Project description:MicroRNAs (miRNAs) are 19-24 nucleotide (nt) noncoding RNAs that play important roles in abiotic stress responses in plants. High temperatures have been the subject of considerable attention due to their negative effects on plant growth and development. Heat-responsive miRNAs have been identified in some plants. However, there have been no reports on the global identification of miRNAs and their targets in tomato at high temperatures, especially at different elevated temperatures. Here, three small-RNA libraries and three degradome libraries were constructed from the leaves of the heat-tolerant tomato at normal, moderately and acutely elevated temperatures (26/18°C, 33/33°C and 40/40°C, respectively). Following high-throughput sequencing, 662 conserved and 97 novel miRNAs were identified. Of these miRNAs, 96 and 150 miRNAs were responsive to the moderately and acutely elevated temperature, respectively. Following degradome sequencing, 349 sequences were identified as targets of 138 conserved miRNAs, and 13 sequences were identified as targets of eight novel miRNAs. The expression levels of four miRNAs and five target genes obtained by quantitative real-time PCR (qRT-PCR) were largely consistent with the sequencing results. This study enriches the number of heat-responsive miRNAs and lays a foundation for the elucidation of the miRNA-mediated regulatory mechanism in tomatoes at elevated temperatures.
Project description:Elevated temperatures due to global warming seriously threaten crops production. Understanding molecular mechanisms of cellular responses to heat stress will help to improve crop tolerance to high temperature and yield. In this work, we show that deacetylation of non-histone proteins mediated by the rice cytoplasmic histone deacetylase HDA714 is required for plant tolerance to heat stress. HDA714 expression and protein accumulation are induced by heat stress. HDA714 loss-of-function affects specifically plant response to heat (42°C) while its over-expression enhances plant tolerance to the stress. Interestingly, heat stress led to decreases of overall protein lysine acetylation in rice plants, which depends on HDA714 function. HDA714-mediated deacetylation of metabolic enzymes stimulates glycolysis under heat stress. In addition, HDA714 protein is found within heat-induced stress granules (SGs), many identified rice SG proteins show lysine acetylation at normal temperature (25 °C), which is augmented in hda714 mutants. Finally, HDA714 interacts with and deacetylates several SG proteins and HDA714 loss-of-function impairs SG formation. Collectively, these results indicate that HDA714-mediated cellular protein lysine deacetylation responds to heat stress, affects metabolic activities, regulates SGs formation, and confers heat tolerance in rice plants.
Project description:Life is resilient because living systems are able to respond to elevated temperatures with an ancient gene expression program called the heat shock response (HSR). Our global analysis revealed a modular HSR dependent on the severity of the stress in yeast. Interestingly, at all temperatures analyzed, the transcription of hundreds of genes is upregulated among them the molecular chaperones, which protect proteins from aggregation. However, for approximately 90% of the regulated genes, the function under stress remained enigmatic. Surprisingly, the majority of these upregulated genes is translated but only for a small fraction this results in raised proteins levels. In this context, increased translation is required to counter-balance elevated protein turnover at elevated temperatures. This anaplerotic reaction together with the molecular chaperone system allows yeast to buffer proteotoxic stress. When the capacity of this system is exhausted at extreme temperatures, translation is stopped via phase transition and growth stops.
Project description:Regulated cell death (RCD) is crucial for plant development, as well as in decision-making in plant-pathogen interactions. Previous studies revealed components of the molecular network controlling RCD, including different proteases. However, the identity, the proteolytic network as well as molecular components involved in the initiation and execution of distinct plant RCD processes, still remain largely elusive. We analyzed the proteome of Z. mays leaves treated with the effector avrRxo1, the mycotoxin Fumonisin B1 (FB1), or the phytohormone salicylic acid (SA) to dissect plant cellular processes related to cell death and plant immunity. We found highly distinct and time-dependent biological processes being activated on proteome level in response to avrRxo1, FB1 and SA. This study characterizes distinct RCD responses in Z. mays and provides a framework for the mechanistic exploration of components involved in the initiation and execution of cell death.
Project description:Regulated cell death (RCD) is crucial for plant development, as well as in decision-making in plant-pathogen interactions. Previous studies revealed components of the molecular network controlling RCD, including different proteases. However, the identity, the proteolytic network as well as molecular components involved in the initiation and execution of distinct plant RCD processes, still remain largely elusive. We analyzed the N-terminome of Z. mays leaves treated with the Xanthomonas effector avrRxo1, the mycotoxin Fumonisin B1 (FB1), or the phytohormone salicylic acid (SA) to dissect plant cellular processes related to cell death and plant immunity. We found highly distinct and time-dependent biological processes being activated on N-terminome level in response to avrRxo1, FB1 and SA. This study characterizes distinct RCD responses in Z. mays and provides a framework for the mechanistic exploration of components involved in the initiation and execution of cell death.
Project description:This Project investigates the impact of elevated temperatures and relative humidity on the aging process of chia seeds (Salvia hispanica L.). The study employs proteomics to examine molecular responses to accelerated aging in two chia genotypes. The results underscore the importance of evaluating changes in proteins of aged seeds to gain insights into the biological mechanisms responsible for maintaining chia seed integrity during the aging process.
Project description:Chilling is a major stress to plants of subtropical and tropical origins including maize. To reveal molecular mechanisms underlying chilling tolerance and chilling survival, we investigated maize transcriptome responses to chilling stress in differentiated leaves and roots as well as in crowns with meristem activity for survival. Chilling stress on maize shoots and roots is found to each contribute to seedling lethality in maize. Comparison of maize lines with different chilling tolerance capacity reveals that chilling survival in maize is highly associated with upregulation in leaves and crowns of abscisic acid response pathway, transcriptional regulators and cold response as well as downregulation of heat response in crowns. Comparison of chilling treatment on whole and part of the plants reveals that response to distal-chilling is very distinct from, and sometimes opposite to, response to local- or whole-plant chilling in both leaves and roots, suggesting a communication between shoots and roots in environmental perception. In sum, this study details chilling responses in leaves, roots and crowns and reveals potential chilling survival mechanism in maize, which lays ground for further understanding survival and tolerance mechanisms under low but non-freezing temperatures in tropical and subtropical plants.