Characterization of TaCOMT genes associated with stem lignin content in common wheat and development of a gene-specific marker

Stem lignin content(SLC) in common wheat(Triticum aestivum L.) contributes to lodging resistance. Caffeic acid 3-O-methyltransferase(COMT) is a key enzyme involved in lignin biosynthesis. Characterization of TaCOMT genes and development of gene-specific markers could enable marker-assisted selection in wheat breeding. In the present study, the full-length genomic DNA(gDNA) sequences of TaCOMT genes located on chromosomes 3 A, 3 B, and 3 D were cloned by homologous cloning. Two allelic variants, TaCOMT-3 Ba and TaCOMT-3 Bb, were identified and differed by a 222-bp insertion/deletion(InDel) in the 3′-untranslated region(3′-UTR). A co-dominant gene-specific marker based on this InDel was developed and designated as Ta COMT-3 BM. A total of 157 wheat cultivars and advanced lines grown in four environments were used to validate the associations between allelic patterns and SLC. The SLC of cultivars with TaCOMT-3 Ba was significantly(P<0.01) higher than that of those with TaCOMT-3 Bb, and the marker TaCOMT-3 BM could be effectively used in wheat breeding.

Purification and Structural Analysis of a Selective Toxin Fraction Produced by the Plant Pathogen Setosphaeria turcica

Thirteen fractions from the pathogenic plant fungus Setosphaeria turcica race 1 were separated and collected using high performance liquid chromatography （HPLC）. Their toxic activities were assayed through leaf puncturing on corn differentials （OH43, OH43Ht1, OH43Ht2, and OH43HtN）, and the results revealed that eight fractions were toxic and fraction 6 was specifically toxic to OH43Ht1, which could be taken as a gene-selective toxin fraction. Fraction 6 was finely purified via HPLC and condensed by freeze desiccation. Its chemical structure was analyzed with EI-MS, IR, HMBC, ^1H-NMR, and two-dimensional NMR. The results suggested that fraction 6 contained an unsaturated double bond, carbonyl and methylene groups with molecular weight of 142.

Isolation,identification and artificial inoculation of Ustilago esculenta on Zizania latifolia

The smut Ustilago esculenta is an endophytic fungus that invades Zizania latifolia(Jiaobai)and plays an important role in inducing the host stem to form a swollen gall.The aims of this study were to investigate isolation,identification and inoculation methods of U.esculenta from Jiaobai.The spore suspension culturing method was the best method of isolating U.esculenta,and yeast-like fungal strains and septate hyphal strains were obtained.The universal primers ITS1 and ITS4 amplified a ribosomal DNA spacer element from all tested strains,while specific primers for Lam16A gene generated a 442 bp product only with septate hyphae strains.De novo transcriptome assembly results showed that the yeast-like fungal strains did not match Ustilago,and genomic analysis suggested the septate hyphae strains were highly similar to known smut fungi.Therefore,the septate hyphae strains were identified as U.esculenta,which indicated that the ITS primers were not species-specific but that Lam16A-specific primers can distinguish U.esculenta accurately and easily.In vitro,U.esculenta grew quickly on PDA medium at 28°C in darkness.Furthermore,an inoculation method was established to produce swollen stems by injecting a spore suspension of U.esculenta at OD600=2.5 into the basal culm internode of male Jiaobai.

China-CIMMYT collaboration enhances wheat improvement in China

China and CIMMYT have collaborated on wheat improvement for over 40 years and significant progress has been achieved in five aspects in China.A standardized protocol for testing Chinese noodle quality has been established with three selection criteria, i.e.,gluten quality, starch viscosity and flour color are identified as being responsible for noodle quality.Genomic approaches have been used to develop and validate genespecific markers, leading to the establishment of a KASP platform, and seven cultivars have been released through application of molecular marker technology.Methodology for breeding adult-plant resistance to yellow rust, leaf rust and powdery mildew, based on the pleiotropic effect of minor genes has been established, resulting in release of six cultivars.More than 330 cultivars derived from CIMMYT germplasm have been released and are now grown over 9% of the Chinese wheat production area.Additionally, physiological approaches have been used to characterize yield potential and develop high-efficiency phenotyping platforms.CIMMYT has also provided valuable training for Chinese scientists.Development of climate-resilient cultivars with application of new technology will be the priority for future collaboration.