Saranga, Y. | bioRxiv Science

bioRxiv2019

Variation in phosphorus and sulfur content shapes the genetic architecture and phenotypic associations within wheat grain ionome

Dissection of the genetic basis of ionome is crucial for the understanding of the physiological and biochemical processes underlying mineral accumulation in seeds, as well as for efficient crop breeding. Most of the elements essential for plants are metals stored in seeds as chelate complexes with phytic acid or sulfur-containing compounds. We assume that the involvement of phosphorus and sulfur in metal chelation is the reason for strong phenotypic associations within ionome. Thus, we adjusted element concentrations for the effect of variation in phosphorus and sulfur seed content. The genetic architecture of wheat grain ionome was characterize by QTL analysis using a cross between durum and wild emmer wheat. Adjustment for variation in P and S drastically changed phenotypic associations within ionome and considerably improved QTL detection power and accuracy, resulting in identification of 105 QTLs and 437 QTL effects for 11 elements. A search for candidate genes revealed some strong functional associations of genes involved in transport and metabolism of ions and elements. Thus, we have shown that accounting for variation in P and S is crucial for understanding of the physiological and genetic regulation of mineral composition of wheat grain ionome and can be implemented for other plants.

genetics↗

bioRxiv2019

Genomic architecture of phenotypic plasticity of complex traits in tetraploid wheat in response to water stress

Phenotypic plasticity is one of the main mechanisms of adaptation to abiotic stresses via changes in critical developmental stages. Altering flowering phenology is a key evolutionary strategy of plant adaptation to abiotic stresses in order to achieve maximum possible reproduction. The current study is the first to apply the linear regression residuals as a drought plasticity scores, while taking into account the differences in flowering phenology and trait variation under non-stress conditions. We characterized the genomic architecture of 17 complex traits and their drought plasticity using a mapping population derived from a cross between durum wheat (Triticum durum) and wild emmer wheat (T. dicoccoides). We identified 79 QTLs, of which 33 were plastic in response to water stress and exhibited epistatic interactions and/or pleiotropy between the initial and plasticity traits. Vrn-B3 (TaTF1) residing within an interval of a major drought-escape QTL was proposed as a candidate gene. The favorable alleles for most of the plasticity QTLs were contributed by wild emmer, demonstrating the high potential of wild relatives for wheat improvement. Our study presents a new approach for quantification of plant adaptation to various stresses and provides new insights into the genetic basis of wheat complex traits under water-deficit stress.\n\nHighlightThe study presents a new approach for quantification of plant adaptation to various stresses and provides new insights into the genetic basis of wheat complex traits under water-deficit stress.

genetics↗