Van Nguyen Loc, Takahashi Ryoji, Githiri Stephen Mwangi, Rodriguez Tito O, Tsutsumi Nobuko, Kajihara Sayuri, Sayama Takasi, Ishimoto Masao, Harada Kyuya, Suematsu Keisuke, Abiko Tomomi, Mochizuki Toshihiro
Graduate School of Bioresource and Environmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan.
NARO Institute of Crop Science, 2-1-2 Kannondai, Tsukuba, Ibaraki, 305-8518, Japan.
Theor Appl Genet. 2017 Apr;130(4):743-755. doi: 10.1007/s00122-016-2847-3. Epub 2017 Jan 17.
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.
利用一种新的表型评价方法，在大豆根系中检测到了耐缺氧和耐涝性的最大潜力QTL。涝害是限制世界湿润地区大豆产量的主要环境胁迫因素。根系发育是大豆耐缺氧性的重要指标。然而，关于缺氧条件下根系发育的遗传控制知之甚少。本研究旨在鉴定缺氧条件下负责根系发育的数量性状位点（QTL）。使用从缺氧敏感品种立长叶和耐涝地方品种井出大豆杂交产生的重组自交系（RIL）。对幼苗进行缺氧处理，并通过处理前后根系性状的数值变化来评估根系发育。我们发现230个多态性标记，分布在所有20条染色体（Chrs.）上，跨度为2519.2 cM。利用这些标记，我们在Chrs. 11、12、13和14上发现了11个与根长（RL）、根长发育（RLD）、根表面积（RSA）、根表面积发育（RSAD）、根直径（RD）和平均根直径变化（CARD）相关的QTL，以及7个与这些根系性状耐缺氧性相关的QTL。其中包括Chr. 12上标记Satt052和Satt302之间的RLD和RSAD的QTL，它们是大豆耐缺氧性的重要标记；这些QTL在两年间是稳定的。为了验证这些QTL，我们培育了一个近等基因系，其QTL区域来自井出大豆。该品系在缺氧和涝害条件下均表现良好，表明该区域包含一个或多个对根系发育有重大影响的基因。这些发现可能有助于对缺氧条件下负责根系发育的基因进行精细定位和图位克隆。
