Investigating gene expression patterns involved in salinity tolerance mechanisms in Thinopyrum distichum

Abstract

Thinopyrum distichum (Thunb.) Á. Löve is a salt-tolerant, wheat wild relative native to the Western Cape and Eastern Cape coastal regions of South Africa; however, the mechanisms governing this species’ halophytic nature remain underexplored. RNA was extracted from root and shoot tissues of Th. distichum under acute salt stress (350 mmol l⁻¹ NaCl) for qPCR. Expression changes in osmotic adjustment (NCED1, NIP), reactive oxygen species (ROS) homeostasis (SRO1, PRX), and ion homeostasis via the salt overly sensitive (SOS) pathway (HKT7, NHX2) in shoots and roots were analysed. HKT7 was downregulated in both tissue types, with a statistically significant downregulation in the shoots (average log₂(FC) = −2.160, p = 0.008), suggesting Th. distichum may maintain ion homeostasis by accumulating salt via the SOS pathway. No statistically significant variation in NCED1, NIP, SRO1, PRX or NHX2 gene expression was seen. This study provides insight into the biological mechanisms responsible for abiotic stress tolerance and underscores the potential of transferring Th. distichum genes for enhancing wheat salt tolerance in South Africa.