Quantitative analysis of six lignans in fruits with different colours of <i>Schisandra chinensis</i> by HPLC

<div><p>A simple and rapid high-performance liquid chromatography method was utilised for the simultaneous determination of six major lignans in <i>Schisandra chinensis</i> with different colours continuously for the next 2 years. Six lignans were successfully separated on a C₁₈ column at 254 nm using a gradient of acetonitrile and water. The assay was applied for analysing six lignans in the different colours of fruits of <i>S. chinensis</i> such as red, pink or white, and the component stability for the next 2 years was also detected. The result indicated that the total content of lignans in fruits with different colours varied remarkably, which was relatively high in red fruits, followed by white fruits and the lowest in pink fruits. Moreover, the contents of lignans in the samples of <i>S. chinensis</i> examined for the next 2 years changed irregularly and marginally.</p></div

Genome-wide identification and role of <i>MKK</i> and <i>MPK</i> gene families in clubroot resistance of <i>Brassica rapa</i>

<div><p>Mitogen-activated protein kinase (MAPK or MPK) cascades play key roles in responses to various biotic stresses, as well as in plant growth and development. However, the responses of MPK and MPK kinase (MKK) in Chinese cabbage <i>(Brassica rapa</i> ssp. <i>pekinensis)</i> to <i>Plasmodiophora brassicae</i>, a causal agent of clubroot disease in <i>Brassica</i> crops, are still not clear. In the present study, a total of 11 <i>B</i>. <i>rapa MKK</i> (<i>BraMKK</i>) and 30 <i>BraMPK</i> genes were identified and unevenly distributed in 6 and 10 chromosomes, respectively. The synteny analysis indicated that these genes experienced whole-genome triplication and segmental and tandem duplication during or after the divergence of <i>B</i>. <i>rapa</i>, accompanied by the loss of three MKK and two MPK orthologs of <i>Arabidopsis</i>. The <i>BraMKK</i> and <i>BraMPK</i> genes were classified into four groups with similar intron/exon structures and conserved motifs in each group. A quantitative PCR analysis showed that the majority of <i>BraMKK</i> and <i>BraMPK</i> genes were natively expressed in roots, hypocotyls, and leaves, whereas 5 <i>BraMKK</i> and 16 <i>BraMPK</i> genes up-regulated in the roots upon <i>P</i>. <i>brassicae</i> infection. Additionally, these 5 <i>BraMKK</i> and 16 <i>BraMPK</i> genes exhibited a significantly different expression pattern between a pair of clubroot-resistant/susceptible near-isogenic lines (NILs). Furthermore, the possible modules of MKK-MPK involved in <i>B</i>. <i>rapa</i>-<i>P</i>. <i>brassicae</i> interaction are also discussed. The present study will provide functional clues for further characterization of the MAPK cascades in <i>B</i>. <i>rapa</i>.</p></div

Expression levels of <i>MKK</i> (A) and <i>MPK</i> (B) genes in roots after treatment with <i>P</i>. <i>brassicae</i> in both NILs.

<p><i>Actin</i> and <i>18s rRNA</i> expression levels were used to normalize the data. All data is the mean of 3 biological replicates ± S.E. Significant differences are showed by * (<i>p</i>< 0.05) and ** (<i>p</i>< 0.01).</p

The exon/intron structure of <i>MKK</i> (A) and <i>MPK</i> (B) genes in <i>B</i>. <i>rapa</i>.

<p>Exons are represented by colorful boxes, and introns are reprensented by black lines. Introns and exons of <i>BraMKKs</i> and <i>BraMPKs</i> are grouped according to the phylogenetic classification (A-D). The exon and intron sizes can be estimated by the scale at the bottom.</p

Image_2_Identification and characterization of putative effectors from Plasmodiophora brassicae that suppress or induce cell death in Nicotiana benthamiana.TIF

Clubroot, caused by Plasmodiophora brassicae, is a major disease of crucifers. Effector proteins are important virulence factors in host recognition of pathogens and the interactions between pathogens and hosts. Secretory proteins, as effector candidates, have been studied in the interaction between Plasmodiophora brassicae and its hosts. In this study, 518 secretary proteins were screened from the Plasmodiophora brassicae genome. A total of 63 candidate effectors that induce or suppress cell death were identified using agroinfiltration-mediated transient expression in Nicothiana benthamiana. The candidate effectors, Pb4_102097 and Pb4_108104 showed high expressing level in the stage of rest spore maturity, could induce cell death and were associated with H2O2 accumulation in N. benthamiana leaves. In addition, 55 candidate effectors that could suppress BAX (Bcl-2-associated X protein) induced cell death, and 21 out of which could suppress the immunity caused by bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000 expressing avrRps4 in Arabidopsis. Based on the expression pattern in different stages, 28 candidate effectors showed high expression levels during the primary and secondary infection stage. Five candidate effectors containing the RXLR motif functioned in the cytoplasm and cell membrane.</p

Table_3_Identification and characterization of putative effectors from Plasmodiophora brassicae that suppress or induce cell death in Nicotiana benthamiana.XLSX

Clubroot, caused by Plasmodiophora brassicae, is a major disease of crucifers. Effector proteins are important virulence factors in host recognition of pathogens and the interactions between pathogens and hosts. Secretory proteins, as effector candidates, have been studied in the interaction between Plasmodiophora brassicae and its hosts. In this study, 518 secretary proteins were screened from the Plasmodiophora brassicae genome. A total of 63 candidate effectors that induce or suppress cell death were identified using agroinfiltration-mediated transient expression in Nicothiana benthamiana. The candidate effectors, Pb4_102097 and Pb4_108104 showed high expressing level in the stage of rest spore maturity, could induce cell death and were associated with H2O2 accumulation in N. benthamiana leaves. In addition, 55 candidate effectors that could suppress BAX (Bcl-2-associated X protein) induced cell death, and 21 out of which could suppress the immunity caused by bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000 expressing avrRps4 in Arabidopsis. Based on the expression pattern in different stages, 28 candidate effectors showed high expression levels during the primary and secondary infection stage. Five candidate effectors containing the RXLR motif functioned in the cytoplasm and cell membrane.</p

Synteny mapping of <i>MKK</i> genes in <i>B</i>. <i>rapa</i>, <i>B</i>. <i>napus</i> and <i>A</i>. <i>thaliana</i> chromosomes.

<p>Circle represents each chromosome of <i>B</i>. <i>rapa</i>, <i>B</i>. <i>napus</i> and <i>A</i>. <i>thaliana</i>. Synteny relationships were lined by Circos (<a href="http://circos.ca/" target="_blank">http://circos.ca/</a>). Lines with four different colors indicated four groups (A-D) of <i>MKK</i> gene family. Genes located on <i>B</i>. <i>napus</i> A genome are syntenic with genes of <i>B</i>. <i>rapa</i> and <i>A</i>. <i>thaliana</i>.</p

Image_1_Identification and characterization of putative effectors from Plasmodiophora brassicae that suppress or induce cell death in Nicotiana benthamiana.TIF

Clubroot, caused by Plasmodiophora brassicae, is a major disease of crucifers. Effector proteins are important virulence factors in host recognition of pathogens and the interactions between pathogens and hosts. Secretory proteins, as effector candidates, have been studied in the interaction between Plasmodiophora brassicae and its hosts. In this study, 518 secretary proteins were screened from the Plasmodiophora brassicae genome. A total of 63 candidate effectors that induce or suppress cell death were identified using agroinfiltration-mediated transient expression in Nicothiana benthamiana. The candidate effectors, Pb4_102097 and Pb4_108104 showed high expressing level in the stage of rest spore maturity, could induce cell death and were associated with H2O2 accumulation in N. benthamiana leaves. In addition, 55 candidate effectors that could suppress BAX (Bcl-2-associated X protein) induced cell death, and 21 out of which could suppress the immunity caused by bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000 expressing avrRps4 in Arabidopsis. Based on the expression pattern in different stages, 28 candidate effectors showed high expression levels during the primary and secondary infection stage. Five candidate effectors containing the RXLR motif functioned in the cytoplasm and cell membrane.</p

Table_2_Identification and characterization of putative effectors from Plasmodiophora brassicae that suppress or induce cell death in Nicotiana benthamiana.XLSX

Clubroot, caused by Plasmodiophora brassicae, is a major disease of crucifers. Effector proteins are important virulence factors in host recognition of pathogens and the interactions between pathogens and hosts. Secretory proteins, as effector candidates, have been studied in the interaction between Plasmodiophora brassicae and its hosts. In this study, 518 secretary proteins were screened from the Plasmodiophora brassicae genome. A total of 63 candidate effectors that induce or suppress cell death were identified using agroinfiltration-mediated transient expression in Nicothiana benthamiana. The candidate effectors, Pb4_102097 and Pb4_108104 showed high expressing level in the stage of rest spore maturity, could induce cell death and were associated with H2O2 accumulation in N. benthamiana leaves. In addition, 55 candidate effectors that could suppress BAX (Bcl-2-associated X protein) induced cell death, and 21 out of which could suppress the immunity caused by bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000 expressing avrRps4 in Arabidopsis. Based on the expression pattern in different stages, 28 candidate effectors showed high expression levels during the primary and secondary infection stage. Five candidate effectors containing the RXLR motif functioned in the cytoplasm and cell membrane.</p

Table_3_Identification and Mapping of the Clubroot Resistance Gene CRd in Chinese Cabbage (Brassica rapa ssp. pekinensis).XLSX

<p>The rapid spread of clubroot disease, which is caused by Plasmodiophora brassicae, threatens Brassicaceae crop production worldwide. Breeding plants that have broad-spectrum disease resistance is one of the best ways to prevent clubroot. In the present study, eight Chinese cabbage germplasms were screened using published clubroot-resistant (CR) loci-/gene-linked markers. A CR gene Crr3 potential carrier “85-74” was detected which linked to marker BRSTS61; however, “85-74” shows different responses to local pathogens “LAB-19,” “LNND-2,” and “LAB-10” from “CR-73” which harbors Crr3. We used a next-generation sequencing-based bulked segregant analysis approach combined with genetic mapping to detect CR genes in an F₂ segregant population generated from a cross between the Chinese cabbage inbred lines “85-74” (CR) and “BJN3-1” (clubroot susceptible). The “85-74” line showed resistance to a local pathogen “LAB-19” which was identified as race 4; a genetic analysis revealed that the resistance was conferred by a single dominant gene. The CR gene which we named CRd was mapped to a 60 kb (1 cM) region between markers yau389 and yau376 on chromosome A03. CRd is located upstream of Crr3 which was confirmed based on the physical positions of Crr3 linked markers. The identification of CRd linked markers can be applied to marker-assisted selection in the breeding of new CR cultivars of Chinese cabbage and other Brassica crops.</p