsy insertions in Esa are strictly confined to pericentromeric heterochromatin and associated with dramatic centromere expansion.In contrast,Gypsy insertions in Spa have been largely suppressed over the last million years,likely as a result of a combination of an inherent molecular mechanism of preferential DNA removal and purifying selection at Gypsy elements.Additionally,species-specific clades of Gypsy elements shaped the distinct genome architectures of Aly and Esa.

Evolution of TWIN SISTER of FT(TSF) Genes in Brassicaceae

FT and its homolog, TWIN SISTER OF FT(TSF), act redundantly as integrators in flora transition pathways in Arabidopsis thaliana. The evolution of these key fl wering regulatory genes during Brassicaceae speciation has not been well studied; therefore, we investigated their evolution in 13 sequenced Brassicaceae species. While the phylogenetic analysis indicated that FT gene evolution has followed two independent lineagespecifi routes, TSF evolution does not appear to have been completely consistent within the Brassicaceae lineage I and lineage II division. The two TSF copies in the Thellungiella genus were divided into A and B groups in the phylogenetic analysis. Examination of conserved non-coding sequences and conserved domains within a 5 kb region upstream of the TSF start codon revealed the same group division inferred by the phylogenetic analysis. In addition, TSF genes retained syntenic relationships among genes in the same group, but not between group A and group B.The two copies of the TSF gene in the Thellungiella species were syntenic to the TSF genes in group A and group B, respectively. We also identifie TSF-A gene residues in the syntenic region of group B species, but no TSF-B residues could be found in the group A syntenic region. Therefore,we inferred that the TSF genes in lineage II species experienced a duplication event after diversificatio from lineage I. Following their split from Thellungiella, Brassica species lost the ancestral TSF gene and retained the duplicated copy.

Biofumigation: An alternative strategy for the control of plant parasitic nematodes

Plant-parasitic nematodes wreak havoc on the yield and quality of crops worldwide.Damage from these pests is estimated to exceed US$100 bllion annually but is likely higher due to misdiagnosis.Nematode damage may be catastrophic,but historically the solution has been damaging as well.Use of the synthetic nematicide methyl bromide(MBr)poses risks to the environment and to human health.Biofumigation,the use of plant material and naturally produced compounds to control pests,is an increasingly feasible method of pest management.The process acts through the growth or incorporation of plant material into the soil,that,over the course of its degradation,releases glucosinolates that break down into nematotoxic isothiocyanates.These secondary plant metabolites exist naturally in commonly grown plants,most of which belong to the Brassicaceae family.Research endeavors have increasingly explored the potential of biofumigation.The reaction of target pests,the selection of biofumigant,and ideal environments for efficacy continue to be evaluated.This review seeks to provide a cost and benefit assessment of the status of biofumigation for the control of plant-parasitic nematodes as an alternative to conventional methyl bromide usage.

Segmental Translocation Contributed to the Origin of the Brassica S-locus

Self-incompatibility(SI),which has recurred during the evolution of plants,is one of the most important cross-pollination mating systems.Three S-loci have been reported in Brassicaceae,namely,Arabidopsis lyrata(Al),Brassica(Br),and Leavenworthia alabamica(La)S-loci.Here,through multi-genomic comparative analysis of 20 species,we revealed that the most ancient S-locus was formed prior to the divergence of Brassicaceae lineage I and II.Itwas retained and inherited by Arabidopsis,as the Al S-locus in Brassicaceae lineage I.Furthermore,we found that the Br S-locus,which has been widely used in the breeding of Brassica crops to generate hybrid seeds,was formed through segmental translocation(ST)in the hexaploid ancestor of Brassica in Brassicaceae lineage II.The Br S-locus was evolved through a ST from one of the triplicated ancestral S-locus paralogs in the Brassica hexaploidy ancestor,while the other two S-locus paralogs were lost.Together with the previous discovery that the La S-locus was formed through a secondary origin in Brassicaceae lineage I,we conclude the monophyletic origin of Al and Br S-loci and clarify the evolutionary route of S-loci in the Brassicaceae family.Our findings will contribute to evolutionary studies and breeding applications of the S-locus in Brassicaceae.

Phytohormonal and metabolism analysis of Brassica rapa L.ssp.pekinensis with different resistance during Plasmodiophorabrassicae infection

Clubroot of Chinese cabbage(Brassica rapa L.ssp.pekinensis),caused by the obligate parasite Plasmodiophora brassicae,accounts for serious yield losses.The aim of our study was to explore the phytohormone levels and metabolome changes in the roots of resistant and susceptible B.rapa genotypes at a late stage of infection,i.e.,28 days post-infection.Both genotypes showed decreased auxin levels after P.brassicae infection except for indole-3-acetic acid.Overall,the susceptible genotype had higher auxin and cytokinin levels after infection,with the exception of trans-zeatin and 3-indolebutyric acid as compared to the resistant genotype.Jasmonic acid levels declined after infection regardless of the genotype.Resistance against clubroot was evident with the increased levels of salicylic acid in the resistant genotype.The susceptible genotype had a higher number of differentially accumulated metabolites(DAMs)(262)than the resistant genotype(238)after infection.Interestingly,132 DAMs were commonly detected in both genotypes when infected with the pathogen,belonging to metabolite classes such as phenolic acids,amino acids,and derivatives,glucosinolates,organic acids,flavonoids,nucleotides and derivatives,and fatty acids.The differential metabolite analysis revealed that metabolites related to amino acid biosynthesis,fatty acid biosynthesis and elongation,glutathione metabolism,and glucosinolate metabolism were highly accumulated in the resistant genotype,suggesting their essential roles in resistance against P.brassicae infection.

Genome of Plant Maca （Lepidium meyenil） Illuminates Genomic Basis for High-Altitude Adaptation in the Central Andes

Maca （Lepidium meyenii Walp, 2n = 8x = 64）, belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru （4000-4500 m）. Considering that the rapid uplift of the central Andes occurred 5-10 million years ago （Ma）, an evolutionary question arises regarding how plants such as maca acquire high-altitude adaptation within a short geological period. Here, we report the high-quality genome assembly of maca, in which two closely spaced maca-specific whole-genome duplications （WGDs; ~6.7 Ma） were identified. Comparative genomic analysis between maca and closely related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway, and secondary metabolite biosynthesis via WGDs. The retention and subsequent functional divergence of many duplicated genes may account for the morphological and physiological changes （i.e., small leaf shape and self-fertility） in maca in a high-altitude environment. In addition, some duplicated maca genes were identified with functions in morphological adaptation （i.e., LEAF CURLING RESPONSIVENESS） and abiotic stress response （i.e., GL YClNE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION2） under positive selection. Collectively, the maca genome provides use- ful information to understand the important roles of WGDs in the high-altitude adaptation of plants in the Andes.

Variation in Plant Morphology and Sinigrin Content in Ethiopian Mustard(Brassica carinata L.)

Ethiopian mustard(Brassica carinata) is mainly grown as a leafy vegetable and oilseed crop. Sinigrin is predominant glucosinolate in the leaves of Ethiopian mustard. It is hydrolyzed by enzyme myrosinase to produce bioactive product specifically allyl-isothiocyanates. Due to sinigrin content, Ethiopian mustard has a mild flavor and it is a healthy addition to human diet. However, sinigrin concentration depends on genotype.Understanding variations of plant morphology and sinigrin content may be the first step for crop improvement. According to the analyses of various plant characteristics among ninety nine Ethiopian mustard accessions, we found significant differences in plant height, chlorophyll content, and petiole length. In addition, sinigrin content was determined using ultra-performance liquid chromatography tandem quadrupole mass spectrometers/tunable ultraviolet detector(UPLC-TQS/TUV). We found a significant difference in sinigrin content among leaves of 94 Ethiopian mustard accessions. Except for petiole length, the sinigrin content was negatively correlated with leaf area, leaf width, number of primary branches, and plant height. This information will help Ethiopian mustard breeders in screening breeding lines for new accessions.

Juicy Stories on Female Reproductive Tissue Development: Coordinating the Hormone Flows

In the past 20-30 years, developmental biologists have made tremendous progress in identifying genes required for the specifica-tion of individual cell types of an organ and in describing how they interact in genetic networks. In comparison, very little is known about the mechanisms that regulate tissue polarity and overall organ patterning. Gynoecia and fruits from members of the Brassicaceae family of flowering plants provide excellent model systems to study organ patterning and tissue specification because they become partitioned into distinct domains whose formation is determined by polarity establishment both at a cellular and whole tissue level. Interactions among key regulators of Arabidopsis gynoecium and fruit development have revealed a network of upstream transcription factor activities required for such tissue differentiation. Regulation of the plant hormone auxin is emerging as both an immediate downstream output and input of these activities, and here we aim to provide an overview of the current knowledge regarding the link between auxin and female reproductive development in plants. In this review, we will also demonstrate how available data can be exploited in a mathematical modeling approach to reveal and understand the feedback regulatory circuits that underpin the polarity establishment, necessary to guide auxin flows.