Potential for genetic improvement of sugarcane as a source of biomass for biofuels

Sugarcane (Saccharum spp. hybrids) has great potential as a major feedstock for biofuel production worldwide. It is considered among the best options for producing biofuels today due to an exceptional biomass production capacity, high carbohydrate (sugar + fiber) content, and a favorable energy input/output ratio. To maximize the conversion of sugarcane biomass into biofuels, it is imperative to generate improved sugarcane varieties with better biomass degradability. However, unlike many diploid plants, where genetic tools are well developed, biotechnological improvement is hindered in sugarcane by our current limited understanding of the large and complex genome. Therefore, understanding the genetics of the key biofuel traits in sugarcane and optimization of sugarcane biomass composition will advance efficient conversion of sugarcane biomass into fermentable sugars for biofuel production. The large existing phenotypic variation in Saccharum germplasm and the availability of the current genomics technologies will allow biofuel traits to be characterized, the genetic basis of critical differences in biomass composition to be determined, and targets for improvement of sugarcane for biofuels to be established. Emerging options for genetic improvement of sugarcane for the use as a bioenergy crop are reviewed. This will better define the targets for potential genetic manipulation of sugarcane biomass composition for biofuels

Downregulation of pyrophosphate: d-fructose-6-phosphate 1-phosphotransferase activity in sugarcane culms enhances sucrose accumulation due to elevated hexose-phosphate levels

Analyses of transgenic sugarcane clones with 45–95% reduced cytosolic pyrophosphate: d-fructose-6-phosphate 1-phosphotransferase (PFP, EC 2.7.1.90) activity displayed no visual phenotypical change, but significant changes were evident in in vivo metabolite levels and fluxes during internode development. In three independent transgenic lines, sucrose concentrations increased between three- and sixfold in immature internodes, compared to the levels in the wildtype control. There was an eightfold increase in the hexose-phosphate:triose-phosphate ratio in immature internodes, a significant restriction in the triose phosphate to hexose phosphate cycle and significant increase in sucrose cycling as monitored by 13C nuclear magnetic resonance. This suggests that an increase in the hexose-phosphate concentrations resulting from a restriction in the conversion of hexose phosphates to triose phosphates drive sucrose synthesis in the young internodes. These effects became less pronounced as the tissue matured. Decreased expression of PFP also resulted in an increase of the ATP/ADP and UTP/UDP ratios, and an increase of the total uridine nucleotide and, at a later stage, the total adenine nucleotide pool, revealing strong interactions between PPi metabolism and general energy metabolism. Finally, decreased PFP leads to a reduction of PPi levels in older internodes indicating that in these developmental stages PFP acts in the gluconeogenic direction. The lowered PPi levels might also contribute to the absence of increases in sucrose contents in the more mature tissues of transgenic sugarcane with reduced PFP activity

Sugarcane RD&E: over managed and underperforming?

In general, few productivity improvements in sugarcane have occurred during the past three decades. At the same time, production costs have increased and production statistics reflect decreased yields globally. In comparison to the 'golden years' of new technology and improved germplasm in the second half of the previous century, little more than optimisation of existing practises has emerged from the past two decades. Given the slowdown in new technology delivery, it is not surprising that many industries have placed more scrutiny on how they manage their Research & Development institutions and investments. The result of this 'slowdown' has created a perception that poor management of research projects and programs by scientists is at the core of the problem. This has led to the introduction of 'real' managers with the subsequent management of R&D as if it is a 'normal' production and sales business through well established 'business models'. Strong emphasis has been placed on project selection, project management and minimising risk. Research, especially in the discovery phase, is a very high-risk endeavour and a high proportion of all projects fail. Institutions that have a low appetite for risk quickly run out of new technology innovation. Because of the inability to predict, a discovery project cannot easily accommodate management issues such as budgeting, milestone definition and timeframes. Managers generally prefer D and Extension over R because of the higher predictability and lower perceived failure rate. The key to proper management of R&D is a recognition that researchers and managers operate under very different codes of conduct. If this is not properly managed, then conflict between researchers and the rest of the business follows. It has become customary to view RD&E as a unit following a systems' approach. Despite obvious advantages of this approach, it often fails to recognise the most significant shortfall(s) in the value chain. This practice can unnecessarily inflate the cost, slow project progress and is dependent on consensus that tends to favour the lowest common denominator or more vocal team members. Consensus and innovation tend to be opposing objectives, as innovation requires thinking with an 'outside the box' mindset. Consequently, innovation can be stifled using this approach. Peer review is a great tool to measure progress in projects and selecting projects for development. It is not suited for selection of new innovative ideas. With no obvious improvement in technology delivery and adoption, it is timely to ask whether the current approaches are achieving their objectives. In addressing this question it is important to look at the global evolution of R&D models and modern trends in highly innovative businesses. Instead of trying to ensure that every research project entering the technology funnel delivers a product, a greater emphasis is needed to create an innovative environment where all role players are focussed on key strategic objectives, and all research results are seen as key learnings for future deployment