Identification of quantitative trait locus for abscisic acid responsiveness on chromosome 5A and association with dehydration tolerance in common wheat seedlings

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• 作者：Julio C.M. Iehisa ; Takakazu Matsuura ; Izumi C. Mori ; Shigeo Takumi
• 关键词：ABA ; abscisic acid ; ABA8&prime ; OH ; ABA 8&prime ; -hydroxylase activity ; Cor ; cold responsive ; CS ; Chinese Spring ; DRE ; dehydration-responsive element ; DPA ; days post-anthesis ; GI ; germination index ; Hope5A ; a CS chromosome substitution line with chromosome 5A of Hope ; LEA ; late embryogenesis abundant ; LOD ; log-likelihood ; QTL ; quantitative trait locus ; RL ; root length ; RRGI ; relative root growth inhibition ; RSGI ; relative shoot growth inhibition ; SL ; shoot length ; SSR ; simple sequence repeat
• 刊名：Journal of Plant Physiology
• 出版年：15 January, 2014
• 年：2014
• 卷：171
• 期：2
• 页码：25-34
• 全文大小：1957 K

文摘

The phytohormone abscisic acid (ABA) plays important roles in response to environmental stress as well as in seed maturation and dormancy. In common wheat, quantitative trait loci (QTLs) for ABA responsiveness at the seedling stage have been reported on chromosomes 1B, 2A, 3A, 6D and 7B. In this study, we identified a novel QTL for ABA responsiveness on chromosome 5A using an F₂ population derived from a cross between the common wheat cultivar Chinese Spring (CS) and a chromosome substitution line of CS with chromosome 5A of cultivar Hope (Hope5A). This QTL was found in a similar chromosomal region to previously reported QTLs for drought tolerance and seed dormancy. Physiological characterization of the QTL revealed a small effect on dehydration tolerance and seed dormancy. The rate of water loss from leaves during dehydration was lower, and transcript accumulation of the cold responsive (COR)/late embryogenesis abundant (LEA) genes Wrab18 and Wdhn13 tended to be higher under dehydration stress in F₂ individuals carrying the Hope allele of the QTL, which also showed higher ABA responsiveness than the CS allele-carrying individuals. Seed dormancy of individuals carrying the Hope allele also tended to be lower than those carrying the CS allele. Our results suggest that variation in ABA responsiveness among common wheat cultivars is at least partly determined by the 5A QTL, and that this QTL contributes to development of dehydration and preharvest sprouting tolerance.