Abstract
Transitory starch plays a central role in the life cycle of plants. Many aspects of this important metabolism remain unknown; however, starch granules provide insight into this persistent metabolic process. Therefore, monitoring alterations in starch granules with high temporal resolution provides one significant avenue to improve understanding. Here, a previously established method that combines LCSM and safranin-O staining for in vivo imaging of transitory starch granules in leaves of Arabidopsis thaliana was employed to demonstrate, for the first time, the alterations in starch granule size and morphology that occur both throughout the day and during leaf aging. Several starch-related mutants were included, which revealed differences among the generated granules. In ptst2 and sex1-8, the starch granules in old leaves were much larger than those in young leaves; however, the typical flattened discoid morphology was maintained. In ss4 and dpe2/phs1/ss4, the morphology of starch granules in young leaves was altered, with a more rounded shape observed. With leaf development, the starch granules became spherical exclusively in dpe2/phs1/ss4. Thus, the presented data provide new insights to contribute to the understanding of starch granule morphogenesis.
Highlights
The glucosyl residues in the backbone of amylopectin are linked by α-1,4-linkages and the branching points are interconnected by α-1,6-linkages
Starch granules of the wild type and several starch-related mutants were detected in vivo using laser confocal scanning microscopy (LCSM)-based imaging combined with safranin-O staining
The ratio of the diameters of starch granules in old leaves of dpe1/phs1/ss4 increased and the single values were more evenly distributed, compared with young leaves, indicating that the starch granules in old leaves became more spherical and had a more even appearance
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Ptst, a single starch granule per chloroplast was observed, suggesting that PTST2 is involved in starch initiation. A lack of SS4 changed the number of starch granules and their shape from the typical flattened discoid morphology to one that was much more spherical This alteration does not occur in ptst; the granules in ptst were larger but still flattened [7,8]. The irregular edges of the starch granules in sex were concluded to occur as a consequence of uneven metabolism at the starch granule surface Supportive of this hypothesis, the smaller granules revealed a more even size and morphology than those of the larger ones [15]. The analysis of starch granules in their natural environment—without purification—is of significant interest and may lead to a more complete description of the granule parameters
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
