Abstract: 【Objective】 The objectives of the present study are to map the D-myo-inositol 3 phosphate synthase (MIPS EC 5.5.1.4) gene MIPS1 to enrich genetic information of this gene, and to develop molecular markers specific for the MIPS1 mutation for marker assisted selection of low phytic acid (LPA) trait of the mutant line Gm-lpa-TW-1. 【Method】 The candidate chromosome, in which MIPS1 is located, was identified by using soybean whole genome sequence and bioinformatics tools. The results were then verified through classical linkage analysis between microsatellites markers and the LPA trait using the F2:3 population derived from the cross between Gm-lpa-TW-1×Zhongdou 27. Cleaved amplified polymorphic sequences (CAPS) makers specific to the MIPS1 mutation of Gm-lpa-TW-1 were developed based on sequence information of all 4 MIPS genes; the usefulness of CAPS marker was verified using another segregating F2:3 population. 【Result】 Four MIPS genes were identified in soybean and MIPS1 was mapped on chromosome 18 (Linkage Group G) and proved to be the Glyma18g02210 gene. The DNA sequence of MPIS1 starts at 1 364 774 bp and is positioned on the upside of SSR markers Satt570(3 162 690 bp)and Satt115 (10 422 881 bp) at the genetic distance of 5.5 and 15.2 cM, respectively. A co-dominant CAPS marker, which completely segregates with the LPA trait, was developed and verified for the mutant MIPS1 gene of Gm-lpa-TW-1. 【Conclusion】 The present study mapped the MIPS1 on chromosome 18 for the first time, greatly enriched the genetic knowledge of this gene. The CAPS marker developed for the LPA trait of Gm-lpa-TW-1 can be used for marker assisted selection of this important trait and thus can enhance the efficiency of LPA soybean breeding.

Key words: soybean, low phytic acid, mutant, MIPS1 gene mapping, CAPS markers