Meta-analysis of the effect of overexpression of CBF/DREB family genes on drought stress response

Abstract

Transcription factors C-repeat/dehydration-responsive element binding proteins (CBF/DREB) play an important role in plant response to abiotic stresses. Over-expression of various CBF/DREB genes in diverse plants have been reported, but inconsistency of gene donor, recipient genus, parameters used in evaluating the transgenic plants have made it difficult to elucidate the complex physiological mechanisms by which DREBs impact drought tolerance. We performed a meta-analysis to categorize the response of plant parameters involved in drought tolerance in DREB-overexpressed plants and to evaluate experimental variables that affects transgenic plant performance. The results from across different studies indicated that 8 and 2 of 13 measured parameters exhibited a significant response by increasing or decreasing values by 25% or more in drought-stressed and in non-stressed, control plants, respectively. Among the examined moderating variables, promoters, type of media and stress, donor genus, and recipient genus significantly affected the extent of DREBs' influence. In plants subjected to drought stress, the overexpression of DREB genes derived from Arabidopsis led to greater increases in Fv/Fm (maximum quantum efficiency of photosystem II), relative water content, and proline content. These findings should guide future research on the function of the DREB genes in plant drought tolerance and the use of genetic engineering in drought tolerance breeding.