Source-Sink Relationships and Its Effect on Plant Productivity: Manipulation of Primary Carbon and Starch Metabolism

The rate of photo-assimilation in source organs (source strength) and the rate of conversion of this photo-assimilate into end products in sink organs (sink strength) are the two key metabolic processes that determine plant productivity and yield. Enhancement of either the source or the sink processes alone will often have limited returns due to the feedback inhibition from the other process. Consequently, maximizing plant productivity requires synergistic improvement of both source and sink processes. In this chapter, we will talk about the advancements in improving plant productivity through the modification of primary carbon metabolism in source and sink organs, with special emphasis on starch metabolism. Furthermore, we will discuss the future directions for enhancing source and sink processes in crop species via the usage of modern genome editing techniques.