ABSTRACT: Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH), the progeny of heat-primed plants (PH) presented higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were those of signal transduction, transcription, energy, defense, and protein destination and storage, respectively.
Project description:Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH), the progeny of heat-primed plants (PH) presented higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were those of signal transduction, transcription, energy, defense, and protein destination and storage, respectively. Pot experiments (25 cm in diameter and 22 cm in depth) were conducted at the Experimental Station of Nanjing Agricultural University, Nanjing, China (32Ë30ʹN and 118Ë42ʹE). During the first generation, wheat plants were divided into two groups: one group were not primed (N) while the other were heat-primed (P) at pre-anthesis (at a day/night temperature of 32/28ËC for two days at the seven-leaf stage and the nine-leaf stage) and post-anthesis (34/30ËC for seven days at the 10th day after anthesis). At maturity, seeds from both groups were harvested. Seedlings (the progeny generation) from each group seed were further divided two sub-groups: one was subjected to high temperature stress at a day/night temperature of 34/30ËC, while the other was set at 26/22ËC for six days from the 10th day after anthesis (DAA). During both priming and high-temperature stress, plants under different treatments were moved into sepatarate growth chambers at preset temperatures. Thereafter, four treatments were established: NC, progeny of non-primed plants without post-anthesis high temperature stress; NH, progeny of non-primed plants with post-anthesis high temperature stress; PC, progeny of primed plants without post-anthesis high temperature stress; and PH, progeny of primed plants with post-anthesis high temperature stress.
Project description:Ambient temperature is one of the most important environment factors that direct all organisms for morphogenesis, metabolisms and growth. Plants have evolved efficient mechanisms adapting temperature fluctuation such as heat stress response (HSR). Although transcriptional regulatory network of plant HSR has been established, little is known on the genome-wide transcriptional changes within first several minutes upon heat shock (HS). To precisely measure the very first wave of transcriptional response to HS, we investigated the nascent RNA and mature mRNA from plant leaf tissue exposure to 5-min HS treatment using global run-on sequencing (GRO-seq) and RNA sequencing (RNA-seq) methods. We found that only a small group of genes were both up- or down-regulated at nascent RNA and mRNA levels. Primed plants that already exposed to a mild heat stress induced a more drastic transcriptomic alteration than naïve plants which had not experienced a heat stress. Group A1 HEAT SHOCK TRANSCRIPTION FACTORs (HsfA1s) are the major transcription factors in charge of the very early transcriptional HSR. Within 5-minute HS, we also observed that: 1) Engaged RNA polymerase II (Pol II) was accumulated downstream of transcription start sites; 2) 5' pause-release is a rate limiting step for induction of some heat shock protein genes; 3) A good number of genes switched transcription modes; 4) Pervasive read-through was induced at terminators. Plants' HSR is transcriptionally very quick. GRO-seq is sensitive and robust to detect quick response to HS. Heat stress memory takes place at multiple steps of transcription cycles such as Pol II recruitment, 5' pausing, elongation and termination.
Project description:We evaluated the effect of a 2h pre-treatment at 38°C on the response of Arabidopsis thaliana 6d-old seedlings to a 2h heat shock at 43°C applied 24 h later. A shotgun proteomics approach using total protein extracts was used to compare the proteome of seedlings from four type of samples, using 4 replicates: C=Control (just before heat shock on day 7) P= Primed (on day 7, 22 h after priming performed on day 6) H= Heat shock (on day 7, 2h after heat shock) PH= Priming + heat shock (on day 7, for primed seedlings, 2h after heat shock).
Project description:Elevated temperature occurring at reproductive stage has great impact on gametophyte development and therefore ultimate fruit or seed set in plants, the underlying molecular mechanisms are less understood. We investigated the effect of elevated temperature stress on reproductive development in Arabidopsis with tissue-specific transcriptome profiling and observed distinct response patterns between vegetative and reproductive tissues. Heat stress exposure affected reproductive developmental programs including early phases of anther/ovule development and meiosis process, and genes participating in the unfolded protein response (UPR) were enriched among the heat up-regulated reproductive tissue-specific genes. We found that the bzip28bzip60 double mutant defective in UPR were sensitive to elevated temperature stress in terms of reduced silique length and fertility comparing to the wild-type plants. Comparison of heat responsiveness between the wild-type and bzip28zip60 plants identified 521 genes that were regulated by bZIP28 and bZIP60 upon heat stress at reproductive stage, most of which were non-canonical UPR genes. Further ChIP-Seq data revealed 133 direct targets of bZIP28 in Arabidopsis seedlings subjected to heat stress, of which 39 target genes were up-regulated by heat stress at reproductive stage. Our results provide novel insights into heat responsiveness in reproductive tissues and demonstrate the protective roles of UPR for maintaining fertility upon heat stress in plants.
Project description:Elevated temperature occurring at reproductive stage has great impact on gametophyte development and therefore ultimate fruit or seed set in plants, the underlying molecular mechanisms are less understood. We investigated the effect of elevated temperature stress on reproductive development in Arabidopsis with tissue-specific transcriptome profiling and observed distinct response patterns between vegetative and reproductive tissues. Heat stress exposure affected reproductive developmental programs including early phases of anther/ovule development and meiosis process, and genes participating in the unfolded protein response (UPR) were enriched among the heat up-regulated reproductive tissue-specific genes. We found that the bzip28bzip60 double mutant defective in UPR were sensitive to elevated temperature stress in terms of reduced silique length and fertility comparing to the wild-type plants. Comparison of heat responsiveness between the wild-type and bzip28zip60 plants identified 521 genes that were regulated by bZIP28 and bZIP60 upon heat stress at reproductive stage, most of which were non-canonical UPR genes. Further ChIP-Seq data revealed 133 direct targets of bZIP28 in Arabidopsis seedlings subjected to heat stress, of which 39 target genes were up-regulated by heat stress at reproductive stage. Our results provide novel insights into heat responsiveness in reproductive tissues and demonstrate the protective roles of UPR for maintaining fertility upon heat stress in plants.
Project description:The study was aimed to investigate by differential proteomics heat stress response mechanisms in tomato anthers collected from flowers of Solanum lycopersicum cv Saladette (SAL), already annotated as a thermo-tolerant tomato genotype and flowers from Solanum lycopersicum cv M82, reported as a thermo-sensitive genotype. Proteins constitutively present at higher or lower level in the tolerant genotype and/or proteins whose abundance was modulated by growth under high temperature in both genotypes were identified, thus leading to define processes involved in the heat stress response and responsible for efficient reduction of the adverse effects of HS. Results showed differences in the abundance of ninety-six proteins and their functional classification highlighted that heat stress mainly affected metabolic pathways, such as energy metabolism (glycolysis and sucrose degradation), nitrogen assimilation and amino acid biosynthesis and modulated the expression of proteins involved in the folding and degradation machinery and ROS detoxification systems
Project description:Expression data from B. japonicum stress response; aerobic treatment of B. japoncium culture under different stress conditons; pH stress (8 and 4; 4 h); salt stress (80 mM NaCl; 4 h); heat shock (43 °C; 15 min) and temperature stress (35.2 °C; 48 h); as reference wildtype without treatment (AG media; pH 6.9; without NaCl; 28 °C) was used heat shock data were verified by using rpoH-mutant strains B. japonicum 5009; B. japonicum 5032 and B. japonicum 09-32 as described in Narberhaus et al. 1997
Project description:Whether and how organisms can inherit environmental information from their parents is a major question in evolutionary theory. Plants have evolved to link reproductive development to seasonal environmental cues and seed dormancy is highly contingent on the environmental temperature during seed set, although the mechanism by which seeds acquire seasonal timing information is unclear. Here we show that loss of maternal like heterochromatin protein 1 (LHP1) causes an inability of progeny seeds to sense temperature and that this is linked mechanistically to reduced ABA levels in seeds and hyperaccumulation of free nitrate. Remarkably, single cell transcriptomics reveals that in both maternal fruit and seed tissues, the effect of small changes in temperature closely phenocopies the lhp1 mutant phenotype and ABA biosensor imaging reveal large fluxes of maternal ABA into seeds is modulated by temperature cues. We show that temperature activates ABA production in leaves and that maternal ABA is necessary and sufficient for progeny seeds to acquire seed dormancy. Thus, we reveal that the climate experience of mother plants causes adaptation of progeny behaviour via hormone transport during seed set.
Project description:Whether and how organisms can inherit environmental information from their parents is a major question in evolutionary theory. Plants have evolved to link reproductive development to seasonal environmental cues and seed dormancy is highly contingent on the environmental temperature during seed set, although the mechanism by which seeds acquire seasonal timing information is unclear. Here we show that loss of maternal like heterochromatin protein 1 (LHP1) causes an inability of progeny seeds to sense temperature and that this is linked mechanistically to reduced ABA levels in seeds and hyperaccumulation of free nitrate. Remarkably, single cell transcriptomics reveals that in both maternal fruit and seed tissues, the effect of small changes in temperature closely phenocopies the lhp1 mutant phenotype and ABA biosensor imaging reveal large fluxes of maternal ABA into seeds is modulated by temperature cues. We show that temperature activates ABA production in leaves and that maternal ABA is necessary and sufficient for progeny seeds to acquire seed dormancy. Thus, we reveal that the climate experience of mother plants causes adaptation of progeny behaviour via hormone transport during seed set.
Project description:Previous studies have shown the increased thermo-tolerance of pathogenic bacteria if pre-exposed to temperatures above their optimal levels prior to a particular heat treatment. It was unclear, however, whether there was a direct relationship between the different gene expression and the induced thermo-tolerance. Microarray analysis was performed to identify the differentially expressed genes during heat stress by comparing the transcriptome of L. monocytogenes under optimal temperature (37°C), and thermo-tolerance inducing (48°C for 30 minutes. A majority of the differentially expressed genes were up-regulated at heat shock as compared to those that were down-regulated when the cells were exposed to thermo-tolerance inducing conditions. Though many of the differentially expressed genes could be tentatively classified based on the current functional classification of genes (COG) per the NCBI database, many of the gene loci could not been attributed to a specific function due to the current limited knowledge on the functional genomics of L. monocytogenes.