Overexpression of MYB Genes and Increased Abiotic Stress Tolerance: A Meta-Analysis.

Abstract

Background: The MYB family of proteins is a large group of transcription factors found in all eukaryotes studied to date that has expanded significantly in plants where they are involved in a wide diversity of processes from development to abiotic stress responses. The overexpression of various MYB genes has been reported to improve stress tolerance in different plant species. However, due to the variety of plant species studied and the types of gene donors/recipients, along with different experimental conditions, it is difficult to interpret the roles of MYB genes in abiotic stress tolerance from published data.Result: We investigated the plant characteristics involved in cold, drought, and salt stress in MYB-overexpressing plants through the meta-analysis approach, and analyzed the degrees of influence on plant performance by experimental variables. The results show that two of the four measured plant parameters in cold-stressed plants, two of the six in drought-stressed, and four of the 13 in salt-stressed were significantly impacted by MYB overexpression by 22% or more. By contrast, only two of the 13 plant parameters were significantly impacted in non-stressed plants by 18% or more. Conclusions: These data suggest that the treatment medium, donor/recipient species, and donor type significantly influence the effects of MYB overexpression on drought stress tolerance. Under salt stress, the donor/recipient species, donor type, and stress duration all significantly affected the extent of MYB-mediated salt stress tolerance. This study compiles and analyzes the data across studies to help us understand the complex interactions that dictate the efficacy of heterologous MYB expression designed for improved abiotic stress tolerance in plants.