| Wheat is a member of the Triticae group of cereals and indisputably one of the major food crops of the world and a foundation of human nutrition worldwide. Fungus disease is an important biotic stress that greatly impacts the productivity of wheat. With the fast progress of plant molecular biology and plant functional genomics, the complicated resistance reaction process of plant have been understood much clearly, and more and more resistance genes and related genes have been cloned. To effectively analyze the potential resistance functions of these genes and tranform them into wheat to get resistant cultivars are in great need for crop resistance breeding (molecular breeding). In this experiment, two resistance-related genes TaTBL and TaTST were respectively transformed into wheat susceptible cultuvar Yangmai158 and transgenic plants were identified by PCR analysis. Increased resistance of transgenic plants to powdery mildew was observed after inoculation of wheat powdery mildew pathogen fungus Erysiphe graminis f.sp. tritici conidiospores on detached leaf segments. Besides stable transformation, transient expression system were also performed to identify resistance functions of six resistance-related genes TaTBL TaPK1 TaTSTs Glb3s2, Cht4 and Glb3s6. Over-expression of five of them in wheat epidermal cells can partly inhibit penetration of conidiospores and formation of haustoria, and to some extent increase the resistance of expression cells to powdery mildew.1.1 Transformation of two resistance-related genes into wheat and resistance analysis of transgenic plants.Anthocyanin synthesis regulatory genes Cl/Lc were used to optimize the parameters of gene-gun transformation protocol through counting of red spots on wheat calli after transient expression. Two plant expression vectors respectively carrying the wheat resistance-related genes TaTBL and TaTST driven by the ubi promoter and the bar gene with resistance to PPT were constructed. And then immature embryo derived calli of wheat cultivar of Yangl58 which has a high regeneration efficiency in tissue culture were used to perform particle bombardment. Through two sets of bialaphos screening and regeneration of resistance calli, 50 and 30 bialaphos-tolerrent plants of the two genesrespectively were got out of about 500 initial calli. Genomic DNA were extracted and PCR was conducted with primers designed based on the sequence of bar gene, ubi promoter and target genes. Totally five plants transformed with the TaTBL gene and 6 plants transformed with the TaTST showed positive bands, which means exogenous genes have been integrated into host genomic DNA. Seedling leaves of transgenic plant were challenge inoculated with Erysiphe graminis f.sp. tritici conidispores and increased resistance was observed to varied degrees for different transformant.1.2 Analysis of wheat resistance-related genes by a transient expression systemTransient expression system was used to analyze the functions of six wheat resistance-related genes: TaTBL(Beclinl-like gene), TaPK1(serine/threonine protein kinase gene), TaTST(thiosulfate sulfurtransferase) Glb3s2( β -l,3-glucosidase) Cht4(chitinase gene) and Glb3s6(β -1,3-glucosidase) which had an increased expression against induction by Erysiphe graminis f.sp. tritici in other research. Target genes were constructed into plant expression vectors and transformed into leaf epidermal cells of powdery mildew-susceptible wheat variety by particle bombardment. GUS gene was co-transformed with either target gene to mark transformed cells. After transformation, leaf surface was inoculated with Erysiphe graminis f.sp. tritici conidiospores. 48 hours after inoculation, penetration of the fungus and formation of haustoria in transformed cells were observed to evaluate the effects of the target gene's products on the invasion of powdery mildew. The results implied that five of these six genes, TaTBL, TaPKl, TaTST, Glb3s2 and Cht4, when transiently expressed in leaf epidermal cells of susceptible wheat variety, can partially inhibit penetration of conidios...
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