title: Mapping quantitative trait loci for root development under hypoxia conditions in soybean (Glycine max L. Merr.).
abstract: Greatest potential, QTLs for hypoxia and waterlogging tolerance in soybean roots were detected using a new phenotypic evaluation method. Waterlogging is a major environmental stress limiting soybean yield in wet parts of the world. Root development is an important indicator of hypoxia tolerance in soybean. However, little is known about the genetic control of root development under hypoxia. This study was conducted to identify quantitative trait loci (QTLs) responsible for root development under hypoxia. Recombinant inbred lines (RILs) developed from a cross between a hypoxia-sensitive cultivar, Tachinagaha, and a tolerant landrace, Iyodaizu, were used. Seedlings were subjected to hypoxia, and root development was evaluated with the value change in root traits between after and before treatments. We found 230 polymorphic markers spanning 2519.2 cM distributed on all 20 chromosomes (Chrs.). Using these, we found 11 QTLs for root length (RL), root length development (RLD), root surface area (RSA), root surface area development (RSAD), root diameter (RD), and change in average root diameter (CARD) on Chrs. 11, 12, 13 and 14, and 7 QTLs for hypoxia tolerance of these root traits. These included QTLs for RLD and RSAD between markers Satt052 and Satt302 on Chr. 12, which are important markers of hypoxia tolerance in soybean; those QTLs were stable between 2 years. To validate the QTLs, we developed a near-isogenic line with the QTL region derived from Iyodaizu. The line performed well under both hypoxia and waterlogging, suggesting that the region contains one or more genes with large effects on root development. These findings may be useful for fine mapping and positional cloning of gene responsible for root development under hypoxia.
authors.affiliation: Graduate School of Bioresource and Environmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan. nguyenvanloc1012@gmail.com.
authors.forename: Loc
authors.initials: L
authors.lastname: Van Nguyen
authors.affiliation: NARO Institute of Crop Science, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8518, Japan.
authors.forename: Ryoji
authors.initials: R
authors.lastname: Takahashi
authors.affiliation: Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi, Kenya.
authors.forename: Stephen Mwangi
authors.initials: SM
authors.lastname: Githiri
authors.affiliation: Graduate School of Life and Environmental Sciences, University of Tsukuba, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8518, Japan.
authors.forename: Tito O
authors.initials: TO
authors.lastname: Rodriguez
authors.affiliation: University Farm, Kyushu University, 111 Harumachi, Kasuya-cho, Kasuya-gun, Fukuoka, 811-2307, Japan.
authors.forename: Nobuko
authors.initials: N
authors.lastname: Tsutsumi
authors.affiliation: University Farm, Kyushu University, 111 Harumachi, Kasuya-cho, Kasuya-gun, Fukuoka, 811-2307, Japan.
authors.forename: Sayuri
authors.initials: S
authors.lastname: Kajihara
authors.affiliation: NARO Institute of Crop Science, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8518, Japan.
authors.forename: Takasi
authors.initials: T
authors.lastname: Sayama
authors.affiliation: NARO Institute of Crop Science, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8518, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Ishimoto
authors.affiliation: Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan.
authors.forename: Kyuya
authors.initials: K
authors.lastname: Harada
authors.affiliation: Graduate School of Bioresource and Environmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Suematsu
authors.affiliation: Graduate School of Bioresource and Environmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Abiko
authors.affiliation: Graduate School of Bioresource and Environmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Mochizuki
mesh_terms: D002874:Chromosome Mapping; D008040:Genetic Linkage; D005819:Genetic Markers; D000860:Hypoxia / Q000235:genetics*; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development*; D040641:Quantitative Trait Loci; D013025:Glycine max / Q000235:genetics* / Q000254:growth & development; D013312:Stress, Physiological
chemical_list: D005819:Genetic Markers