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.
P chromosomes may carry a genetic system that inhibits the Ph gene in wheat. Abnormal chromosome synapsis in wheat-Agropyron cristatum addition line II-21-2 (additional 1·4 recombinant P chromosome) was observed in this study. The results of cytogenetics and Ph1 gene amplification showed that the Ph1 gene was normal and the average number of quadrivalents or hexavalents was determined to be 0.41 and 0.13, respectively, in pollen-mother cells of wheat-Agropyron cristatum addition line II-21-2. The analysis of dual-color GISH/FISH showed that the P chromosomes were not directly involved in the composition of multivalents but could inhibit the effect of the Ph gene, leading to synapsis of wheat homoeologous chromosomes and translocation between wheat homoeologous chromosomes such as 3B-3D chromosomes. The characteristic of P chromosomes’ promoting synapsis of wheat homoeologous chromosomes may have potential application in the genetic improvement of wheat.
YANG GuoHui YANG XinMing WANG RuiHui GAO AiNong LI LiHui LIU WeiHua
