Identification of CoDREB Genes for Drought and Cold Tolerance in Camellia oleifera

Abstract

DREB is a plant-specific transcription factor family that plays a pleiotropic regulatory role in response to abiotic stresses such as drought and cold. In this study, we identified 51 DREB genes of Camellia oleifera. These CoDREBs ranged from 88 to 518 amino acids (average/median 259/237 aa). The predicted molecular weights (MW) of the CoDREB proteins ranged from 9.7 kDa to 59.6 kDa, and the isoelectric points (pI) ranged from 4.62 to 10.44. A gene structure analysis showed that 43/51 (84.3%) CoDREBs were intronless, and the number of exons varied from one to three. Then, we focused on the response of CoDREB genes in terms of plant drought and cold acclimation. Under short-/long-term drought stress, CoDREB1.2/4.1/4.4/4.8/4.12/4.15/5.1/5.3/5.5/6.2 have different regulations in response to long-term drought response, and CoDREB1.4/2.5/4.6/4.1/6.3/6.5 specifically in the short term. Additionally, in response to mild/severe drought and followed by recovery, we found that CoDREBs may be involved in a complex drought-responsive regulatory network. Under cold stress, CoDREB5.2 and CoDREB6.5 are significantly up-regulated, and CoDREB may participate in the regulation of the low-temperature response of C. oleifera.