Comparative physiological and transcriptomic analyses reveal different stress adaptation strategies controlling...

Tartary buckwheat is the most important traditional minor crop in the high and cold mountain area of southwest China. Its growth and development were seriously inhibited by chilling stress. However, the molecular and physiological adaptive mechanisms of chilling stress tolerance in Tartary buckwheat are still not well understood.

This study performed physiological and transcriptome analyses on the seedlings of two low-temperature resistance (LT-R) and three LT sensitive (LT-S) Tartary buckwheat cultivars under normal (22℃) and low (4℃) temperature conditions. The results revealed that LT-R cultivars exhibited smaller changes in oxidative damage and photosynthetic pigment levels (chlorophyll a and chlorophyll b contents) compared to LT-S cultivars. They also exhibited significant increases in antioxidant enzyme activity. A total of 2932, 4114, 3975, 2499, and 5905 differentially expressed genes (DEGs) were identified in the five materials after chilling stress, respectively. DEGs were enriched in photosynthesis, glutathione (GSH) metabolism, cell wall synthesis, flavonoid biosynthesis, carbon metabolism, peroxisome, and membrane stability-related pathways. Several AP2/ERF, bHLH, bZIP, DOF, GATA, HSF, MYB, NAC, and WRKY transcription factors also responded to chilling stress in both LT-R and LT-S cultivars.

The results increase our understanding of the chilling stress tolerance in Tartary buckwheat seedlings and identify multiple key regulatory factors in the stress response, and also indicate that chilling stress affects photosynthesis and GSH metabolism of and that changes in these pathways might contribute to mechanisms of chilling stress tolerance in Tartary buckwheat.