Honggang Wang

Wheat Ms2 encodes for an orphan protein that confers male sterility in grass species

Male sterility is a valuable trait for plant breeding and hybrid seed production. The dominant male-sterile gene Ms2 in common wheat has facilitated the release of hundreds of breeding lines and cultivars in China. Here, we describe the map-based cloning of the Ms2 gene and show that Ms2 confers male sterility in wheat, barley and Brachypodium. MS2 appears as an orphan gene within the Triticinae and expression of Ms2 in anthers is associated with insertion of a retroelement into the promoter. The cloning of Ms2 has substantial potential to assemble practical pipelines for recurrent selection and hybrid seed production in wheat.

Characterization of Three Novel Wheat-Thinopyrum intermedium Addition Lines with Novel Storage Protein Subunits and Resistance to Both Powdery Mildew and Stripe Rust.

Wide hybridization is an effective approach for enhancing the resistance of bread wheat(Triticum aestivum L.)to biotic and abiotic stresses by introducing favorable alien genes(Sepsi et al.,2008).Wheatgrass,Thinopyrum intermedium(Host)Barkworth&D.R.Dewey or Agropyron intermedium(Host)

Comparative Transcriptome Analyses of Resistant and Susceptible Near-Isogenic Wheat Lines following Inoculation with Blumeria graminis f. sp. tritici.

Powdery mildew is one of the most important diseases of wheat. In this study, the leaf RNA samples of wheat NILs carrying powdery mildew resistant and susceptible Pm2 alleles (L031 and Chancellor) and its F1 hybrid at two time points (16 h and 96 h postinoculation) were used for RNA-seq analysis. We carry comparison between similar materials at different times and between different materials at same times. The overlapping DEGs between the dominant phenotypes (L031 and F1 hybrid) and the recessive phenotype (Chancellor) were 1028 and 2214 DEGs, which were clearly lower than those between the dominant and recessive parents and thus could provide relatively accurate and valuable information. GO and KEGG enrichment analysis of DEGs revealed that other than the expected defense-related genes, differential up- and downregulation of genes from many other signaling networks were also involved. Comparative transcriptome analysis also revealed that early-stage postinoculation is important and suitable time points to study expression profiles and signaling pathways of resistance-related genes following fungal inoculation. qRT-PCR analyses showed highly consistent expression patterns of genes with RNA-seq data. The results will aid in the identification of genes and signaling pathways involved in powdery mildew response in wheat.

Molecular cytogenetic identification of a wheat–Thinopyrum ponticum translocation line resistant to powdery mildew

Thinopyrum ponticum (2 n=70) serves as a valuable gene pool for wheat improvement. Line SN0224, derived from crosses between Th. ponticum and the common wheat cultivar Yannong15, was identified in the present study. Cytogenetic observations showed that SN0224 contains 42 chromosomes in the root-tip cells and 21 bivalents in the pollen mother cells, thereby demonstrating its cytogenetic stability. Genomic in situ hybridization, probed with the total genomic DNA of Th. ponticum, produced hybridization signals in the distal region of two wheat chromosome arms. After inoculation with the Blumeria graminis f. sp. tritici (Bgt) isolates, SN0224 exhibited immunity. Segregation in F 1s and F 2s from the cross SN0224/cv. Huixianhong indicated that SN0224 carries a single dominant gene for powdery mildew (Pm) resistance, which was temporarily designated PmSn0224. Three markers Barc212, Xwmc522 and Xbarc1138 were detected to be linked with PmSn0224. Based on the locations of the markers, PmSn0224 was located on the chromosome 2A. None of the three markers above is linked with the previously reported PM resistance genes on chromosome 2A, and none of the previously reported PM resistance genes on chromosome 2A is related to Th. ponticum. Therefore, PmSn0224 is likely a novel gene putatively from Th. ponticum.

Chromosome Pairing in Hybrid Progeny between Triticum aestivum and Elytrigia elongata

In this study, the intergeneric hybrids F1, F2, BC1F1, BC1F2, and BC2F1 from Elytrigia elongata and Triticum aestivum crosses were produced to study their chromosome pairing behavior. The average E. elongata chromosome configuration of the two F1 hybrids agreed with the theoretical chromosome configuration of 21I+7II, indicating that the genomic constitution of this F1 hybrid was ABDStStEeEbEx. Compared with the BC1F1 generation, the BC2F1 generation showed a rapid decrease in the number of E. elongata chromosomes and the BC1F2 generation showed a more extensive distribution of E. elongata chromosomes. In addition, pairing between wheat and E. elongata chromosomes was detected in each of the wheat-E. elongata hybrid progenies, albeit rarely. Our results demonstrated that genomic in situ hybridization (GISH) using an E. elongata genomic DNA probe offers a reliable approach for characterizing chromosome pairing in wheat and E. elongata hybrid progenies.

Chromosomal constitutions of five wheat – Elytrigia elongata partial amphiploids as revealed by GISH, multicolor GISH and FISH

Abstract A combination of meiotic pairing analysis and in situ hybridization (genomic in situ hybridization [GISH], multicolor GISH [mcGISH] and fluorescence in situ hybridization [FISH]) of five Triticum aestivum (Linnaeus, 1753) - Elytrigia elongata (Podpěra, 1902) (2n = 10x = 70) amphiploids was employed to investigate the genomic constitution and relationships between wheat and alien chromosomes. GISH, multicolor GISH and FISH patterns of mitotic chromosomes indicate that the genomic constitution of the five partial amphiploids (XY693, XY7430, SN19, SN20 and SN122) are 14A + 12B + 14D + 8Js + 8J, 12A + 16B + 14D + 2St + 8Js + 2J + 2 W-E, 14A + 14B + 14D + 4St + 8Js, 14A + 14B + 14D + 2St + 10Js + 2J, and 14A + 14B + 14D + 2St + 8Js + 4J, respectively. Analysis of meiotic chromosome pairing in the F1 hybrids between these five partial amphiploids suggests that SN20 and SN122 are the most closely related amphiploids and are somewhat related with XY693 and XY7430. However, the alien chromosome constitutions of SN19 differed from the other four amphiploids. In addition, a new pairing between wheat and E. elongata chromosomes was distinguished in some cells of the hybrids SN19 × XY7430, SN20 × XY7430 and SN122 × XY7430.

QTL for flag leaf size and their influence on yield-related traits in wheat

Flag leaf-related traits (FLRTs) are determinant traits affecting plant architecture and yield potential in wheat (Triticum aestivum L.). In this study, three related recombinant inbred line (RIL) populations with a common female parent were developed to identify quantitative trait loci (QTL) for flag leaf width (FLW), length (FLL), and area (FLA) in four environments. A total of 31 QTL were detected in four environments. Two QTL for FLL on chromosomes 3B and 4A (QFll-3B and QFll-4A) and one for FLW on chromosome 2A (QFlw-2A) were major stable QTL. Ten QTL clusters (C1–C10) simultaneously controlling FLRTs and yield-related traits (YRTs) were identified. To investigate the genetic relationship between FLRTs and YRTs, correlation analysis was conducted. FLRTs were found to be positively correlated with YRTs especially with kernel weight per spike and kernel number per spike in all the three RIL populations and negatively correlated with spike number per plant. Appropriate flag leaf size could benefit the formation of high yield potential. This study laid a genetic foundation for improving yield potential in wheat molecular breeding programs.

An efficient experiment design helps to identify differential expressed genes (DEGs) in RNA-seq data in studies of plant qualitative traits

In this study, we conducted comparative transcriptome analysis between homozygous dominant parent and heterozygous F1 hybrid with homozygous recessive parent in qualitative trait study of common wheat (Triticum aestivum L.). Two sets of near-isogenic lines (NILs) were used: one set of NILs carrying powdery mildew resistance and susceptible Pm2 alleles, the other set of NILs carrying different awn inhibition gene B1 alleles. The results demonstrated that 2,932 DEGs were identified between L031 (Pm2Pm2) and Chancellor (pm2pm2), while 1,494 DEGs presented between F1 hybrid (Pm2pm2) and Chancellor, the co-regulated DEGs were 1,028. For the wheat awn inhibition gene B1 test, 720 DEGs were identified between SN051-2 (B1B1) and SN051-1 (b1b1), and 231 DEGs were identified between F1 hybrid (B1b1) and SN051-1, the co-regulated DEGs were 180. Hierarchical clustering analysis of co-regulated DEGs showed that dominant parent and F1 hybrid were clustered as the nearest neighbors, while recessive parent showed an apparent departure. The results showed that the overlapping DEGs between dominant parent and F1 hybrid with recessive parent reduced the number of interested DEGs to only one-quarter (or one-third) of that between dominant and recessive parent, these overlapping loci could provide insights into molecular mechanisms that are affected by causal mutations.