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A 23‐kDa, root exudate polypeptide co‐segregates with aluminum resistance in Triticum aestivum
Author(s) -
Basu Urmila,
Good Allen G.,
Aung Taing,
Slaski Jan J.,
Basu Atanu,
Briggs Keith G.,
Taylor Gregory J.
Publication year - 1999
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1999.106108.x
Subject(s) - callose , biology , population , backcrossing , exudate , phenotype , botany , horticulture , cultivar , cell wall , genetics , gene , demography , sociology
We previously reported that treatment with aluminum (Al) leads to the accumulation of several polypeptides (12‐, 23‐, and 43.5‐kDa) in root exudates of an Al‐resistant cultivar of Triticum aestivum . In this report, we examine the segregation of the 23‐kDa, Al‐induced polypeptide and the Al‐resistant phenotype in single F 2 plants arising from a cross between Al‐resistant and Al‐sensitive doubled‐haploid (DH) lines. Single plants and plant populations were screened for sensitivity/resistance to Al using synthesis of 1,3‐ β ‐glucans (callose) as a sensitive marker for Al injury. Callose production in the Al‐sensitive cv. Katepwa was approximately 3‐fold higher than observed in the Al‐resistant cv. Maringa, or a near‐isogenic line derived from Katepwa and Maringa (Alikat), over a broad range of Al concentrations (0–100 μ M ). Similar results were observed with DH lines developed from cv. Katepwa, which produced two–four times more callose than DH lines developed from cv. Alikat. When single plants from F 1 and F 2 populations derived from a cross between DH Katepwa and DH Alikat were scored for Al‐induced callose production after 4 days exposure to 100 μ M Al, all F 1 plants were Al‐resistant and F 2 plants segregated approximately 3:1 for Al‐resistance/sensitivity. A backcross population derived from crossing Al‐resistant F 1 with Al‐sensitive Katepwa, segregated 1:1 for Al‐resistance/sensitivity. Thus, the Al‐resistant phenotype is inherited in a monogenic, dominant fashion in our DH lines. Enhanced accumulation of the Al‐induced, 23‐kDa polypeptide in root exudates was a trait which co‐segregated with the Al‐resistant phenotype in F 2 populations. This polypeptide was strongly labeled with S‐methionine after 3 days of Al exposure and 6 h labeling. When root exudate polypeptides were separated by immobilized metal ion affinity chromatography, the 23‐kDa polypeptide demonstrated significant Al‐binding capacity. This polypeptide has been purified to near‐homogeneity, providing an opportunity to isolate the gene(s) encoding this polypeptide.