Genetic dissection and identification of stripe rust resistance genes in the wheat cultivar Lanhangxuan 121, a cultivar selected from a space mutation population.

Stripe rust is a devastating disease of wheat worldwide. Chinese wheat cultivar Lanhangxuan 121 (LHX121), selected from an advanced line L92-47 population that had been subjected to space mutation breeding displayed a consistently higher level of resistance to stipe rust than its parent in multiple field environments. The aim of this research was to establish the number and types of resistance genes in parental lines L92-47 and LHX121 using separate segregating populations. The first population developed from a cross between LHX121 and susceptible cultivar Xinong 822 comprised 278 F2:3 lines. The second validation population comprised 301 F2:3 lines from a cross between L92-47 and susceptible cultivar Xinong 979. Lines of two population were evaluated for stripe rust response at three sites during the 2018-2020 cropping season. Affymetrix 660 K SNP arrays were used to genotype the lines and parents. Inclusive composite interval mapping detected QTL QYrLHX.nwafu-2BS, QYrLHX.nwafu-3BS, and QYrLHX.nwafu-5BS for resistance in all three environments. Based on previous studies and pedigree information, QYrLHX.nwafu-2BS and QYrLHX.nwafu-3BS were likely to be Yr27 and Yr30 that are present in the L92-47 parent. QYrLHX.nwafu-5BS (YrL121) detected only in LHX121 was mapped to a 7.60 cM interval and explained 10.67-22.57% of the phenotypic variation. Compared to stripe rust resistance genes previously mapped to chromosome 5B, YrL121 might be a new adult plant resistance QTL. Furthermore, there were a number of variations signals using 35 K SNP array and differentially expressed genes using RNA-seq between L92-47 and LHX121 in the YrL121 region, indicating that they probably impair the presence and/or function of YrL121. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-024-01461-0.

Assembly and characterization of the complete mitochondrial genome of Ventilago leiocarpa.

KEY MESSAGE: We reported the mitochondrial genome of Ventilago leiocarpa for the first time. Two and one sites lead to the generation of stop and stat codon through editing were verified. Ventilago leiocarpa, a member of the Rhamnaceae family, is frequently utilized in traditional medicine due to the medicinal properties of its roots. In this study, we successfully assembled the mitogenome of V. leiocarpa using both BGI short reads and Nanopore long reads. This mitogenome has a total length of 331,839 bp. The annotated results showed 36 unique protein-coding, 16 tRNA and 3 rRNA genes in this mitogenome. Furthermore, we confirmed the presence of a branched structure through the utilization of long reads mapping, PCR amplification, and Sanger sequencing. Specifically, the ctg1 can form a single circular molecule or combine with ctg4 to form a linear molecule. Likewise, ctg2 can form a single circular molecule or can be connected to ctg4 to form a linear molecule. Subsequently, through a comparative analysis of the mitogenome and cpgenome sequences, we identified ten mitochondrial plastid sequences (MTPTs), including two complete protein-coding genes and five complete tRNA genes. The existence of MTPTs was verified by long reads. Colinear analysis showed that the mitogenomes of Rosales were highly divergent in structure. Finally, we identified 545 RNA editing sites involving 36 protein-coding genes by Deepred-mt. To validate our findings, we conducted PCR amplification and Sanger sequencing, which confirmed the generation of stop codons in atp9-223 and rps10-391, as well as the generation of a start codon in nad4L-2. This project reported the complex structure and RNA editing event of the V. Leiocarpa mitogenome, which will provide valuable information for the study of mitochondrial gene expression.

Identification of two novel QTL for Fusarium head blight resistance in German wheat cultivar Centrum.

Fusarium head blight (FHB) is a devastating disease that occurs in warm and humid environments. The German wheat Centrum has displayed moderate to high levels of FHB resistance in the field for many years. In this study, an F6:8 recombinant inbred line (RIL) population derived from cross Centrum × Xinong 979 was evaluated for FHB response following point inoculation in five environments. The population and parents were genotyped using the GenoBaits Wheat 16 K Panel. Stable quantitative trait loci (QTL) associated with FHB resistance in Centrum were mapped on chromosome arms 2DS and 5BS. The most effective QTL, located in 2DS, was identified as a new chromosome region represented by a 1.4 Mb interval containing 17 candidate genes. Another novel QTL was mapped in chromosome arm 5BS of a 5BS-7BS translocation chromosome. In addition, two environmentally-sensitive QTL were mapped on chromosome arms 2BL from Centrum and 5AS from Xinong 979. Polymorphisms of flanking allele-specifc quantitative PCR (AQP) markers AQP-6 for QFhb.nwafu-2DS and 16K-13073 for QFhb.nwafu-5BS were validated in a panel of 217 cultivars and breeding lines. These markers could be useful for marker-assisted selection of FHB resistance and also provide a starting point for fine mapping and marker-based cloning of the resistance genes.

Slow stripe rusting in Chinese wheat Jimai 44 conferred by Yr29 in combination with a major QTL on chromosome arm 6AL.

KEY MESSAGE: YrJ44, a more effective slow rusting gene than Yr29, was localized to a 3.5-cM interval between AQP markers AX-109373479 and AX-109563479 on chromosome 6AL. "Slow rusting" (SR) is a type of adult plant resistance (APR) that can provide non-specific durable resistance to stripe rust in wheat. Chinese elite wheat cultivar Jimai 44 (JM44) has maintained SR to stripe rust in China since its release despite exposure to a changing and variable pathogen population. An F2:6 population comprising 295 recombinant inbred lines (RILs) derived from a cross between JM44 and susceptible cultivar Jimai 229 (JM229) was used in genetic analysis of the SR. The RILs and parental lines were evaluated for stripe rust response in five field environments and genotyped using the Affymetrix Wheat55K SNP array and 13 allele-specific quantitative PCR-based (AQP) markers. Two stable QTL on chromosome arms 1BL and 6AL were identified by inclusive composite interval mapping. The 1BL QTL was probably the pleiotropic gene Lr46/Yr29/Sr58. QYr.nwafu-6AL (hereafter named YrJ44), mapped in a 3.5-cM interval between AQP markers AX-109373479 and AX-109563479, was more effective than Yr29 in reducing disease severity and relative area under the disease progress curve (rAUDPC). RILs harboring both YrJ44 and Yr29 displayed levels of SR equal to the resistant parent JM44. The AQP markers linked with YrJ44 were polymorphic and significantly correlated with stripe rust resistance in a panel of 1,019 wheat cultivars and breeding lines. These results suggested that adequate SR resistance can be obtained by combining YrJ44 and Yr29 and the AQP markers can be used in breeding for durable stripe rust resistance.

Development of breeder chip for gene detection and molecular-assisted selection by target sequencing in wheat.

Wheat is an essential food crop and its high and stable yield is suffering from great challenges due to the limitations of current breeding technology and various stresses. Accelerating molecularly assisted stress-resistance breeding is critical. Through a meta-analysis of published loci in wheat over the last two decades, we selected 60 loci with main breeding objectives, high heritability, and reliable genotyping, such as stress resistance, yield, plant height, and resistance to spike germination. Then, using genotyping by target sequencing (GBTS) technology, we developed a liquid phase chip based on 101 functional or closely linked markers. The genotyping of 42 loci was confirmed in an extensive collection of Chinese wheat cultivars, indicating that the chip can be used in molecular-assisted selection (MAS) for target breeding goals. Besides, we can perform the preliminary parentage analysis with the genotype data. The most significant contribution of this work lies in translating a large number of molecular markers into a viable chip and providing reliable genotypes. Breeders can quickly screen germplasm resources, parental breeding materials, and intermediate materials for the presence of excellent allelic variants using the genotyping data by this chip, which is high throughput, convenient, reliable, and cost-efficient. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01359-3.

Expression of interleukin-1ß, interleukin-4, interferon-γ and tumour necrosis factor α in different tissue in a dinitrochlorobenzene-induced ear swelling test in mice.

OBJECTIVE: To study the expression of interleukin-1ß (IL-1ß), interleukin-4 (IL-4), interferon-γ (IFN-γ) and tumour necrosis factor α (TNF-α) in different tissue in a dinitrochlorobenzene (DNCB)-induced ear swelling test in mice and further evaluate the correlation between the cytokine expression in different tissues and the degree of ear swelling. METHODS: The mice were sensitised with a 0.50% DNCB solution on their back for 3 days. After 7 days, the thickness of their ears was measured and grouped. Different concentrations of the DNCB solution were challenged in the left ear of each group of mice, and the right ear was used as the control. The thickness of both ears was measured every 24 h, and the mice were sacrificed 72 h after the challenge. The expressions of IL-1ß, IL-4, IFN-γ and TNF-α in the mouse serum, lymph node and ear tissue were quantified by enzyme-linked immunosorbent assay, respectively. RESULTS: There was a linear positive correlation between the swelling index of the mouse lateral ear and the challenge concentration of DNCB (r = 0.96, p < 0.01). The high expression of IL-1ß and IL-4 in the lateral ear tissue of the mice was positively correlated with the ear swelling index 48 h after the challenge. The correlation coefficient was 0.78 (p < 0.01). Furthermore, IFN-γ and TNF-α had no significant correlation with the ear swelling index 48 h after the challenge. CONCLUSION: There is a correlation between the degree of ear swelling in mice and the concentration of DNCB and the expression of IL-1ß and IL-4 in the lateral ear tissue. There is a sub-clinical skin sensitivity state in contact allergy.

BdFAR4, a root-specific fatty acyl-coenzyme A reductase, is involved in fatty alcohol synthesis of root suberin polyester in Brachypodium distachyon.

Suberin is a complex hydrophobic polymer of aliphatic and phenolic compounds which controls the movement of gases, water, and solutes and protects plants from environmental stresses and pathogenic infection. The synthesis and regulatory pathways of suberin remain unknown in Brachypodium distachyon. Here we describe the identification of a B. distachyon gene, BdFAR4, encoding a fatty acyl-coenzyme A reductase (FAR) by a reverse genetic approach, and investigate the molecular relevance of BdFAR4 in the root suberin synthesis of B. distachyon. BdFAR4 is specifically expressed throughout root development. Heterologous expression of BdFAR4 in yeast (Saccharomyces cerevisiae) afforded the production of C20:0 and C22:0 fatty alcohols. The loss-of-function knockout of BdFAR4 by CRISPR/Cas9-mediated gene editing significantly reduced the content of C20:0 and C22:0 fatty alcohols associated with root suberin. In contrast, overexpression of BdFAR4 in B. distachyon and tomato (Solanum lycopersicum) resulted in the accumulation of root suberin-associated C20:0 and C22:0 fatty alcohols, suggesting that BdFAR4 preferentially accepts C20:0 and C22:0 fatty acyl-CoAs as substrates. The BdFAR4 protein was localized to the endoplasmic reticulum in Arabidopsis thaliana protoplasts and Nicotiana benthamiana leaf epidermal cells. BdFAR4 transcript levels can be increased by abiotic stresses and abscisic acid treatment. Furthermore, yeast one-hybrid, dual-luciferase activity, and electrophoretic mobility shift assays indicated that the R2R3-MYB transcription factor BdMYB41 directly binds to the promoter of BdFAR4. Taken together, these results imply that BdFAR4 is essential for the production of root suberin-associated fatty alcohols, especially under stress conditions, and that its activity is transcriptionally regulated by the BdMYB41 transcription factor.

Chemical constituents, biological activities and anti-rheumatoid arthritic properties of four citrus essential oils.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease with predominant synovitis that has no complete cure or preventive treatment. Citrus essential oils, used in natural fragrances, contain a variety of functional ingredients that are worthy of investigation for their potential as natural anti-inflammatory drug sources. In this study, essential oils were hydro distilled from the peels of four citrus species: Citrus sinensis (L.) Osbeck (CSEOs), Citrus paradisi Macfad. (CPEOs), Citrus limon (L.) Osbeck (CLEOs) and Citri Reticulatae Pericarpium (CREOs). Altogether, 81 compounds were identified using gas chromatography-mass spectrometry (GC-MS), of which d-limonene (17.96%-94.66%) was an abundant component of all four oils. The stable 1,1-diphenyl-2-pyrrole hydrazine (DPPH) free radical test showed that all four essential oils had excellent antioxidant properties (IC50 , 0.76-13.86 µg/mL). Furthermore, the oils remarkably increased the first G1 phase of the cell cycle, which inhibited the pro-inflammatory factor expression. An immunohistochemical analysis indicated that the four essential oils inhibited the expression of tumor necrosis factor-α and cyclooxygenase-2 and they exhibited anti-inflammatory activity in a rat model that was similar to that of the common drug, Ibuprofen. These results show that the CSEOs, CPEOs, CLEOs, and CREOs have significant antirheumatic activities and thus have great potential in developing functional food or drugs for treating RA.

Variation in Compositions and Biological Activities of Essential Oils from Four Citrus Species: Citrus limon, Citrus sinensis, Citrus paradisi, and Citrus reticulata.

Species of the genus Citrus are cultivated in many regions of China and are widely used for medicinal purposes. In the present study, essential oils (EOs) were extracted from four different Citrus species using steam distillation. The chemical components of these four essential oils were separated using gas chromatography-mass spectrometry, and 52 compounds were confirmed. D-limonene was found to be the most abundant compound. All four essential oils demonstrated varied but remarkable radical scavenging capacity (IC50 ; 0.77-13.9 %). Citrus paradisi essential oil exhibited excellent antioxidant activity. Compared to ibuprofen, topical application of the four Citrus spp. essential oils significantly inhibited ear edema formation in mice. Furthermore, essential oils from the four Citrus species reduced the expression levels of interleukin-6 (IL-6), cyclooxygenase-2 (COX-2) and nuclear transcription factor kappa B p65 (NF-κB) to different degrees. The cytotoxicity of the four essential oils on BV2 microglial cells was determined using the MTT assay (IC50 ; 321.37-1558.87 µg/mL), wherein Citrus limon essential oil showed the lowest cytotoxicity. The essential oils of Citrus limon, Citrus reticulata, and Citrus paradisi had an inhibitory effect on the lung cancer cell lines H1299 by inducing a G0/G1 cell cycle arrest. Cluster and principal component analyses were used to determine the relationship among the Citrus species. These results suggest that the four Citrus essential oils have potential for use as active ingredients in functional foods or cosmeceutical products.

Investigation and Identification of Food Poisoning Caused by Clostridium botulinum Type B1 in Shenzhen, China.

Clostridium botulinum produces botulinum neurotoxins (BoNTs), which cause people who ingest them to become seriously ill and sometimes die. In recent years, sporadic food poisoning cases associated with C. botulinum have occurred across the world. In 2016, two men were admitted to our hospital in Shenzhen, China, with foodborne botulism. In this study, we report on these two typical C. botulinum-related food poisoning incidents and the steps taken to identify and characterize the causative pathogen. We characterized the bacterial pathogen isolated from the first patient using cooked meat medium and egg yolk agar bacterial cultures under anaerobic conditions, and morphologically identified the isolate using Gram staining. The in vivo bioassay results in mice showed that the minimum lethal dose of the BoNTs produced by our isolate was 0.001-0.0001 mg/mL (LD50 of the culture was estimated to be 1.5812 mg/kg). Whole genome sequencing (WGS) results showed that the isolate was identified as C. botulinum B1 Okra. The causative strain was successfully isolated from the intestinal lavage fluid collected from the initial patient.

The Essential Oil Derived from Perilla frutescens (L.) Britt. Attenuates Imiquimod-Induced Psoriasis-like Skin Lesions in BALB/c Mice.

Psoriasis is reported to be a common chronic immune-mediated skin disease characterized by abnormal keratinocytes and cell proliferation. Perilla leaves are rich in essential oils, fatty acids, and flavonoids, which are recognized for their antioxidant and anti-inflammatory effects. In this study, the alleviating effect of essential oil (PO) extracted from Perilla frutescens stems and leaves on imiquimod (IMQ) -induced psoriasis-like lesions in BALB/c mice were investigated. Results showed that PO ameliorated psoriasis-like lesions in vivo, reduced the expression of lymphocyte antigen 6 complex locus G6D (Ly-6G), which is a marker of neutrophil activation, and inhibited the expression of inflammatory factors interleukin 1 (IL-1), interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase 2 (COX2). In addition, PO significantly decreased the expression of cytokines such as IL-6, IL-1, interleukin 23 (IL-23), interleukin 17 (IL-17), and nuclear factor kappa-B (NF-κB). Furthermore, the down-regulation of mRNA levels of psoriasis-related pro-inflammatory cytokines, such as IL-17, interleukin 22 (IL-22), IL-23, interferon-α (IFN-α), and Interferon-γ (IFN-γ) was observed with the treatment of PO. All results show a concentration dependence of PO, with low concentrations showing the best results. These results suggest that PO effectively alleviated psoriasis-like skin lesions and down-regulated inflammatory responses, which indicates that PO could potentially be used for further studies on inflammation-related skin diseases such as psoriasis and for the treatment of psoriasis such as psoriasis natural plant essential oil resources.

Aromatic-turmerone ameliorates DSS-induced ulcerative colitis via modulating gut microbiota in mice.

Curcuma longa L. is one of the traditional Chinese herbs in the list of medicinal and food homology. Aromatic-turmerone is the main ingredient in turmeric essential oil. The aim of the present study is to investigate the treatment of Aromatic-turmerone on DSS-included colitis and its regulatory effect on intestinal flora disorder. Male KM mice supplemented with different concentration of aromatic-turmerone and mesalazine are subjected to 2% DSS in drinking water to induce colitis. Colon and cecum contents were collected for colitis lesion evaluation and inflammation-related gene analysis and colon contents for gut microbiota. The results show that treatments with Aromatic-turmerone significantly prevents colon shortening, alleviates the damage of colonic tissue, and reduces colonic inflammatory cytokines TNF-α and COX-2. Furthermore, the 16S rDNA gene sequence data indicate that Aromatic-turmerone improve the abundance of bacterial species, maintain some beneficial bacteria, and reduce harmful bacteria. Aromatic-turmerone downregulates the colonic inflammatory cytokines and modulates the abundance of intestinal flora, which is conductive to ameliorates DSS-induced colitis. Regularly intake of the edible herb may be help to prevent ulcerative colitis-related diseases.

Ripe for reassessment: A synthesis of available molecular data for the speciose diatom family Bacillariaceae.

The Bacillariaceae is a very species-rich family of raphid diatoms and includes the large and taxonomically difficult genus Nitzschia, whose species are often small-celled and finely structured and have few discrete morphological characters visible in the light microscope. The classification of Nitzschia is still mostly based on one developed in the second half of the 19th century by Grunow, who separated the genus into a series of sections largely on cell shape and symmetry, the position of the raphe, transverse extension of the fibulae, and folding of the valve. We assembled and analysed single-gene and concatenated alignments of nSSU, nLSU, rbcL, psbC and cox1 to test Grunow's and subsequent classifications and to examine selected morphological characters for their potential to help define monophyletic groups. The maximum likelihood trees were equivocal as to monophyly of the family itself but showed good support for each of eight main clades of Bacillariaceae, three of which corresponded more or less to existing genera (Hantzschia, Cylindrotheca and Bacillaria). The other five main clades and some subclades comprised groups of Nitzschia species or assemblies of Nitzschia species with other genera (Pseudo-nitzschia, Fragilariopsis, Neodenticula, Tryblionella, Psammodictyon). Relationships between most of the eight main clades were not resolved robustly but all analyses recovered Nitzschia as non-monophyletic. The Grunowian classification of Nitzschia into sections was not supported, though in some respects (e.g. treatment of sigmoid species) it is better than subsequent reclassifications. Several of the main clades and subclades are cryptic (lacking morphological synapomorphies) and homoplasy is common in both light microscopical and ultrastructural characters (to the extent that organisms initially assigned to the same species sometimes prove to belong to a different main clade). Nevertheless, some characters, including the structure of the raphe canal and girdle, seem to be sufficiently conservative evolutionarily to give a provisional estimate of relationships if molecular data are unavailable. No new formal classifications are proposed but various options are explored and research needs identified.

Morphology, phylogeny, and molecular dating in Plagiogrammaceae family focused on Plagiogramma-Dimeregramma complex (Urneidophycidae, Bacillariophyceae).

Although previous phylogenetic analyses suggested that the araphid diatom family Plagiogrammaceae is monophyletic, there is still not a clear understanding of relationships among the genera, and the taxonomy of several genera--Dimeregramma and Plagiogramma--remains questionable in light of paraphyly for both genera using molecular and morphological data. We have expanded the available DNA for molecular work for dozens of plagiogrammacean clones and analyzed 29 morphological characters from plagiogrammarian taxa and closely related genera, to increase understanding of the evolutionary history and systematics of the family and re-evaluate the current taxonomical classification of plagiogrammacean genera. The addition of more taxa and more data confirm the results from previous molecular phylogenies: most plagiogrammacean genera are monophyletic, except for Dimeregramma and Plagiogramma. Interestingly, the morphological analysis resolves only Talaroneis and Glyphodesmis as monophyletic. Given these results, we feel there is limited support for retaining Dimeregramma and Plagiogramma as distinct genera, and formally propose amending Plagiogramma and transferring six Dimeregramma species. As the Plagiogrammaceae is also one of the first-diverging clades of pennate diatoms, we also used these molecular data to estimate the age of the family, based on multiple calibration points derived from fossil taxa within or close to the Plagiogrammaceae. The results indicated that the Plagiogrammaceae evolved more than 114 million year ago and its diversification appears to correspond to a time of climate cooling. Additionally, we described a new monotypic genus (Coccinelloidea) with one new species C. gracilis, and five new species within established genera, e.g. Plagiogramma marginalis, Plagiogramma harenae, Plagiogramma porcipellis, Neofragilaria montgomeryii and Psammogramma anacarae.

The Taxonomy and Diversity of Proschkinia (Bacillariophyta), A Common But Enigmatic Genus from Marine Coasts.

Detailed morphological documentation is provided for established Proschkinia taxa, including the generitype, P. bulnheimii, and P. complanata, P. complanatula, P. complanatoides and P. hyalosirella, and six new species. All established taxa are characterized from original material from historical collections. The new species described in this paper (P. luticola, P. staurospeciosa, P. impar, P. modesta, P. fistulispectabilis, and P. rosowskii) were isolated from the Western Pacific (Yellow Sea coast of Korea) and the Atlantic (Scottish and Texas coasts). Thorough documentation of the frustule, valve and protoplast architecture revealed the combination of characters diagnostic of the genus Proschkinia: a single-lobed chloroplast; a broad girdle composed of U-shaped, perforated bands; the position of the conopeate raphe-sternum relative to the external and internal valve surface; and the presence of an occluded process through the valve, termed the "fistula". Seven strains of Proschkinia were grown in culture and five of these were sequenced for nuclear ribosomal SSU and plastid-encoded rbcL. Phylogenetic analysis recovered a clade of Proschkinia with Fistulifera, another fistula-bearing diatom genus, and together these were sister to a clade formed of the Stauroneidaceae; in turn, all of these were sister to a clade composed of Parlibellus and two monoraphid genera Astartiella and Schizostauron. Despite morphological similarities between Proschkinia and the Naviculaceae, these two taxa are distant in our analysis. We document the variation in the morphology of Proschkinia, including significant variability in the fistula, suggesting that fistula ultrastructure might be one of the key features for species identification within the genus.

Identification of New Sources of Resistance to Crown Rot and Fusarium Head Blight in Wheat.

Crown rot (CR) and Fusarium head blight (FHB) are two serious wheat diseases caused by Fusarium pathogens in China. To identify new resistant sources for CR and FHB, 205 Chinese wheat cultivars collected from Huang-Huai wheat-growing region in China were screened for resistance. Cunmai633, LS4607, Pubing01, and Hongyun2 showed seedling resistance to CR with disease index (DI) less than 0.25. Sixteen cultivars showed adult-plant resistance to CR with DI lower than 0.10. Twenty-six cultivars showed moderate resistance to CR at seedling stage with DI from 0.26 to 0.35, and 63 cultivars showed moderate adult-plant resistance with DI from 0.11 to 0.20. Among them, Cunmai633, LS4607, Pubing01, Xinong916, Zhengda161, Xumai14017, Zhengpinmai30, Bainong8822, Jimai216, Huacheng865, Fengyumai5, and Tianmin319 showed resistance or moderate resistance to CR at both seedling and adult plant stages, with Cunmai633 showing the best resistance. Most of the cultivars (>76%) were susceptible to FHB in both the 2017 and 2018 experiments with DI > 0.40. However, some cultivars demonstrated excellent FHB resistance. For example, Zhongyu1526, Tianminxiaoyan369, and Yangao168 were resistant (DI ≤ 0.25) in 2017 and moderately resistant (0.26 ≤ DI ≤ 0.40) in 2018; Zhongwo9 was moderately resistant in 2017 (DI = 0.38) and resistant in 2018 (DI = 0.25). Eight cultivars (Cunmai608, Zhengmai162, Minfeng266, Junda159, LS4607, Deyan1603, Pumai1165, and Fengmai12) showed moderate FHB resistance with DI lower than 0.40 in both experiments. LS4607 showed moderate resistance to both diseases. The resistant cultivars identified in this study can be used for mapping the resistance genes and improving resistance to CR and/or FHB.

TaCER1-1A is involved in cuticular wax alkane biosynthesis in hexaploid wheat and responds to plant abiotic stresses.

To protect above-ground plant organs from excessive water loss, their surfaces are coated by waxes. The genes involved in wax formation have been investigated in detail in Arabidopsis but scarcely in crop species. Here, we aimed to isolate and characterize a CER1 enzyme responsible for formation of the very long-chain alkanes present in high concentrations especially during late stages of wheat development. On the basis of comparative wax and transcriptome analyses of various wheat organs, we selected TaCER1-1A as a primary candidate and demonstrated that it was located to the endoplasmic reticulum, the subcellular compartment for wax biosynthesis. A wheat nullisomic-tetrasomic substitution line lacking TaCER1-1A had significantly reduced amounts of C33 alkane, whereas rice plants overexpressing TaCER1-1A showed substantial increases of C25 -C33 alkanes relative to wild type control. Similarly, heterologous expression of TaCER1-1A in Arabidopsis wild type and the cer1 mutant resulted in increased levels of unbranched alkanes, iso-branched alkanes and alkenes. Finally, the expression of TaCER1-1A was found activated by abiotic stresses and abscisic acid treatment, resulting in increased production of alkanes in wheat. Taken together, our results demonstrate that TaCER1-1A plays an important role in wheat wax alkane biosynthesis and involved in responding to drought and other environmental stresses.

LYK4 is a component of a tripartite chitin receptor complex in Arabidopsis thaliana.

LysM receptor-like kinases (LYKs) of Arabidopsis thaliana (namely LYK1, LYK4 and LYK5) play a major role in chitin perception and immunity against pathogenic fungi. Chitin-induced heterodimerization of LYK1 and LYK5 has been previously reported, but protein interaction partners of LYK4 have not yet been identified. In this study, by analysing mutants we confirmed a role of LYK4 in chitin perception, and found that the ectodomain of LYK4 homodimerizes and also interacts with the ectodomain of LYK5 in vitro. Pull-down experiments with proteins expressed in protoplasts indicated LYK4-LYK4 and LY4-LYK5 interactions in planta. When protoplasts were treated with chitoheptaose or chitin, a protein complex was immunoprecipitated that appeared to be composed of LYK1, LYK4, and LYK5. Similar experiments with proteins expressed in lyk mutant plants suggested that elicitor treatment induced a physical interaction between LYK1 and LYK5 but not between LYK1 and LYK4. Bimolecular fluorescence complementation experiments substantiated these findings. Overall, our data suggest that LYK4 functions as a LYK5-associated co-receptor or scaffold protein that enhances chitin-induced signaling in Arabidopsis.

Three Fatty Acyl-Coenzyme A Reductases, BdFAR1, BdFAR2 and BdFAR3, are Involved in Cuticular Wax Primary Alcohol Biosynthesis in Brachypodium distachyon.

Plant cuticular wax is a heterogeneous mixture of very long chain fatty acids (VLCFAs) and their derivatives. Primary alcohols are the dominant wax components throughout leaf development of Brachypodium distachyon (Brachypodium). However, the genes involved in primary alcohol biosynthesis have not been investigated and their exact biological function remains unclear in Brachypodium to date. Here, we monitored the leaf wax profile and crystal morphology during Brachypodium leaf morphogenesis, and isolated three Brachypodium fatty acyl-CoA reductase (FAR) genes, named BdFAR1, BdFAR2 and BdFAR3, then analyzed their biochemical activities, substrate specificities, expression patterns, subcellular localization and stress induction. Transgenic expression of BdFAR genes in yeast (Saccharomyces cerevisiae), tomato (Solanum lycopersicum), Arabidopsis (Arabidopsis thaliana) and Brachypodium increased the production of primary alcohols. The three BdFAR genes were preferentially expressed in Brachypodium aerial tissues, consistent with known sites of wax primary alcohol deposition, and localized in the endoplasmic reticulum (ER) in Arabidopsis protoplasts. Finally, expression of the BdFAR genes was induced by drought, cold and ABA treatments, and drought stress significantly increased cuticular wax accumulation in Brachypodium. Taken together, these results indicate that the three BdFAR genes encode active FARs involved in the biosynthesis of Brachypodium wax primary alcohols and respond to abiotic stresses.

Three endoplasmic reticulum-associated fatty acyl-coenzyme a reductases were involved in the production of primary alcohols in hexaploid wheat (Triticum aestivum L.).

BACKGROUND: The cuticle covers the surface of the polysaccharide cell wall of leaf epidermal cells and forms an essential diffusion barrier between the plant and the environment. The cuticle is composed of cutin and wax. Cuticular wax plays an important role in the survival of plants by serving as the interface between plants and their biotic and abiotic environments, especially restricting nonstomatal water loss. Leaf cuticular waxes of hexaploid wheat at the seedling stage mainly consist of primary alcohols, aldehydes, fatty acids, alkane and esters. Primary alcohols account for more than 80% of the total wax load. Therefore, we cloned several genes encoding fatty acyl-coenzyme A reductases from wheat and analyzed their function in yeast and plants. We propose the potential use of these genes in wheat genetic breeding. RESULTS: We reported the cloning and characterization of three TaFARs, namely TaFAR6, TaFAR7 and TaFAR8, encoding fatty acyl-coenzyme A reductases (FAR) in wheat leaf cuticle. Expression analysis revealed that TaFAR6, TaFAR7 and TaFAR8 were expressed at the higher levels in the seedling leaf blades, and were expressed moderately or weakly in stamen, glumes, peduncle, flag leaf blade, sheath, spike, and pistil. The heterologous expression of three TaFARs in yeast (Saccharomyces cerevisiae) led to the production of C24:0 and C26:0 primary alcohols. Transgenic expression of the three TaFARs in tomato (Solanum lycopersicum) and rice (Oryza sativa) led to increased accumulation of C24:0-C30:0 primary alcohols. Transient expression of GFP protein-tagged TaFARs revealed that the three TaFAR proteins were localized to the endoplasmic reticulum (ER), the site of wax biosynthesis. The three TaFAR genes were transcriptionally induced by drought, cold, heat, powdery mildew (Blumeria graminis) infection, abscisic acid (ABA) and methyl jasmonate (MeJa) treatments. CONCLUSIONS: These results indicated that wheat TaFAR6, TaFAR7 and TaFAR8 are involved in biosynthesis of very-long-chain primary alcohols in hexaploid wheat and in response to multiple environmental stresses.