Open AccessSenescence‐inducible LEC2 enhances triacylglycerol accumulation in leaves without negatively affecting plant growth
Author(s) -
Kim Hyun Uk,
Lee KyeongRyeol,
Jung SuJin,
Shin Hyun A,
Go Young Sam,
Suh MiChung,
Kim Jong Bum
Publication year - 2015
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.12354
Subject(s) - biology , arabidopsis , biochemistry , senescence , wild type , phosphatidic acid , endoplasmic reticulum , ectopic expression , microbiology and biotechnology , diacylglycerol kinase , fatty acid , phospholipid , gene , enzyme , mutant , protein kinase c , membrane
Summary The synthesis of fatty acids and glycerolipids in wild‐type Arabidopsis leaves does not typically lead to strong triacylglycerol ( TAG ) accumulation. LEAFY COTYLEDON 2 ( LEC 2) is a master regulator of seed maturation and oil accumulation in seeds. Constitutive ectopic LEC 2 expression causes somatic embryogenesis and defects in seedling growth. Here, we report that senescence‐inducible LEC 2 expression caused a threefold increase in TAG levels in transgenic leaves compared with that in the leaves of wild‐type plants. Plant growth was not severely affected by the accumulation the TAG in response to LEC 2 expression. The levels of plastid‐synthesized lipids, mono‐ and di‐galactosyldiacylglycerol and phosphatidylglycerol were reduced more in senescence‐induced LEC 2 than in endoplasmic reticulum‐synthesized lipids, including phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol. Senescence‐induced LEC 2 up‐regulated the expression of many genes involved in fatty acid and TAG biosynthesis at precise times in senescent leaves, including WRINKLED 1 ( WRI 1 ), which encodes a fatty acid transcription factor. The expressions of glycerol‐3‐phosphate dehydrogenase 1 and phospholipid:diacylglycerol 2 were increased in the transgenic leaves. Five seed‐type oleosin‐encoding genes, expressed during oil‐body formation, and the seed‐specific FAE 1 gene, which encodes the enzyme responsible for the synthesis of C20:1 and C22:1 fatty acids, were also expressed at higher levels in senescing transgenic leaves than in wild‐type leaves. Senescence‐inducible LEC 2 triggers the key metabolic steps that increase TAG accumulation in vegetative tissues.