Genetic Dissection of ICP-Detected Nutrient Accumulation in the Whole Seed of Common Bean (Phaseolus vulgaris L.)

Abstract

Nutrient transport to grain legume seeds is not well studied and can benefit from modern methods of elemental analysis including spectroscopic techniques. Some cations such as potassium (K) and magnesium (Mg) are needed for plant physiological purposes. Meanwhile, some minerals such as copper (Cu), iron (Fe), molybdenum (Mo), and zinc (Zn) are important micronutrients. Phosphorus (P) is rich in legumes, while sulfur (S) concentration is related to essential amino acids. In this research, the goal was to analyze a genetic mapping population of common bean (Phaseolus vulgaris L.) with inductively coupled plasma (ICP) spectrophotometry to determine concentrations of and to discover quantitative trait loci (QTL) for 15 elements in ground flour of whole seeds. The population was grown in randomized complete block design experiments that had been used before to analyze Fe and Zn. A total of 21 QTL were identified for nine additional elements, of which four QTL were found for Cu followed by three each for Mg, Mn, and P. Fewer QTL were found for K, Na and S. Boron (B) and calcium (Ca) had only one QTL each. The utility of the QTL for breeding adaptation to element deficient soils and association with previously discovered nutritional loci are discussed.

Keywords: dry bean grain; inductively coupled plasma spectroscopy; mineral and non-mineral elements; pulse legume; quantitative trait loci; seed nutrient concentration.

FIGURE 1

Genetic linkage map showing quantitative trait loci (QTL) for elements detected by inductively coupled plasma (ICP) method in the DOR364 × G19833 (DG) mapping population. QTL are shown as different colored bars for Boron (B), Calcium (Ca), Copper (Cu), Iron (Fe), Magnesium (Mg), Manganese (Mn), Phosphorus (P), Potassium (K), Sodium (Na), Sulfur (S), and Zinc (Zn) with cross marks indicating peak likelihood ratio values. Genetic markers consist of simple sequence repeat (SSR) anchor and restriction fragment length polymorphism (RFLP) markers from Blair et al. (2003, 2008, 2010a) along with genes from the phytate biosynthesis pathway (IPK2, ITPKb, MIPSs, and MIPSv) and the protein marker for phaseolin (Phs) highlighted in red and green text, respectively, all shown to the right of each chromosome/linkage group. Map distances between markers are shown on the scale to the left of the chromosome/linkage groups for the DG population.