Arabidopsis heat shock transcription factor HSFA7b positively mediates salt stress tolerance by binding to an E-box-like motif to regulate gene expression

Abstract

Plant heat shock transcription factors (HSFs) are involved in heat and other abiotic stress responses. However, their functions in salt tolerance are little known. In this study, we characterized the function of a HSF from Arabidopsis, AtHSFA7b, in salt tolerance. AtHSFA7b is a nuclear protein with transactivation activity. ChIP-seq combined with an RNA-seq assay indicated that AtHSFA7b preferentially binds to a novel cis-acting element, termed the E-box-like motif, to regulate gene expression; it also binds to the heat shock element motif. Under salt conditions, AtHSFA7b regulates its target genes to mediate serial physiological changes, including maintaining cellular ion homeostasis, reducing water loss rate, decreasing reactive oxygen species accumulation, and adjusting osmotic potential, which ultimately leads to improved salt tolerance. Additionally, most cellulose synthase-like (CSL) and cellulose synthase (CESA) family genes were inhibited by AtHSFA7b; some of them were randomly selected for salt tolerance characterization, and they were mainly found to negatively modulate salt tolerance. By contrast, some transcription factors (TFs) were induced by AtHSFA7b; among them, we randomly identified six TFs that positively regulate salt tolerance. Thus, AtHSFA7b serves as a transactivator that positively mediates salinity tolerance mainly through binding to the E-box-like motif to regulate gene expression.

Genome-wide characterization of tea plant (Camellia sinensis) Hsf transcription factor family and role of CsHsfA2 in heat tolerance

“…CsHsfA7 was found to be up-regulated by heat shock stress, which was consistent with our previous findings [45]. Overexpression of OsHsfA7 enhanced salt and drought tolerance in transgenic rice [76], while AtHsfA7b positively regulated salt stress tolerance in A. thaliana [31]. Hence, the specific functions of CsHsfA7 in response to heat stress remain to be elucidated.…”

“…Although O. sativa HsfB2b expression was strongly induced by heat, salt, abscisic acid (ABA) and polyethylene glycol (PEG) treatments but not cold stress, OsHsfB2b overexpression increased the drought and salt sensitivity in rice [28]. However, Hordeum vulgare HsfB2c was proposed to be positively regulating the drought stress tolerance in barley [29], and CmHSFA4 and AtHSFA7b positively regulated salt stress tolerance in chrysanthemum and Arabidopsis, respectively [30,31]. Moreover, OsHsfC1b and T. aestivum HsfC2a overexpression improved salt tolerance and thermotolerance in transgenic O. sativa and wheat, respectively [32,33].…”

Genome-Wide Analysis of the Shi-Related Sequence Family and Functional Identification of GmSRS18 Involving in Drought and Salt Stresses in Soybean

“…In rice, OSBZ8, an ABRE-binding factor, may regulate the salt tolerance in Indica rice [60]. AtHSFA7b positively regulated the salinity tolerance in Arabidopsis through binding to the E-BOX motif [61]. The E-BOX motif acts as an important component in salinity tolerance response.…”

Genome-Wide Analysis of the Heat Shock Transcription Factor Gene Family in Brassica juncea: Structure, Evolution, and Expression Profiles

“…In Arabidopsis, overexpression HsfA1a positively affects tolerance of multiple stresses by inducing the expression of HSP (Qian et al, 2014). For example, AtHSFA7b positively regulates salt tolerance of chrysanthemum and Arabidopsis (Li et al, 2018;Zang et al, 2019). HbHsfA7a was significantly upregulated under low-temperature stress in the other hardy rubber (Li et al, 2019c).…”

“…In Arabidopsis, overexpression of AtHsfA6b improves tolerance to salt and drought stress (Huang et al, 2016). In addition, AtHsfA7b protein can directly bind to E-box motifs and/or HSEs to regulate a series of genes related to salt tolerance (Zang et al, 2019). HSF genes also play an important role in plant growth and development.…”