A long and stressful day: Photoperiod shapes aluminium tolerance in plants

Aluminium (Al), a limiting factor for crop productivity in acidic soils (pH & LE; 5.5), imposes drastic constraints for food safety in developing countries. The major mechanisms that allow plants to cope with Al involve manipulations of organic acids metabolism and DNA-checkpoints. When assumed individually both approaches have been insufficient to overcome Al toxicity. On analysing the centre of origin of most cultivated plants, we hypothesised that day-length seems to be a pivotal agent modulating Al tolerance across distinct plant species. We observed that with increasing distance from the Equator, Al tolerance decreases, suggesting a relationship with the photoperiod. We verified that long-day (LD) species are generally more Al-sensitive than short-day (SD) species, whereas genetic conversion of tomato for SD growth habit boosts Al tolerance. Reduced Al tolerance correlates with DNA-checkpoint activation under LD. Furthermore, DNA-checkpoint-related genes are under positive selection in Arabidopsis accessions from regions with shorter days, suggesting that photoperiod act as a selective barrier for Al tolerance. A diel regulation and genetic diversity affect Al tolerance, suggesting that day -length orchestrates Al tolerance. Altogether, photoperiodic control of Al tolerance might contribute to solving the historical obstacle that imposes barriers for developing countries to reach a sustainable agriculture.

Automated summary

Aluminium is a major limiting factor for crop productivity in acidic soils and has significant implications for food safety in developing countries. The mechanisms that allow plants to cope with aluminium toxicity include manipulations of organic acid metabolism and DNA checkpoints. However, individually these approaches have been insufficient to overcome aluminium toxicity. Our analysis suggests that day-length may be a pivotal factor in modulating aluminium tolerance across different plant species.