Cloning And Analysis Of Disease Resistance And Stress Tolerance Relative Genes In Triticum Aestivum

Many of the plant disease resistance genes that have been isolated encode proteins with a putative nucleotide binding site and leucine-rich repeats (NBS-LRR resistance genes). Oligonucleotide primers based on conserved motifs in and around the NBS of known NBS-LRR resistance proteins were used to amplify sequences from 6VS arm microdissected from Triticum aestivum-Haynaldia villosa 6VS substitution line H1-2-8 and H.villosa genome DNA by polymerase chain reaction (PCR). Eight classes of sequences were obtained from 6VS arm and 12 classes were from H.villosa genome DNA. Nested PCR analysis and southern hybridization analysis showed that no polymorphism between H.villosa, Pm97034 and susceptible parent Wan7 107 was detected with the clones from 6VS arm, whereas three clones from H.villosa genome DNA: RH42, RH55, and RH66 showed polymorphism. RGA6 cloned from H.villosa genome DNA was characterized identity to NBS, and show high homology to resistance genes as RPM1 and RPP13 in Arabiadopsis, LRR19 in wheat, and I2C-1 in tomato.cDNA library constructed from T.aestivum-H.villosa translocation line Pm97034 was screened by hybridization with RGA6. Four positive cDNA clones were obtained. R3-2-2 showing 60-90% identity with eukaryotic sulfite oxidases (SO) contained an open reading frame (ORF) of 647bp encoding 140 amino acid (aa), and contained a conserved Moco-dimer domain in the ORF. R6-2-2 showed an ORF containing an Euk-porin domain of 279aa with 20-40% identity to the eukaryotic voltage-dependent anion channel (VDAC) proteins. R8-1-1 showed a complete ORF of 1810bp encoding 493aa with 80-90% identity to plant catalases. R9-1-1 showed an ORF containing a BTB/POZ conserved domain of 204aa with 30-70% identity to pox virus and zinc finger (POZ) proteins. R3-2-2 and R9-1-1 were the first cDNA clones containingconserved domain of SO and POZ respectively isolated from wheat. R8-1-1 contained a complete ORF with 81% identity to Cat-3. Aspects of the role of R8-1-1 may be same with Cat-3, and it would offer the opportunity for improvement of stress tolerance of wheat.