Isolation, chromosomal location, and expression analysis of putative powdery mildew resistance genes in wheat (Triticum aestivum L.)
Special and degenerate primers are designed according to the conservative sequence of barley powdery mildew resistance genes Mla1, Mla6, and Mla13. Two wheat Mla-like orthologs, TaMla-2 and TaMla-3 are cloned and sequenced from the cDNA of wheat resistant-powdery mildew line TAM104R by RT-PCR method. TaMla-2 and TaMla-3 encode distinct but highly related coiled-coil nucleotide-binding site leucine-rich repeat type (NBS-LRR) resistant disease proteins and both reveal about 74 and 81% identity with amino acid sequence of Mla1, respectively. They are multiple copies in wheat genomes, one copy of them is mapped on wheat chromosome 1AL and two on 1BL using Chinese Spring nulli-tetra-somic lines and ditelosomic lines of 1A, 1B and 1D in southern analysis. This result suggests that may be the two Mla-like genes originated from the two diploid ancestral genomes, respectively. The expression pattern analysis of semi-quantitative PCR shows the TaMla genes are mainly expressed in leaf and sheath, and expression level is enhanced in organs infected by Erysiphe graminis, suggesting that TaMla-2 and TaMla-3 are powdery mildew resistance related-genes in wheat.
KeywordsTriticum aestivum Powdery mildew resistance Mla-ortholog Gene cloning Chromosome location Expression
We thank Professor Xiayu Duan and associate professor Yilin Zhou in Institute of Plant Protection, CAAS for inoculating and identifying all materials by Erysiphe graminis f. sp. tritici. This work was supported by grants from the Ministry of Science and Technology of China (J00-A-002, 2004BA525B03) and NSFC(30540057).
- Hartl L, Mohler V, Zeller FJ, Schweizer G (2000) Identification of AFLP markers closely linked to the powdery mildew resistance genes Pm1c and Pm4a in common wheat (Triticum aestivum L.). Gemome 42:322–329Google Scholar
- Heun M, Friebe B (1990) Introgression of powdery mildew resistance from rye into wheat. Phytopathology 80:242–245Google Scholar
- Kong LR, Dong YC, Jia JZ (1999) Location of a powdery mildew resistance gene in Am6, an amphidiploid between Triticum durum and Aegilops tauschii, and its utilization. Acta Phytophylacica Sinica 26:116–120Google Scholar
- McIntosh et al (1995) Catalogue of gene symbols for wheat. In Li ZS, Xin ZY (eds) Proceedings of the 8th International Wheat Genet Symp. Scientech Press, Beijing, pp1333–1500Google Scholar
- Wang XW, Wang JL, Duan XY, Zhou WJ, Sheng BQ, Zhu LH, Zhang WJ (2001) Resistance analysis and mapping of a powdery mildew resistance gene Pm20 in common wheat background. Chin Sci Bull 44:666–668Google Scholar
- Wei FS, Werner KG, Morroll SM, Kurth J, Mao L, Wing R, Leister D, Schulze-Lefert P, Wise RP (1999) The Mla (Powdery Mildew) resistance cluster is associated with three NBS-LRR gene families and suppressed recombination within a 240-kb DNA interval on chromosome 5S (1HS) of barley. Genetics 153:1929–1948PubMedGoogle Scholar
- Wise RP, Ellingboe AH (1983) Infection kinetics of Erysiphe graminis f. sp. hordei on barley with different alleles at the Mla locus. Phytopathology 73:1220–1222Google Scholar
- Xiao SY, Ellwood S, Calis O, Patrick E, Li TY, Coleman M, Turner JG (2001) Broad-spectrum mildew resistance in Arabidopsisthaliana mediated by RPW8 Science 291:118–120Google Scholar
- Xie CJ, Sun QX, Ni ZF, Yang TM, Nevo E, Fahima T (2003) Chromosomal location of a Triticum dicoccoides-derived powdery mildew resistance gene in common wheat by using microsatellite markers. Thero Appl Genet 106:341–345Google Scholar
- Zhou F, Kurth J, Wei FS, Elliott C, Valè G, Yahiaoui N, Keller B, Somerville S, Wise R, Schulze-Lefert P (2001) Cell-autonomous expression of barley Mla1 confers race-specific resistance to the powdery mildew fungus via a Rar1-independent signaling pathway. Plant Cell 13:337–350PubMedCrossRefGoogle Scholar