scholarly journals The Arabidopsis MYB96 Transcription Factor Mediates ABA-Dependent Triacylglycerol Accumulation in Vegetative Tissues under Drought Stress Conditions

Plants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 296 ◽  
Author(s):  
Hong Gil Lee ◽  
Mid-Eum Park ◽  
Bo Yeon Park ◽  
Hyun Uk Kim ◽  
Pil Joon Seo
Keyword(s):  
Transcription Factor ◽  
Drought Stress ◽  
Molecular Networks ◽  
Plant Fitness ◽  
Plant Tolerance ◽  
Adaptive Responses ◽  
Vegetative Tissues ◽  
Tag Biosynthesis ◽  
Triacylglycerol Accumulation ◽  
Tag Accumulation

Triacylglycerols (TAGs), a major lipid form of energy storage, are involved in a variety of plant developmental processes. While carbon reserves mainly accumulate in seeds, significant amounts of TAG have also been observed in vegetative tissues. Notably, the accumulation of leaf TAGs is influenced by environmental stresses such as drought stress, although underlying molecular networks remain to be fully elucidated. In this study, we demonstrate that the R2R3-type MYB96 transcription factor promotes TAG biosynthesis in Arabidopsis thaliana seedlings. Core TAG biosynthetic genes were up-regulated in myb96-ox seedlings, but down-regulated in myb96-deficient seedlings. In particular, ABA stimulates TAG accumulation in the vegetative tissues, and MYB96 plays a fundamental role in this process. Considering that TAG accumulation contributes to plant tolerance to drought stress, MYB96-dependent TAG biosynthesis not only triggers plant adaptive responses but also optimizes energy metabolism to ensure plant fitness under unfavorable environmental conditions.

scholarly journals Drought stress - related functional characterization of transcription factor GmNAC085 in soybean

2020 ◽  
Vol 16 (4) ◽  
pp. 641-648
Author(s):  
Tran Thi Khanh Hoa ◽  
Huynh Ngoc Tuyet ◽  
Nguyen Phuong Thao ◽  
Hoang Thi Lan Xuan
Keyword(s):  
Transcription Factor ◽  
Drought Stress ◽  
Shoot Growth ◽  
Functional Characterization ◽  
Water Shortage ◽  
Plant Tolerance ◽  
Wild Type ◽  
Peroxidase Enzyme ◽  
Scavenging Enzymes

Studies on soybean GmNAC085 transcription factor revealed that the gene expression in plants was induced by water shortage treatments and its overexpression in the model plant Arabidopsis displayed improved plant tolerance characteristics towards drought stress. In this study, we continued analyzing the biological functions of GmNAC085 using transgenic soybean system overexpressing GmNAC085 gene, by targeting at a number of plant physiological features and biochemical activities in response to limited water growing condition. Compared to the wild-type, the transgenic line demonstrated that it possessed stress tolerance characters, including enhanced elongation of taproot, minimized reduction of shoot growth, lower intracellular H2O2 content and stronger peroxidase enzyme activity under drought condition. The results of this study therefore suggest the transgenic plants had better drought tolerance and the GmNAC085 plays important role in aiding plants to cope with water deficit condition, probably via regulating the growth of roots and shoots, and activities of reactive-oxygen-species- scavenging enzymes.

scholarly journals Ectopic overexpression of a type-II DGAT (CeDGAT2-2) derived from oil-rich tuber of Cyperus esculentus enhances accumulation of oil and oleic acid in tobacco leaves

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yu Gao ◽  
Yan Sun ◽  
Huiling Gao ◽  
Ying Chen ◽  
Xiaoqing Wang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Negative Impact ◽  
Value Added ◽  
Cyperus Esculentus ◽  
Wild Type ◽  
Tobacco Leaves ◽  
Vegetative Tissues ◽  
Oil Storage ◽  
Tag Biosynthesis

Abstract Background Engineering triacylglycerol (TAG) accumulation in vegetative tissues of non-food crops has become a promising way to meet our increasing demand for plant oils, especially the renewable production of biofuels. The most important target modified in this regard is diacylglycerol acyltransferase (DGAT) enzyme responsible for the final rate-limiting step in TAG biosynthesis. Cyperus esculentus is a unique plant largely accumulating oleic acid-enriched oil in its underground tubers. We speculated that DGAT derived from such oil-rich tubers could function more efficiently than that from oleaginous seeds in enhancing oil storage in vegetative tissues of tobacco, a high-yielding biomass crops. Results Three CeDGAT genes namely CeDGAT1, CeDGAT2-1 and CeDGAT2-2 were identified in C. esculentus by mining transcriptome of developing tubers. These CeDGATs were expressed in tissues tested, with CeDGAT1 highly in roots, CeDGAT2-1 abundantly in leaves, and CeDGAT2-2 predominantly in tubers. Notably, CeDGAT2-2 expression pattern was in accordance with oil dynamic accumulation during tuber development. Overexpression of CeDGAT2-2 functionally restored TAG biosynthesis in TAG-deficient yeast mutant H1246. Oleic acid level was significantly increased in CeDGAT2-2 transgenic yeast compared to the wild-type yeast and ScDGA1-expressed control under culture with and without feeding of exogenous fatty acids. Overexpressing CeDGAT2-2 in tobacco led to dramatic enhancements of leafy oil by 7.15- and 1.7-fold more compared to the wild-type control and plants expressing Arabidopsis seed-derived AtDGAT1. A substantial change in fatty acid composition was detected in leaves, with increase of oleic acid from 5.1% in the wild type to 31.33% in CeDGAT2-2-expressed tobacco and accompanied reduction of saturated fatty acids. Moreover, the elevated accumulation of oleic acid-enriched TAG in transgenic tobacco exhibited no significantly negative impact on other agronomic traits such as photosynthesis, growth rates and seed germination except for small decline of starch content. Conclusions The present data indicate that CeDGAT2-2 has a high enzyme activity to catalyze formation of TAG and a strong specificity for oleic acid-containing substrates, providing new insights into understanding oil biosynthesis mechanism in plant vegetative tissues. Overexpression of CeDGAT2-2 alone can significantly increase oleic acid-enriched oil accumulation in tobacco leaves without negative impact on other agronomy traits, showing CeDGAT2-2 as the desirable target gene in metabolic engineering to enrich oil and value-added lipids in high-biomass plants for commercial production of biofuel oils.

scholarly journals NAC Transcription Factor PwNAC11 Activates ERD1 by Interaction with ABF3 and DREB2A to Enhance Drought Tolerance in Transgenic Arabidopsis

2021 ◽  
Vol 22 (13) ◽  
pp. 6952
Author(s):  
Mingxin Yu ◽  
Junling Liu ◽  
Bingshuai Du ◽  
Mengjuan Zhang ◽  
Aibin Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Drought Stress ◽  
Stress Response ◽  
Transcriptional Activation ◽  
Dominant Role ◽  
State Level ◽  
Energy Conversion Efficiency ◽  
Nac Transcription Factor ◽  
Wild Plants ◽  
Transgenic Lines

NAC (NAM, ATAF1/2, and CUC2) transcription factors are ubiquitously distributed in eukaryotes and play significant roles in stress response. However, the functional verifications of NACs in Picea (P.) wilsonii remain largely uncharacterized. Here, we identified the NAC transcription factor PwNAC11 as a mediator of drought stress, which was significantly upregulated in P. wilsonii under drought and abscisic acid (ABA) treatments. Yeast two-hybrid assays showed that both the full length and C-terminal of PwNAC11 had transcriptional activation activity and PwNAC11 protein cannot form a homodimer by itself. Subcellular observation demonstrated that PwNAC11 protein was located in nucleus. The overexpression of PwNAC11 in Arabidopsis obviously improved the tolerance to drought stress but delayed flowering time under nonstress conditions. The steady-state level of antioxidant enzymes’ activities and light energy conversion efficiency were significantly increased in PwNAC11 transgenic lines under dehydration compared to wild plants. PwNAC11 transgenic lines showed hypersensitivity to ABA and PwNAC11 activated the expression of the downstream gene ERD1 by binding to ABA-responsive elements (ABREs) instead of drought-responsive elements (DREs). Genetic evidence demonstrated that PwNAC11 physically interacted with an ABA-induced protein—ABRE Binding Factor3 (ABF3)—and promoted the activation of ERD1 promoter, which implied an ABA-dependent signaling cascade controlled by PwNAC11. In addition, qRT-PCR and yeast assays showed that an ABA-independent gene—DREB2A—was also probably involved in PwNAC11-mediated drought stress response. Taken together, our results provide the evidence that PwNAC11 plays a dominant role in plants positively responding to early drought stress and ABF3 and DREB2A synergistically regulate the expression of ERD1.

scholarly journals The SUGAR-DEPENDENT1 Lipase Limits Triacylglycerol Accumulation in Vegetative Tissues of Arabidopsis

2013 ◽  
Vol 162 (3) ◽  
pp. 1282-1289 ◽  
Author(s):  
A. A. Kelly ◽  
H. van Erp ◽  
A.-L. Quettier ◽  
E. Shaw ◽  
G. Menard ◽  
...  
Keyword(s):  
Vegetative Tissues ◽  
Triacylglycerol Accumulation

scholarly journals Characterisation of DGAT1 and DGAT2 from Jatropha curcas and their functions in storage lipid biosynthesis

2014 ◽  
Vol 41 (3) ◽  
pp. 321 ◽  
Author(s):  
Ronghua Xu ◽  
Tianquan Yang ◽  
Ruling Wang ◽  
Aizhong Liu
Keyword(s):  
Linoleic Acid ◽  
Jatropha Curcas ◽  
Molecular Mechanisms ◽  
Functional Divergence ◽  
Critical Role ◽  
Linoleic Acid Content ◽  
Transgenic Yeast ◽  
Kennedy Pathway ◽  
Tag Biosynthesis ◽  
Tag Accumulation

Diacylglycerol acyltransferases (DGATs) catalyse the final step of triacylglycerol (TAG) biosynthesis of the Kennedy pathway, and play a critical role during TAG accumulation in developing oleaginous seeds. In this study, the molecular cloning and characterisation of two DGAT genes, JcDGAT1 and JcDGAT2, from jatropha (Jatropha curcas L., a potential biodiesel plant) is presented. Using heterogonous overexpression techniques, both JcDGAT1 and JcDGAT2 were able to restore TAG biosynthesis in a yeast mutant H1246 strain, and enhance the quantity of TAG biosynthesis by 16.6 and 14.3%, respectively, in strain INVSc1. In transgenic tobacco, overexpression of JcDGAT1 and JcDGAT2 resulted in an increase in seed oil content of, respectively, 32.8 and 31.8%. Further, the functional divergence of JcDGAT1 and JcDGAT2 in TAG biosynthesis was demonstrated by comparing the fatty acid compositions in both the transgenic yeast and tobacco systems. In particular, JcDGAT2 incorporated a 2.5-fold higher linoleic acid content into TAG than JcDGAT1 in transgenic yeast and exhibited a significant linoleic acid substrate preference in both yeast and tobacco. This study provides new insights in understanding the molecular mechanisms of DGAT genes underlying the biosynthesis of linoleic acids and TAG in plants.

Adaptive responses to drought of two Retama raetam subspecies from Tunisia

2021 ◽  
Author(s):  
Ricardo GIL ◽  
Dhikra ZAYOUD ◽  
Zeineb OUERGHI ◽  
Monica BOSCAIU ◽  
Oscar VICENTE ◽  
...  
Keyword(s):  
Drought Stress ◽  
Glycine Betaine ◽  
Soluble Sugars ◽  
Co2 Concentration ◽  
Photosynthetic Parameters ◽  
Adaptive Responses ◽  
Retama Raetam ◽  
Physiological Adaptations ◽  
Use Efficiency ◽  
Desert Climate

Abstract Aims The survival and ecological distribution of plants in arid habitats are mainly conditioned by water availability and physiological adaptations to withstand drought. In the present study, we have compared the physiological responses to drought of two Retama raetam (retama) subspecies from Tunisia, one of them living under the desert climate (subsp. raetam) and the other one growing on the coast (subsp. bovei). Methods To physiologically characterize the two R. raetam subspecies, and to elucidate their main mechanisms underlying their tolerance to drought stress, parameters related to seed germination, growth, photosynthesis (net photosynthetic rate, intracellular CO2 concentration, transpiration rate, stomatal conductance and water use efficiency), and accumulation of osmolytes (proline, glycine betaine and soluble sugars) were determined in four-month-old plants subjected to stress for up to one month. Important findings Drought significantly inhibited germination, growth, and all the evaluated photosynthetic parameters. Plants of R. raetam subsp. bovei were severely affected by drought after three weeks of treatment when photosynthesis rates were up to 7-fold lower than in the controls. At the same time, proline and glycine betaine significantly accumulated compared to the irrigated controls, but much less than in R. raetam subsp. raetam; in the latter subspecies, proline and glycine betaine increased to levels 24-fold and 6-fold higher, respectively, than in the corresponding controls. In summary, the population living in the desert region exhibited stronger tolerance to drought stress than that adapted to the semiarid littoral climate, suggesting that tolerance in R. raetam is dependent on accumulation of osmolytes.

scholarly journals The Rhodococcus opacus PD630 Heparin-Binding Hemagglutinin Homolog TadA Mediates Lipid Body Formation

2010 ◽  
Vol 76 (21) ◽  
pp. 7217-7225 ◽  
Author(s):  
Daniel P. MacEachran ◽  
M. E. Prophete ◽  
A. J. Sinskey
Keyword(s):  
Kinetic Studies ◽  
Lipid Body ◽  
Dry Weight ◽  
Rhodococcus Opacus ◽  
Lipid Bodies ◽  
Heparin Binding ◽  
Tag Biosynthesis ◽  
Tag Accumulation

ABSTRACT Generally, prokaryotes store carbon as polyhydroxyalkanoate, starch, or glycogen. The Gram-positive actinomycete Rhodococcus opacus strain PD630 is noteworthy in that it stores carbon in the form of triacylglycerol (TAG). Several studies have demonstrated that R. opacus PD630 can accumulate up to 76% of its cell dry weight as TAG when grown under nitrogen-limiting conditions. While this process is well studied, the underlying molecular and biochemical mechanisms leading to TAG biosynthesis and subsequent storage are poorly understood. We designed a high-throughput genetic screening to identify genes and their products required for TAG biosynthesis and storage in R. opacus PD630. We identified a gene predicted to encode a putative heparin-binding hemagglutinin homolog, which we have termed tadA (triacylglycerol accumulation deficient), as being important for TAG accumulation. Kinetic studies of TAG accumulation in both the wild-type (WT) and mutant strains demonstrated that the tadA mutant accumulates 30 to 40% less TAG than the parental strain (WT). We observed that lipid bodies formed by the mutant strain were of a different size and shape than those of the WT. Characterization of TadA demonstrated that the protein is capable of binding heparin and of agglutinating purified lipid bodies. Finally, we observed that the TadA protein localizes to lipid bodies in R. opacus PD630 both in vivo and in vitro. Based on these data, we hypothesize that the TadA protein acts to aggregate small lipid bodies, found in cells during early stages of lipid storage, into larger lipid bodies and thus plays a key role in lipid body maturation in R. opacus PD630.

scholarly journals The Arabidopsis Cys2/His2 zinc finger transcription factor ZAT18 is a positive regulator of plant tolerance to drought stress

2017 ◽  
Vol 68 (11) ◽  
pp. 2991-3005 ◽  
Author(s):  
Mingzhu Yin ◽  
Yanping Wang ◽  
Lihua Zhang ◽  
Jinzhu Li ◽  
Wenli Quan ◽  
...  
Keyword(s):  
Drought Stress ◽  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Leaf Water ◽  
Pathway Enrichment Analysis ◽  
Antioxidant Enzyme Activities ◽  
Sequencing Analysis ◽  
Plant Tolerance ◽  
Drought Treatment ◽  
Positive Regulator

Abstract Environmental stress poses a global threat to plant growth and reproduction, especially drought stress. Zinc finger proteins comprise a family of transcription factors that play essential roles in response to various abiotic stresses. Here, we found that ZAT18 (At3g53600), a nuclear C2H2 zinc finger protein, was transcriptionally induced by dehydration stress. Overexpression (OE) of ZAT18 in Arabidopsis improved drought tolerance while mutation of ZAT18 resulted in decreased plant tolerance to drought stress. ZAT18 was preferentially expressed in stems, siliques, and vegetative rosette leaves. Subcellular location results revealed that ZAT18 protein was predominantly localized in the nucleus. ZAT18 OE plants exhibited less leaf water loss, lower content of reactive oxygen species (ROS), higher leaf water content, and higher antioxidant enzyme activities after drought treatment when compared with the wild type (WT). RNA sequencing analysis showed that 423 and 561 genes were transcriptionally modulated by the ZAT18 transgene before and after drought treatment, respectively. Pathway enrichment analysis indicated that hormone metabolism, stress, and signaling were over-represented in ZAT18 OE lines. Several stress-responsive genes including COR47, ERD7, LEA6, and RAS1, and hormone signaling transduction-related genes including JAZ7 and PYL5 were identified as putative target genes of ZAT18. Taken together, ZAT18 functions as a positive regulator and plays a crucial role in the plant response to drought stress.

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