Oil crops for the future
Introduction
The World faces enormous challenges such as increasing productivity while lowering environmental footprints, coping with climate change, and providing renewable alternatives to fossil oil. The potential for plant oils to replace fossil oil is immense due to similarities in chemical structures. Nevertheless, there should be an economic advantage to use plant oil instead of fossil oil and sufficient quantity available to realize their full potential. Plant materials optimized in their molecular structures may replace the fossil material in the product and save energy plus processing costs. Crossbreeding facilitated by genomics and genetic engineering may lead to new oil crops that may replace fossil oils in a changing world.
This article shows how modern breeding methods (including latest molecular tools) and directed basic research may enhance the production of plant oils, lower production costs and environmental footprints, and optimize the oil quality for various non-food uses. Previous research in the area has led to the development of many new oil qualities [1]. Examples of genetic engineered oil crops with altered oil quality that have very recently been deregulated for commercial production are the super high oleic acid safflower [2••] and rape seed with ‘fish’ fatty acids (very long-chain omega-3 fatty acids) [3••]. The safflower oil could be used for many industrial applications due its extreme oxidation stability and unprecedented high oleic acid content and the rape seed oil to replace fish oil in feed for farmed fishes.
Our review highlights our efforts to domesticate the wild plant Lepidium spp. as a cold hardy, perennial high-yielding oil crop and develop added-value oils in Crambe spp. — a dedicated industrial oil crop, to replace fossil oil in the chemical industry. We also describe how photosynthates can be re-directed from starch to oil in tubers and endosperm — thus providing methods to increase plant oil production. We further describe metabolic engineering efforts that enable production of insect pheromone precursors in seed oil to replace today’s synthetic production of pheromones forecast-effective and environmentally friendly pest management. Moreover, we provide insights on the function of autophagy in crop fitness and oil accumulation.
Section snippets
Domestication and breeding of Lepidium as perennial oil crop
Many agricultural production systems involve annual crop sowing and tilling, and are energy inefficient and allow pollution of the aquatic environment due to nutrient leaching from agricultural fields. Comparatively, perennial seed crops provide better ecosystem services through higher energy use efficiency, carbon storage and better soil and water management [4,5,6•]. Similarly, biennial crops outperform annual crops in providing ecosystem services. Hence, Lepidium campestre (field cress;
Developing Crambe as an industrial oil crop platform
C. abyssinica is an oil crop with high levels (55–60%) of erucic acid (22:1) in its seed oil. Crambe has been proposed as an ideal crop for producing oil qualities intended for industrial purposes [14,15] and is currently developed for several purposes, for example, increased 22:1-content and production of a novel wax containing oil [16•]. Erucic acid is an added-value fatty acid, and its derivative erucamide is widely used in the plastic industry [17]. Oil (triacylglycerol, TAG) consists of a
Modifying carbon allocation in cereals and tuber crops
Cereal, root and tuber crops are generally rich in carbohydrates with typically very little fat. Breeding crop representatives into yielding oil could be of interest from two perspectives, namely, (i) increasing the diversity of crops for vegetable oil, and (ii) improving the nutritional balance of carbohydrate rich crops. Uniquely among cereals and tuber bearing plants, oat (Avena sativa) and yellow nutsedge (Cyperus esculentus) can produce appreciable amounts of oil in their endosperm (up to
Biopesticides: production of pheromones in plants
The larvae of many Lepidoptera (moths and butterflies) are major pests in agriculture, forestry and on stored products. Mate finding and reproduction in moths relies on female-produced sex pheromones attracting male moths from a distance [33]. The need for insect pheromones for pest control is increasing, as pheromones provide a very specific and environmentally benign form of insect pest management. Although synthetic insect pheromones can be produced in large volumes and used for mating
More oil through manipulation of autophagy
The intracellular storage and use of lipids are crucial for maintaining energy balance. When the balance becomes compromised by stress, starvation or developmental transition, a eukaryotic cell activates countermeasure mechanisms, among which autophagy (from Greek ‘eat oneself’) is considered to be especially important. During autophagy, a bulk cytoplasm or select cellular components, for example, a certain type of organelles or proteins, are engulfed by double-membrane vesicles and delivered
Conclusions
The above research highlights involved multiple strategies using modern breeding and biotechnological methods to meet the growing needs of consumers and industry for vegetable oils, including those comprised fatty acid structures for high-value applications. These efforts also have broader societal significance. For example, developing L. campestre as a perennial crop will lead to increased farmer profitability in regions such as northern Scandinavia that have limited crop alternatives due to
Conflict of interest statement
Nothing declared.
References and recommended reading
Papers of particular interest, published within the period of review, have been highlighted as:
• of special interest
•• of outstanding interest
Acknowledgements
We apologize to colleagues whose work has not been cited due to space limitation. This work was financed by grants from the Swedish Foundation for Strategic Research (SSF), the Swedish Foundation for Strategic Environmental Research (MISTRA) and Swedish University of Agricultural Sciences (SLU).
References (51)
The necessity and possibility of perennial grain crops
Renew Agric Food Syst
(2005)- et al.
Development of ultra-high erucic acid oil in the industrial oil crop Crambe abyssinica
Plant Biotechnol J
(2012) - et al.
Disrupting autophagy restores peroxisome function to an Arabidopsis lon2 mutant and reveals a role for the LON2 protease in peroxisomal matrix protein degradation
Plant Cell
(2013) - et al.
Understanding and manipulating plant lipid composition: metabolic engineering leads the way
Curr Opin Plant Biol
(2016) - et al.
Seed-specific RNAi in safflower generates a superhigh oleic oil with extended oxidative stability
Plant Biotechnol J
(2018) - et al.
Metabolic engineering of omega-3 long-chain polyunsaturated fatty acids in plants using an acyl-CoA Delta6-desaturase with omega3-preference from the marine microalga Micromonas pusilla
Metab Eng
(2010) - et al.
Prospects for developing perennial grain crops
BioScience
(2006) - et al.
Development and evolution of an intermediate wheatgrass domestication program
Sustainability
(2018) - et al.
Barley yield increases with under-sown Lepidium campestre
Acta Agric Scand B
(2010) - et al.
Domestication of Lepidium campestre as part of Mistra biotech, a research programme focused on agro biotechnology for sustainable food
Allopolyploidization and evolution of species with reduced floral structures in Lepidium L. (Brassicaceae)
Proc Natl Acad Sci U S A
Identification of genes regulating traits targeted for domestication of field cress (Lepidium campestre) as a biennial and perennial oilseed crop
BMC Genet
Pinpointing genes underlying annual/perennial transitions with comparative genomics
BMC Genomics
Breeding perennial grain crops based on wheat
Crop Sci
Molecular and genomic tools provide insights on crop domestication and evolution
Adv Agron
Crambe oil ‐ a potential new hydraulic oil and quenchant
Ind Lubr Tribol
Oil Crop Platforms for Industrial Uses: Outputs from the EPOBIO Project
Dedicated industrial oilseed crops as metabolic engineering platforms for sustainable industrial feedstock production
Sci Rep
Recent developments and perspectives of industrial rapeseed breeding
Lipid/Fett
Stereospecific analyses of seed triacylglycerols from high-erucic acid brassicaceae: detection of erucic acid at thesn-2 position in Brassica oleracea L. genotypes
J Am Oil Chem Soc
Modification of Brassica oil using conventional and transgenic approaches
Crop Sci
Bottlenecks in erucic acid accumulation in genetically engineered ultrahigh erucic acid Crambe abyssinica
Plant Biotechnol J
Activities of acyl-CoA:diacylglycerol acyltransferase (DGAT) and phospholipid:diacylglycerol acyltransferase (PDAT) in microsomal preparations of developing sunflower and safflower seeds
Planta
Lipids in grain tissues of oat (Avena sativa): differences in content, time of deposition, and fatty acid composition
J Exp Bot
Characterization of oil and starch accumulation in tubers of Cyperus esculentus var. sativus (Cyperaceae): a novel model system to study oilreserves in nonseed tissues
Am J Bot
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2022, Progress in Lipid ResearchCitation Excerpt :Thus, the modification of DGAT1 expression via various TFs offers a new suite of tools for further enhancement of seed TAG content in oil crops. There has also been considerable interest in the ME of cereals to increase their oil content and modify FA composition resulting in grains with increased nutritional value [918,919]. In cereal kernels, oil is mainly associated with the embryo and with some in the endosperm [918], although oat (Avena sativa) represents an exception where up to 18% of the DW of the endosperm is accounted for by oil [920].