Carbohydrate storage in herbs: the forgotten functional dimension of the plant economic spectrum

Background and Aims Although the plant economic spectrum seeks to explain resource allocation strategies, carbohydrate storage is often omitted. Belowground storage organs are the centre of herb perennation, yet little is known about the role of their turnover, anatomy, and carbohydrate storage in relation to the aboveground economic spectrum. Methods We collected aboveground traits associated with the economic spectrum, storage organ turnover traits, storage organ inner structure traits, and storage carbohydrate concentrations for approximately eighty temperate meadow species. Key Results The suites of belowground traits were largely independent from one another, but there was significant correlation between the aboveground traits with both inner structure and storage carbohydrates. Anatomical traits diverged according to leaf nitrogen concentration on one side and vessel area and dry matter content on the other; carbohydrates separated along leaf nitrogen and plant height. Conclusions Contrary to our expectations, aboveground traits and not storage organ turnover were correlated with anatomy and storage carbohydrates. Belowground traits associated with the aboveground economic spectrum also did not fall clearly within the fast-slow economic continuum, thus indicating the presence of a more complicated economic space. Our study implies that the generally over-looked role of storage within the plant economic spectrum represents an important dimension of plant strategy.

Starch and Glycogen Analyses: Methods and Techniques

For complex carbohydrates, such as glycogen and starch, various analytical methods and techniques exist allowing the detailed characterization of these storage carbohydrates. In this article, we give a brief overview of the most frequently used methods, techniques, and results. Furthermore, we give insights in the isolation, purification, and fragmentation of both starch and glycogen. An overview of the different structural levels of the glucans is given and the corresponding analytical techniques are discussed. Moreover, future perspectives of the analytical needs and the challenges of the currently developing scientific questions are included.

Comparative transcriptome analysis reveals storage carbohydrates related genes in kelp Saccharina japonica

Background Saccharina japonica is a brown macroalga commercially cultivated in China for almost a century. As a natural raw material, it has been widely used to extract carbohydrates, e.g. alginate and mannitol, for food, pharmaceutical, and potentially for biofuel production. However, the molecular mechanisms of biosynthesis and regulation of these compounds in this species are not comprehensive and less well understood. Results In this study, we performed whole transcriptome and differential transcript expression analyses of S. japonica sporophyte of distinct developmental stages. Combined with the phenotype of blade and the content of alginate and mannitol, the sporophyte could be divided into four developmental stages. Accordingly, 589 million clean reads were generated, and 98,497 novel transcripts and 4,514 novel genes were identified by transcriptome analysis. Gene expression analysis revealed that 2,542 genes were differentially expressed. KEGG analysis indicated that these genes were significantly enriched in “Carbon metabolism”, “Photosynthesis”, and “Photosynthesis-antenna proteins” pathways, which were important for carbohydrates metabolism during sporophyte development. Through a systematic analysis, the genes encoding enzymes for biosynthesis of cell wall carbohydrates (including alginate, fucoidan and cellulose) and cytoplasm storage carbohydrates (mannitol, laminarin and trehalose) were identified, representing good candidates for further functional studies. Conclusion The work presented is the first transcriptome analysis of sporophytes development and provides a dynamic view of carbohydrate metabolism process and an important resource for functional genomics studies in S. japonica. The results obtained lay the basis for elucidating the molecular mechanism of carbohydrate biosynthesis and for genetic breeding of carbohydrates-related traits in kelp.