Search

Abstract Background Commercial cultivars of perennial ryegrass infected with selected Epichloë fungal endophytes are highly desirable in certain pastures as the resulting mutualistic association has the capacity to confer agronomic benefits (such as invertebrate pest deterrence) largely due to fungal produced secondary metabolites (e.g., alkaloids). In this study, we investigated T2 segregating populations derived from two independent transformation events expressing diacylglycerol acyltransferase (DGAT) and cysteine oleosin (CO) genes designed to increase foliar lipid and biomass accumulation. These populations were either infected with Epichloë festucae var. lolii strain AR1 or Epichloë sp. LpTG-3 strain AR37 to examine relationships between the introduced trait and the endophytic association. Here we report on experiments designed to investigate if expression of the DGAT + CO trait in foliar tissues of perennial ryegrass could negatively impact the grass-endophyte association and vice versa. Both endophyte and plant characters were measured under controlled environment and field conditions. Results Expected relative increases in total fatty acids of 17–58% accrued as a result of DGAT + CO expression with no significant difference between the endophyte-infected and non-infected progeny. Hyphal growth in association with DGAT + CO expression appeared normal when compared to control plants in a growth chamber. There was no significant difference in mycelial biomass for both strains AR1 and AR37, however, Epichloë-derived alkaloid concentrations were significantly lower on some occasions in the DGAT + CO plants compared to the corresponding null-segregant progenies, although these remained within the reported range for bioactivity. Conclusions These results suggest that the mutualistic association formed between perennial ryegrass and selected Epichloë strains does not influence expression of the host DGAT + CO technology, but that endophyte performance may be reduced under some circumstances. Further investigation will now be required to determine the preferred genetic backgrounds for introgression of the DGAT + CO trait in combination with selected endophyte strains, as grass host genetics is a major determinant to the success of the grass-endophyte association in this species.

Under favourable conditions, perennial ryegrass (Lolium perenne) engineered to accumulated high lipid (HL) carbon sink in their leaves was previously shown to also enhance photosynthesis and growth. The greater aboveground biomass was found to be diminished in a dense canopy compared to spaced pots. Besides, the underlying genetic regulatory network linking between leaf lipid sinks and these physiological changes remains unknown. In this study, we demonstrated that the growth advantage was not displayed in HL Lolium grown in spaced pots under low lights. Under standard lights, analysis of differentiating transcripts in HL Lolium reveals that the plants had elevated transcripts involved in lipid metabolism, light capturing, photosynthesis, and sugar signalling while reduced expression of genes participating in sugar biosynthesis and transportation. The plants also had altered several transcripts involved in mitochondrial oxidative respiration and redox potential. Many of the above upregulated or downregulated transcript levels were found to be complemented by growing the plants under low light. Overall, this study emphasizes the importance of carbon and energy homeostatic regulatory mechanisms to overall productivity of the HL Lolium through photosynthesis, most of which are significantly impacted by low irradiances.

The article discusses the importance and prospect of integration of Chinese digital resources in an English platform, resources and services. It states that a library has an obligation to meet user's demand regarding the search for all relevant resources, regardless of languages. It notes that the task of integrating Chinese digital resource into library's English platform is not easy because of its uncertainties and circumstance beyond the control of East Asian libraries. The article also explores the popular of resource integration in Chinese academic libraries known as subject navigation.

This article presents information on five fundamental elements that a new librarian should pay attention to in order to get a new East Asian collection started in the right direction, that will result, in time, in a "beautiful picture." These five fundamental elements are User relations, Vendor relations, Colleague relations, Inter-collegiate relations, and Gifts and Exchanges. To develop a new East Asian collection, the librarian must know who are the primary users, what their information needs are, and how to maintain close ties with them. Undoubtedly, in an academic library, the major users of the East Asian collections would be faculty and students in the appropriate departments, institutes and research program. To obtain materials selected according to guidelines set up in the collection development policy, the librarian needs to develop good vendor relations to facilitate the purchase of those materials and their distribution to the library. A new East Asian collection is usually a one-librarian situation, and organizationally the collection is nestled in the mainstream collections. It does not have the division of labor that is found in a regular East Asian Library. To accomplish the work needing to be done, the East Asian studies librarian needs cooperation and support from colleagues in almost all other library departments or units.

This study examines user and service data from 2002-2006 at the East Asian Gateway Service for Chinese and Korean Academic Journal Publications (Gateway Service), the University of Pittsburgh. Descriptive statistical analysis reveals that the Gateway Service has been consistently playing the leading role in global document delivery service as well as in global resource sharing. [ABSTRACT FROM AUTHOR]