Transcription factors as tools for genetic engineering of plant drought tolerance

Los estreses abióticos como la sequía, la alta salinidad en el suelo y el frío afectan negativamente el crecimiento de las plantas. La sequía es uno de los problemas más importantes que limita la productividad de los cultivos. Para diseñar estrategias que permitan desarrollar plantas más tolerantes al estrés hídrico es importante comprender los mecanismos a través de los cuales las plantas perciben y transducen las señales de estrés para la generación de respuestas adaptativas. Las vías de transducción de señales, que se inician con la percepción de la señal de estrés, tienen como blanco final una serie de factores de transcripción que controlan la expresión de genes cuyos productos contribuyen a proteger y reparar las células del daño causado por el estrés. El empleo de genes que codifican para estos factores de transcripción constituye un enfoque muy efectivo para producir plantas tolerantes al estrés, ya que un solo gen puede alterar la expresión de un gran número de genes, dando como resultado una respuesta mucho más amplia y eficaz. En la última década se ha elucidado la función de varios factores de transcripción que controlan la respuesta a la sequía, como los DREB/CFB y los AREB/ABF, entre otros. En este artículo se describen estos factores de transcripción y su utilización para desarrollar plantas transgénicas tolerantes a la sequía.Abiotic stresses such as drought, high salinity and cold negatively affect plant growth. Drought is the major factor that limits crop productivity. Understanding the mechanisms by which plants perceive the stress signal and transmit it to the cellular machinery to activate adaptive responses is of great importance to develop strategies for the genetic engineering of drought tolerance. The signal transduction cascades triggered by water-deficit stress lead to the activation of transcription factors that control the expression of stress-responsive genes, whose products contribute to protect and mitigate the stress-induced cellular damage. The use of these transcription factors constitutes a highly effective approach for producing stress-tolerant plants. This is based on the observations that a single regulatory gene induces the expression of a number of different stress-responsive genes, thus leading to a wide-arrayed and efficient response. In the last decade, the function of several transcription factors that control waterdeficit response (such as DREB/CFB and AREB/ABF) has been elucidated. This article focuses in the use of the these transcription factors as tools to engineer drought tolerance in plants.Fil: Muñiz García, María Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Capiati, Daniela Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

The protein phosphatase 2A catalytic subunit StPP2Ac2b enhances susceptibility to Phytophthora infestans and senescence in potato

The serine/threonine protein phosphatases type 2A (PP2A) are involved in several physiological responses in plants, playing important roles in developmental programs, stress responses and hormone signaling. Six PP2A catalytic subunits (StPP2Ac) were identified in cultivated potato. Transgenic potato plants constitutively overexpressing the catalytic subunit StPP2Ac2b (StPP2Ac2b-OE) were developed to determine its physiological roles. The response of StPP2Ac2b-OE plants to the oomycete Phytophthora infestans, the causal agent of late blight, was evaluated. We found that overexpression of StPP2Ac2b enhancessusceptibility to the pathogen. Further bioinformatics, biochemical, and molecular analyses revealed that StPP2Ac2b positively regulates developmental and pathogen-induced senescence, and that P. infestans infection promotes senescence, most likely through induction of StPP2Ac2b expression.Fil: Muñiz García, María Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Grossi, Cecilia Eugenia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Ulloa, Rita Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Capiati, Daniela Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

AREB/ABF Proteins are Master Transcription Factors That Mediate Aba-Dependent Gene Regulation During Water-Stress

As sessile organisms plants have to cope with changing environmental conditions. Drought and salinity, which cause water-deficit in plant cells, are common adverse factors that limit plant growth and productivity. Understanding the mechanisms by which plants perceive environmental signals and transmit them to the cellular machinery to activate adaptive responses is of great importance to biology and to rational engineering of crop plants. Abscisic acid (ABA) plays a pivotal role in stress responses in plants. This chapter reviews the involvement of ABA and AREB/ABF transcription factors in the signal transduction mechanisms that activate stress responses that control the expression of stress-responsive genes.Fil: Muñiz García, María Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Capiati, Daniela Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

Heterologous expression of Arabidopsis ABF4 gene in potato enhances tuberization through ABA-GA crosstalk regulation

Potato (Solanum tuberosum L.) tuberization is regulated by many signals, such as abscisic acid (ABA),sucrose and gibberellic acid (GA). ABA and sucrose are positive modulators, while GA is an inhibitor of the process. ABF (ABRE-binding factor) proteins are transcription factors involved in ABA and stress signaling. Previously, we reported that S. tuberosum StABF1 could mediate the ABA effects on tuberization. The aim of the present study was to evaluate the potential use of ABF genes to enhance tuberization and to determine the molecular mechanism involved. For this purpose, transgenic potato plants expressing the Arabidopsis ABF4 or ABF2 genes were generated, and their tuberization capacity and response to tuberization-related signals were analyzed in vitro. The results indicate that both ABF4 and ABF2 proteins positively regulate potato tuber induction; however, only ABF4 expression significantly increases the number and weight of the tubers obtained, without stunting growth. ABF4 and ABF2 transgenic plants exhibit ABA hypersensitivity during tuberization, accompanied by a GA-deficient phenotype. ABF4 expression triggers a significant rise in ABA levels in stolons under tuber-inducing conditions as compared with wild-type plants and a transcriptional deregulation of GA metabolism genes. Our results demonstrate that Arabidopsis ABF4 functions in potato ABA-GA signaling crosstalk during tuberization by regulating the expression of ABA and GA-metabolism genes. ABF4 gene might be a potential tool to increase tuber production, since its heterologous expression in potato enhances tuber induction without affecting plant growth.Fil: Muñiz García, María Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; ArgentinaFil: Stritzler, Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; ArgentinaFil: Capiati, Daniela Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Argentin

The protein phosphatase 2A catalytic subunit StPP2Ac2b is involved in the control of potato tuber sprouting and source-sink balance in tubers and sprouts

Sprouting negatively affects the quality of stored potato tubers. Understanding the molecular mechanisms that control this process is important for the development of potato varieties with desired sprouting characteristics. Serine/threonine protein phosphatase type 2A (PP2A) has been implicated in several developmental programs and stress responses in plants. PP2A comprises a catalytic (PP2Ac), a scaffolding (A), and a regulatory (B) subunit. In cultivated potato, six PP2Ac isoforms were identified, named StPP2Ac1, 2a, 2b, 3, 4, and 5. In this study we evaluated the sprouting behavior of potato tubers overexpressing the catalytic subunit 2b (StPP2Ac2b-OE). The onset of sprouting and initial sprout elongation is significantly delayed in StPP2Ac2b-OE tubers; however, sprout growth is accelerated during the late stages of development, due to a high degree of branching. StPP2Ac2b-OE tubers also exhibit a pronounced loss of apical dominance. These developmental characteristics are accompanied by changes in carbohydrate metabolism and response to gibberellic acid, and a differential balance between abscisic acid, gibberellic acid, cytokinins, and auxin. Overexpression of StPP2Ac2b alters the source-sink balance, increasing the source capacity of the tuber, and the sink strength of the sprout to support its accelerated growth.Fil: Muñiz García, María Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Cortelezzi, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Capiati, Daniela Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin

Water-deficit stress signal transduction pathways in plants: From sensing to response

As sessile organisms plants have to cope with changing environmental conditions. Drought and salinity, which causes water-deficit in plant cells, are common adverse factors that limit plant growth and productivity. Understanding the mechanisms by which plants perceive environmental signals and transmit them to cellular machinery to activate adaptive responses is of great importance to biology and to rational engineering of crop plants. This chapter reviews the signal transduction mechanisms that activate water-deficit stress responses and the regulation of transcription factors that control the expression of stress-responsive genes. The general components of stress signal transduction pathway for drought and salt stress are considered. Signal perception, receptor-coupled phosphorelay, phosphoinositol-induced Ca2+ changes, Ca2+-coupled phosphoprotein cascades,  mitogen-activated protein kinase cascade and transcriptional activation of stress responsive genes are the main signal transduction steps addressed. Abscisic acid (ABA) plays a pivotal role in stress responses in plants. Therefore, the hormone implications are also reviewed. The transcription factors responsible for reprogramming gene expression in response to stress are described. Finally, the physiological and biochemical responses that lead to plant tolerance to water-deficit stress are addressed.Fil: Capiati, Daniela Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Muñiz García, María Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Ulloa, Rita Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentin