Investigation of lignin biosynthesis in sugarcane for improved lignocellulosic ethanol production

As oil use increases at a rate unsustainable for the environment and unmatchable by current levels of oil production, a major shift towards renewable energy is necessary. By expanding the current knowledge of lignin biosynthesis and its manipulation in sugarcane, this PhD contributes to the production of economically viable second generation bioethanol, a fuel produced from plant biomass. The findings of this thesis contribute to the limited knowledge of lignin biosynthesis and deposition in sugarcane, and the application of biotechnology to produce sugarcane, and the resulting bagasse, with a modified cell wall. Reducing or modifying the lignin content in the cell wall of bagasse can reduce production costs and increase yields of bioethanol. This makes bioethanol more economically competitive with oil as an alternative energy source. A move to using bioethanol over fossil based transport fuels will have global economic and environmental benefits

Sugarcane transgenics expressing MYB transcription factors show improved glucose release

Additional file 1: Figure S1. Nucleotide and amino acid alignments of MYB31 and MYB42. Alignments of published (Fornalé et al. 2006) and cloned nucleotide and amino acid sequences (ORF and UTR) for ZmMYB31 (NM_001112479) and ZmMYB42 (NM_001112539). Alignments were made using the Kyoto University Bioinformatics Center website ( http://www.genome.jp/tools-bin/clustalw ) and amino acid translations were made using the ORF region of each MYB nucleotide sequences and Vector NTI software. The start and stop codons are underlined in nucleotide sequence alignments with the 5′ and 3′ UTR regions being upstream and downstream of the start and stop codons respectively. The R2 and R3 motifs in each sequence are underlined with light gray and dark grey shading respectively

Genome Editing in Trees: From Multiple Repair Pathways to Long-Term Stability

The CRISPR technology continues to diversify with a broadening array of applications that touch all kingdoms of life. The simplicity, versatility and species-independent nature of the CRISPR system offers researchers a previously unattainable level of precision and control over genomic modifications. Successful applications in forest, fruit and nut trees have demonstrated the efficacy of CRISPR technology at generating null mutations in the first generation. This eliminates the lengthy process of multigenerational crosses to obtain homozygous knockouts (KO). The high degree of genome heterozygosity in outcrossing trees is both a challenge and an opportunity for genome editing: a challenge because sequence polymorphisms at the target site can render CRISPR editing ineffective; yet an opportunity because the power and specificity of CRISPR can be harnessed for allele-specific editing. Examination of CRISPR/Cas9-induced mutational profiles from published tree studies reveals the potential involvement of multiple DNA repair pathways, suggesting that the influence of sequence context at or near the target sites can define mutagenesis outcomes. For commercial production of elite trees that rely on vegetative propagation, available data suggest an excellent outlook for stable CRISPR-induced mutations and associated phenotypes over multiple clonal generations

Cell wall composition and lignin biosynthetic gene expression along a developmental gradient in an Australian sugarcane cultivar

Sugarcane bagasse is an abundant source of lignocellulosic material for bioethanol production. Utilisation of bagasse for biofuel production would be environmentally and economically beneficial, but the recalcitrance of lignin continues to provide a challenge. Further understanding of lignin production in specific cultivars will provide a basis for modification of genomes for the production of phenotypes with improved processing characteristics. Here we evaluated the expression profile of lignin biosynthetic genes and the cell wall composition along a developmental gradient in KQ228 sugarcane. The expression levels of nine lignin biosynthesis genes were quantified in five stem sections of increasing maturity and in root tissue. Two distinct expression patterns were seen. The first saw highest gene expression in the youngest tissue, with expression decreasing as tissue matured. The second pattern saw little to no change in transcription levels across the developmental gradient. Cell wall compositional analysis of the stem sections showed total lignin content to be significantly higher in more mature tissue than in the youngest section assessed. There were no changes in structural carbohydrates across developmental sections. These gene expression and cell wall compositional patterns can be used, along with other work in grasses, to inform biotechnological approaches to crop improvement for lignocellulosic biofuel production

Studies on reproductive performance of beef cattle in a subtropical environment. 1. Conception rate, length of oestrous cycle and length of gestation

Data from 198 cow matings and 209 heifer matings were provided by animals equally distributed between 9-wk mating periods in either spring, summer or autumn during 1961-65 at " Brian Pastures " in south-eastern Queensland. First service and over-all C.R.s showed no effect from the influence of season of mating, year, class of animal or lactational status. Calving rate was similarly unaffected. Recorded services per conception were higher for the spring-mating than for the autumn group. There was a positive association between live-weight change during the 1st mth of mating and 1st-service C.R. Length of oestrous period was 20.5 0.96 days for cows and 20.9 0.96 days for heifers. Gestation length was 278.6 1 .00 days for cows and 278.7 1.00 days for heifers. Oestrous period and gestation length were not affected by any of the factors considered.-A.S

MOESM5 of RNAi downregulation of three key lignin genes in sugarcane improves glucose release without reduction in sugar production

Additional file 5: Table S5. Glucose (mg/g) released via limited enzymatic hydrolysis. Glucose released per gram of bagasse measured at six time points for CCoAOMT, F5H and COMT RNAi plants. The glucose released is shown with the standard error of the mean. Samples significantly different to controls after a one-way ANOVA, p < 0.05 are shown in bold. Plants for each line are listed in ascending order of total lignin content. Avg is the mean of the lines within each construct

MOESM3 of Sugarcane transgenics expressing MYB transcription factors show improved glucose release

Additional file 3: Table S2. Normalized lignin biosynthetic genes ΔCt values for MYB-expressing plants. Values normalized against average control ΔCt value for each gene. Values represent initial expression screening of leaf tissue and post-harvest expression results from young internode tissue and maturing internode tissue. NE: Normalized expression with standard error of the mean shown. Samples significantly different to the controls after ANOVA, p = 0.05, are shown in bold. Control n = 3. Plants are listed in ascending total lignin content for each line