Study On The Difference Of Wax And Related Genes In Triticum Monococcum And Triticum Dicoccoides

Cuticular wax is a major component of cuticle,covering the outermost surfaces of wheat.It serves mainly as a waterproof barrier,restraining uncontrolled nonstomatal water loss in wheat.Cuticular wax also protects plants against excess bacterial and fungal pathogens as well as insects.So the study on cuticular wax synthesis pathways in wheat and research for related control gene has been attracting the attention of researchers.Observation in field found that the surface of Triticum monococcum is glossy,while it is glaucous in Triticum dicoccoides.This may be indicative of differences in wax content and composition,which is likely due to the introducing of B genome.In this paper,the differences of cuticular wax in different stages and organs in Triticum monococcum and Triticum dicoccoides were studied by Gas Chromatography-Flame Ionization Detector(GC-FID),Mass Spectrometer(MS)and Scanning Electronic Microscopy(SEM).We also searched for candidate genes and established a regeneration system in Triticum monococcum.The results are as follows:1.The research for wax components in Triticum monococcum and Triticum dicoccoides in different organs found that the components were similar in leaf blade and spike of Triticum monococcum and leaf blade of Triticum dicoccoides,which mainly consist of primary alcohol(72.32% 57.28%),followed by alkanes(11.12% 23.92%).The content of alkanes(49.98%)in the leaf sheath of Triticum monococcum was the highest,followed by primary alcohol(19.99%)and diketone(15.02%).Leaf sheath and spike in Triticum dicoccoides were mainly composed of diketone(90.13%,86.04%),and then the alkane(2.35%,5.35%)and primary alcohol(2.92%,3.96%).2.The study of the development of wax in Triticum monococcum and Triticum dicoccoides in spike found that the amount of wax accumulation increased gradually along the growth period.The proportion of C26 alcohols in Triticum monococcum decreased,while the proportion of C29 alkanes gradually increased.In Triticum dicoccoides the proportion of ?-diketone increased first and then decreased,while the proportion of OH-?-diketone decreased first and then increased,C29 alkane gradually increased and the primary alcohol showed a decreasing trend.3.The results of GC detection showed that with physiological developmental of Triticum dicoccoides,the total wax load accumulated.The cuticular wax of leaf blade of different stages were mainly consist of primary alcohol(76.49%-80.20%),followed by alkanes(7.52%-10.15%).The proportion of primary alcohol and alkanes reduced and the proportion of diketones increased.4.Study on the wax crystal found that it was in the shape of platelets in leaf blade,spike and leaf sheath of Triticum monococcum and leaf of Triticum dicoccoides.It was rod-like in leaf sheath and spike of Triticum dicoccoides.In Triticum monococcum,there was no crystal in the spike in the first day of heading,and it was sparse through out the heading stage.In Triticum dicoccoides rod-like crystals began to appear in the first day of heading,and it was serried.Compared with other organs,wax in spike was the most sparse in Triticum monococcum and wax in leaf blade was the most dense.The wax crystals on the surface of spike,leaf sheath and flag leaf in Triticum dicoccoides were relatively dense.Wax crystals became much sparser on heading stage leaves than seed bearing stage in Triticum dicoccoides and became more intense on filling stage leaves.5.We obtained one related gene sequence to CER-U which was related to barley diketone synthesis in Triticum monococcum and Aegilops speltoides Tausch respectively and the similarity were 79.9% and 90.2%.We got one gene sequence similar to CER-Q in Aegilops speltoides Tausch and the similarity was 88.8%,while we did not receive similar sequence in Triticum monococcum.In Triticum monococcum,there were three sequences similar to CER-C and the similarity were 85.2%,71.7% and 64.3% respectively.Aegilops speltoides Tausch has two genes related to CER-C and similarity were 82.9% and 88.7%.6.We established immature embryo regeneration system in Triticum monococcum.The results showed that the best explant for callus induction was immature embryos 14-16 days after anthesis and the induction rate was 95.53%-98.34%.In addition,the 1-3 days of low temperature pretreatment(4?)of the immature inflorescence could improve the rate of induction.In the regeneration process,MSE3 with 2.0 mg/L 2,4-D and 0.5 mg/L ABA was used as the induced medium.Adding MSE3 at the rate of adding 0.5mg/L 6-BA and 0.25mg/L IAA was done for differentiation medium.