Identification and Fine‐Mapping of a Soybean Quantitative Trait Locus on Chromosome 5 Conferring Tolerance to Iron Deficiency Chlorosis

Abstract

I ron deficiency chlorosis is an abiotic stress prevalent in soybean. Soils with a pH greater than 8 cause Fe to become unavailable for plant uptake. High soil pH is often accompanied in calcareous soils by bicarbonate release, which acts as a pH buffer and exacerbates IDC in soybeans because of the inability of the plant to acidify the rhizosphere (Hansen et al., 2003; Inskeep and Bloom, 1987). This lack of Fe availability reduces chlorophyll production, visually observed as interveinal chlorosis of leaves in soybean, which ultimately hinders photochemical capacity ABSTRACT Iron deficiency chlorosis (IDC) is an important nutrient stress for soybean [Glycine max (L.) Merr.] grown in high-pH soils. Despite numerous agronomic attempts to alleviate IDC, genetic tolerance remains the most effective preventative measure against symptoms. In this study, two association mapping populations and a biparental mapping population were used for genetic mapping of IDC tolerance. Quantitative trait loci (QTLs) were identified on chromosomes Gm03, Gm05, and Gm06. Heterogenous inbred families were developed to fine-map the Gm05 QTL, which was uniquely supported in all three mapping populations. Fine-mapping resulted in a QTL with an interval size of 137 kb on the end of the short arm of Gm05, which produced up to a 1.5-point reduction in IDC severity on a 1 to 9 scale in near isogenic lines.

Soybean BARCSoySNP6K: An assay for soybean genetics and breeding research

“…The BARCSoySNP6K assay has been applied in various genetic research, e.g., it has been used to construct linkage maps (Lee et al ., 2015), identify QTL/genes controlling a number of traits such as sudden death syndrome resistance (Wen et al ., 2014; Lightfoot et al ., 2018), aphid resistance (Bhusal et al ., 2017; Zhang et al ., 2017), charcoal rot resistance (Vinholes et al ., 2019), Phytophthora sojae , Pythium irregulare and Fusarium graminearum resistance (Stasko et al ., 2016; Million et al ., 2019), salt tolerance (Do et al ., 2018), waterlogging (Ye et al ., 2018), iron deficiency chlorosis (Merry et al ., 2019), nitrogen fixation (Huo et al ., 2019), growth period (Liu et al ., 2016), seed isoflavone content (Li et al ., 2018), oil and fatty acids (Priolli et al ., 2019), protein content (Nascimento et al ., 2018) and yield (Ye et al ., 2018). These studied not only confirmed previously identified QTL but also resulted in the discovery of new QTL, candidate genes or pathways controlling these traits.…”

“…It will be an option to genotype materials if the array technology reaches its life span or costs more. The 6K assay is also a source for developing KASPer markers because the sequence flanking the SNPs have been screened for their specificity in the genome and their ability to distinguish among the homozygote alleles and heterozygote allele, examples of the success for designing the KASPer markers from 6K or SoySNP50K SNPs have been reported previously (Zhang et al ., 2017; Merry et al ., 2019).…”

Development of A Controlled-Environment Assay To Induce Iron Deficiency Chlorosis In Soybean By Adjusting Calcium Carbonates, pH, And Nodulation

“…The rst pair consisted of the cultivar 'Corsoy 79' (PI 518669), which has low resistance to IDC, and the cultivar 'Dawson' (PI 542403), which has high resistance to IDC, and is described as the "Check Genotypes Experiment" henceforth. The second pair consisted of near isogenic lines (NIL) that differ in resistance to IDC, developed from a cross between the genotypes 'Fiskeby III' (PI 438471) and 'Mandarin (Ottawa)' (PI 548379), as described by Merry et al (2019). The speci c pair used was from family 609 as described in Merry et al (2019).…”

“…The second pair consisted of near isogenic lines (NIL) that differ in resistance to IDC, developed from a cross between the genotypes 'Fiskeby III' (PI 438471) and 'Mandarin (Ottawa)' (PI 548379), as described by Merry et al (2019). The speci c pair used was from family 609 as described in Merry et al (2019). The experiment involving these lines will henceforth be referred to as the "NIL Experiment".…”

“…The experiment involving these lines will henceforth be referred to as the "NIL Experiment". The NIL genotypes are highly isogenic (F 11:12 ) and differ at a ~ 137 kb region on Gm05 known to harbor a quantitative trait locus (QTL) controlling IDC resistance (Merry et al 2019).…”