The role of transcriptional coactivator ADA2b in Arabidopsis abiotic stress responses

Abstract

Plant growth and crop production can be greatly affected by common environmental stresses such as drought, high salinity and low temperatures. Gene expression is affected by several abiotic stresses. Stress-inducible genes are regulated by transcription factors and epigenetic mechanisms such as histone modifications. In this Mini-Review, we have explored the role of transcriptional adaptor ADA2b in Arabidopsis responses to abiotic stress. ADA2b is required for the expression of genes involved in abiotic stress either by controlling H3 and H4 acetylation in the case of salt stress or affecting nucleosome occupancy in low temperatures response.

Figure 1

ADA2b is a key regulator of abiotic stress. (A) ada2b-1 mutants are drought tolerant; photo was taken 20 d after water starvation. (B) Whole plant transpiration of wild type (white square) and ada2b-1 (black square) mutant plants. Changes in soil water content during drought stress is indicated. (C) The effect of ADA2a, ADA2b and GCN5 on salt-induced RD29b expression. Wild-type Ws, ada2a-1, ada2a-2 and gcn5-1 plants were subjected to salt stress (100 mM NaCl) for various time as indicated. RNA were isolated from whole seedling and real-time Reverse Transcription PCR was performed using specific primers for RD29b. Fold induction of these genes after exposure to 100 mM NaCl were calculated by normalizing values from salt-treated plants with those from untreated samples. Values are presented on a logarithmic scale. For each mutant and wild-type plants, triplicate samples in each experiment were assayed twice. Three independent experiments were performed, error bars represent SE where n = 4. (D) Schematic representation of ADA2b function. ADA2b promotes histone acetyaltion in salt-induced genes and confers salt tolerance whereas it represses freezing and drought tolerant in Arabidopsis.