Differential Gene Expression Associated with Altered Isoflavone and Fatty Acid Contents in Soybean Mutant Diversity Pool

Abstract

Soybean seeds are consumed worldwide owing to their nutritional value and health benefits. In this study we investigated the metabolic properties of 208 soybean mutant diversity pool (MDP) lines by measuring the isoflavone and fatty acid contents of the seed. The total isoflavone content (TIC) ranged from 0.88 mg/g to 7.12 mg/g and averaged 3.08 mg/g. The proportion of oleic acid among total fatty acids (TFA) ranged from 0.38% to 24.66% and averaged 11.02%. Based on the TIC and TFA among the 208 MDP lines, we selected six lines with altered isoflavone content and six lines with altered oleic acid content compared with those of the corresponding wild-types for measuring gene expression. Each of twelve genes from the isoflavone and fatty acid biosynthesis pathways were analyzed at three different seed developmental stages. Isoflavone biosynthetic genes, including CHI1A, IFS1, and IFS2, showed differences in stages and expression patterns among individuals and wild-types, whereas MaT7 showed consistently higher expression levels in three mutants with increased isoflavone content at stage 1. Expression patterns of the 12 fatty acid biosynthetic genes were classifiable into two groups that reflected the developmental stages of the seeds. The results will be useful for functional analysis of the regulatory genes involved in the isoflavone and fatty acid biosynthetic pathways in soybean.

Genome wide association study to detect genetic regions related to isoflavone content in a mutant soybean population derived from radiation breeding

“…The soybean mutant population used in this study was developed as a mutant diversity pool (MDP) by our group. Its agronomic traits, contents of functional components, and expression levels of genes related to certain phytochemicals have been described in other studies ( Kim et al, 2020 , 2021 ).…”

“…Overall, our results and those of other studies suggest that isoflavone contents in soybean seeds are more influenced by genetic effects than by year effects, indicating that isoflavone contents in soybean seeds are traits that can be genetically manipulated. We conducted correlation analyses for 12 types of isoflavones across two years (2020 and 2021), and detected strong positive correlations between total isoflavones and glucosides [DZI, GLI, and GNI (r = 0.64-0.94 in 2020 and r = 0.67-0.89 in 2021)]; and between total isoflavones and malonyl glucosides [MDZI, MGLI and MGNI (r = 0.64-0.94 in 2020 and r = 0.67-0.89 in 2021)]. We detected weaker positive correlations between total isoflavones and aglycones [DZE, GLE, and GNE (r = 0.46-0.82 in 2020 and r = 0.12-0.20 in 2021)]; and between total isoflavones and acetyl glucosides [ADZI and AGNI (r = 0.26-0.96 in 2020 and r = 0.47-0.95 in 2021)].…”

“…We conducted correlation analyses for 12 types of isoflavones across two years (2020 and 2021), and detected strong positive correlations between total isoflavones and glucosides [DZI, GLI, and GNI (r = 0.64-0.94 in 2020 and r = 0.67-0.89 in 2021)]; and between total isoflavones and malonyl glucosides [MDZI, MGLI and MGNI (r = 0.64-0.94 in 2020 and r = 0.67-0.89 in 2021)]. We detected weaker positive correlations between total isoflavones and aglycones [DZE, GLE, and GNE (r = 0.46-0.82 in 2020 and r = 0.12-0.20 in 2021)]; and between total isoflavones and acetyl glucosides [ADZI and AGNI (r = 0.26-0.96 in 2020 and r = 0.47-0.95 in 2021)]. Across both years, DZI (r = 0.93 * * * , r = 0.89 * * * ), GNI (r = 0.94 * * * , r = 0.89 * * * ), MDZI (r = 0.94 * * * , r = 0.94 * * * ), MGNI (r = 0.94 * * * , r = 0.96 * * * ) and ADZI (r = 0.95 * * * , r = 0.96 * * * ) showed significantly strong positive correlations with TI and with each other, consistent with the results of other studies (Azam et al, 2020;Yoon et al, 2021).…”

Identification of Loci Governing Agronomic Traits and Mutation Hotspots via a GBS-Based Genome-Wide Association Study in a Soybean Mutant Diversity Pool

“…The data for five qualitative (GT, FC, SCC, SHC, and SA) and six quantitative (DF, MD, SI, PH, NN, and RN) agronomic traits, as well as six phytochemical traits (TIC, PA, SAF, OA, LA, and ALA) for the 192 soybean MDP lines were obtained from earlier studies [ 40 , 41 ].…”

“…The 192 soybean MDP lines in the M 12 generation were phenotypically assessed for the following 11 agronomic traits: growth type (GT), flower color (FC), seed coat color (SCC), seed hilum color (SHC), and stem anthocyanin (SA) (i.e., qualitative traits); and days of flowering (DF), maturity days (MD), seed index (SI), plant height (PH), node number (NN), and ramification number (RN) (i.e., quantitative traits) (additional details are provided in Kim et al [ 40 ]). The following six phytochemical traits were also analyzed: total isoflavone content (TIC) and the contents of five fatty acids, namely palmitic acid (PA; C16:0), stearic acid (SAF; C18:0), oleic acid (OA; C18:1), linoleic acid (LA; C18:2), and α-linolenic acid (ALA; C18:3) (additional details are provided in Kim et al [ 41 ]).…”