The transcription factor MYB1 activates DGAT2 transcription to promote triacylglycerol accumulation in sacha inchi (Plukenetia volubilis L.) leaves under heat stress

Triacylglycerol (TAG) accumulation is frequently triggered in vegetative tissues experiencing heat stress, which may increases plant basal plant thermo-tolerance by sequestering the toxic lipid intermediates that contribute to membrane damage or cell death under stress conditions. However, stress-re...

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Published in:Plant physiology and biochemistry 2024-03, Vol.208, p.108517-108517, Article 108517
Main Authors: Yang, Tianquan, Niu, Qian, Dai, Huan, Tian, Xiaoling, Ma, Junchao, Pritchard, Hugh W., Lin, Liang, Yang, Xiangyun
Format: Article
Language:English
Subjects:
Diacylglycerol acyltransferase genes
Heat stress
Heat-Shock Response - genetics
Lipidomics
Plant Leaves - genetics
Plant Leaves - metabolism
Plant Oils - metabolism
Sacha inchi
Transcription Factors - genetics
Transcription Factors - metabolism
Transcriptome
Triacylglycerol
Triglycerides - metabolism
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Summary:Triacylglycerol (TAG) accumulation is frequently triggered in vegetative tissues experiencing heat stress, which may increases plant basal plant thermo-tolerance by sequestering the toxic lipid intermediates that contribute to membrane damage or cell death under stress conditions. However, stress-responsive TAG biosynthesis and the underlying regulatory mechanisms are not fully understood. Here, we investigated the lipidomic and transcriptomic landscape under heat stress in the leaves of sacha inchi (Plukenetia volubilis L.), an important oilseed crop in tropical regions. Under heat stress (45 °C), the content of polyunsaturated TAGs (e.g., TAG18:2 and TAG18:3) and total TAGs were significantly higher, while those of unsaturated sterol esters, including ZyE 28:4, SiE 18:2 and SiE 18:3, were dramatically lower. Transcriptome analysis showed that the expression of PvDGAT2-2, encoding a type II diacylglycerol acyltransferase (DGAT) that is critical for TAG biosynthesis, was substantially induced under heat stress. We confirmed the function of PvDGAT2-2 in TAG production by complementing a yeast mutant defective in TAG biosynthesis. Importantly, we also identified the heat-induced transcription factor PvMYB1 as an upstream activator of PvDGAT2-2 transcription. Our findings on the molecular mechanism leading to TAG biosynthesis in leaves exposed to heat stress have implications for improving the biotechnological production of TAGs in vegetative tissues, offering an alternative to seeds. •Lipidomic and transcriptomic analysis revealed physiological and molecular changes under heat stress in sacha inchi seedlings leaves.•Triacylglycerols, especially polyunsaturated TAGs, substantially accumulate in sacha inchi leaves under heat stress.•Expression of the type II diacylglycerol acyltransferase gene PvDGAT2-2 is upregulated under heat stress and participates in TAG biosynthesis.•The heat-induced transcription factor PvMYB1 activates PvDGAT2-2 transcription in sacha inchi leaves under heat stress.
ISSN:0981-9428
1873-2690
DOI:10.1016/j.plaphy.2024.108517