Cloning of genes involved in the early response of wheat towards Russian wheat aphid infestation

[摘要] English: The interaction between wheat (Triticum aestivum) and the Russianwheat aphid (Diuraphis noxia) was investigated on a molecular level. Theresistant cultivar, Tugela DN1, was infested with the Russian wheat aphidand tissue harvested at 3 hour time intervals for 24 hours. Differentialdisplay RT-PCR was used to clone genes that were inducibly expressed usingprimers specific to the conserved subdomain VIb of the kinase domain ofprotein kinases. Differentially expressed genes were found as early as threehours after infestation. These fragments were cloned and sequenced.A total of 11 differentially expressed cDNA fragments were analyzed.Four showed homology to genes encoding proteins involved in normalcellular metabolism, such as the Rubisco large subunit, indole-3-gylcerolphosphate lyase that produces indole that could act as a volatile messengermolecule, triose-phosphate isomerase that is involved in glycolysis and 2-isopropylmalate synthase that is involved in leucine biosynthesis.Of the other cDNAs, three clones showed homology to severalhypothetical proteins with no defined functions, while the other threeshowed no homology at all with any other known genes.One of the unknown clones (D20) was selected for further analysis.The gene was inducibly expressed only in the infested resistant plants, butnot in the infested susceptible plants. The expression of the gene wasinduced within 3 h after infestation reaching a maximum expression level 6h.p.i. The gene is present as a single copy within the genomes of susceptibleand 5 different resistance lines. An attempt to clone the full length genewas only partially successful since after the sequences were combinedhomology was found with several hypothetical genes from rice and maize.However, no identity and function could be given.

[发布机构] University of the Free State