Starch Deficiency Enhances Lipid Biosynthesis and Turnover in Leaves

Journal Article · Fri Aug 03 00:00:00 EDT 2018 · Plant Physiology (Bethesda)

DOI:https://doi.org/10.1104/pp.18.00539· OSTI ID:1573094

Yu, Linhui  ^[1]; Fan, Jilian  ^[1]; Yan, Chengshi  ^[1]; Xu, Changcheng  ^[1]

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1. Biology Department, Brookhaven National Laboratory, Upton, New York 11973

Starch and lipids represent two major forms of carbon and energy storage in plants, and play central roles in diverse cellular processes. However, whether and how starch and lipid metabolic pathways interact to regulate metabolism and growth is poorly understood. In this paper, we show that lipids can partially compensate for the lack of function of transient starch during normal growth and development in Arabidopsis (Arabidopsis thaliana). Disruption of starch synthesis resulted in a significant increase in fatty acid synthesis via posttranslational regulation of the plastidic acetyl-CoA carboxylase and a concurrent increase in the synthesis and turnover of membrane lipids and triacylglycerol. Genetic analysis showed that blocking fatty acid peroxisomal β-oxidation, the sole pathway for metabolic breakdown of fatty acids in plants, significantly compromised or stunted the growth and development of mutants defective in starch synthesis under long days or short days, respectively. We also found that the combined disruption of starch synthesis and fatty acid turnover resulted in increased accumulation of membrane lipids, triacylglycerol and soluble sugars and altered fatty acid flux between the two lipid biosynthetic pathways compartmentalized in either the chloroplast or the endoplasmic reticulum. Finally and collectively, our findings provide insight into the role of fatty acid β-oxidation and the regulatory network controlling fatty acid synthesis, and reveal the mechanistic basis by which starch and lipid metabolic pathways interact and undergo crosstalk to modulate carbon allocation, energy homeostasis and plant growth.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0012704
• OSTI ID: 1573094
• Alternate ID(s): OSTI ID: 1464113
• Report Number(s): BNL-207940-2018-JAAM; /plantphysiol/178/1/118.atom
• Journal Information: Plant Physiology (Bethesda), Journal Name: Plant Physiology (Bethesda) Vol. 178 Journal Issue: 1; ISSN 0032-0889
• Publisher: American Society of Plant Biologists (ASPB)
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES