The tale of two Ions Na and Cl: unraveling onion plant responses to varying salt treatments.

Background: Exploring the adaptive responses of onions (Allium cepa L.) to salinity reveals a critical challenge for this salt-sensitive crop. While previous studies have concentrated on the effects of sodium (Na), this research highlights the substantial yet less-explored impact of chloride (Cl) accumulation.

Sodium accumulation has minimal effect on metabolite profile of onion bulbs.

Onions (Allium cepa L.) are considered a salt-sensitive crop. However, to date, little evidence supports this claim and information about the physiological and metabolomic effects of Na accumulation in onion plants is lacking.

Acclimatisation of guard cell metabolism to long-term salinity.

Stomatal movements are enabled by changes in guard cell turgor facilitated via transient accumulation of inorganic and organic ions imported from the apoplast or biosynthesized within guard cells. Under salinity, excess salt ions accumulate within plant tissues resulting in osmotic and ionic stress. To elucidate whether (a) Na and Cl concentrations increase in guard cells in response to long-term NaCl exposure and how (b) guard cell metabolism acclimates to the anticipated stress, we profiled the ions and primary metabolites of leaves, the apoplast and isolated guard cells at darkness and during light, that is, closed and fully opened stomata.

Metabolite profiling of onion landraces and the cold storage effect.

Today, commercial onion breeders focus almost entirely on conventional farming which reduces diversity in the market and leads to loss of desirable traits such as those that impact nutritional and sensory aspects of onions. A way to preserve phenotypic and genetic diversity is to re-evaluate traditional landraces to introduce their benefits to the broader public. Common onion genotypes vary greatly in their storability.