Identification of unique osmotic response mechanisms in Aegilops biuncialis Vis. compared to Triticum aestivum L. Mv9kr1.

A wild relative of wheat is goatgrass (Aegilops biuncialis Vis., Ae.b.), that has genotypes exhibiting better drought tolerance than bread wheat, and which can be used as gene sources for breeders to reduce stress-induced yield loss of wheat. This study compared the osmotic stress [33 mM polyethylene glycol (PEG), 5 days] response of two Ae.b. accessions (Ae.b. 382 from dry habitat and Ae.b. 642 from rainy habitat), and the drought-tolerant wheat variety Mv9kr1. The aim of the experiment was to identify unique response mechanisms in Ae.b. reducing the harmful effects of osmotic stress, compared to wheat. The osmotic treatment generally decreased FW and length of Ae.b. 382 and Mv9kr1 but not in Ae.b. 642. Some parameters exhibited equal trends across genotypes, such as the activation of GR, or the upregulation of an ABA-MYB2-ferulic acid signalling chain. Several variables showed distinct levels in Ae.b. 642, such as APX activity, JA and SA analogue levels, or several phenolic compounds exhibiting antioxidant properties, such as vanillic acid, luteolin or apigenin. Such observed differences may partly explain the better stress-tolerance of Ae.b. 642. The experiment revealed that both Ae.b. 382 and Ae.b. 642 exhibit a strongly different pattern in the investigated parameters, compared to Mv9kr1, with the differences most prominent between Ae.b. 642 and Mv9kr1. The introduction of related Ae.b. genes into new wheat cultivars could be useful for the improvement of stress tolerance.