Search

In plants, genes involved in the Phenylpropanoid/monolignol pathway play important roles in lignin biosynthesis and plant immunity. However, their biological function in Lilium remains poorly characterized. Comparative RNA sequencing of the expression profiles of the monolignol pathway genes from fungi-resistant species Lilium regale after inoculation with Botrytis cinerea was performed. One upregulated caffeoyl-CoA O-methyltransferase gene, LrCCoAOMT, was cloned for functional characterization by reverse genetic methods. LrCCoAOMT encodes a putative protein of 246 amino acids and is highly expressed in stem tissues and responsive to salicylic acid (SA) signaling and B. cinerea infection. LrCCoAOMT was largely directed to the cytoplasm. LrCCoAOMT overexpression in Arabidopsis resulted in an increased lignin deposition in vascular tissues and conferred resistance to B. cinerea infection in transgenic plants. Transient transformation of LrCCoAOMT in nonresistant Lilium sargentiae leaves also identified the defense function to B. cinerea. In addition, transcript levels of genes involved in the monolignol and SA-dependent signaling pathways were altered in transgenic Arabidopsis, suggesting that LrCCoAOMT might play vital roles in the resistance of L. regale to B. cinerea related to the levels of lignin and the regulation of SA signaling. This is the first report to functionally characterize a CCoAOMT gene in Lilium, a potential molecular target for lily molecular improvement.

The lily, a famous bulbous flower, is seriously affected by high temperatures, which affect their growth and production. To date, the signalling pathways and the molecular mechanisms related to heat response in Lilium have not been elucidated. In this study, a comparative transcriptome analysis was performed in an important thermo-tolerant flower, L. longiflorum, and a thermo-sensitive flower, L. distichum. Lily seedlings were first exposed to heat stress at 42°C for different lengths of time, and the optimal time-points (2 h and 24 h) were selected for RNA sequencing (RNA-seq). Approximately 66.51, 66.21, and 65.36 Mb clean reads were identified from three libraries of L. longiflorum (LL_CK, LL_T2h and LL_T24h, respectively) and 66.18, 66.03, and 65.16 Mb clean reads were obtained from three libraries of L. distichum (LD_CK, LD_T2h and LD_T24h, respectively) after rRNA removing. A total of 34,301 unigenes showed similarity to known proteins in the database NCBI non-redundant protein (NR), Swiss-Prot proteins, InterPro proteins, Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG). In addition, 1,621 genes were differentially expressed in the overlapping libraries between LL_DEGs and LD_DEGs; of these genes, 352 DEGs were obviously upregulated in L. longiflorum and downregulated in L. distichum during heat stress, including 4-coumarate, CoA ligase (4CL), caffeoyl-CoA O-methyltransferase (CCoAOMT), peroxidase, pathogenesis-related protein 10 family genes (PR10s), 14-3-3 protein, leucine-rich repeat receptor-like protein kinase, and glycine-rich cell wall structural protein-like. These genes were mainly involved in metabolic pathways, phenylpropanoid biosynthesis, plant-pathogen interactions, plant hormone signal transduction, and kinase signalling pathways. Quantitative RT-PCR was performed to validate the expression profiling of these DEGs in RNA-seq data. Taken together, the results obtained in the present study provide a comprehensive sequence resource for the discovery of heat-resistance genes and reveal potential key components that are responsive to heat stress in lilies, which may help to elucidate the heat signal transcription networks and facilitate heat-resistance breeding in lily.

The dissertation consists of three essays in information economics. In the first chapter, "Social Learning in General Information Environments," I consider a variant of the model of herd behavior introduced by Banerjee (1992) and Bikhchandani, Hirshleifer, and Welch (1992). I study a social learning model in which agents make decisions sequentially and learn about an unknown payoff-relevant state through two sources – a signal about the state itself (a state-signal) and a signal about the actions taken by previous agents (an action-signal). The objective is to provide general conditions on the action-signals that lead the agents to eventually behave as if they know the state, i.e., that lead to information aggregation. When the agents’ action-signals are what I call weakly separating, it is shown that information aggregation occurs when the agents’ state-signals are unboundedly informative in the sense of Smith and Sorensen (2000). This result provides a unifying criterion to evaluate when information aggregation occurs. The theory is illustrated with applications to privacy protection on digital platforms and the analysis of robustness of information aggregation to third-party manipulation. The second chapter is entitled "Platform Design for Costly Learning''. This chapter studies the optimal design of information disclosure on a platform to incentivize its users to collectively acquire costly information about the quality of a product. A constant flow of users arrive in sequential order. Each user observes information disclosed by the platform and may acquire a costly private signal about the product quality before making his purchase decision. Within a large class of environments, I show that it is optimal for the platform to release no information early on to induce user exploration, and, at a later point in time, publish a list of potentially good products once and for all. Compared to an environment without intervention, the optimal design induces a Pareto improvement for the consumers and the platform. Finally, in the third chapter, "Monopoly Pricing with Endogenous Information Response," I study how endogenous informational responses of third parties affect consumer and producer surpluses in a monopoly pricing setting. The analysis is motivated by the fact that rapid developments in digital technology have given consumers access to new information sources that allow them to learn about a product prior to making purchase decisions. These media sources are typically controlled by third parties (e.g., IMDb in the movie industry). To understand these phenomenon, I study a mechanism design problem for a seller who posts a selling mechanism to sell a product to a consumer. Unlike the standard mechanism design paradigm, a third party observes the seller’s choice of selling mechanism and then designs the information structure of a signal about the product quality. The consumer observes the signal realization as well as the information structure, and then chooses an action in the selling mechanism. It is shown that the seller cannot benefit from designing a mechanism that directly punishes the third party. Equilibrium selling mechanisms and signal structures are also studied for the case when the third party cares about a weighted sum of the buyer's and the seller's surpluses.

Epoxy group-functionalized biobased elastomer poly(dibutyl itaconate-ter-isoprene-ter-glycidyl methacrylate) (PDBIIG) was synthesized via redox emulsion polymerization using glycidyl methacrylate (GMA) as the epoxy group-included monomer. The silica/PDBIIG nanocomposite was prepared without adding silane coupling agents. The ring-opening reaction, which occurred between the hydroxyl groups on the silica surfaces and the epoxy groups of the PDBIIG chains during mixing and vulcanization, was confirmed via bound rubber tests and Fourier transform infrared spectroscopy. This reaction was facilitated through heat treatment at 150 °C effectively. The introduction of covalent bonds significantly improved the interfacial interaction and dispersion of silica, which was indicated by transmission electron microscopy and rubber process analyzer (RPA) results. With the same silica loading and compounding procedure, the inclusion of 3.7 wt % GMA increased the modulus at 100% strain by 150.0% and the modulus at 300% str...