Transcriptome analysis reveals the potential lncRNA-mRNA modules involved in genetic male sterility and fertility of Chinese cabbage (brassica rapa L. ssp. pekinensis).

BACKGROUND: Long non-coding RNAs (lncRNAs) play a crucial role in regulating gene expression vital for the growth and development of plants. Despite this, the role of lncRNAs in Chinese cabbage (Brassica rapa L. ssp. pekinensis) pollen development and male fertility remains poorly understood. RESULTS: In this study, we characterized a recessive genic male sterile mutant (366-2 S), where the delayed degradation of tapetum and the failure of tetrad separation primarily led to the inability to form single microspores, resulting in male sterility. To analyze the role of lncRNAs in pollen development, we conducted a comparative lncRNA sequencing using anthers from the male sterile mutant line (366-2 S) and the wild-type male fertile line (366-2 F). We identified 385 differentially expressed lncRNAs between the 366-2 F and 366-2 S lines, with 172 of them potentially associated with target genes. To further understand the alterations in mRNA expression and explore potential lncRNA-target genes (mRNAs), we performed comparative mRNA transcriptome analysis in the anthers of 366-2 S and 366-2 F at two stages. We identified 1,176 differentially expressed mRNAs. Remarkably, GO analysis revealed significant enrichment in five GO terms, most notably involving mRNAs annotated as pectinesterase and polygalacturonase, which play roles in cell wall degradation. The considerable downregulation of these genes might contribute to the delayed degradation of tapetum in 366-2 S. Furthermore, we identified 15 lncRNA-mRNA modules through Venn diagram analysis. Among them, MSTRG.9997-BraA04g004630.3 C (ß-1,3-glucanase) is associated with callose degradation and tetrad separation. Additionally, MSTRG.5212-BraA02g040020.3 C (pectinesterase) and MSTRG.13,532-BraA05g030320.3 C (pectinesterase) are associated with cell wall degradation of the tapetum, indicating that these three candidate lncRNA-mRNA modules potentially regulate pollen development. CONCLUSION: This study lays the foundation for understanding the roles of lncRNAs in pollen development and for elucidating their molecular mechanisms in regulating male sterility in Chinese cabbage.

Yellow leaf green tea modulates the AMPK/ACC/SREBP1c signaling pathway and gut microbiota in high-fat diet-induced mice to alleviate obesity.

BACKGROUND: Yellow leaf green tea (YLGT) is a new variety of Camellia sinensis (L.) O. Ktze, which has yellow leaves and the unique qualities of 'three green through three yellow'. The present study aimed to investigate the anti-obesity effect of YLGT in mice fed a high-fat diet (HFD) and to explore the potential mechanisms by regulating the AMPK/ACC/SREBP1c signaling pathways and gut microbiota. RESULTS: The results showed that YLGT aqueous extract reduced body weight, hepatic inflammation, fat accumulation and hyperlipidemia in HFD-induced C57BL/6J mice, and also accelerated energy metabolism, reduced fat synthesis and suppressed obesity by activating the AMPK/CPT-1α signaling pathway and inhibiting the FAS/ACC/SREBP-1c signaling pathway. Fecal microbiota transplantation experiment further confirmed that the alteration of gut microbiota (e.g. increasing unclassified_Muribaculaceae and decreasing Colidextribacter) might be an important cause of YLGT water extract inhibiting obesity. CONCLUSION: In conclusion, YLGT has a broad application prospect in the treatment of obesity and the development of anti-obesity function beverages. © 2024 Society of Chemical Industry.

Genome-wide characterization of the wall-associated kinase-like (WAKL) family in sesame (Sesamum indicum) identifies a SiWAKL6 gene involved in resistance to Macrophomina Phaseolina.

BACKGROUND: Sesame charcoal rot caused by Macrophomina phaseolina is one of the most serious fungal diseases in sesame production, and threatens the yield and quality of sesame. WAKL genes are important in the plant response to biotic stresses by sensing and transmitting external signals to the intracellular receptor. However, there is still a lack about the WAKL gene family and its function in sesame resistance to M. phaseolina. The aim of this study was to interpret the roles of WAKL genes in sesame resistance to M. phaseolina. RESULTS: In this study, a comprehensive study of the WAKL gene family was conducted and 31 WAKL genes were identified in the sesame genome. Tandem duplication events were the main factor in expansion of the SiWAKL gene family. Phylogenetic analysis showed that the sesame SiWAKL gene family was divided into 4 groups. SiWAKL genes exhibited different expression patterns in diverse tissues. Under M. phaseolina stress, most SiWAKL genes were significantly induced. Notably, SiWAKL6 was strongly induced in the resistant variety "Zhengzhi 13". Functional analysis showed that SiWAKL6 was induced by salicylic acid but not methyl jasmonate in sesame. Overexpression of SiWAKL6 in transgenic Arabidopsis thaliana plants enhanced their resistance to M. phaseolina by inducing the expression of genes involved in the salicylic acid signaling pathway and reconstructing reactive oxygen species homeostasis. CONCLUSIONS: Taken together, the results provide a better understanding of functions about SiWAKL gene family and suggest that manipulation of these SiWAKL genes can improve plant resistance to M. phaseolina. The findings contributed to further understanding of functions of SiWAKL genes in plant immunity.

Metabolome and transcriptome analyses of anthocyanin biosynthesis reveal key metabolites and candidate genes in purple wheat (Triticum aestivum L.).

Wheat (Triticum aestivum L.) is continuously subjected to genetic improvement to optimize grain quality. Purple wheat has recently gained attention because of its high anthocyanin and nutrient content. In this study, we performed an integrated transcriptome and metabolome analysis of the inbred wheat lines ZM152 (white wheat line) and ZM163 (purple wheat line) to elucidate molecular networks and identify potential genes regulating anthocyanin synthesis. A total of 564 metabolites were detected, of which 47 metabolite contents differed significantly between the two lines. Twenty-five flavonoids, including four anthocyanins, were significantly higher in purple wheat. High contents of cyanidin 3-rutinoside and malvidin 3-glucoside might contribute to the purple coloration of the wheat grains. Consistently, gene ontology and pathway enrichment analyses revealed that flavonoid and anthocyanin biosynthesis were mostly enriched, and the expression of anthocyanin structural genes was specifically upregulated in purple wheat lines, while transcription factors (TFs) were mostly downregulated in purple wheat lines. Especially, the correlation analysis showed the anthocyanin synthesis-related genes CHS (TraesCS2B02G048400) and UFGT (TraesCS7A02G155400) were likely regulated negatively by the TFs MYB4 (TraesCS1A02G268800, TraesCS1B02G279400), TT8 (TraesCS1D02G094200, TraesCS1B02G113100, and TraesCS1A02G102400), which thus could be considered important regulatory genes in the anthocyanin biosynthesis pathway of purple wheat lines. In summary, these results offer new insights into anthocyanin biosynthesis and accumulation of purple wheat, and provide very useful candidate genes for future colored wheat breeding.

Cytological and transcriptomic analyses provide insights into the pollen fertility of synthetic allodiploid Brassica juncea hybrids.

KEY MESSAGE: Imbalanced chromosomes and cell cycle arrest, along with down-regulated genes in DNA damage repair and sperm cell differentiation, caused pollen abortion in synthetic allodiploid Brassica juncea hybrids. Interspecific hybridization is considered to be a major pathway for species formation and evolution in angiosperms, but the occurrence of pollen abortion in the hybrids is common, prompting us to recheck male gamete development in allodiploid hybrids after the initial combination of different genomes. Here, we investigated the several key meiotic and mitotic events during pollen development using the newly synthesised allodiploid B. juncea hybrids (AB, 2n = 2× = 18) as a model system. Our results demonstrated the partial synapsis and pairing of non-homologous chromosomes concurrent with chaotic spindle assembly, affected chromosome assortment and distribution during meiosis, which finally caused difference in genetic constitution amongst the final tetrads. The mitotic cell cycle arrest during microspore development resulted in the production of anucleate pollen cells. Transcription analysis showed that sets of key genes regulating cyclin (CYCA1;2 and CYCA2;3), DNA damage repair (DMC1, NBS1 and MMD1), and ubiquitin-proteasome pathway (SINAT4 and UBC) were largely downregulated at the early pollen meiosis stages, and those genes involved in sperm cell differentiation (DUO1, PIRL1, PIRL9 and LBD27) and pollen wall synthesis (PME48, VGDH11 and COBL10) were mostly repressed at the late pollen mitosis stages in the synthetic allodiploid B. juncea hybrids (AB). In conclusion, this study elucidated the related mechanisms affecting pollen fertility during male gametophyte development at the cytological and transcriptomic levels in the synthetic allodiploid B. juncea hybrids.

Integrative Transcriptome, miRNAs, Degradome, and Phytohormone Analysis of Brassica rapa L. in Response to Plasmodiophora brassicae.

Clubroot is an infectious root disease caused by Plasmodiophora brassicae in Brassica crops, which can cause immeasurable losses. We analyzed integrative transcriptome, small RNAs, degradome, and phytohormone comprehensively to explore the infection mechanism of P. brassicae. In this study, root samples of Brassica rapa resistant line material BrT24 (R-line) and susceptible line material Y510-9 (S-line) were collected at four different time points for cytological, transcriptome, miRNA, and degradome analyses. We found the critical period of disease resistance and infection were at 0-3 DAI (days after inoculation) and 9-20 DAI, respectively. Based on our finding, we further analyzed the data of 9 DAI vs. 20 DAI of S-line and predicted the key genes ARF8, NAC1, NAC4, TCP10, SPL14, REV, and AtHB, which were related to clubroot disease development and regulating disease resistance mechanisms. These genes are mainly related to auxin, cytokinin, jasmonic acid, and ethylene cycles. We proposed a regulatory model of plant hormones under the mRNA-miRNA regulation in the critical period of P. brassicae infection by using the present data of the integrative transcriptome, small RNAs, degradome, and phytohormone with our previously published results. Our integrative analysis provided new insights into the regulation relationship of miRNAs and plant hormones during the process of disease infection with P. brassicae.

bra-miR167a Targets ARF8 and Negatively Regulates Arabidopsis thaliana Immunity against Plasmodiophora brassicae.

Clubroot is a soil-borne disease caused by Plasmodiophora brassicae, which can seriously affect the growth and production of cruciferous crops, especially Chinese cabbage crops, worldwide. At present, few studies have been conducted on the molecular mechanism of this disease's resistance response. In this experiment, we analyzed the bioinformation of bra-miR167a, constructed a silencing vector (STTM167a) and an overexpression vector (OE-miR167a), and transformed them to Arabidopsis to confirm the role of miR167a in the clubroot resistance mechanism of Arabidopsis. Afterwards, phenotype analysis and expression level analysis of key genes were conducted on transgenic plants. From the result, we found that the length and number of lateral roots of silence transgenic Arabidopsis STTM167a was higher than that of WT and OE-miR167a. In addition, the STTM167a transgenic Arabidopsis induced up-regulation of disease resistance-related genes (PR1, PR5, MPK3, and MPK6) at 3 days after inoculation. On the other hand, the auxin pathway genes (TIR1, AFB2, and AFB3), which are involved in maintaining the balance of auxin/IAA and auxin response factor (ARF), were down-regulated. These results indicate that bra-miR167a is negative to the development of lateral roots and auxins, but positive to the expression of resistance-related genes. This also means that the STTM167a can improve the resistance of clubroot by promoting lateral root development and the level of auxin, and can induce resistance-related genes by regulating its target genes. We found a positive correlation between miR167a and clubroot disease, which is a new clue for the prevention and treatment of clubroot disease.

Modulating effects of Hericium erinaceus polysaccharides on the immune response by regulating gut microbiota in cyclophosphamide-treated mice.

BACKGROUND: The gut microbiota (GM) is recognized as a significant contributor to the immune system. In the present study, the effects of Hericium erinaceus polysaccharides (HEP) on immunoregulation and GM in cyclophosphamide (CTX)-treated mice were investigated to elucidate the attenuate of immunosuppression by modulating GM. RESULTS: The results revealed that HEP significantly improved the body weight and immune organ index in immunodeficient mice (P < 0.05). They significantly increased operational taxonomic units (OTUs) (P < 0.05), adjusted the α and ß diversity of the GM, and the bacterial community structure was more similar to that of control group. Taxonomic composition analysis found that HEP increased the abundance of Alistipse, uncultured_bacterium_f_Muribaculaceae, Lachnospiraceae_NK4A136_group, uncultured_bacterium_f_Lachnospiracea, uncultured_bacterium_f_Ruminococcaceae and Ruminococcaceae_UCG-014, and decreased Lactobacillus, Bacteroides, and Alloprevotella, suggesting that HEP can improve the GM structure and inhibit CTX-induced GM dysregulation. Moreover, HEP increased short-chain fatty acid (SCFA)-producing bacteria, recovered SCFA levels, alleviated immunosuppression caused by CTX, enhanced the serum immune cytokine factors, and upregulated TLR4/NF-κB pathway key proteins (TLR4, NF-κB p65) at mRNA and protein levels. CONCLUSION: Hericium erinaceus polysaccharides effectively regulated GM and enhancement of intestinal immune function, so they have the potential to be developed as functional ingredients or foods to modulate immune responses. © 2022 Society of Chemical Industry.

Uncovering the genetic basis of gluten aggregation parameters by genome-wide association analysis in wheat (Triticum aestivum L.) using GlutoPeak.

BACKGROUND: Numerous studies have shown that gluten aggregation properties directly affect the processing quality of wheat, however, the genetic basis of gluten aggregation properties were rarely reported. RESULTS: To explore the genetic basis of gluten aggregation properties in wheat, an association population consisted with 207 wheat genotypes were constructed for evaluating nine parameters of aggregation properties on GlutoPeak across three-year planting seasons. A total of 940 significant SNPs were detected for 9 GlutoPeak parameters through genome-wide association analysis (GWAS). Finally, these SNPs were integrated to 68 non-redundant QTL distributed on 20 chromosomes and 54 QTL was assigned as pleiotropic loci which accounting for multiple parameters of gluten aggregation property. Furthermore, the peak SNPs representing 54 QTL domonstrated additive effect on all the traits. There was a significant positive correlation between the number of favorable alleles and the phenotypic values of each parameter. Peak SNPs of two novel QTL, q3AL.2 and q4DL, which contributing to both PMT (peak maximum time) and A3 (area from the first minimum to torque 15 s before the maximum torque) parameters, were selected for KASP (Kompetitive Allele Specific PCR) markers development and the KASP markers can be used for effectively evaluating the quality of gluten aggregation properties in the association population. CONCLUSION: The rapid and efficient GlutoPeak method for gluten measurement can be used for early selection of wheat breeding. This study revealed the genetic loci related to GlutoPeak parameters in association population, which would be helpful to develop wheat elite lines with improved gluten aggregation through molecular marker-assisted breeding.

BrWAX2 plays an essential role in cuticular wax biosynthesis in Chinese cabbage (Brassica rapa L. ssp. pekinensis).

KEY MESSAGE: Map-based cloning was used to identify the BrWAX2 gene, which was involved in the cuticular wax biosynthesis. The malfunction of BrWAX2 together with other reduced expression of genes in alkane-forming pathway caused the glossy phenotype. Cuticular wax covering the outer plant surface plays various roles in protecting against biotic and abiotic stresses. Wax-less mutant shows glossy in stem and leaf surface and plays important roles in enriching Chinese cabbage germplasm resources for breeding brilliant green varieties. However, genes responsible for the glossy trait in Chinese cabbage are rarely reported. In this study, we identified a glossy Chinese cabbage line Y1211-1. Genetic analysis indicated that the glossy trait in Y1211-1 was controlled by a single recessive locus, BrWAX2 (Brassica rapa WAX 2). Using bulked segregant sequencing (BSA-Seq) and kompetitive allele-specific PCR (KASP) assays, BrWAX2 was fine-mapped to an interval of 100.78 kb. Functional annotation analysis, expression analysis, and sequence variation analysis revealed that Bra032670, homologous to CER1 in Arabidopsis, was the most likely candidate gene for BrWAX2. The gene Bra032670 was absent in glossy mutant. Cuticular wax composition analysis and RNA-Seq analysis suggested that the absence of BrWAX2 together with the decreased expression of other genes in alkane-forming pathway reduced the wax amount and caused the glossy phenotype. Furthermore, we developed and validated the functional marker BrWAX2-sp for BrWAX2. Overall, these results provide insight into the molecular mechanism underlying cuticular wax biosynthesis and reveal valuable information for marker-assisted selection (MAS) breeding in Chinese cabbage.

Molecular characterization of a novel victorivirus infecting Corynespora cassiicola.

A novel victorivirus was detected in an isolate of Corynespora cassiicola strain 20180909-03 and was named "Corynespora cassiicola victorivirus 1" (CcVV1). The complete genome sequence of this virus is 5140 bp in length and contains 57% GC with two large open reading frames (ORFs) overlapping at the tetranucleotide AUGA. The ORFs were predicted to encode a coat protein (CP) and an RNA-dependent RNA polymerase (RdRp), respectively, which are conserved in dsRNA fungal viruses of the family Totiviridae. Comparison and phylogenetic analysis of the deduced amino acid sequences of RdRp and CP showed that CcVV1 is a new member of the genus Victorivirus. This is the first report of a genomic sequence of a victorivirus infecting Corynespora cassiicola.

Complete genome sequence of a novel fusarivirus from the phytopathogenic fungus Corynespora cassiicola.

Corynespora cassiicola is an important phytopathogenic fungus that severely impairs crop production. Here, we report the molecular characterization of a novel positive-sense single-stranded RNA (+ssRNA) mycovirus, Corynespora cassiicola fusarivirus 1 (CcFV1), isolated from C. cassiicola strain 20200826-3-1. Excluding the poly(A) tail, the genome of the virus is 6491 nt in length and contains three putative open reading frames (ORFs). The large ORF1 encodes a polypeptide of 1524 aa with a conserved RNA-dependent RNA polymerase (RdRp) domain and a helicase (Hel) domain. BLASTp analysis showed that CcFV1 ORF1 has the highest similarity to Setosphaeria turcica fusarivirus 1 (StFV1, 50.45% identity, E-value 0.0). ORF2 encodes a polypeptide with a conserved chromosome segregation ATPase (Smc) domain. The smaller ORF3 encodes a polypeptide with an unknown function. Phylogenetic analysis based on the ORF1- encoded polypeptide showed that CcFV1 is phylogenetically related to members of the newly proposed family "Fusariviridae". Thus, we suggest that CcFV1 might be a novel member of the family "Fusariviridae", and is the first to be discovered in C. cassiicola.

Ferulic acid improves intestinal barrier function through altering gut microbiota composition in high-fat diet-induced mice.

PURPOSE: A high-fat diet (HFD) induces gut microbiota (GM) disorders, leading to intestinal barrier dysfunction and inflammation. Ferulic acid (FA) has shown anti-obesity effects, e.g., reducing body weight and food intake. However, the mechanism linking the anti-obesity effects of FA and GM modulation remains obscure. The present study aimed to clarify the mechanism underlying the anti-obesity effects of FA and modulation of the GM. METHODS: C57BL/6 J mice were fed by a low-fat diet (LFD) and HFD with or without FA at a dose of 100 mg/kg of body weight by oral gavage for 12 weeks. Using high-throughput sequencing, gas chromatography, real-time fluorescence quantitative PCR and immunohistochemical staining, the attenuation of obesity by FA were assessed via intestinal barrier integrity, inflammation, and the GM. RESULTS: FA reduced weight gain, improved HFD-induced GM imbalance, significantly enhanced intestinal short-chain fatty acid (SCFA)-producing bacteria (e.g., Olsenella, Eisenbergiella, Dubosiella, Clostridiales_unclassified, and Faecalibaculum) along with SCFA accumulation and its receptors' expression, decreased endotoxin-producing bacteria or obesity-related bacterial genera, and serum endotoxin (lipopolysaccharides), and inhibited the colonic TLR4/NF-κB pathway. Thus, FA can mitigate colonic barrier dysfunction and intestinal inflammation, induce the production of SCFAs and inhibit endotoxins by modulating the GM. CONCLUSION: These results indicate that enhancement of intestinal barrier by altering the GM may be an anti-obesity target of FA and that FA can be used as a functional compound with great developmental values.

Quantitative traits loci mapping and molecular marker development for total glutenin and glutenin fraction contents in wheat.

BACKGROUND: Glutenin contents and compositions are crucial factors influencing the end-use quality of wheat. Although the composition of glutenin fractions is well known, there has been relatively little research on the genetic basis of glutenin fractions in wheat. RESULTS: To elucidate the genetic basis for the contents of glutenin and its fractions, a population comprising 196 recombinant inbred lines (RILs) was constructed from two parents, Luozhen No.1 and Zhengyumai 9987, which differ regarding their total glutenin and its fraction contents (except for the By fraction). Forty-one additive Quantitative Trait Loci (QTL) were detected in four environments over two years. These QTL explained 1.3% - 53.4% of the phenotypic variation in the examined traits. Forty-three pairs of epistatic QTL (E-QTL) were detected in the RIL population across four environments. The QTL controlling the content of total glutenin and its seven fractions were detected in clusters. Seven clusters enriched with QTL for more than three traits were identified, including a QTL cluster 6AS-3, which was revealed as a novel genetic locus for glutenin and related traits. Kompetitive Allele-Specific PCR (KASP) markers developed from the main QTL cluster 1DL-2 and the previously developed KASP marker for the QTL cluster 6AS-3 were validated as significantly associated with the target traits in the RIL population and in natural varieties. CONCLUSIONS: This study identified novel genetic loci related to glutenin and its seven fractions. Additionally, the developed KASP markers may be useful for the marker-assisted selection of varieties with high glutenin fraction content and for identifying individuals in the early developmental stages without the need for phenotyping mature plants. On the basis of the results of this study and the KASP markers described herein, breeders will be able to efficiently select wheat lines with favorable glutenin properties and develop elite lines with high glutenin subunit contents.

The mechanism of sesame resistance against Macrophomina phaseolina was revealed via a comparison of transcriptomes of resistant and susceptible sesame genotypes.

BACKGROUND: Sesame (Sesamum indicum) charcoal rot, a destructive fungal disease caused by Macrophomina phaseolina (Tassi) Goid (MP), is a great threat to the yield and quality of sesame. However, there is a lack of information about the gene-for-gene relationship between sesame and MP, and the molecular mechanism behind the interaction is not yet clear. The aim of this study was to interpret the molecular mechanism of sesame resistance against MP in disease-resistant (DR) and disease-susceptible (DS) genotypes based on transcriptomics. This is the first report of the interaction between sesame and MP using this method. RESULTS: A set of core genes that response to MP were revealed by comparative transcriptomics and they were preferentially associated with GO terms such as ribosome-related processes, fruit ripening and regulation of jasmonic acid mediated signalling pathway. It is also exhibited that translational mechanism and transcriptional mechanism could co-activate in DR so that it can initiate the immunity to MP more rapidly. According to weighted gene co-expression network analysis (WGCNA) of differentially expressed gene sets between two genotypes, we found that leucine-rich repeat receptor-like kinase (LRR-RLK) proteins may assume an important job in sesame resistance against MP. Notably, compared with DS, most key genes were induced in DR such as pattern recognition receptors (PRRs) and resistance genes, indicating that DR initiated stronger pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Finally, the study showed that JA/ET and SA signalling pathways all play an important role in sesame resistance to MP. CONCLUSIONS: The defence response to MP of sesame, a complex bioprocess involving many phytohormones and disease resistance-related genes, was illustrated at the transcriptional level in our investigation. The findings shed more light on further understanding of different responses to MP in resistant and susceptible sesame.

Identification of genomic regions affecting grain peroxidase activity in bread wheat using genome-wide association study.

BACKGROUND: Peroxidase (POD) activity plays an important role in flour-based product quality, which is mainly associated with browning and bleaching effects of flour. Here, we performed a genome-wide association study (GWAS) on POD activity using an association population consisted with 207 wheat world-wide collected varieties. Our study also provide basis for the genetic improvement of flour color-based quality in wheat. RESULTS: Twenty quantitative trait loci (QTLs) were detected associated with POD activity, explaining 5.59-12.67% of phenotypic variation. Superior alleles were positively correlated with POD activity. In addition, two SNPs were successfully developed to KASP (Kompetitive Allele-Specific PCR) markers. Two POD genes, TraesCS2B02G615700 and TraesCS2D02G583000, were aligned near the QTLs flanking genomic regions, but only TraesCS2D02G583000 displayed significant divergent expression levels (P < 0.001) between high and low POD activity varieties in the investigated association population. Therefore, it was deduced to be a candidate gene. The expression level of TraesCS2D02G583000 was assigned as a phenotype for expression GWAS (eGWAS) to screen regulatory elements. In total, 505 significant SNPs on 20 chromosomes (excluding 4D) were detected, and 9 of them located within 1 Mb interval of TraesCS2D02G583000. CONCLUSIONS: To identify genetic loci affecting POD activity in wheat grain, we conducted GWAS on POD activity and the candidate gene TraesCS2D02G583000 expression. Finally, 20 QTLs were detected for POD activity, whereas two QTLs associated SNPs were converted to KASP markers that could be used for marker-assisted breeding. Both cis- and trans-acting elements were revealed by eGWAS of TraesCS2D02G583000 expression. The present study provides genetic loci for improving POD activity across wide genetic backgrounds and largely improved the selection efficiency for breeding in wheat.

Non-homologous chromosome pairing during meiosis in haploid Brassica rapa.

KEY MESSAGE: Cytological observations of chromosome pairing showed that evolutionarily genome duplication might reshape non-homologous pairing during meiosis in haploid B. rapa. A vast number of flowering plants have evolutionarily undergone whole genome duplication (WGD) event. Typically, Brassica rapa is currently considered as an evolutionary mesohexaploid, which has more complicated genomic constitution among flowering plants. In this study, we demonstrated chromosome behaviors in haploid B. rapa to understand how meiosis proceeds in presence of a single homolog. The findings showed that a diploid-like chromosome pairing was generally adapted during meiosis in haploid B. rapa. Non-homologous chromosomes in haploid cells paired at a high-frequency at metaphase I, over 50% of examined meiocytes showed at least three pairs of bivalents then equally segregated at anaphase I during meiosis. The fluorescence immunostaining showed that the cytoskeletal configurations were mostly well-organized during meiosis. Moreover, the expressed genes identified at meiosis in floral development was rather similar between haploid and diploid B. rapa, especially the expression of known hallmark genes pivotal to chromosome synapsis and homologous recombination were mostly in haploid B. rapa. Whole-genome duplication evolutionarily homology of genomic segments might be an important reason for this phenomenon, which would reshape the first division course of meiosis and influence pollen development in plants.

Anti-Inflammatory Properties In Vitro and Hypoglycaemic Effects of Phenolics from Cultivated Fruit Body of Phellinus baumii in Type 2 Diabetic Mice.

Dietary intervention in type 2 diabetes mellitus (T2DM) is a hotspot in international research because of potential threats to human health. Phellinus baumii, a wild fungus traditionally used as a food and medicine source, is now cultivated in certain East Asian countries, and is rich in polyphenols, which are effective anti-inflammatory ingredients useful in treatment of T2DM, with fewer side effects than drugs. To examine the hypoglycaemic effects of Phellinus baumii phenolics (PPE), the metabolite profiles of T2DM mice induced by streptozotocin after PPE intervention were systematically analyzed. Here, 10 normal mice were given normal saline as control group, and 50 model mice were randomly assigned to five groups and daily intragastric administrated with saline, metformin (100 mg/kg), and PPE (50, 100, 150 mg/kg of body weight), for 60 days. The pro-inflammatory factor contents of lipopolysaccharide stimulation of RAW 264.7 cells were decreased in a dose-dependent manner after PPE treatment, we propose that PPE could exert anti-inflammatory properties. PPE could also effectively reduce blood glucose levels, increased insulin sensitivity, and improved other glucolipid metabolism. Q-PCR results suggested that the hypoglycemic effects of PPE might be through activating IRS1/PI3K/AKT pathway in diabetic mice. These results suggest that PPE has strong potential as dietary components in the prevention or management of T2DM.

Ectopic overexpression of a cotton plastidial Na+ transporter GhBASS5 impairs salt tolerance in Arabidopsis via increasing Na+ loading and accumulation.

MAIN CONCLUSION: GhBASS5 is a member of the bile acid sodium symporter (BASS) gene family from cotton and a plastid-localized Na+ transporter that negatively regulates salt tolerance of plants. Soil salinization is a major constraint on global cotton production, and Na+ is the most dominant toxic ion in salinity stress. Hence, insights into the identities and properties of transporters that catalyze Na+ movement between different tissues and within the cell compartments are vital to understand the salt-tolerant mechanisms of plants. Here, we identified the GhBASS5 gene, a member of the bile acid sodium symporter (BASS) gene family from cotton, served as a plastidic Na+ transporter. GhBASS5 encodes a membrane protein localized in the plastid envelope. It was highly expressed in cotton roots and predominantly existed in the vascular cylinder. Heterogenous expression of GhBASS5 in Arabidopsis chloroplasts promoted Na+ uptake into chloroplasts, which contributed to an increased cytoplasmic Na+ concentration. And GhBASS5-overexpressed transgenic plants showed an increase in Na+ translocation from roots to shoots and an elevated Na+ content in both roots and shoots, but a dramatic decrease in the Na+ efflux from root tissues and the K+/Na+ ratio, especially under salt stress conditions. Furthermore, overexpressing GhBASS5 greatly damaged plastid functions and enhanced salt sensitivity in transgenic Arabidopsis when compared with wild-type plants under salt stress. Additionally, the salt-responsive transporter genes that regulate K+/Na+ homeostasis were dramatically expressed in GhBASS5-overexpressed lines, especially under salt stress conditions. Taken together, our results suggest that GhBASS5 is a plastid-localized Na+ transporter, and high expression of GhBASS5 impairs salt tolerance of plants via increasing Na+ transportation and accumulation at both cell and tissue levels.

Role of a cotton endoreduplication-related gene, GaTOP6B, in response to drought stress.

MAIN CONCLUSION: Cotton GaTOP6B is involved in cellular endoreduplication and a positive response to drought stress via promoting plant leaf and root growth. Drought is deemed as one of adverse conditions that could cause substantial reductions in crop yields worldwide. Since cotton exhibits a moderate-tolerant phenotype under water-deficit conditions, the plant could therefore be used to characterize potential new genes regulating drought tolerance in crop plants. In this work, GaTOP6B, encoding DNA topoisomerase VI subunit B, was identified in Asian cotton (Gossypium arboreum). Virus-induced gene silencing (VIGS) and overexpression (OE) were used to investigate the biological function of GaTOP6B in G. arboreum and Arabidopsis thaliana under drought stress. The GaTOP6B-silencing plants showed a reduced ploidy level, and displayed a compromised tolerance phenotype including lowered relative water content (RWC), decreased proline content and antioxidative enzyme activity, and an increased malondialdehyde (MDA) content under drought stress. GaTOP6B-overexpressing Arabidopsis lines, however, had increased ploidy levels, and were more tolerant to drought treatment, associated with improved RWC maintenance, higher proline accumulation, and reduced stomatal aperture under drought stress. Transcriptome analysis showed that genes involved in the processes like cell cycle, transcription and signal transduction, were substantially up-regulated in GaTOP6B-overexpressing Arabidopsis, promoting plant growth and development. More specifically, under drought stress, the genes involved in the biosynthesis of secondary metabolites such as phenylpropanoid, starch and sucrose were selectively enhanced to improve tolerance in plants. Taken together, the results demonstrated that GaTOP6B could coordinately regulate plant leaf and root growth via cellular endoreduplication, and positively respond to drought stress. Thus, GaTOP6B could be a competent candidate gene for improvement of drought tolerance in crop species.