Project description:Perennial plants, like fruit trees grown in temperate regions, are characterized by bud dormancy, a rest state that protects the bud from cold during winter. At the same time, these plants have developed a requirement for winter chill for correct flowering. However, winters are becoming increasingly warm in temperate regions, resulting in dramatic effects on the flowering output and therefore crop yield. A compound that successfully compensates for missing winter chill is hydrogen cyanamide, which has been used to synchronize and advance flowering time in a range of commercially important fruit crops. Hydrogen cyanamide also represents a unique tool for researchers to study controlled endodormancy release. Here, we treated dormant sweet cherry flower buds with hydrogen cyanamide, sampling flower buds at different time points after treatment. RNAseq revealed more than 6,000 hydrogen cyanamide-responsive genes. In accordance with these results, hydrogen cyanamide treatment increased the levels of jasmonoyl-isoleucine (JA-Ile) and the cytokinins trans-zeatin riboside (tZR), dihydrozeatin (DZ) and dihydrozeatin riboside (DZR). Furthermore, hydrogen cyanamide affected the expression of antioxidant- and cell wall loosening-associated transcripts. These results suggest a complex mechanism of action for hydrogen cyanamide-induced endodormancy release, including key roles for JA-Ile, zeatin-type cytokinins and hydrogen cyanide.
Project description:To study the floral volatile compounds of standard Malus robusta flowers (Mr), and its progeny with strongly and weakly fragrant flowers
Project description:Plants perceive herbivory induced volatiles and respond to them by upregulating their defenses. So far, the organs responsible for volatile perception remain poorly described. Here, we show that responsiveness to the herbivory induced green leaf volatile (Z)-3-hexenyl acetate (HAC) in terms of volatile emission, transcriptional regulation and jasmonate defense hormone activation is largely constrained to younger maize leaves. Older leaves are much less sensitive to HAC. In a given leaf, responsiveness to HAC is high at immature developmental stages and drops off rapidly during maturation. Responsiveness to the non-volatile elicitor ZmPep3 shows an opposite pattern, demonstrating that this form of hyposmia (i.e. decreased sense of smell) is not due to a general defect in jasmonate defense signaling in mature leaves. Neither stomatal conductance nor leaf cuticle composition explain the unresponsiveness of older leaves to HAC, suggesting perception mechanisms upstream of jasmonate signaling as driving factors. Finally, we show that hyposmia in older leaves is not restricted to HAC, and extends to the full blend of herbivory induced volatiles. In conclusion, our work identifies immature maize leaves as dominant stress volatile sensing organs. The tight spatiotemporal control of volatile perception may facilitate within-plant defense signaling to protect young leaves, and may allow plants with complex architectures to explore the dynamic odor landscapes at the outer periphery of their shoots
Project description:Smoke inhalation from a structure fire is a common route of cyanide poisoning in the U.S. Cyanide inhibits cellular respiration, often leading to death. Its rapid distribution throughout the body can result in injuries to multiple organs, and cyanide victims were reported to experience myocardial infarction and other cardiac complications. We performed oligonucleotide microarrays to establish cardiac transcriptomes of an animal model of nose-only inhalation exposure to hydrogen cyanide (HCN), which is relevant to smoke inhalation. We also profiled cardiac transcriptomes after subcutaneous injection of potassium cyanide (KCN). Although the KCN injection model has been often used to evaluate medical countermeasures, this study demonstrated that cardiac transcriptomes are largely different from that of the HCN inhalation model at multiple time points within 24 hours after exposure.
Project description:pQBR103 is a naturally occurring plasmid known to alter the behaviour of its host, Pseudomonas fluorescens. This plasmid encodes a predicted translational regulator, rsmQ which is a homologue of known global regulators within Pseudomonas. Within this study we compared Pseudomonas fluorescens SBW25 plasmid free cells with cells carrying either WT pQBR103 or pQBR103 lacking rsmQ. Using comparative quantitative proteomics and RNAseq we showed that the loss of rsmQ leads to widespread proteomic changes in the absence of changes in mRNA abundance, suggesting RsmQ is a translational regulator of its host chromosome.
Project description:Plants are targets of volatile organic compounds (VOCs) released as a part of plant-plant communication, within-plant self-signaling and plant-microbe interactions. Therefore, understanding VOC perception and downstream signaling is vital for unraveling the mechanisms behind information exchange in plants, which remain largely unexplored. Using the hormone-like function of volatile terpenoids in reproductive organ development as a system with a visual marker for communication, we demonstrated that among the four petunia karrikin-insensitive receptors, PhKAI2ia stereo-specifically perceives the (-)-germacrene D signal, triggering a karrikin-like signaling cascade. This study provides new insights into plant olfaction, uncovers the role(s) of the unique intermediate clade of KAI2 receptors, illuminates the involvement of KAI2ia-dependent signaling pathway in volatile communication and gives insight into the long-standing question about the nature of potential endogenous karrikin-like ligand(s).
Project description:Molecular hydrogen is a hopeful agent for oxidative stress-related and/or inflammatory disorders. However, the molecular mechanism for these therapeutic effects of hydrogen still remains to be fully elucidated. We examined whether molecular hydrogen alters gene expression levels in normal mouse livers by DNA microarray analysis. We identified 140 mouse genes that were upregulated (31 genes) or downregulated (109 genes) after three weeks of the inhalation of 2% hydrogen-containing air with oral intake of hydrogen-rich water. Ingenuity Pathway Analysis revealed that hydrogen influenced expression of NF-kB- and NFAT-regulated genes. Western blot analysis showed that hydrogen attenuated Erk, p38 MAPK, and NF-kB signaling in mouse livers.
Project description:Methanococcus maripaludis is a methanogenic Archaea that conserves energy from molecular hydrogen to reduce carbon dioxide to methane. Chemostat grown cultures limited for hydrogen, phosphate, or leucine were compared to determine the regulatory response to hydrogen limitation. This was done by comparing hydrogen limited cultures to both leucine limited and phosphate limited cultures. Slow and rapid growing samples limited for either hydrogen or phosphate were compared to determine the regulatory effects of growth rate. Keywords: archaea, hydrogen, leucine, phosphate, nutrient limitation, growth rate, methanogen