Genetic associations determine the effects of intergenerational and transgenerational stress memory for salinity exposure histories in barley.

key messageEnhancing salt tolerance genetically through defining the genetic and physiological mechanisms intergenerational and transgenerational stress memory that contributes to sustainable agriculture by reducing the reliance on external inputs such as irrigation and improving the adaptability of barley to changing climate conditions. Salinity stress poses a substantial challenge to barley production worldwide, adversely affecting crop yield, quality, and agricultural sustainability. To address this, the present study utilized a genome-wide association san (GWAS) to identify genetic associations underlying intergenerational and transgenerational stress memory in response to salinity in a diverse panel of 138 barley accessions. We compared seeds from a second-generation group without salinity exposure (C1C2) to seeds from groups that experienced single-generation salt stress two generations ago (S1C2; transgenerational memory) or one generation ago (C1S2; intergenerational memory), as well as seeds from a group exposed to salinity across both generations (S1S2; combined memory effects). Our results revealed that historical salt stress, irrespective of the number of prior generations affected, induced significant changes in traits such as spike length, spikelets per spike, grains per spike, grain weight, thousand-kernel weight, and markedly increment in antioxidant components levels of enzymatic and non-enzymatic antioxidants. These findings indicate that prior exposure to salinity leaves lasting physiological and biochemical effects that enhance the plant's ability to respond to subsequent stress. Notably, the GWAS analysis identified highly significant genetic associations and candidate genes such as HORVU.MOREX.r3.4HG0383450 linked to most of these traits under salinity exposure histories. In conclusion, intergenerational and transgenerational stress memory plays a pivotal role in enhancing barley's salt tolerance, offering valuable insights for breeding programs aimed at developing resilient barley cultivars.