Reduced Triacylglycerol Mobilization during Seed Germination and Early Seedling Growth in Arabidopsis Containing Nutritionally Important Polyunsaturated Fatty Acids

Shrestha, Pushkar; Callahan, Damien L.; Singh, Surinder P.; Petrie, James R.; Zhou, Xue-Rong

doi:10.3389/fpls.2016.01402

Cited by 18 publications

(15 citation statements)

References 27 publications

(35 reference statements)

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“…However, the mechanisms that biochemically inhibit plastid localized acetyl‐CoA carboxylase activity due to the production of HFA in the endoplasmic reticulum are still unknown. Similar reduced oil content within transgenic seeds accumulating novel fatty acids has also been reported for a range of different transgenic plants and novel fatty acids produced (Knutzon et al., ; Larson, Edgell, Byrne, Dehesh, & Graham, ; Li et al., ; Mansour et al., ; Shrestha, Callahan, Singh, Petrie, & Zhou, ). Therefore, successful TAG composition engineering will also need to successfully recover any reduced oil penalty that novel fatty acid production has on seed oil accumulation.…”

Section: Introductionsupporting

confidence: 65%

“…The likely reason for the low oil content of the transgenics relative to the nontransgenic control was that similar to wild type (Li et al, 2006) the fae1 line has the ability to greatly increase fatty acid synthesis in response to additional light, but in each transgenic line the novel fatty acid-induced inhibition of fatty acids (Bates et al, 2014) limits this response to varying degrees (Figures 1b and 4b). Considering that reduced seed oil content has been indicated in many different instances of novel fatty acid (Knutzon et al, 1999;Larson et al, 2002;Li et al, 2012;Lunn et al, 2018;Mansour et al, 2014;Shrestha et al, 2016), it is likely that other novel fatty acid engineering strategies will demonstrate similar seed oil results based on light conditions. When interpreting conclusions on the effect of novel fatty acid engineering on total seed oil accumulation, we found that both the 5) is likely due to the differences in rate of fatty acid synthesis versus fatty acid modification.…”

Section: Effect Of Photoperiod Length On Novel Fatty Acid Engineerimentioning

confidence: 99%

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The effect of light conditions on interpreting oil composition engineering in Arabidopsis seeds

Karki

Bates

2018

Plant Direct

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Arabidopsis thaliana is the most developed and utilized model plant. In particular, it is an excellent model for proof-of-concept seed oil engineering studies because it accumulates approximately 37% seed oil by weight, and it is closely related to important Brassicaceae oilseed crops. Arabidopsis can be grown under a wide variety of conditions including continuous light; however, the amount of light is strongly correlated with total seed oil accumulation. In addition, many attempts to engineer novel seed oil fatty acid compositions in Arabidopsis have reported significant reductions in oil accumulation; however, the relative reduction from the nontrans- between transgenic lines and nontransgenic controls is dependent on both the light conditions and the type of oil content measurement utilized. In addition, the light conditions effect the relative accumulation of the novel fatty acids between various transgenic lines. Therefore, the success of novel fatty acid proof-of-concept engineering strategies on both oil accumulation and fatty acid composition in Arabidopsis seeds should be considered in light of the select growth and measurement conditions prior to moving engineering strategies into crop plants. K E Y W O R D Shydroxylated fatty acids, light, ricinoleate, triacylglycerol | INTRODUCTIONThe fatty acids within triacylglycerols (TAGs, oils) are the most energy dense form of biological carbon storage. TAGs which accumulate in the seeds of oilseed crops are an important nutritional source for both calories and essential fatty acids required in human diets. In addition, seed oils also represent a renewable resource for industrial chemicals and biofuels (Carlsson, Yilmaz, Green, Stymne, & Hofvander, 2011;Durrett, Benning, & Ohlrogge, 2008;Dyer, Stymne, Green, & Carlsson, 2008). However, many of the most nutritionally valuable or industrially useful fatty acids do not accumulate in major oilseed crops, but accumulate in microalgae or in terrestrial plants with poor agronomic features (Badami & Patil, 1980;Gunstone, Harwood, & Dijkstra, 2007). Therefore, the bioengineering wileyonlinelibrary.com/journal/pld3 | 1 of oilseed crops to accumulate TAG with novel fatty acid compositions for use in food or industrial feedstocks has been a goal of the plant lipid community for over 20 years. Most engineering of plants to produce novel TAG fatty acid compositions has been first demonstrated in Arabidopsis thaliana seeds, and the wide range of unique fatty acid compositions produced has been reviewed extensively (Aznar-Moreno & Durrett, 2017;Bates, 2016;Cahoon et al., 2007;Carlsson et al., 2011;Dyer et al., 2008;Haslam et al., 2013;Lee, Chen, & Kim, 2015;Lu, Napier, Clemente, & Cahoon, 2011;Napier, 2007;Napier, Haslam, Beaudoin, & Cahoon, 2014;Ruiz-Lopez, Usher, Sayanova, Napier, & Haslam, 2015;Singh, Zhou, Liu, Stymne, & Green, 2005;Vanhercke, Wood, Stymne, Singh, & Green, 2013).Despite the over two decades of plant lipid engineering, we still cannot predict the effect of most engineering approaches on the final f...

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Section: Introductionsupporting

confidence: 65%

Section: Effect Of Photoperiod Length On Novel Fatty Acid Engineerimentioning

confidence: 99%

The effect of light conditions on interpreting oil composition engineering in Arabidopsis seeds

Karki

Bates

2018

Plant Direct

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“…Total lipids extracted from 1 mg of T 4 homozygous seeds were dissolved 1 mL of butanol/methanol (1/1, v/v) containing 10 mM butylated hydroxytoluene. DAG and TAG species that contained DHA were analyzed using MRM mode by LC-MS as previously described ( Shrestha et al, 2016 ). The ratio of the peak area of individual species among total DHA-containing DAGs or TAGs was calculated.…”

Section: Methodsmentioning

confidence: 99%

Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase

et al. 2018

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Metabolic engineering of the omega-3 (ω3) long chain polyunsaturated fatty acid biosynthesis pathway has generated fish oil-like levels of pharmaceutically and nutritionally important docosahexaenoic acid (DHA) in plant seeds. However, the majority of DHA has been accumulated at the sn-1 and sn-3 positions of triacylglycerol (TAG) in these engineered seeds, leaving only a minor amount (∼10%) at sn-2 position and indicating a strong discrimination (or, a very poor specificity) for DHA by seed lysophosphatidic acid acyltransferases (LPAATs), which mediate the acylation of sn-2 position of glycerol backbone. In order to increase the level of DHA at sn-2 position of TAG and to increase overall DHA level in seeds, we attempted to discover DHA-preferring LPAATs. Several LPAATs for acylation of the sn-2 position of the TAG glycerol backbone were investigated for substrate preference for DHA. In transiently expressing these LPAATs in Nicotiana benthamiana, a Mortierella alpina LPAAT had the highest substrate specificity for accumulating DHA onto oleoyl-lysophosphatidic acid (oleoyl-LPA), while the plant LPAATs tested showed lower preference for DHA. In a competition assay with a pool of four ω3 acyl-Coenzyme A (CoA) substrates involved in the DHA biosynthesis pathway, LPAATs from both M. alpina and Emiliania huxleyi showed a high preference for DHA-CoA acylation onto oleoyl-LPA. When docosahexaenoyl-LPA was used as the acyl receiver, M. alpina LPAAT also showed a high preference for DHA-CoA. Stable overexpression of M. alpina LPAAT in an Arabidopsis line that expressed the DHA biosynthesis pathway significantly increased both the total DHA levels and the distribution of DHA onto the sn-2 position of seed TAG. LC-MS analysis of the seed TAG species also confirmed that overexpression of M. alpina LPAAT increased di-DHA and tri-DHA TAGs, suggesting that the M. alpina LPAAT could enrich DHA at the TAG sn-2 position, leading to a metabolic engineering of oil seed for channeling DHA into the sn-2 position of TAG and to a higher DHA level.

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“…The relationship between seed reserves and germination has been studied mainly in economically-important species such as Oryza sativa ( Sun et al, 2015 ), Glycine max ( Bellaloui et al, 2017 ), Sorghum bicolor ( Elmaki et al, 1999 ), Linum usitatissimum ( Kanmaz and Ova, 2015 ) and in the model plant species Medicago truncatula ( Vandecasteele et al, 2011 ) and Arabidopsis thaliana ( Shrestha et al, 2016 ). These previous studies on seed reserve mobilization during germination have given little attention to wild grassland species and have mainly focused either on only one type of reserves ( Kim et al, 2009 ; Shaik et al, 2014 ) or a single species (usually crops) ( Goyoaga et al, 2011 ; Ataíde et al, 2013 ; Lopes et al, 2013 ).…”

Section: Introductionmentioning

confidence: 99%

Mobilization and Role of Starch, Protein, and Fat Reserves during Seed Germination of Six Wild Grassland Species

et al. 2018

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Since seed reserves can influence seed germination, the quantitative and qualitative differences in seed reserves may relate to the germination characteristics of species. The purpose of our study was to evaluate the correlation between germination and seed reserves, as well as their mobilization during germination of six grassland species (Chloris virgata, Kochia scoparia, Lespedeza hedysaroides, Astragalus adsurgens, Leonurus artemisia, and Dracocephalum moldavica) and compare the results with domesticated species. We measured starch, protein, and fat content in dry seeds and the initial absorption of water during imbibition. Starch, soluble protein, fat, and soluble sugar content also were determined at five stages during germination. Starch, protein, and fat reserves in dry seeds were not significantly correlated with germination percentage and rate (speed), but soluble sugar and soluble protein contents at different germination stages were positively significantly correlated with germination rate for the six species. Starch was mainly used during seed imbibition, and soluble protein was used from the imbibition stage to the highest germination stage. Fat content for all species remained relatively constant throughout germination for six species, regardless of the proportion of other seed reserves in the seeds. Our results for fat utilization differ from those obtained for cultivated grasses and legumes. These results provide new insight on the role of seed reserves as energy resources in germination for wild species.

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Reduced Triacylglycerol Mobilization during Seed Germination and Early Seedling Growth in Arabidopsis Containing Nutritionally Important Polyunsaturated Fatty Acids

Cited by 18 publications

References 27 publications

The effect of light conditions on interpreting oil composition engineering in Arabidopsis seeds

The effect of light conditions on interpreting oil composition engineering in Arabidopsis seeds

Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase

Mobilization and Role of Starch, Protein, and Fat Reserves during Seed Germination of Six Wild Grassland Species

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