Identification by IEF of zeins from genes located in recombinant inbreds

--C. M. Wilson

Zeins of individual seeds from two sets of maize recombinant inbreds derived from F2 populations T232xCM37 (48 lines) and CO159xTx303 (41 lines) (Burr et al., Genetics 118:519, 1988) were assayed by IEF in agarose (Wilson et al., Theor. Appl. Genet. 77:217, 1989). Each band of the parental inbreds was given an IEF number by relating it to the positions of zeins in standard inbreds. The occurrence of zeins in three seeds from each of the recombinant inbreds was determined. Only 3 or 4 inbred lines appeared to be segregating. Loci positions were kindly assigned by B. Burr (see MNL64, 1990 maps).. Eleven zein genes were placed on chromosome 4S, four on chromosome 4L (near the centromere), and 3 on chromosome 7S (Table 1). The recombinant inbred linkages agreed with the positions suggested by the earlier work.

IEF bands previously reported (Wilson, TAG, plus MNL report above) are associated with the linkage groups as follows:ZpL1a-f (4S): 17.5, 14/19, 32, 35, 36, 37, 60;

Table 1. Linkage groups for zein genes in recombinant inbreds.
Linkage   Inbred Inbred
Group Chrom. CM37 T232
ZpL1a 4S-29 18 20
ZpL1b 4S-31 32 31.5
ZpL1c 4S-31 36 29.5
ZpL1d* 4S-34 33.5 33.5
ZpL2a 4L-74 47.5 45
*33.5 bands differentiated by intensity.
Linkage   Inbred Inbred
Group Chrom. CO159 Tx303
ZpL1e 4S-30 17.5 18,60
ZpL1f 4S-33 35 32,36
ZpL2b 7S-21 21.5,53 38
ZpL3a 4L-78 44 44.5
ZpL2a/3a (4L): 28, 30.5, 32y, 33, 33.5, 49, 54.5; ZpL2b (7S): 10, 21, 22, 38.

Genes for zein bands 32 and 33.5 occurred on both arms of chromosome 4. Totals for identifiably different (by IEF position alone) zeins which have been mapped are 13 for ZpL1a/f, 11 for ZpL2a/3a, and 6 for ZpL2b, for a total of 30 genes for AB zeins in the four recombinant inbreds plus the 13 crosses studied earlier. Recent work (C. M. Wilson, Plant Physiol. 1991, in press) suggests that these are minimum numbers, for serial analysis by HPLC in addition to IEF shows that apparently identical zein IEF bands in two inbreds may differ by HPLC.

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