Multilevel response to heat and cold stress in cauliflower (Brassica oleracea var. botrytis)

Abstract Abiotic stress, including heat and cold stress, are among the most detrimental to crop production. Despite previous studies, our understanding of how physiological and molecular responses enable crop plants to adapt to temperature stress remains unsatisfactory and requires further exploration. Under cold and heat stress, as well as during recovery after direct stress treatments, we observed increased electrolyte leakage in cauliflower leaves. Furthermore, after exposure to heat, a decrease in chlorophyll levels and photosynthetic conversion capacity was observed, indicating chloroplast senescence induction progressed throughout. This decrease was also observed after the recovery phase, suggesting irreversible changes in chloroplast function. Interestingly, chloroplasts under cold stress do not exhibit functional and most likely, structural changes. At the molecular level, heat stress, particularly heat recovery, had a negative impact on the cauliflower transcriptome by decreasing the abundance of numerous transcripts in cauliflower leaves. Cold and heat stress also affected a variety of transcription factors (e.g., MYB and WRKY family members). In the future, our results may contribute to the development of cauliflower varieties with improved tolerance to both high and low temperatures. That may be crucial for the global crop industry and food safety.