http://hdl.handle.net/2440/34068 2013-05-21T18:54:45Z http://hdl.handle.net/2440/77466 Title: Endo-(1,4)-β-Glucanase gene families in the grasses: temporal and spatial Co-transcription of orthologous genes Author: Buchanan, Margaret; Burton, Rachel Anita; Dhugga, Kanwarpal; Rafalski, Antoni J.; Tingey, Scott J.; Shirley, Neil John; Fincher, Geoffrey Bruce Abstract: BACKGROUND Endo-(1,4)-β-glucanase (cellulase) glycosyl hydrolase GH9 enzymes have been implicated in several aspects of cell wall metabolism in higher plants, including cellulose biosynthesis and degradation, modification of other wall polysaccharides that contain contiguous (1,4)-β-glucosyl residues, and wall loosening during cell elongation. RESULTS The endo-(1,4)-β-glucanase gene families from barley (Hordeum vulgare), maize (Zea mays), sorghum (Sorghum bicolor), rice (Oryza sativa) and Brachypodium (Brachypodium distachyon) range in size from 23 to 29 members. Phylogenetic analyses show variations in clade structure between the grasses and Arabidopsis, and indicate differential gene loss and gain during evolution. Map positions and comparative studies of gene structures allow orthologous genes in the five species to be identified and synteny between the grasses is found to be high. It is also possible to differentiate between homoeologues resulting from ancient polyploidizations of the maize genome. Transcript analyses using microarray, massively parallel signature sequencing and quantitative PCR data for barley, rice and maize indicate that certain members of the endo-(1,4)-β-glucanase gene family are transcribed across a wide range of tissues, while others are specifically transcribed in particular tissues. There are strong correlations between transcript levels of several members of the endo-(1,4)-β-glucanase family and the data suggest that evolutionary conservation of transcription exists between orthologues across the grass family. There are also strong correlations between certain members of the endo-(1,4)-β-glucanase family and other genes known to be involved in cell wall loosening and cell expansion, such as expansins and xyloglucan endotransglycosylases. CONCLUSIONS The identification of these groups of genes will now allow us to test hypotheses regarding their functions and joint participation in wall synthesis, re-modelling and degradation, together with their potential role in lignocellulose conversion during biofuel production from grasses and cereal crop residues. Description: Extent: 19p. 2011-12-31T13:30:00Z http://hdl.handle.net/2440/73513 Title: Characterization of the wheat gene encoding a grain-specific lipid transfer protein TdPR61, and promoter activity in wheat, barley and rice Author: Kovalchuk, Nataliya; Smith, Jessica Anne; Bazanova, Natalia; Pyvovarenko, Tatiana; Singh, Rohan Ranjit; Shirley, Neil John; Ismagul, Ainur Zhumagalikyzy; Johnson, Alexander Arthur Theodore; Milligan, Andrew Simon; Hrmova, Maria; Langridge, Peter; Lopato, Sergiy 2011-12-31T13:30:00Z http://hdl.handle.net/2440/70528 Title: Rice DUR3 mediates high-affinity urea transport and plays an effective role in improvement of urea acquisition and utilization when expressed in Arabidopsis Author: Wang, Wei-Hong; Kohler, Barbara; Cao, Feng-Qiu; Liu, Guo-Wei; Gong, Yuan-Yong; Sheng, Song; Song, Qi-Chao; Cheng, Xiao-Yuan; Garnett, Trevor Paul; Okamoto, Mamoru; Qin, Rui; Mueller-Roeber, Bernd; Tester, Mark Alfred; Liu, Lai-Hua 2011-12-31T13:30:00Z http://hdl.handle.net/2440/70007 Title: Cell wall modifications in maize pulvini in response to gravitational stress Author: Zhang, Qisen; Taylor, Jillian; Shirley, Neil John; Burton, Rachel; Fincher, Geoffrey Abstract: Changes in cell wall polysaccharides, transcript abundance, metabolite profiles, and hormone concentrations were monitored in the upper and lower regions of maize (Zea mays) pulvini in response to gravistimulation, during which maize plants placed in a horizontal position returned to the vertical orientation. Heteroxylan levels increased in the lower regions of the pulvini, together with lignin, but xyloglucans and heteromannan contents decreased. The degree of substitution of heteroxylan with arabinofuranosyl residues decreased in the lower pulvini, which exhibited increased mechanical strength as the plants returned to the vertical position. Few or no changes in noncellulosic wall polysaccharides could be detected on the upper side of the pulvinus, and crystalline cellulose content remained essentially constant in both the upper and lower pulvinus. Microarray analyses showed that spatial and temporal changes in transcript profiles were consistent with the changes in wall composition that were observed in the lower regions of the pulvinus. In addition, the microarray analyses indicated that metabolic pathways leading to the biosynthesis of phytohormones were differentially activated in the upper and lower regions of the pulvinus in response to gravistimulation. Metabolite profiles and measured hormone concentrations were consistent with the microarray data, insofar as auxin, physiologically active gibberellic acid, and metabolites potentially involved in lignin biosynthesis increased in the elongating cells of the lower pulvinus. 2010-12-31T13:30:00Z