Impact of mips1, lpa1, and lpa2 Alleles for Low Phytic Acid Content on Agronomic, Seed Quality, and Seed Composition Traits of Soybean

Abstract

Soybean [Glycine max (L.) Merr] is an important agronomic crop around the world, used largely for animal feed. However, ∼75% of the phosphorus (P) in soybean grain is in the form of phytic acid (PA) or phytate, the cation salt form of PA, which cannot be digested by monogastric and agastric animals including swine, poultry, and aquacultural animals, leading to decreased field efficiency and environmental detriment due to P runoff. Soybean lines have been developed with a reduced PA content using mutant alleles of three genes involved in the PA pathway: either the combination of lpa1 and lpa2 or mips1. However, the relationship among these alleles was unknown. This study was conducted to explore the impact of these three mutant alleles on soybean agronomic, seed quality, and seed composition traits. A population consisting of 30 recombinant inbred lines developed from a cross between V03‐5901 (mips1) × 04‐05N32 (lpa1/lpa2) was planted along with the parents at two locations in Virginia in 2014 and 2015. The results showed that (i) an additive relationship existed among the three different mutant alleles, resulting in lower PA content as more low‐PA (LPA) mutant alleles were added; (ii) the lines with lpa1 allele had the highest field emergence, and thus lpa1 may be a good trait with which to create a commercially viable LPA soybean cultivar; and (iii) the interaction between the mips1 and lpa2 alleles resulted in raffinose content significantly lower than with either allele on its own. The findings of this study provided breeders with references for developing LPA soybean cultivars combined with other desirable traits.

Genetic interactions regulating seed phytate and oligosaccharides in soybean (Glycine max L.)

“…Compared to this study, the triple mutants from Averitt et al [48] showed higher sucrose (8.25%), lower raffinose (0.86%) and lower stachyose (3.69%) levels; however, only phytate and raffinose levels were significantly different from the mips mutant. Despite the fact that the lowest phytate level (ranging from 0.227-4.864 mg g -1 ) was attained for triple mutant in Averitt et al [48], it was not significantly different from mrp-l/mrp-n mutant, and this observation is consistent with the current study. Different seed phytate levels of triple mutants in these two studies could be due to dissimilarities in the genetic backgrounds of the parental lines used in two studies.…”

“…These findings confirm the interaction of MIPS and MRP genes in regulating phytate and RFO biosynthesis pathways in soybean. The MIPS and MRP gene interactions were previously studied using soybean breeding lines originating from V03-5901 (mips) x 04-05N32 (mrp-l/mrp-n) cross [48]. Compared to this study, the triple mutants from Averitt et al [48] showed higher sucrose (8.25%), lower raffinose (0.86%) and lower stachyose (3.69%) levels; however, only phytate and raffinose levels were significantly different from the mips mutant.…”

“…The MIPS and MRP gene interactions were previously studied using soybean breeding lines originating from V03-5901 (mips) x 04-05N32 (mrp-l/mrp-n) cross [48]. Compared to this study, the triple mutants from Averitt et al [48] showed higher sucrose (8.25%), lower raffinose (0.86%) and lower stachyose (3.69%) levels; however, only phytate and raffinose levels were significantly different from the mips mutant. Despite the fact that the lowest phytate level (ranging from 0.227-4.864 mg g -1 ) was attained for triple mutant in Averitt et al [48], it was not significantly different from mrp-l/mrp-n mutant, and this observation is consistent with the current study.…”

Seed mineral reserves and vigour of Bambara groundnut (Vigna subterranea L.) landraces differing in seed coat colour

“…The loss in mineral element concentration and dry matter of cotyledons are related to phytic acid degradation. Phytic acid accounts for 1%–8% of the dry weights of legume seeds (Averitt et al., 2017), during germination, it is broken down by enzyme phytase in a hydrolysis reaction, releasing Pi, metal ions, and myo -inositol for use by the growing individual.…”

Registration of USDA‐N6003LP Soybean Germplasm with Low Seed Phytate

“…The phytate content of each sample was determined using an indirect Fe colorimetric method as reported in previous studies (Burleson et al, 2012; Averitt et al, 2017). Briefly, 0.5 g of soybean powder was extracted with 10 mL of 0.5 M HCl.…”