Suppression subtraetive hybridization (SSH) employed to investigated gene expression after Russian wheat aphid infestation.

摘要

The Russian wheat aphid (RWA; Diuraphis noxia Mordvilko) is a major pest on wheat, barley and other Triticale in South Africa. During this study, SSH was employed to isolate gene sequences that are involved in wheat resistance against RWA infestation.Gene fragments related to several resistance gene families were identified (E value < 10~(-5)) and constituted 18% of the isolated SSH fragments. This includes a leucine rich-like fragment and leucine zipper-nucleotide binding site-leucine rich repeats(LZ-NBS-LRR) homologous to Aegilops tauschii. The expression of these fragments during plant infestation was confirmed through Northern blot hybridisations and quantitative RT-PCR. Hybridisations and quantification were performed using uninfested wheat RNA and RNA extracted at day two, three, four and five after infestation. On average, the resistance fragments exhibited increased expression after two days of infestation (2-11 fold), less expression at day three (2 - 9 fold down-regulation) and gradualup-regulation of the gene expression during day four (8 - 350 fold) and day five (890 - 10 200 fold).