Advances in genetic improvement of Camelina sativa for biofuel and industrial bio-products
Introduction
Depleting non-renewable fossil-fuel resources, rising emissions of greenhouse gases, fuel demand, and escalating prices are forcing towards sustainable alternative fuels. Biofuels have been identified as an important component of our future energy supply because they are renewable, efficient and clean burning fuels. Various edible vegetable oil crops like soybean, palm, rape seed, groundnut, sunflower and flax, and non-edible oils like cotton and jatropha are used for biodiesel production [1]. Currently, palm, soybean, rape seed and sunflower are the major biodiesel producing plants accounting 79% of the total world production of biodiesel. However, these feed stocks compete with food crop for high quality arable land and water. Therefore, oilseed crops used for biofuel production should be from non-human food sources to sustain food production [2]. Crambe (Crambe abyssinica), Camelina sativa, Jatropha curcas, Pongamia pinnata, Carinata (Brassica carinata) and Pennycress (Thlaspi arvense) are the few important alternative oilseed plants [3], [4]. Thermal efficiency, emissions and fuel consumptions have shown that camelina, pennycress and carinata had very similar engine performance to the traditional oils [5]. Yield of jatropha and others diminishes substantially on marginal land, Camelina sativa, however, grows well on marginal land with low inputs like less water, fertilizers and pesticides and has recently emerged as a promising low cost renewable source for biodiesel and industrial bio-products [6]. Use of camelina diesel reduces green house gases [GHG] emission up to 40–60% in comparison to petroleum diesel [7]. Therefore, it is essential to increase oil content and modify fatty acids to optimum composition specific for biodiesel fuel properties, nutrition and high value-added industrial products [8], [9]. Due to the limited germplasm of pre-commercial lines of C. sativa, conventional breeding is not a very promising approach; therefore, studies should focus on genetic engineering which can be achieved with relative ease and in a shorter time compared to other oilseed crops [9], [10], [11], [12]. It has been estimated that the fossil fuel reserves will be consumed by the year 2050. Hence, developing genetically superior plants for biofuel production is an efficient alternative and sustainable key to improve the competency and viability of biofuels [13].
Camelina improvement has been largely remained unexploited due to the limited availability of genetic and genomic tools [14], [15], [16]. However, the current interest in research on camelina agronomic potential, molecular markers, genetic resources including ‘omics’, genetic/metabolic engineering etc, has provided major concerned advances. The objective of this paper is to present available literature for this low cost non-food sustainable oil seed crop in an integrated form to specifically discuss the recent biotechnological advances made in genetic improvement to show up its potential for efficient utilization for biofuel and industrial applications. The review also highlights several challenges hindering genetic improvement of camelina and the strategies to overcome them which needs to be addressed in future researches to ensure wider application and economic viability of camelina as a biofuel and industrial crop.
Section snippets
Camelina: beneficial attributes
Camelina [Camelina sativa (L.) Cranz], (false flax, gold-of-pleasure) is a primeval but underexploited oilseed crop of the family Brassicaceae with a genome size of 750 Mbp with 2n=40 chromosomes [15]. Traditionally, it has been used for both human consumption and several non-food applications such as the production of soap, cosmetics, oil for lamp and safe paints [17]. Camelina is a better crop for bio-diesel production because it is a fast growing, self pollinating, hexaploid plant with short
Genetic improvement of camelina
The genus Camelina belongs to the tribe Camelineae of the family Brassicaceae. The other members of this tribe are the model plant, Arabidopsis thaliana and the weedy species,Capsella bursa pastoris. The genus Camelina has 11 species [21], of which only five species; C. sativa, C. microcarpa, C. rumelica, C. alyssum, and C. hispida are present in Europe and USA, and three species, C. sativa, C. microcarpa, and C. alyssum belongs to Canada. Among them, only C. sativa and C. microcarpa are
Molecular markers
Molecular markers have been widely exploited for genetic diversity estimation, germplasm categorization, predicting heterosis or genetic variation monitoring in breeding processes [32]. However, very few studies have been conducted to explore the genetic diversity and relationship of camelina germplasm. Phenotypic variation in seed quality characterstics is important for genetic manipulations of camelina and its establishment as an oilsedd crop. Of 130 camellina accessions investigated to see
In-vitro regeneration
Quality of the biodiesel produced from Camelina sativa could be efficiently improved by genetic engineering. A pre-requisite for effective genetic transformation is a competent in vitro regeneration system [46]. In vitro culture targets totipotency of plant cells and any explant tissues can be used as regeneration systems. Regeneration follows either through organogenesis or somatic embryogenesis. In vitro studies on Camelina sativa have been mainly centered on: (1) Shoot organogenesis and
Resistance to abiotic stresses
Camelina is cold and drought tolerant as compared to other oil seed crops [57]. However, the mechanism(s) underlying the stress-tolerance of camelina is not apparent right now [58]. It may be due to the covering of the aerial parts of camelina plants with a cuticle which is composed of cutin (composed of glycerol and long chain C16, C18 fatty acids) and waxes (straight long chain ≥C20 aliphatics). The cuticular wax reduces the non-stomatal water loss and damage from insects and pathogens and
Increase in seed size and oil content
Camelina is a small seeded plant. Increase in seed size is essential for Camelina, to improve emergence in dry, windy environment for stand establishment [60] and to enhance seed recovery with mechanized harvesting. Increase in photosynthetic activity and changes in carbon flow, and source/sink activities may enhance plant growth and seed characteristics. Camelina transgenic plants over-expressing Arabidopsis purple acid phosphatase 2 (AtPAP2) has shown early flowering, rapid growth, and
Industrial by products
Due to the depletion in fossil fuel and increased global climate change, there is a great interest to use plants for the production of industrial materials on large scale at low cost in a sustainable manner.
Camelina as an industrial protein production platform
Camelina seeds are shown to be economically viable platform to produce foreign value-added industrial protein(s) important as industrial enzymes, antibodies and binding proteins. Such potential has been demonstrated by transforming camelina with a green protein fluorescent (GFP) gene tagged with endoplasmic retention sequence KHDEL under the control of soybean seed-specific promoter, glycinin 1. The seeds of the transgenic plants produce GFP at 6% of the total protein or about 2% of the seed
Challenges for improvement of Camelina
- 1.
C. sativa has allohexapolyploid genome. As a result, most traits are controlled by multiple loci; hence their improvement through breeding and genetic manipulations will be more difficult to achieve due to their complex mode of inheritance. However, a detailed and advanced knowledge of the genomics, transcriptomics and germplasm diversity will speed up; provide accuracy and efficiency to both the approaches to design oilseed lines for the biofuel and other industries [15], [16].
- 2.
The camelina oil
Conclusions and future prospects
- •
This review emphasizes the potential of Camelina sativa for biofuel and industrial applications and discusses the challenges and putative solutions.
- •
Due to the lack of genetic variability and mutants in camelina, genetic engineering is a preffered alternative (direct way to modify fatty acid compositions by altering specific genes) for manipulation of its oil for food or non food applications to make it more competitive to other oil crops.
- •
Genetic similarity to Arabidopsis, simple and effective
Acknowledgements
MS is thankful to DST (SERB) for Young Scientist Award (SB/YS/LS-190-2014). PKJ is grateful to University Grants Commission (UGC)-SAP, Department of Biotechnology (DBT) and Department of Science and Technology (DST) (SERB/SB/SO/PS/67/2013), New Delhi for financial support to his laboratory for genetic improvement of crop plants.
References (144)
- et al.
Biodiesel production through the use of different sources and characterization of oils and their esters as the substitute of diesel: a review
Renew Sust Energy Rev
(2010) - et al.
Platform crops amenable to genetic engineering – a requirement for successful production of bio-industrial oils through genetic engineering
Biocatal Agric Biotechnol
(2014) - et al.
Development of an Agrobacterium-mediated stable transformation method for industrial oilseed crop Crambe abyssinica ‘BelAnn’
Ind Crops Prod
(2012) - et al.
Compression ignition engine performance and emission evaluation of industrial oilseed biofuel feedstocks camelina, carinata, and pennycress across three fuel pathways
Fuel
(2014) - et al.
A life cycle assessment of biodiesel derived from the niche filling energy crop camelina in the USA
Appl Energy
(2012) - et al.
Camelina sativa: an ideal platform for the metabolic engineering and field production of industrial lipids
Biochimie
(2016) Oil-seed crop: Camelina sativa
Ind Crops Prod
(1997)- et al.
Breeding for modified fatty acid composition via experimental mutagenesis in Camelina sativa (L.) Crtz
Ind Crops Prod
(1998) - et al.
Identification of three genes encoding microsomal oleate desaturases (FAD2) from the oilseed crop Camelina sativa
Plant Physiol Biochem
(2011) - et al.
Proteomics of seed development, desiccation tolerance, germination, and vigor
Plant Physiol Biochem
(2015)
Evolutionary history of plant microRNAs
Trends Plant Sci
Extracellular lipids of Camelina sativa: characterization of chloroform-extractable waxes from aerial and subterranean surfaces
Phytochemistry
Brassicaceae germplasm diversity for agronomic and seed quality traits under drought stress
Ind Crops Prod
The compatibility of potential bioderived fuels with jet A-1 aviation kerosene
Appl Energy
Constitutive flavonoids deter flea beetle insect feeding in Camelina sativa L
Biochem Syst Ecol
Over-expression of AtPAP2 in Camelina sativa leads to faster plant growth and higher seed yield
Biotech Biofuels
Renewable jet fuel
Curr Opin Biotechnol
Identification and functional characterization of genes encoding the omega-3 polyunsaturated fatty acid biosynthetic pathway from the coccolithophore Emiliania huxleyi
Phytochem
Production of mono-and sesquiterpenes in Camelina sativa oilseed
Planta
Camelina sativa: a new crop with biofuel potential introduced in India
Curr Sci
Generation of transgenic plants of a potential oilseed crop Camelina sativa by Agrobacterium-mediated transformation
Plant Cell Rep
Transformation of the oilseed crop Camelina sativa by Agrobacterium-mediated floral dip and simple largescale screening of transformants
In Vitro Cell Dev Biol Plant
Camelina seed transcriptome: a tool for meal and oil improvement and translational research
Plant Biotechnol J
Successful high-level accumulation of fish oil omega-3 long-chain polyunsaturated fatty acids in a transgenic oilseed crop
Plant J
Modifying plants for biofuel and biomaterial production
Plant Biotech J
Genetic mapping of agronomic traits in false flax (Camelina sativa subsp. Sativa)
Genome
Polyploid genome of Camelina sativa revealed by isolation of fatty acid synthesis genes
BMC Plant Biol
The emerging biofuel crop Camelina sativa retains a highly undifferentiated hexaploid genome structure
Nat Commun
Camelina oil as a fuel for diesel transport engines
Ind Crops Prod
Biodiesel from alternative oilseed feedstocks: camelina and field pennycress
Biofuels
Camelina as a sustainable oilseed crop: contributions of plant breeding and genetic engineering
Biotechnol J
Brassicaceae: chromosome number index and database on CD-Rom
Plant Syst Evol
Camelina sativa: for biofuels and bioproducts
Camelina (Camelina sativa (L). Crantz) as an alternative oilseed: molecular and ecogeographic analyses
Genome
Hybridization between Camelina sativa (L.) Crantz (false flax) and North American Camelina species
Plant Breed
Sexual hybridization between Capsella bursa‐pastoris (L.) Medik (♀) and Camelina sativa (L.) Crantz (♂)(Brassicaceae)
Plant Breed
Selection of induced mutants with improved linolenic acid content in camelina
Fett/Lipid
Camelina mutants resistant to acetolactate synthase inhibitor herbicides
Mol Breed
Genetic diversity in camelina germplasm as revealed by seed quality characteristics and RAPD polymorphism
Plant Breed
Evaluation of genetic diversity in a Camelina sativa (L.) Crantz collection using microsatellite markers and biochemical traits
Gen Res Crop Evol
h-TBP: an approach based on intron-length polymorphism for the rapid isolation and characterization of the multiple members of the β- tubulin gene family in Camelina sativa (L.) Crantz
Mol Breed
Genomic fingerprinting of Camelina species using cTBP as molecular marker
Am J Plant Sci
Singlenucleotide polymorphism identification and genotyping in Camelina sativa
Mol Breed
Gene discovery and tissue-specific transcriptome analysis in chickpea with massively parallel pyrosequencing and web resource development
Plant Physiol
Comparative deep transcriptional profiling of four developing oilseeds
Plant J
De novo assembly and characterization of Camelina sativa transcriptome by paired-end sequencing
BMC Genom
Cited by (51)
High oleic castor as a new source of biodiesel 2G
2023, Industrial Crops and ProductsExtraction of lipids from oleaginous plants and valorization of the residues obtained
2023, Valorization of Biomass to Bioproducts: Biochemicals and BiomaterialsCamelina germination under osmotic stress − Trend lines, time-courses and critical points
2022, Industrial Crops and ProductsPlants: a sustainable platform for second-generation biofuels and biobased chemicals
2022, Handbook of BiofuelsCRISPR/Cas genome editing to optimize pharmacologically active plant natural products
2021, Pharmacological ResearchCitation Excerpt :Table 3 presents application of CRISPR/Cas genome editing tool in different medicinal plants for production of valuable secondary metabolites. Camelina sativa (Brassicaceae), also known as false-flax, has gained considerable interest during the recent past for biotechnological improvement and for industrial use owing to its distinctive seed oil fatty acid composition [with high amount of oil (45 %) which a rich source of unsaturated fatty acids] potentiating its high-value in bio-fuel industry, human nutrition, pharmaceuticals (especially terpenoids) and cosmetics [96,97]. Camelina is an age old plant distributed mainly in the Europe and Central Asia.
Altered redox processes, defense responses, and flowering time are associated with survival of the temperate Camelina sativa under subtropical conditions
2020, Environmental and Experimental BotanyCitation Excerpt :Only 0.5% of the released varieties are related to heat tolerance (https://mvd.iaea.org/). Ethyl methanesulfonate (EMS) mutagenized Camelina has been reported (Büchsenschütz-Nothdurft et al., 1998), and some Camelina breeding by mutagenesis has been undertaken, however never with the focus on stress tolerance (Sainger et al., 2017; https://mvd.iaea.org/). Camelina is sensitive to heat stress; a short heat-exposure at 35 °C significantly inhibited photosynthesis and dramatically decreased yield (Carmo-Silva and Salvucci, 2012).