RESUMEN
BACKGROUND: Common bean (Phaseolus vulgaris) is an essential crop with high economic value. The growth of this plant is sensitive to environmental stress. Heat shock factor (Hsf) is a family of antiretroviral transcription factors that regulate plant defense system against biotic and abiotic stress. To date, few studies have identified and bio-analyzed Hsfs in common bean. RESULTS: In this study, 30 Hsf transcription factors (PvHsf1-30) were identified from the PFAM database. The PvHsf1-30 belonged to 14 subfamilies with similar motifs, gene structure and cis-acting elements. The Hsf members in Arabidopsis, rice (Oryza sativa), maize (Zea mays) and common bean were classified into 14 subfamilies. Collinearity analysis showed that PvHsfs played a role in the regulation of responses to abiotic stress. The expression of PvHsfs varied across different tissues. Moreover, quantitative real-time PCR (qRT-PCR) revealed that most PvHsfs were differentially expressed under cold, heat, salt and heavy metal stress, indicating that PvHsfs might play different functions depending on the type of abiotic stress. CONCLUSIONS: In this study, we identified 30 Hsf transcription factors and determined their location, motifs, gene structure, cis-elements, collinearity and expression patterns. It was found that PvHsfs regulates responses to abiotic stress in common bean. Thus, this study provides a basis for further analysis of the function of PvHsfs in the regulation of abiotic stress in common bean.
Asunto(s)
Genoma de Planta/genética , Factores de Transcripción del Choque Térmico/genética , Phaseolus/genética , Biología Computacional , Evolución Molecular , Regulación de la Expresión Génica de las Plantas , Factores de Transcripción del Choque Térmico/metabolismo , Respuesta al Choque Térmico , Motivos de Nucleótidos , Especificidad de Órganos , Phaseolus/fisiología , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Secuencias Reguladoras de Ácidos Nucleicos/genética , Plantones/genética , Plantones/fisiología , Estrés FisiológicoRESUMEN
One of the most important questions in cell biology is how cell fate is determined when exposed to extreme stresses such as heat shock. It has been long understood that organisms exposed to high temperature stresses typically protect themselves with a heat shock response (HSR), where accumulation of denatured or unfolded proteins triggers the synthesis of heat shock proteins (HSPs) through the heat shock transcription factor, e.g., heat shock factor 1 (HSF1). In this study, a dynamical model validated with experiments is presented to analyse the role of HSF1 SUMOylation in response to heat shock. Key features of this model are inclusion of heat shock response and SUMOylation of HSF1, and HSP synthesis at molecular level, describing the dynamical evolution of the key variables involved in the regulation of HSPs. The model has been employed to predict the SUMOylation levels of HSF1 with different external temperature stimuli. The results show that the SUMOylated HSF1 levels agree closely with the experimental findings. This demonstrates the validity of this nonlinear dynamic model for the important role of SUMOylation in response to heat shock.
Asunto(s)
Proteínas de Unión al ADN , Sumoilación , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción del Choque Térmico/genética , Proteínas de Choque Térmico/genética , Respuesta al Choque TérmicoRESUMEN
The role of Heat Shock Transcription Factor 6 (HSFA6a & HSFA6b) in response to abiotic stresses such as ABA, drought, salinity, drought, and osmotic stress is individually well established. Unfortunately, the functional redundancy between the HSFA6a and HSFA6b as well as the consequences of simultaneous editing of both in response to aforementioned stresses remains elusive. Therefore, this study was designed with the aim of addressing whether there is any functional redundancy between HSFA6a and HSFA6b as well as to decipher their role in abiotic stresses tolerance in Arabidopsis thaliana, by using the CRISPR-Cas9. We have generated the single (hsfa6a and hsfa6b) as well as double mutants (hsfa6a/hsfa6b-1 and hsfa6a/hsfa6b-2) of HSFA6a and HSFA6b with higher frequencies of deletion, insertion, and substitution. The phenotypic characterization of generated double and single mutants under abiotic stresses such as ABA, mannitol, and NaCl identified double mutants more tolerant to subjected abiotic stresses than those of their single mutants. It warrants mentioning that we have identified that HSFA6a and HSFA6b also involved in other major ABA responses, including ABA-inhibited seed germination, stomatal movement, and water loss. In addition to the above, the simultaneous editing of HSFA6a and HSFA6b lead to a reduced ROS accumulation, accompanied by increased expression of much abiotic stress and ABA-responsive genes, including involved in regulation of ROS level. In conclusion, these results suggest that HSFA6a and HSFA6b may offer abiotic stress tolerance by regulating the ROS homeostasis in plants.
Asunto(s)
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/fisiología , Sistemas CRISPR-Cas/genética , Factores de Transcripción del Choque Térmico/genética , Proteínas de Choque Térmico/genética , Homeostasis , Presión Osmótica , Especies Reactivas de Oxígeno/metabolismo , Factores de Transcripción/genética , Proteínas de Arabidopsis/metabolismo , Secuencia de Bases , Regulación de la Expresión Génica de las Plantas , Vectores Genéticos/metabolismo , Germinación , Factores de Transcripción del Choque Térmico/metabolismo , Proteínas de Choque Térmico/metabolismo , Mutación/genética , Fenotipo , Estomas de Plantas/fisiología , Plantas Modificadas Genéticamente , Reproducibilidad de los Resultados , Semillas/crecimiento & desarrollo , Estrés Fisiológico/genética , Factores de Transcripción/metabolismo , Transcripción GenéticaRESUMEN
Sedum alfredii Hance, a cadmium (Cd)/zinc (Zn)/lead (Pb) co-hyperaccumulating species, is a promising phytoremediation candidate because it accumulates substantial amounts of heavy metal ions without showing any obvious signs of poisoning. The heat shock transcription factor (Hsf) family plays crucial roles in plant growth, development, and stress responses. Although the roles of some Hsfs in abiotic stress have been well studied in model plants, the Hsf family has not been systematically investigated in heavy metal hyperaccumulators. Here, we comprehensively analyzed the Hsf gene family in S. alfredii based on a transcriptome under Cd stress. There were 22 Hsf members that were identified and phylogenetically clustered into three classes, namely, SaHsfA, SaHsfB, and SaHsfC. All of the three classes shared similar motifs. The expression profiles of the 22 Hsf members showed significant differences: 18 SaHsfs were responsive to Cd stress, as were multiple SaHsp genes, including SaHsp18.1, SaHsp22, SaHsp26.5, SaHsp70, SaHsp90, and SaHsp101. Two class A4 members, SaHsfA4a and SaHsfA4c, exhibited transcriptional activation activities. Overexpression of SaHsfA4a and SaHsfA4c in transgenic yeast indicated an improved tolerance to Cd stress and Cd accumulation. Our results suggest SaHsfs play important regulatory roles in heavy metal stress responses, and provide a reference for further studies on the mechanism of heavy metal stress regulation by SaHsfs.
Asunto(s)
Cadmio/metabolismo , Regulación de la Expresión Génica de las Plantas , Factores de Transcripción del Choque Térmico/genética , Proteínas de Plantas/genética , Sedum/genética , Sedum/fisiología , Contaminantes del Suelo/metabolismo , Secuencia de Aminoácidos , Biodegradación Ambiental , Factores de Transcripción del Choque Térmico/química , Factores de Transcripción del Choque Térmico/metabolismo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Sedum/química , Alineación de Secuencia , Estrés Fisiológico , TranscriptomaRESUMEN
As the terminal components of signal transduction, heat stress transcription factors (Hsfs) mediate the activation of multiple genes responsive to various stresses. However, the information and functional analysis are very limited in non-model plants, especially in cassava (Manihot esculenta), one of the most important crops in tropical areas. In this study, 32 MeHsfs were identified from the cassava genome; the evolutionary tree, gene structures and motifs were also analysed. Gene expression analysis found that MeHsfs were commonly regulated by Xanthomonas axonopodis pv. manihotis (Xam). Amongst these MeHsfs, MeHsf3 was specifically located in the cell nucleus and showed transcriptionally activated activity on heat stress elements (HSEs). Through transient expression in Nicotiana benthamiana leaves and virus-induced gene silencing (VIGS) in cassava, we identified the essential role of MeHsf3 in plant disease resistance, by regulating the transcripts of Enhanced Disease Susceptibility 1 (EDS1) and pathogen-related gene 4 (PR4). Notably, as regulators of defence susceptibility, MeEDS1 and MePR4 were identified as direct targets of MeHsf3. Moreover, the disease sensitivity of MeHsf3- and MeEDS1-silenced plants could be restored by exogenous salicylic acid (SA) treatment. Taken together, this study highlights the involvement of MeHsf3 in defence resistance through the transcriptional activation of MeEDS1 and MePR4.
Asunto(s)
Manihot/metabolismo , Manihot/microbiología , Enfermedades de las Plantas/microbiología , Ácido Salicílico/metabolismo , Factores de Transcripción del Choque Térmico/metabolismo , Proteínas de Plantas/metabolismo , Transducción de Señal/fisiología , Xanthomonas/patogenicidadRESUMEN
Desiccation tolerance (DT) is the crucial ability of seeds to resist desiccation. However, the regulatory mechanisms of seed DT are not fully understood. In this study, two heat shock cis-elements (HSEs) were identified in the Brassica napus galactinol synthase (BnGolS1) promoter and shown to bind the heat shock transcription factor A4a (BnHSFA4a). Transcriptional expression of BnHSFA4a was induced at the early stage of DT acquisition, prior to increased BnGolS1 activity and galactinol production. Ectopic overexpression of BnHSFA4a (oxBnHSFA4a) in Arabidopsis enhanced DT, particularly during DT re-establishment. OxBnHSFA4a up-regulated the expression of GolS1, GolS2, and raffinose synthase 2 (BnRS2) in Arabidopsis and increased the enzymatic activity of GolS and RS and the concentration of raffinose family oligosaccharides (RFOs). Additionally, the overexpression lines exhibited increased antioxidant abilities. In contrast, the Arabidopsis mutant athsfa4a was more sensitive to dehydration, showing decreases in the efficiency of DT re-establishment, RFO contents, and oxidation resistance. Complementation analysis indicated that DT was rescued in athsfa4a/BnHSFA4a seeds to similar levels compared with those of Col-0. Taken together, these results indicated that BnHSFA4a probably functions in the regulation of GolS expression and activity, and activation of the antioxidative system and other stress response factors to improve DT.
Asunto(s)
Brassica napus/fisiología , Desecación , Galactosiltransferasas/genética , Regulación de la Expresión Génica de las Plantas , Factores de Transcripción del Choque Térmico/genética , Proteínas de Plantas/genética , Secuencia de Aminoácidos , Brassica napus/enzimología , Brassica napus/genética , Brassica napus/crecimiento & desarrollo , Galactosiltransferasas/química , Galactosiltransferasas/metabolismo , Factores de Transcripción del Choque Térmico/química , Factores de Transcripción del Choque Térmico/metabolismo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Alineación de SecuenciaRESUMEN
Heat shock transcription factor (HSF) regulates the expression of genes encoding molecular chaperones and stress-responsive proteins. Conversion of HSF from a monomer to a homotrimer or heterotrimer is essential for its binding to heat shock elements (HSEs) comprised of inverted repeats of the pentamer nGAAn. Here, we constructed various human HSF1 derivatives and analyzed their transcriptional activity through the continuously and discontinuously arranged nGAAn units. We identified a short stretch of amino acids that inhibits the activation ability of HSF1, especially through discontinuous HSEs. This stretch is conserved in HSFs of various organisms, interacts with the hydrophobic repeat regions that mediate HSF oligomerization, and impedes homotrimer formation and DNA binding. This conserved domain plays an important role in maintaining HSF in an inactive monomeric form.