Introgression of Novel Traits from a Wild Wheat Relative Improves Drought Adaptation in Wheat  

Abstract

Root architecture traits are an important component for improving water stress adaptation. However, selection for aboveground traits under favorable environments in modern cultivars may have led to an inadvertent loss of genes and novel alleles beneficial for adapting to environments with limited water. In this study, we elucidate the physiological and molecular consequences of introgressing an alien chromosome segment (7DL) from a wild wheat relative species (Agropyron elongatum) into cultivated wheat (Triticum aestivum). The wheat translocation line had improved water stress adaptation and higher root and shoot biomass compared with the control genotypes, which showed significant drops in root and shoot biomass during stress. Enhanced access to water due to higher root biomass enabled the translocation line to maintain more favorable gas-exchange and carbon assimilation levels relative to the wild-type wheat genotypes during water stress. Transcriptome analysis identified candidate genes associated with root development. Two of these candidate genes mapped to the site of translocation on chromosome 7DL based on single-feature polymorphism analysis. A brassinosteroid signaling pathway was predicted to be involved in the novel root responses observed in the A. elongatum translocation line, based on the coexpression-based gene network generated by seeding the network with the candidate genes. We present an effective and highly integrated approach that combines root phenotyping, whole-plant physiology, and functional genomics to discover novel root traits and the underlying genes from a wild related species to improve drought adaptation in cultivated wheat.

Gas exchange, carbon balance and stomatal traits in wild and cultivated rice (Oryza sativa L.) genotypes

“…There have been several reports that, high grain yield and biomass production is associated with higher leaf photosynthetic rate and grain filling during late reproductive period (Horie et al 2003). Molecular marker mapping studies in rice have shown that wild species can contribute genes for improving the complex traits such as high biomass formation, yield and abiotic stress tolerance, despite their poor phenotype (Placido et al 2013;Nevo and Chen 2010;Swamy and Sarla 2008) and are therefore source enhancing photosynthetic rates into cultivated rice varieties. Almost 80 % of the wild rice accessions studied in the present investigation had higher A than the mean of cultivars, indicating that A in rice has not yet reached the saturation level and therefore, theoretically a scope to enhance the A is still existing.…”

Drought resistance of wheat alien chromosome addition lines evaluated by membership function value based on multiple traits and drought resistance index of grain yield

“…By studying a set of wheat-rye disomic addition lines, Mohammadi et al (2003) found that most of the genes controlling drought tolerance were located on chromosomes 7R, 5R and 3R. A wheat translocation line with an alien chromosome segment (7DL) from Agropyron elongatum was found to have improved water stress adaptation and higher root and shoot biomass compared with the control genotypes (Placido et al, 2013). The presence of the 1RS translocation in spring cultivar "Pavon" increased root biomass and was more tolerant to field environmental stresses than Pavon (Ehdaie et al, 2003).…”

Drought Resistance in Crops: Physiological and Genetic Basis of Traits for Crop Productivity

“…Placido et al (2013) introduced an alien chromosome segment (7DL) from a wild wheat relative species (Agropyron elongatum) into cultivated wheat (Triticum aestivum). The wheat translocation line (TL) showed improved water stress adaptation and higher root and shoot biomass compared with the control genotype, which showed significant drop in root and shoot biomass during stress.…”