Salt tolerance during germination and seedling growth of wild wheat Aegilops tauschii and its impact on the species range expansion

Abstract

Adaptation to edaphic stress may have a key role in plant species range expansion. Aegilops tauschii Coss., the common wheat’s D-genome progenitor native to the Transcaucasus-Middle East region, is a good model to study the relationships between soil salinity and plant distributions: one of its intraspecific sublineages, TauL1b, drove the long-distance eastward expansion of this species range reaching semi-arid-central Asia. Salt tolerance during germination and seedling growth was evaluated in 206 Ae. tauschii accessions by treating seeds with NaCl solutions differing in concentrations. Differences in natural variation patterns were analyzed between sublineages and associated with natural edaphic condition variables, and then compared with reproductive trait variation patterns. The natural variations observed in NaCl-induced-stress tolerance had clear geographic and genetic structure. Seedling growth significantly increased in the TauL1b accessions that were collected from salt-affected soil habitats, whereas germinability did not. Principal component analysis suggested that the NaCl-induced-stress tolerances and reproductive traits might have had a similar degree of influence on Ae. tauschii’s eastward range expansion. Adaptation to salt-affected soils through increased seedling growth was an important factor for the species’ successful colonization of the semi-arid central Asian habitats. TauL1b accessions might provide useful genetic resources for salt-tolerant wheat breeds.

The role of reproductive isolation in allopolyploid speciation patterns: empirical insights from the progenitors of common wheat

“…In fact, TauL1 may represent an ecotype that prefers disturbed habitats where strong selfing (i.e., low likelihood of outcrossing) is adaptive 32 . This view is consistent with the fact that TauL1 accessions often show disturbed-habitat-related phenotypes such as high seed production ability, short vegetative growth span, and increased tolerance to abiotic stress 27 , 33 . In addition, Ae.…”

Genome-Wide Association Study (GWAS) Analysis of Camelina Seedling Germination under Salt Stress Condition

“…Plants may be tolerant to salt stress at one growth stage but sensitive at another, and the effects of salt tolerance at different plant growth stages are usually independent of each other [9,10]. Researchers noted that selection for salt tolerance at germination, seedling stage or early vegetative growth stage did not improve tolerance in adult plants [11,12], while in other studies, salinity stress at early seedling development stage affected plant growth at later growing stages [13] by reducing canopy stand [14], vegetative growth, grain yield and protein content [15]. Therefore, as for plant species with few studies regarding salinity tolerance such as Camelina sativa, investigating the effects of salinity stress at seedling germination stage is the first step for further research exploring effects on plant growth, vegetative development and seed yield.…”

Natural variation in photoperiodic flowering pathway and identification of photoperiod-insensitive accessions in wild wheat, Aegilops tauschii

“…The eastward dispersal could be explained by expansion of the TauL1 habitat range, which appears to be brought especially by one of the sublineages, Tau1b (TauL1b). The TauL1b accessions provide peculiar characteristics such as early heading time, high seed production ability, and salt stress tolerance during seedling growth (Matsuoka et al 2015;Saisho et al 2016). Since the early flowering accessions were found mainly in the eastern habitats, the early heading phenotype was presumed as one of the adaptive characters to the eastern habitats (Matsuoka et al 2008(Matsuoka et al , 2015.…”