Full text in pdf format
A search for RFLP markers to identify genes for aluminum tolerance in maize*
Giovana A. TorresI; Sidney N. ParentoniII; Maurício A. LopesII; Edilson PaívaII
IDepartamento de Biologia, Universidade Federal de Lavras, Caixa Postal 37, 37200-000 Lavras, MG, Brasil.
IICNPMS/EMBRAPA, Caixa Postal 151, 35701-970 Sete Lagoas, MG, Brasil. Send correspondence to E.P.
ABSTRACT
The objective of this study was to identify restriction fragment length polymorphism (RFLP) markers linked to QTLs that control aluminum (Al) tolerance in maize. The strategy used was bulked segregant analysis (BSA) and the genetic material utilized was an F2 population derived from a cross between the Al-susceptible inbred line L53 and Al-tolerant inbred line L1327. Both lines were developed at the National Maize and Sorghum Research Center - CNPMS/EMBRAPA. The F2 population of 1554 individuals was evaluated in a nutrient solution containing a toxic concentration of Al and relative seminal root length (RSRL) was used as a phenotypic measure of tolerance. The RSRL frequency distribution was continuous, but skewed towards Al-susceptible individuals. Seedlings of the F2 population which scored the highest and the lowest RSRL values were transplanted to the field and subsequently selfed to obtain F3 families, Thirty F3 families (15 Al-susceptible and 15 Al-tolerant) were evaluated in nutrient solution, using an incomplete block design, to identify those with the smallest variances for aluminum tolerance and susceptibility. Six Al-susceptible and five Al-tolerant F3 families were chosen to construct one pool of Al-susceptible individuals, and another of Al-tolerant, herein referred as "bulks", based on average values of RSRL and genetic variance. One hundred and thirteen probes were selected, with an average interval of 30 cM, covering the 10 maize chromosomes. These were tested for their ability to discriminate the parental lines. Fifty-four of these probes were polymorphic, with 46 showing codominance. These probes were hybridized with DNA from the two contrasting bulks. Three RFLPs on chromosome 8 distinguished the bulks on the basis of band intensity. DNA of individuals from the bulks was hybridized with these probes and showed the presence of heterozygous individuals in each bulk. These results suggest that in maize there is a region related to aluminum tolerance on chromosome 8.
Keywords: RFLP markers; aluminum tolerance; maize.
REFERENCES
Brenes, E. and Pearson, R.W. (1973). Root responses of three Gramineae species to soil acidity in an oxisoil and an ultisoil. Soil Sci. 116: 295-302.
Chao, S., Baysdorfer, C., Heredia-Diaz, O., Musket, T., Xu, G. and Coe Jr., E.H. (1994). RFLP mapping of partially sequenced leaf cDNA clones in maize. Theor. Appl. Genet. 88: 717-721.
Diers, B.W., Keim, P., Fehr, W.R. and Shoemaker, R.C. (1992). RFLP analysis of soybean seed protein and oil content. Theor. Appl. Genet. 83: 608-612.
Edwards, M.D., Helentjaris, T., Wright, S. and Stuber, C.W. (1992). Molecular-marker-facilitated investigation of quantitative trait loci in maize. Theor. Appl. Genet. 83: 765-774.
EMBRAPA - Empresa Brasileira de Pesquisa Agropecuária (1980). Centro Nacional de Pesquisa em Milho e Sorgo. EMBRAPA, Brasília. (Boletim técnico).
Foy, C.D. and Fleming, A.L. (1978). The physiology of plant tolerance to excess available aluminum and manganese in acid soils. In: Crop Tolerance to Suboptimal Land Conditions (Jung G.A., ed.). Am. Soc. Agron., Madison, WI, pp. 301-328.
Furlani, P.R., Lima, M., Miranda, L.T., Miranda, L.E.C., Sawasaki, E. and Magnavaca, R. (1986). Avaliação de linhagens, materiais comerciais e duas populações de milho para tolerância ao alumínio. Pesq. Agrop. Bras. 21: 655-660.
Garcia Jr., O., Da Silva W.J. and Massei, M.A.S. (1979). An efficient method for screening maize inbreds for aluminum tolerance. Maydica 24: 75-82.
Goedert, W.J., Lobato, E. and Wagner, E. (1980). Potencial agrícola do cerrado brasileiro. Pesq. Agrop. Bras. 15: 1-17.
Howeler, R.H. (1991). Identifying plants adaptable to low pH conditions. In: Plant Soil Interactions at Low pH (Wright, R.J., Baligar, V.C. and Murrmann, R.P., eds.). Kluwer Academic Publishers, Dordrecht, pp. 885-904.
Lopes, A.S. and Cox, F.R. (1977). A survey of the fertility status of surface soil under "cerrado" vegetation in Brazil. Soil Sci. Am. J. 41: 743-747.
Lopes, M.A., Magnavaca, R., Bahia Filho, A.F.C. and Gama, E.E.G. (1987). Avaliação de populações de milho e seus cruzamentos para tolerância a toxidez de alumínio em solução nutritiva. Pesq. Agrop. Bras. 22: 257-263.
Magnavaca, R. (1982). Genetic variability and inheritance of aluminum tolerance in maize. Doctoral thesis, University of Nebraska, Lincoln, NE.
Michelmore, R.W., Paran, I. and Kesseli, R.V. (1991). Identification of markers linked to disease-resistance genes by bulked segregant analysis: a rapid method to detect markers in specific genomic regions by using segregating populations. Proc. Natl. Acad. Sci. USA 88: 9828-9832.
Nienhuis, J., Helentjaris, T., Slocum, M., Ruggero, B. and Schaefer, A. (1987). Restriction fragment length polymorphism analysis of loci associated with insect resistance in tomato. Crop Sci. 27: 797-803.
Olmos, I.J.L. and Camargo, M.N. (1976). Ocorrência de Al tóxico nos solos do Brasil, sua caracterização e distribuição. Ciênc. Cult. 28: 171-180.
Prioli, A.J. (1987). Análise genética da tolerância a toxidez do alumínio em milho (Zea mays L.). Doctoral thesis, Universidade de Campinas, Campinas, SP.
Reiter, R.S., Coors J.G., Sussman, M.R. and Gabelman, W.H. (1991). Genetic analysis of tolerance to low-phosphorus stress in maize using restriction fragment length polymorphisms. Theor. Appl. Genet. 82: 561-568.
Rhue, R.D. and Grogan, C.O. (1977). Screening corn for Al tolerance using different Ca and Mg concentrations. Agron. J. 69: 755-760.
Rhue, R.D., Grogan, C.O., Stockmeyer, E.W. and Everett, H.L. (1978). Genetic control of aluminum tolerance in corn. Crop Sci. 18: 1063-1067.
Saghai-Maroof, M.A., Soliman, K.M., Jorgensen, R.A. and Allard, R.W. (1984). Ribosomal DNA spacer length polymorphisms in barley: Mendelian inheritance, chromosomal location and population dynamics. Proc. Natl. Acad. Sci. USA 81: 8014-8018.
Sawasaki, E. and Furlani, P.R. (1987). Genética da tolerância à toxidez do alumínio em linhagens de milho cateto. Bragantia 46: 269-278.
Wang, G.L. and Paterson, A.H. (1994). Assessment of DNA pooling strategies for mapping of QTLs. Theor. Appl. Genet. 88: 355-361
* Part of a thesis presented by G.A.T. to Universidade Federal de Lavras in partial fulfillment of requirements for the Master's degree.