Fusarium head blight（FHB）,caused primarily by Fusarium graminearum,is a destructive disease of wheat throughout the world.However,the mechanisms of host resistance to FHB are still largely unclear.Deoxynivalenol（DON）produced by F graminearum which enhances the pathogen to spread could be converted into inactive form D3 G by UDP-glycosyltransferases（UGTs）.A DON responsive UGT gene,designated as TaUGT4,was first cloned from wheat in this study.The putative open reading frame（ORF） of TaUGT4 was 1386 bp,encoding 461 amino acids protein.TaUGT4 was placed on chromosome 2D using a set of nulli-tetrasomic lines of wheat cultivar Chinese Spring（CS）.When fused with eGFP at C terminal,TaUGT4 was shown to localize in cytoplasm of the transformed tobacco cells.The transcriptional analysis revealed that TaUGT4 was strongly induced by F graminearum or DON in both of FHB-resistant cultivar Sumai 3 and susceptible cultivar Kenong 199,especially in Sumai 3 under DON treatment.Similar increase of TaUGT4 expression was observed in Sumai 3 and Kenong 199 in response to salicylic acid（SA） treatment.But interestingly,the transcripts level of TaUGT4 in Sumai 3 showed significantly higher than that in Kenong 199 after treated with methyl jasmonate（MeJA）.According to the expression patterns,TaUGT4 might lead to different effects between FHB-resistant genotype and susceptible genotype in the process against F graminearum inoculation.It had also been discussed in this paper that JA signaling pathway might play a significant role in the resistance against F.graminearum compared to SA signaling pathway.
MA XinDU Xu-yeLIU Guo-juanYANG Zai-dongHOU Wen-qianWANG Hong-weiFENG De-shunLI An-feiKONG Ling-rang
Spike number is one of three yield-related factors and is closely related to wheat yield. In the present study, we found that the inhibited and normal tillers of the 3558 line presented phenotypic differences at the elongation stage by morphological and anatomical analysis. We then initiated a proteomic study using two-dimensional electrophoresis （2-DE） and nano- scale liquid chromatography-high-definition tandem mass spectroscopy, to isolate and identify the key proteins and metabolic pathways related to spike-development inhibition. A total of 31 differentially expressed proteins （DEPs）, which were mainly involved in cell cycle regulation, photosynthesis, glycolysis, stress response, and oxidation-reduction reactions, were isolated and identified. 14-3-3-1ike proteins and proliferating cell nuclear antigen （PCNA）, involved in cell-cycle regulation, were dramatically down-regulated in inhibited tillers compared to normal tillers. Six spots corresponding to degraded Rubisco large subunits, involved in photosynthesis, were detected in different locations of the 2-DE gels and were up-regulated in inhibited tillers. In addition, the relative levels of DEPs involved in glycolysis and oxidation- reduction reactions changed dramatically. Development was blocked or delayed at the elongation stage in the inhibited tillers of 3558. Weakened energy metabolism might be one reason that the inhibited tillers could not joint and develop into spikes. These DEPs and related metabolic pathways are significant for understanding the mechanism of spike-development inhibition and studying the spike-development process in wheat.
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most widely distributed and destructive fungal diseases worldwide. Since 1995, most Chinese wheat cultivars have lost their stripe rust resistance due to the subsequent emergence of the new races CYR30, CYR31, CYR32, and CYR33 （Han et al., 2010）. Therefore, it is necessary to seek effective resistance genes and develop new resistance germ- plasm for wheat resistance breeding.
The rich genetic variation preserved in collections of Aegilops tauschii can be readily exploited to improve common wheat using synthetic hexaploid wheat lines. However,hybrid necrosis, which is characterized by progressive death of leaves or plants, has been observed in certain interspecific crosses between tetraploid wheat and Ae. tauschii. The aim of this study was to construct a fine genetic map of a gene(temporarily named Net Jing Y176)conferring hybrid necrosis in Ae. tauschii accession Jing Y176. A triploid F1 population derived from distant hybridization between Ae. tauschii and tetraploid wheat was used to map the gene with microsatellite markers. The newly developed markers Xsdau K539 and Xsdau K561 co-segregated with Net Jing Y176 on chromosome arm 2DS. The tightly linked markers developed in this study were used to genotype 91 Ae. tauschii accessions. The marker genotype analysis suggested that 49.45% of the Ae. tauschii accessions carry Net Jing Y176. Interestingly, hybrid necrosis genotypes tended to appear more commonly in Ae. tauschii ssp. tauschii than in Ae. tauschii ssp. strangulata.
Fengbo XueJun GuoChangying GuanHongwei WangAnfei LiLingrang Kong
