Identification of quantitative trait loci and candidate genes for seed folate content in soybean.

KEY MESSAGE: From 61 QTL mapped, a stable QTL cluster of 992 kb was discovered on chromosome 5 for folate content and a putative candidate gene, Glyma.05G237500, was identified. Folate (vitamin B9) is one of the most essential micronutrients whose deficiencies lead to various health defects in humans. Herein, we mapped the quantitative trait loci (QTL) underlying seed folate content in soybean using recombinant inbred lines developed from cultivars, ZH35 and ZH13, across four environments. We identified 61 QTL on 12 chromosomes through composite interval mapping, with phenotypic variance values ranging from 1.68 to 24.68%. A major-effect QTL cluster (qFo-05) was found on chromosome 5, spanning 992 kb and containing 134 genes. Through gene annotation and single-locus haplotyping analysis of qFo-05 in a natural soybean population, we identified seven candidate genes significantly associated with 5MTHF and total folate content in multiple environments. RNA-seq analysis showed a unique expression pattern of a hemerythrin RING zinc finger gene, Glyma.05G237500, between both parental cultivars during seed development, which suggest the gene might regulate folate content in soybean. This is the first study to investigate QTL underlying folate content in soybean and provides new insight for molecular breeding to improve folate content in soybean.

The nutritional composition of the vegetable soybean (maodou) and its potential in combatting malnutrition.

Introduction: Global malnutrition continues to be a canker owing to poor eating habits and over-reliance on the major staple crops. Vegetable soybean (maodou) is gaining popularity globally as an affordable snack and vegetable. Methods: In this study, we profiled the nutritional composition of 12 soybean cultivars at the vegetable (R6-R7) and mature (R8) stages. We also conducted an RNA-seq analysis during seed development, focusing on key biosynthesis enzymes for quality traits. Results: The results showed that 100 g of maodou contained 66.54% moisture, 13.49% protein, 7.81% fatty acids, 2.47% soluble sugar, abundant content of minerals, and micronutrients, including folate (462.27 µg FW) and carotenoids (3,935.41 µg FW). Also, the isoflavone content of maodou ranged between 129.26 and 2,359.35 µg/g FW. With regard to the recommended daily allowance, 100 g fresh weight of maodou can contribute 26.98, 115.57, and 11.60% of protein, folate, and zinc, respectively, and significant proportions of other nutrients including linoleic acid (21.16%), linolenic acid (42.96%), zinc (11.60%), and iron (18.01%). On a dry weight basis, maodou has two to six folds higher contents of folate, tocopherol, and carotenoid than the mature soybean. Furthermore, RNA-seq analysis revealed that key biosynthesis enzymes of quality traits are differentially expressed during seed development and may contribute to variations in the content of quality traits at the vegetable and mature stages. Correlation analysis of quality traits at both stages revealed that protein only correlated positively with zinc at the vegetable stage but negatively correlated with total tocopherol and total fatty acid at the mature stage. Complex associations among folates, soluble sugar, and isoflavones were also identified. Discussion: This study provides insight into the nutritional contents of vegetable soybean and demonstrates that maodou is essential for meeting the nutritional requirements of most countries.

[Noninvasive continuous measurement of blood glucose concentration via animal skin].

In this study we deliberated over the principles and methods and then took the noninvasive continuous measurement of blood glucose concentration through the skin of rabbits. The glucose oxidase sensor was made by covalent immobilization. The best making method of sensor and stable working condition were sifted. Ten female and 10 male adult white rabbits were allocated into the groups of the ante-ultrasound and post-ultrasound, the injection of glucose, and the high and low frequency ultrasounds. After the skin surface was treated by high or low frenquency ultrasound for 5 minutes on the rabbits, obvious changes (P < 0.01) of post-ultrasound and post-injection of glucose were observed by means of glucose oxidase sensor and microcurrent apparatus. After application of ultrasound to the skin of rabbits, the penetration of glucose through the rabbit skin increased obviously. The change of microcurrent signal that was exchanged by the glucose sensor correlated positively with the concentration of glucose of rabbit body. The blood glucose can be tested by the glucose sensor on the skin surface of living animal.