Cloning, Expression And Functional Analysis Of TaABCF1 Induced By Stripe Rust Fungus

Wheat stripe rust, caused by the fungus Puccinia striiformis f.sp.tritici (Pst), is one of the most damaging and widespread diseases of wheat, often cause huge yield losses in wheat-producing areas of the world. The isolation、expression and function analysis of genes involved in wheat (Triticum aestivum L) defense response to stripe rustis of greatly importance toelucidate the molecular mechanisms of theinteractions between the wheat and stripe rust, also can provide theoretical basis for wheat breeding work. The ATP-binding cassette (ABC) superfamily is one of the largest protein families in plant. Members of this superfamily are involved in a wide variety of processes in plant growth and resistance to environmental stress. In this study, we identified and cloned a new wheat gene similar to the ABC transporter F family member 1. We use two wheat cultivars, "Chuannong 19" (CN19) as the wheat-Pst incompatible cultivar and "Mianyang 11" (MY11) as the compatible cultivar, to study its expression profiles. Meanwhile, we analyse function of this gene in CN19 using the barley stripe mosaic virus induced gene silencing (BSMV-VIGS) assay. The main results were as follows:1. Based on homology cloning and the UniGenesl3 sequence from cDNA library established by our laboratory research team, anABCFl gene cDNA was cloned from wheat, named TaABCF1.The open reading frame (ORF) of the TaABCF1 was 1786 bp in length, and encoded 592 amino acid residues. The TaABCF1 has two tandem ABCs separated by an ～80 residue linker in a single polypeptide chain (ABC-tran-2). The TaABCFl with both Aegilops tauschii ABCF1 and Triticum urartu ABCF1 shared a very high amino acid sequence homology about 99%.2. Characterization of TaABCF1 expression revealed that the gene expression was tissue-specific, also cultivar-specific. In CN19, this gene transcript abundances:stem (P<0.01)> leaf> root (P<0.01); in MY11, this gene transcript abundances:root> leaf> stem (P<0.05).3. The expression profiles of TaABCF1 induced by CY32 were different in CN19 and MY11. The result showed:In CN19, the relative expression of TaABCFl was up-regulated and peaked (P<0.01) at 24 hour post-inoculation (hpi) with CY32, after gradually reduce; In MY11, the relative expression of this gene was changes little, and was up-regulated (P<0.01) at 96-120 hpi until the experiment end.4. The expression profiles of TaABCF1 was characterized in CN19 and MY 11 treated by 4 kinds of exogenous hormones (ABA/SA/JA/ET). The results showed:the responses of TaABCFl to exogenous hormones were different between CN19 and MY11. In CN19, ABA treatment up-regulated TaABCF1 transcription, while ET treatment dwon-regulated TaABCFl transcription, and SA and JA treatment up/dwon-regulated TaABCF1 transcription at different time points; in MY11, the four kinds of hormones both up-regulated TaABCFl transcription.5. The function of TaABCF1 was analyzed by BSMV-VIGS method in CN19. The result showed:the experiment plants treated with BSMV-TaABCF1 grow slow, and were dwarf due to the silence of TaABCF1. The leaves of these plants present the stripe necrosis. Earing time of experiment plants is later 10 daysman that of the control. And experiment plants can produce seeds. New leaf inoculated CY32 appears transparent necrosis, until wilting death, no spores appear. Presumably, TaABCF1 involved in the basic wheat growth and development, also participated in the negative regulation of programmed cell death induced by rust process.