Comprehensive comparative analysis and expression profiles and effects on physiological response of DEAD-box RNA helicase genes in <i>Lumnitzera littorea</i> (Jack) Voigt under cold stress

The DEAD-box family has been shown to play an important role in a variety of abiotic stresses, but little is known in studies of mangrove plants. Here, the effects of cold stress on various physiological changes and the role of the DEAD-box RNA helicase family in response to cold stress were determined. First, we identified 73 DEAD-box RNA helicase family members <i>in L. littorea</i>. Second, the evolutionary relationships between the DEAD family in <i>L. littorea</i> and the model species <i>Arabidopsis thaliana</i> were investigated by evolutionary phylogenetic analysis. Finally, qRT-PCR study of representative DEAD-box genes showed that DEAD-box genes played a major role in the low-temperature stress response of <i>L. littorea</i>. Furthermore, we found that LlDEAD48, LlDEAD36, and LlDEAD47 might be involved in the maintenance of chlorophyll function, and LlDEAD43 might play a role in the maintenance of mitochondrial function in <i>L. littorea</i> under cold stress.