Aegilops sharonensis (Sharon goatgrass) is a valuable source of novel high molecular weight glutenin subunits, resistance to wheat rust, powdery mildew, and insect pests. In this study, we successfully hybridized Ae. sharonensis as the pollen parent to common wheat and obtained backcross derivatives. F1 intergeneric hybrids were verified using morphological observation and cytological and molecular analyses. The phenotypes of the hybrid plants were intermediate between Ae. sharonensis and common wheat. Observations of mitosis in root tip cells and meiosis in pollen mother cells revealed that the F1 hybrids possessed 28 chromosomes. Chromosome pairing at metaphase I of the pollen mother cells in the F1 hybrid plants was low, and the meiotic configuration was 25.94 I + 1.03 II (rod). Two pairs of primers were screened out from 150 simple sequence repeat markers, and primer WMC634 was used to identified the presence of the genome of Ae. sharonensis. Sequencing results showed that the F1 hybrids contained the Ssh genome of Ae. sharonensis. The sodium dodecyl sulfate polyacrylamide gel electrophoresis profile showed that the alien high molecular weight glutenin subunits of Ae. sharonensis were transferred into the F1 and backcross derivatives. The new wheat-Ae. sharonensis derivatives that we have produced will be valuable for increasing resistance to various diseases of wheat and for improving the quality of bread wheat.
Authors:W. Li, Z.Y. Chen, Z. Li, X.F. Zhao, Z.E. Pu, G.Y. Chen, Q.T. Jiang, Y.M. Wei, and Y.L. Zheng
To study the development of starch granules in polyploid wheats, we investigated the expression of starch synthetic genes between the synthetic hexaploid wheat SHW-L1, its parents T. turgidum AS2255 and diploid Ae. tauschii AS60. The synthetic hexaploid wheat SHW-L1 showed significantly higher starch content and grain weight than its parents. Scanning electron microscopy (SEM) showed that SHW-L1 rapidly developed starch granules than AS2255 and AS60. The amount of B-type granule in AS60 was less than that in SHW-L1 and AS2255. RT-qPCR result showed that the starch synthetic genes AGPLSU1, AGPLSU2, AGPSSU1, AGPSSU2, GBSSI, SSIII, PHO1 and PHO2 expressed at earlier stages with larger quantity in SHW-L1 than in its parents during wheat grain development. The expression of the above mentioned genes in AS60 was slower than in SHW-L1 and AS2255. The expression pattern of starch synthase genes was also associated with the grain weight and starch content in all three genotypes. The results suggested that the synthetic hexaploid wheat inherited the pattern of starch granule development and starch synthase gene expression from tetraploid parent. The results suggest that tetraploid wheat could plays more important role for starch quality improvement in hexaploid wheat.
Authors:M.Y. Jiang, Z.R. Wang, K.W. Chen, J.Q. Kan, K.T. Wang, Zs. Zalán, F. Hegyi, K. Takács, and M.Y. Du
After suffering from mechanical injury and fungal infection, grapes are perishable. Botrytis cinerea, the causal agent of gray mould, is a critical pathogen for grapes. In this study, the inhibitory effect of Pseudomonas fluorescens on the formation of gray mould on grapes during the postharvest storage was investigated on “Kyoho” grape. The results suggest that a living cell suspension of P. fluorescens significantly inhibited spore germination of B. cinerea, and significantly reduced the incidence of grape gray mould. Moreover, compared with the control, the fruit inoculated with P. fluorescens had elevated activities of polyphenol oxidase (PPO), peroxidase (POD), catalase (CAT), phenylalanine ammonia-lyase (PAL), chitinase (CHI), and β-1,3-glucanase (GLU). Increase in enzyme activity correlated with enhanced host resistance. In addition, there was little difference in storage quality between the treated group and control group, indicating no adverse effects of the induced defence response on fruit quality.