Genetic basis of isoflavone accumulation during soybean seed development: special focus on water-deficit conditions

• Autores: Juan José Gutiérrez González
• Directores de la Tesis: D. A. Sleper (dir. tes.), Henry T. Nguyen (dir. tes.)
• Lectura: En la University of Missouri–Columbia ( Estados Unidos ) en 2009
• Idioma: inglés
• Número de páginas: 172
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• Resumen

  • Soybean (Glycine max [L] Merr.) seed isoflavones have long been considered a desirable trait to target in selection programs for their contribution to human health and plant defense systems. A continuing effort is being made to assess the beneficial or prejudicial aspects derived from their consumption by humans, and is reflected in the numerous articles about the topic published every year. Within the plant, isoflavones are synthesized in response to several biotic and abiotic stresses. As a consequence, isoflavone seed content is known to be tremendously influenced by environmental conditions being temperature and water regime the two main factors, also likely associated with global climate change. Attempts to modify seed isoflavone contents have not always produced the expected results because their genetic basis is polygenic and complex. Without any doubt, the tremendous variability that isoflavones display over locations and years has hindered the genetic basis underlying their synthesis and accumulation in seeds. Our findings suggest that isoflavone seed concentration is controlled by a complex network of multiple minor-effect loci interconnected by a dense epistatic map of interactions. We hypothesize that the magnitude and significance of the main and epistatic effects of the nodes in the network will vary depending on the genetic background and environmental conditions. In an attempt to unravel the genetic architecture underlying the traits studied, we searched on a genome-wide scale for genomic regions homologous to the most important identified isoflavone biosynthetic genes. Temperature is by far the most well studied factor affecting seed isoflavone accumulation but not much is known about accumulation under drought conditions other than it is significantly elevated by irrigation. Drought is an increasing problem in many regions of the world, thus knowing the factors affecting and the mechanisms regulating the seed isoflavone accumulation will be of vital importance for development of soybean varieties with increasing isoflavone seed content under low soil moisture levels. Overall, we advanced the knowledge of the genetics underlying isoflavone synthesis.