Coping with Drought and Salinity Stresses: Role of Transcription Factors in Crop Improvement

Abstract

Knowledge about the role of transcription factors in the eukaryotic domain, mainly in yeast, Drosophila, human, and later in plants, has significantly advanced since the first discovery of these regulatory proteins in prokaryotes 50 years ago. Transcription factors are involved in a variety of biological processes, including responses to environmental changes. In this chapter, we focus on plant transcription factors involved in the responses to abiotic stresses, mainly drought and salinity. We analyze the modular structure that characterizes common and kingdom-specific groups or families and the main environmental stimuli that modulate the responses through different signaling pathways. Thereafter, we review examples of the roles played by transcription factors in classical breeding approaches for crop improvement. Finally, we revise the discovery, characterization, and use of transcription factors as biotechnological tools. With regard to the last point, we discuss the experimental methods and parameters adopted to evaluate tolerant phenotypes, and the apparent dilemma between crop yield and stress tolerance.24.

Arabidopsis thaliana HomeoBox 1 (AtHB1), a Homedomain‐Leucine Zipper I (HD‐Zip I) transcription factor, is regulated by PHYTOCHROME‐INTERACTING FACTOR 1 to promote hypocotyl elongation

“…The HD‐Zip family is composed of four subfamilies named I–IV (Ariel et al ., ; Ribichich et al ., ). In A. thaliana , subfamily I has 17 members encoding proteins of c .…”

“…The HD-Zip family is composed of four subfamilies named I-IV (Ariel et al, 2007;Ribichich et al, 2014). In A. thaliana, subfamily I has 17 members encoding proteins of c. 35 kDa, which are mainly involved in developmental processes associated with abiotic stress (Ariel et al, 2007;Ribichich et al, 2014).…”

“…The HD-Zip family is composed of four subfamilies named I-IV (Ariel et al, 2007;Ribichich et al, 2014). In A. thaliana, subfamily I has 17 members encoding proteins of c. 35 kDa, which are mainly involved in developmental processes associated with abiotic stress (Ariel et al, 2007;Ribichich et al, 2014). In a recent phylogenetic reconstruction using 178 HD-Zip I proteins from different species that considered not only the HD-Zip motif but also the carboxy-terminal regions (CTRs), A. thaliana HD-Zip I proteins were classified into six groups, named I-VI (Arce et al, 2011).…”

Arabidopsis AtHB7 and AtHB12evolved divergently to fine tune processes associated with growth and responses to water stress

“…Some TFs are regulated by one or more abiotic stress factors such as cold, heat, drought and salinity, which suggests pathway cross-talk [3,4]. …”

“…However, only a small number of these TFs has been functionally studied so far [4]. TF families are classified according to their binding domain and divided in subfamilies according to additional structural and functional characteristics [5,8].…”