ARS | Publication request: Genomic location of a gene conditioning a miniature phenotype in soybean

Submitted to: Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 20, 2011
Publication Date: October 4, 2011
Citation: Ray, J.D., Smith, J.R., Taliercio, E.W., Fritschi, F.B. 2011. Genomic location of a gene conditioning a miniature phenotype in soybean. Plant Biology. 55:26-32.

Interpretive Summary: Previous research identified a miniature soybean mutant that was controlled by a single gene. This mutant is interesting because miniaturization can be overcome by growing the plant at high temperatures. The objective of our research was to locate the gene controlling the miniature trait to a molecular linkage group. Our data confirmed that genetic control was by a single gene. Additionally, we identified three molecular DNA markers located on molecular linkage group B2 that were linked to the miniature trait. One marker, Satt560, co-segregated perfectly with the miniature trait. This indicates that the marker Satt560 is very close to the gene controlling this miniature phenotype. Knowing the location of the gene is the first step in its isolation and characterization. Given the ability to recover a near-normal plant type in response to high temperature, understanding the mechanism of action of the gene may allow insight into the effects of temperature on plant growth and development.

Technical Abstract: Previous research identified a temperature-sensitive miniature soybean [Glycine max (L.) Merr.] mutant that was controlled by a single gene. The miniature trait was originally found in the F2 generation of a three-way cross and designated “D75-M”. Subsequently, the miniature trait was backcrossed into Tracy-M (BC6) and then maintained by harvesting heterozygous plants. The objective of our research was to map the gene conditioning the miniature trait to a molecular linkage group. Segregation of the combined progeny of five plants heterozygous for the miniature trait in a Tracy-M background confirmed that the trait was conditioned by a single gene (27 normal: 36 heterozygous: 30 miniature, 1:2:1, '2 = 4.94, P = 0.08). Additionally, we identified three SSR molecular markers on molecular linkage group B2 linked to the miniature trait. One co-dominant marker, Satt560, co-segregated perfectly with the miniature trait in a combined population of 74 progeny derived from four heterozygous plants. The observed segregation was 23 normal: 28 heterozygous: 23 miniature plants (1:2:1, '2 = 4.38, P = 0.11). The marker and the phenotype of the 74 plants co-segregated perfectly, which indicated that marker Satt560 was very close to the gene conditioning this miniature phenotype.