Tissue-level transcriptomic responses to local and distal chilling reveal potential chilling survival mechanisms in maize

Abstract

Abstract Chilling is a major stress to plants of subtropical and tropical origins, including maize (Zea mays L.). To reveal the molecular mechanisms underlying chilling tolerance and survival in maize, we investigated transcriptomic responses to chilling stress in differentiated leaves and roots as well as in crowns with meristem activity. The application of chilling stress to shoots or roots each contributed to seedling lethality in maize. Comparison of maize lines with different chilling tolerance capacities revealed that chilling survival is highly associated with the up-regulation of abscisic acid biosynthesis and responses as well as transcriptional regulators in leaves and crowns. It was also associated with the down-regulation of translation in leaves and the heat response in crowns. Chilling treatment of all or part of the plants revealed that the response to distal chilling is very distinct from, and sometimes opposite to, the response to local or whole-plant chilling in both leaves and roots, suggesting communication between shoots and roots in the environmental response. This study thus provides information on transcriptomic responses in leaves, roots, and crowns under different chilling stresses in maize, and reveals potential chilling tolerance and survival mechanisms, which lay the ground for improving chilling tolerance in crop plants.