Differential genetic and biochemical responses of Beta vulgaris and Beta maritima under salt stress

Screening and raising salt-tolerant crops on saline land is an affordable and environmentally friendly alternative. This study investigated the physiological and molecular processes in eight Beta vulgaris and Beta maritima accessions.

A preliminary study was carried out to determine the sublethal concentration of NaCl. The chlorophyll content, fresh and dry weights, relative water content, and potassium and sodium ions of all B. maritima and B. vulgaris accessions were shown to be significantly decreased under salt stress (250 mM NaCl). The ability of four accessions of B. maritima to achieve osmotic adjustment by regulating their ions and water intake as well as producing suitable osmolytes, including total soluble proteins and carbohydrates, proline, and glycine betaine (GB), was linked to their salinity tolerance to avoid toxicity caused by excessive ion buildup, unlike B. vulgaris. The overexpression of betaine aldehyde dehydrogenase (BADH) and choline monooxygenase (CMO) for the production of GB in B. maritima under salt stress and the downregulation of the same genes in B. vulgaris accession further supported these findings. Changes in total phenols and flavonoid content were also observed in B. maritima accessions compared to B. vulgaris accessions, which varied significantly.

It was found that, among all the B. maritima and B. vulgaris accessions, B. vulgaris 1 was the most susceptible to salt stress, while B. maritima 1 was the most tolerant to salinity stress.