Project description:Male reproductive tissues are more sensitive to heat stress compared to vegetative tissues, however the basis of this phenomenon is poorly understood. Heat stress transcription factors (Hsfs) regulate the transcriptional changes required for protection and recovery from heat stress. HsfA2 has been characterized as co-activator of HsfA1a in tomato and is considered as one of the major Hsfs accumulating in response to elevated temperatures. The role of HsfA2 in heat stress response of different tissues was examined by exploring the composition and structure of the tissue-specific regulatory networks in transgenic tomato plants with suppressed HsfA2 expression (A2AS). Transcriptome analysis revealed that HsfA2 acts in condition- and tissue-specific manner and that only a subset of heat stress induced genes require HsfA2 for higher expression. Remarkably, although HsfA2 is not essential for thermotolerance in seedlings and flowering plants, it is required for maintenance pollen viability under stress conditions. We show that the activation of Hsf networks is important for the developmentally regulated priming of heat stress response occurring at early stages of anther and pollen development. Thereby, HsfA2 is involved in pollen thermotolerance by directly regulating heat stress responsive genes but also by stimulating the synthesis of molecular chaperones under non-stress conditions. 8 samples
Project description:Male reproductive tissues are more sensitive to heat stress compared to vegetative tissues, however the basis of this phenomenon is poorly understood. Heat stress transcription factors (Hsfs) regulate the transcriptional changes required for protection and recovery from heat stress. HsfA2 has been characterized as co-activator of HsfA1a in tomato and is considered as one of the major Hsfs accumulating in response to elevated temperatures. The role of HsfA2 in heat stress response of different tissues was examined by exploring the composition and structure of the tissue-specific regulatory networks in transgenic tomato plants with suppressed HsfA2 expression (A2AS). Transcriptome analysis revealed that HsfA2 acts in condition- and tissue-specific manner and that only a subset of heat stress induced genes require HsfA2 for higher expression. Remarkably, although HsfA2 is not essential for thermotolerance in seedlings and flowering plants, it is required for maintenance pollen viability under stress conditions. We show that the activation of Hsf networks is important for the developmentally regulated priming of heat stress response occurring at early stages of anther and pollen development. Thereby, HsfA2 is involved in pollen thermotolerance by directly regulating heat stress responsive genes but also by stimulating the synthesis of molecular chaperones under non-stress conditions.
Project description:Heat shock proteins (Hsps) are molecular chaperones primarily involved in maintenance of protein homeostasis. Their function has been best characterized in heat stress (HS) response during which Hsps are transcriptionally controlled by heat stress transcription factors (Hsfs). The role of Hsfs and Hsps in HS-response in tomato was initially examined by transcriptome analysis using the Massive Analysis of cDNA Ends (MACE) method. Approximately 9.6% of all genes expressed in leaves are enhanced in response to HS, including a subset of Hsfs and Hsps. The underlying Hsp-Hsf networks with potential functions in stress responses or developmental processes were further explored by meta-analysis of existing microarray datasets. We identified clusters with differential transcript profiles with respect to abiotic stresses, plant organs and developmental stages. The composition of two clusters points toward two major chaperone networks. One cluster consisted of constitutively expressed plastidial chaperones and other genes involved in chloroplast protein homeostasis. The second cluster represents genes strongly induced by heat, drought and salinity stress, including HsfA2 and many stress-inducible chaperones, but also potential targets of HsfA2 not related to protein homeostasis. This observation attributes a central regulatory role to HsfA2 in controlling different aspects of abiotic stress response and tolerance in tomato.
Project description:Heat shock proteins (Hsps) are molecular chaperones primarily involved in maintenance of protein homeostasis. Their function has been best characterized in heat stress (HS) response during which Hsps are transcriptionally controlled by heat stress transcription factors (Hsfs). The role of Hsfs and Hsps in HS-response in tomato was initially examined by transcriptome analysis using the Massive Analysis of cDNA Ends (MACE) method. Approximately 9.6% of all genes expressed in leaves are enhanced in response to HS, including a subset of Hsfs and Hsps. The underlying Hsp-Hsf networks with potential functions in stress responses or developmental processes were further explored by meta-analysis of existing microarray datasets. We identified clusters with differential transcript profiles with respect to abiotic stresses, plant organs and developmental stages. The composition of two clusters points toward two major chaperone networks. One cluster consisted of constitutively expressed plastidial chaperones and other genes involved in chloroplast protein homeostasis. The second cluster represents genes strongly induced by heat, drought and salinity stress, including HsfA2 and many stress-inducible chaperones, but also potential targets of HsfA2 not related to protein homeostasis. This observation attributes a central regulatory role to HsfA2 in controlling different aspects of abiotic stress response and tolerance in tomato. 2 samples
Project description:To investigate the role of Serine/Arginine-rich proteins RS2Z35 and RS2Z36 in tomato heat stress response and thermotolerance, we established single and double knockouts of the respective splicing factor(s) in tomato We then performed gene expression and splicing analysis using data obtained from RNA-seq of wildtype, single knockout and double knockout plants under control and heat stress conditions (1 h 40°C)