Fine mapping of two recessive powdery mildew resistance genes from Aegilops tauschii accession CIae8.

KEY MESSAGE: Two recessive powdery mildew resistance loci pmAeCIae8_2DS and pmAeCIae8_7DS from Aegilops tauschii were mapped and two synthesized hexaploid wheat lines were developed by distant hybridization. Wheat powdery mildew (Pm), one of the worldwide destructive fungal diseases, causes significant yield loss up to 30%. The identification of new Pm resistance genes will enrich the genetic diversity of wheat breeding for Pm resistance. Aegilops tauschii is the ancestor donor of sub-genome D of hexaploid wheat. It provides beneficial genes that can be easily transferred into wheat by producing synthetic hexaploid wheat followed by genetic recombination. We assessed the Pm resistance level of 35 Ae. tauschii accessions from different origins. Accession CIae8 exhibited high Pm resistance. Inheritance analysis and gene mapping were performed using F2 and F2:3 populations derived from the cross between CIae8 and a Pm susceptible accession PI574467. The Pm resistance of CIae8 was controlled by two independent recessive genes. Bulked segregate analysis using a 55 K SNP array revealed the SNPs were mainly enriched into genome regions, i.e. 2DS (13.5-20 Mb) and 7DS (4.0-15.5 Mb). The Pm resistance loci were named as pmAeCIae8_2DS and pmAeCIae8_7DS, respectively. By recombinant screening, we narrowed the pmAeCIae8_2DS into a 370-kb interval flanked by markers CINAU-AE7800 (14.89 Mb) and CINAU-AE20 (15.26 Mb), and narrowed the pmAeCIae8_7DS into a 260-kb interval flanked by markers CINAU-AE58 (4.72 Mb) and CINAU-AE25 (4.98 Mb). The molecular markers closely linked with the resistance loci were developed, and two synthesized hexaploid wheat (SHW) lines were produced. These laid the foundation for cloning of the two resistance loci and for transferring the resistance into common wheat.

The Regulatory Network of CMPG1-V in Wheat-Blumeria graminis f. sp. tritici Interaction Revealed by Temporal Profiling Using RNA-Seq.

Wheat powdery mildew (Pm), caused by Blumeria graminis f. sp. tritici (Bgt), is a prevalent fungal disease. The diploid wheat relative Haynaldia villosa (H. villosa) showed broad-spectrum resistance (BSR) to Pm. A previous study reported an E3 ligase gene, CMPG1-V from H. villosa, showing BSR to Pm. To elucidate the regulatory network mediated by CMPG1-V, in this study, gene expression profiling of CMPG1-V transgenic plant (CMPG1-VOE) and its receptor Yangmai 158 was analyzed and compared after Bgt inoculation at four infection stages. GO and KEGG analysis revealed obvious reprogramming of SA and ABA signaling, starch/sucrose metabolism, and photosynthesis in CMPG1-VOE, compared with those in Yangmai 158. Transcripts of SA synthesis genes SARD1 and UGT, signaling factors TGA and PRs, and SnRKs in ABA signaling were specifically upregulated in CMPG1-VOE rather than Yangmai 158. Transcripts of LHCII in photosynthesis, GLUC and TPP in starch/sucrose metabolism were also induced distinctly in CMPG1-VOE. WGCNA analysis showed crucial regulatory candidates of CMPG1-V, involving serine/threonine-protein kinase in phosphorylation, glucosyltransferase in flavonoid biosynthesis, defense factor WRKYs, and peroxidase in oxidative stress. Our results facilitate the deciphering of the resistant regulatory network of CMPG1-V and the identification of key candidates which might be employed in breeding programs.

Characterization of the Heavy-Metal-Associated Isoprenylated Plant Protein (HIPP) Gene Family from Triticeae Species.

Heavy-metal-associated (HMA) isoprenylated plant proteins (HIPPs) only exist in vascular plants. They play important roles in responses to biotic/abiotic stresses, heavy-metal homeostasis, and detoxification. However, research on the distribution, diversification, and function of HIPPs in Triticeae species is limited. In this study, a total of 278 HIPPs were identified from a database from five Triticeae species, and 13 were cloned from Haynaldia villosa. These genes were classified into five groups by phylogenetic analysis. Most HIPPs had one HMA domain, while 51 from Clade I had two, and all HIPPs had good collinear relationships between species or subgenomes. In silico expression profiling revealed that 44 of the 114 wheat HIPPs were dominantly expressed in roots, 43 were upregulated under biotic stresses, and 29 were upregulated upon drought or heat treatment. Subcellular localization analysis of the cloned HIPPs from H. villosa showed that they were expressed on the plasma membrane. HIPP1-V was upregulated in H. villosa after Cd treatment, and transgenic wheat plants overexpressing HIPP1-V showed enhanced Cd tolerance, as shown by the recovery of seed-germination and root-growth inhibition by supplementary Cd. This research provides a genome-wide overview of the Triticeae HIPP genes and proved that HIPP1-V positively regulates Cd tolerance in common wheat.

[Abundances and Morphology Patterns of Microplastics Under Different Land Use Types on the Loess Plateau].

As an emerging pollutant to the environment, microplastics have received widespread attention worldwide. The Loess Plateau, as one of the major agricultural production areas in China, has various land use types, but how the abundance and morphological patterns of microplastics differ among soils under different land use types remains unclear. In this study, we collected soils from three different land use types:croplands, apple orchards, and landfills in the Wangdonggou Catchment. Microplastics were separated and extracted using a modified density centrifugation method, and the abundance, composition, and morphological characteristics of the soil were analyzed and characterized using a laser infrared imaging system. The results showed that the average abundance of microplastics in the Wangdonggou Catchment was 4715 n·kg-1, mainly composed of PET, PU, and alkyd varnish(ALK), respectively accounting for 30.39%, 29.58%, and 8.42%. More than 80% of the microplastics were fragmented, and more than 60% of the microplastics were of a size ≤ 50 µm. The average abundance of microplastics varied significantly among land use types:cropland soil (7550 n·kg-1)>apple orchard soil (3440 n·kg-1)>landfill soil (2283 n·kg-1). The average area, width, height, eccentricity, circularity, and other morphological characteristics of microplastics in apple orchard soil were significantly different from those in the cropland and landfill soil.

A systematic review and meta-analysis of the association of ABCC2/ABCG2 polymorphisms with antiepileptic drug responses in epileptic patients.

PURPOSE: Accumulating evidence indicates that genetic polymorphisms in ATP-binding cassette superfamily members, such asABCC2 and ABCG2, alter responses to antiepileptic drugs (AEDs); however, this evidence is controversial and inconclusive. To provide strong evidence of the association between common polymorphisms in ABCC2 and ABCG2 and AED responses in patients with epilepsy, we performed a systematic review and meta-analysis. METHODS: A literature search of electronic databases (PubMed, EBSCO, Ovid and the China National Knowledge Infrastructure) was performed. To evaluate the association of genetic polymorphisms inABCC2 and ABCG2 and risk of AED treatment, we calculated pooled odds ratios (ORs) and 95 % confidence intervals (CIs) using a fixed- or random-effect model. RESULTS: A significant association of theABCC2 rs717620 polymorphism with resistance to AEDs was found in the overall pooled populations (homozygous comparison: OR = 1.77, 95 % CI, 1.27-2.48; dominant model: OR = 1.23, 95 % CI, 1.06-1.43; recessive model: OR = 1.75, 95 % CI, 1.28-2.40) and Asians (dominant model: OR = 1.21, 95 % CI, 1.03-1.42; recessive model: OR = 1.80, 95 % CI, 1.30-2.50). Using a recessive model, a similarly significant association of ABCC2 rs3740066 with AED resistance was observed in the overall pooled populations (OR = 2.29, 95 % CI, 1.44-3.64) and Asians (OR = 2.53, 95 % CI, 1.56-4.08). However, ABCC2 rs2273697, ABCG2 rs2231137 and rs2231142 were not found to be associated with AED responsiveness. CONCLUSION: This meta-analysis suggests thatABCC2 rs717620 and rs3740066 are risk factors that predict responses to AEDs in epileptic patients.