TY - JOUR
T1 - Proximal and Distal Parts of Sweetpotato Adventitious Roots Display Differences in Root Architecture, Lignin, and Starch Metabolism and Their Developmental Fates
AU - Singh, Vikram
AU - Zemach, Hanita
AU - Shabtai, Sara
AU - Aloni, Roni
AU - Yang, Jun
AU - Zhang, Peng
AU - Sergeeva, Lidiya
AU - Ligterink, Wilco
AU - Firon, Nurit
N1 - Publisher Copyright:
© Copyright © 2021 Singh, Zemach, Shabtai, Aloni, Yang, Zhang, Sergeeva, Ligterink and Firon.
PY - 2021/1/21
Y1 - 2021/1/21
N2 - Sweetpotato is an important food crop globally, serving as a rich source of carbohydrates, vitamins, fiber, and micronutrients. Sweetpotato yield depends on the modification of adventitious roots into storage roots. The underlying mechanism of this developmental switch is not fully understood. Interestingly, storage-root formation is manifested by formation of starch-accumulating parenchyma cells and bulking of the distal part of the root, while the proximal part does not show bulking. This system, where two parts of the same adventitious root display different developmental fates, was used by us in order to better characterize the anatomical, physiological, and molecular mechanisms involved in sweetpotato storage-root formation. We show that, as early as 1 and 2 weeks after planting, the proximal part of the root exhibited enhanced xylem development together with increased/massive lignin deposition, while, at the same time, the distal root part exhibited significantly elevated starch accumulation. In accordance with these developmental differences, the proximal root part exhibited up-regulated transcript levels of sweetpotato orthologs of Arabidopsis vascular-development regulators and key genes of lignin biosynthesis, while the distal part showed up-regulation of genes encoding enzymes of starch biosynthesis. All these recorded differences between proximal and distal root parts were further enhanced at 5 weeks after planting, when storage roots were formed at the distal part. Our results point to down-regulation of fiber formation and lignification, together with up-regulation of starch biosynthesis, as the main events underlying storage-root formation, marking/highlighting several genes as potential regulators, providing a valuable database of genes for further research.
AB - Sweetpotato is an important food crop globally, serving as a rich source of carbohydrates, vitamins, fiber, and micronutrients. Sweetpotato yield depends on the modification of adventitious roots into storage roots. The underlying mechanism of this developmental switch is not fully understood. Interestingly, storage-root formation is manifested by formation of starch-accumulating parenchyma cells and bulking of the distal part of the root, while the proximal part does not show bulking. This system, where two parts of the same adventitious root display different developmental fates, was used by us in order to better characterize the anatomical, physiological, and molecular mechanisms involved in sweetpotato storage-root formation. We show that, as early as 1 and 2 weeks after planting, the proximal part of the root exhibited enhanced xylem development together with increased/massive lignin deposition, while, at the same time, the distal root part exhibited significantly elevated starch accumulation. In accordance with these developmental differences, the proximal root part exhibited up-regulated transcript levels of sweetpotato orthologs of Arabidopsis vascular-development regulators and key genes of lignin biosynthesis, while the distal part showed up-regulation of genes encoding enzymes of starch biosynthesis. All these recorded differences between proximal and distal root parts were further enhanced at 5 weeks after planting, when storage roots were formed at the distal part. Our results point to down-regulation of fiber formation and lignification, together with up-regulation of starch biosynthesis, as the main events underlying storage-root formation, marking/highlighting several genes as potential regulators, providing a valuable database of genes for further research.
KW - adventitious root development
KW - gene expression
KW - lignin
KW - root anatomy
KW - starch
KW - storage-root
KW - sweetpotato
UR - http://www.scopus.com/inward/record.url?scp=85100474872&partnerID=8YFLogxK
U2 - 10.3389/fpls.2020.609923
DO - 10.3389/fpls.2020.609923
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C2 - 33552103
AN - SCOPUS:85100474872
SN - 1664-462X
VL - 11
JO - Frontiers in Plant Science
JF - Frontiers in Plant Science
M1 - 609923
ER -