Increasing seed oil content in Brassica species through breeding and biotechnology

Increasing the seed oil content of Brassica species and other major oilseed crops is of paramount importance in maintaining a future supply of vegetable oil for a growing global population. Currently, commercially‐available Brassica species with enhanced seed oil content have all been developed through plant breeding. Many quantitative trait loci including gene interactions are involved in the control of seed oil content. Despite this complexity, manipulation of specific steps in storage lipid biosynthesis using genetic engineering has resulted in transgenic lines of Brassica napus with increased seed oil content. Recent studies suggest that engineering of seed oil content can be guided using methods in metabolic analysis.     

Analyzing seed weight,fatty acid composition,oil, and protein contents in <Emphasis Type="Italic">Vernonia galamensis</Emphasis> germplasm by near-infrared reflectance spectroscopy

Vernonia galamensis is a potential new industrial oilseed crop from the Asteraceae family. The interest in this species is due to the presence of a high vernolic acid content of its seed oil, which is useful in the oleochemical industry for paints and coatings. The development of a rapid, precise, robust, nondestructive, and economical method to evaluate quality components is of major interest to growers, processors, and breeders. NIR reflectance spectroscopy (NIRS) is routinely used for the prediction of quality traits in many crops. This study was conducted to establish a rapid analytical method for determining the quality of intact seeds of V. galamensis. A total of 114 Vernonia accessions were scanned to determine seed weight, FA composition, oil, and protein contents using NIRS. Conventional chemical analysis for FA composition, total oil, and protein contents were performed by GC, Soxhlet extraction, and the Dumas combustion method, respectively. Calibration equations were developed and tested through cross-validation. The coefficient of determination in cross-validation for FA ranged from 0.47 (linoleic acid) to 0.55 (vernolic acid), and for oil, protein, and seed weight from 0.71 (oil) to 0.86 (seed protein). It was concluded that NIRS calibration equations developed for seed weight and seed quality traits can be satisfactorily used as early screening methods in V. galamensis breeding programs.     

Practical considerations in commercial utilization of oilseeds

In the past 40 years oilseeds have gained a dominant position in the U.S. agriculture. Soybeans have made more rapid progress in the feed and food industries than other oilseeds because of the low cost in their production, easy adaptability to solvent processing, and importance to the feed and food industries. The foreign markets have been a great asset to the soybean industry. However, each of the other oilseeds is finding its special place in the industry through modification of the seed by plant breeding, the development of new techniques in oil mill processing and other technical modifications. Even geographical location of a crop can be a deciding factor in the economics of successful operation. Production and processing of oilseeds in other countries often presents economic and food acceptance problems that are entirely different than those in the U.S. Both the favorable and unfavorable factors involved in production, composition, processing and conversion of the protein concentrates into acceptable foods are discussed. The recent oilseed research and development which holds promise for increasing utilization of oilseed in foods is reviewed. This includes progress in the breeding of high protein soybeans, new centrifugal techniques for reducing the gossypol in cottonseed meal, progress in the development and production of glandless cottonseed, processing new varieties of sunflower seed, the potential for new and improved oil solvents, the advantages of extrusion processing of oilseed meals, and other techniques which might be expected to improve the color, flavor, texture and other properties of oilseed proteins for foods. Presented at the AOCS-AACC Joint Protein Short Course, French Lick, Indiana, July 13–16, 1969.     

Effects of Drought Stress on Oil Characteristics of <Emphasis Type="Italic">Carthamus</Emphasis> Species

Safflower (Carthamus tinctorius L.) is one of the oldest domesticated crops, mainly grown as oilseed in the arid and semi arid regions of the world. Cross‐ability of Carthamus species has made wild safflower species a suitable source for transferring drought tolerant genes to cultivated species. This study was conducted to investigate seed yield per plant, oil content and fatty acid composition of some Carthamus species and to identify the effects of drought stress on these measured traits. In this regard, 27 genotypes from C. tinctorius, C. palaestinus, C. oxyacanthus, C. lanatus and C. glaucus were planted in the field under normal and drought‐stress conditions for two years. Results showed that some studied species differed in oil content, seed yield per plant and fatty acid profiles. As an example, the highest seed oil content (32%) was found in genotype number 22 from C. palaestinus, and the lowest (18%) was obtained for the genotype number 11 from C. lanatus. For all the species, oil content was not affected by moisture stress and did not change over different environments. Similar and stable responses of various Carthamus species for fatty acid composition indicated that hybridization between these species for genetic improvement of drought tolerance may have no adverse effects on oil quality. Considerable diversity within species for all measured traits, similarity in fatty acid profiles and almost the same pattern of changes under drought stress showed that the wild species especially the crossable ones, are good candidates to be used in breeding of cultivated safflower.     

Agricultural and genetic potentials of cruciferous oilseed crops

Oilseed crops of the Cruciferae are widely adapted and are of particular importance to countries in the northern latitudes. Cruciferous seed oils from the crops, rapeseed, mustard, Camelina, oilseed radish and Crambe, enter edible or industrial markets, or both. The oil-seed meal can be used either as a high protein feed supplement or as an organic fertilizer. The spring and winter forms of the two species of rapeseed,Brassica napus andB. campestris, are commercially the most important. Advances in crop management and plant breeding have resulted in a 40% to 50% increase in seed yield over the past 25 years. In the next 10 to 15 years, application of newer plant-breeding techniques will result in varieties even higher in yield and seed with improved oil and meal quality. Some of the quality improvements will be new patterns in fatty acid composition, higher oil and protein content, lower fiber content, and removal of the undesirable glucosinolate compounds from the meal. The mustard cropsBrassica juncea andB. hirta are important condiment crops which have considerable potential as edible oil sources. Oilseed radish,Raphanus sativus, yields significantly less seed and oil than other cruciferous oil crops but its oil, which contains a low level of erucic acid (3.7%) and a relatively high content of 16-carbon fatty acids (9.3%), may be useful in blending with normal or zero erucic acid rapeseed oils.Camelina sativa or false flax has many desirable agronomic characteristics but the oil of camelina seed contains too high a level of linolenic acid (36%) to penetrate the edible oil market and too low to compete industrially with linseed oil.Crambe abyssinica andC. hispanica are potentially important producers of high erucic acid industrial oils. Factors limiting Crambe development are the high cost of seed transportation due to the high volume to weight ratio of the threshed seed and the need for extra seed processing steps to render the meal suitable as a high protein feed supplement for livestock and poultry. One of 9 papers presented at the Symposium, “Cruciferous Oilseeds,” ISF-AOCS World Congress, Chicago, September 1970. Contribution No. 425, Research Station, Canada Department of Agriculture, Saskatoon, Saskatchewan, Canada.     

Application of Upstream Open Reading Frames (uORFs) Editing for the Development of Stress-Tolerant Crops

Global population growth and climate change are posing increasing challenges to the production of a stable crop supply using current agricultural practices. The generation of genetically modified (GM) crops has contributed to improving crop stress tolerance and productivity; however, many regulations are still in place that limit their commercialization. Recently, alternative biotechnology-based strategies, such as gene-edited (GE) crops, have been in the spotlight. Gene-editing technology, based on the clustered regularly interspaced short palindromic repeats (CRISPR) platform, has emerged as a revolutionary tool for targeted gene mutation, and has received attention as a game changer in the global biotechnology market. Here, we briefly introduce the concept of upstream open reading frames (uORFs) editing, which allows for control of the translation of downstream ORFs, and outline the potential for enhancing target gene expression by mutating uORFs. We discuss the current status of developing stress-tolerant crops, and discuss uORF targets associated with salt stress-responsive genes in rice that have already been verified by transgenic research. Finally, we overview the strategy for developing GE crops using uORF editing via the CRISPR-Cas9 system. A case is therefore made that the mutation of uORFs represents an efficient method for developing GE crops and an expansion of the scope of application of genome editing technology.     

Mechanics of oil expression from canola

A laboratory-scale oilseed screw press was used to investigate the effects of shaft speed and choke opening and of seed pretreatments, including moisture conditioning, flaking and preheating, on the canola pressing performance. Maximum pressure increased, and press throughput and residual oil (RO) in presscake both decreased, with a reduction in choke opening and with lowering of shaft speed. When either whole seed or flakes were preheated in the range 40–100C, the pressure and throughput increased, and RO decreased. Press throughput and oil output both achieved maxima at a 5.0% moisture content in seed, while the RO showed a continuous increase with increasing seed moisture contents. The observed effects of choke opening and shaft speed on pressure, throughput, RO and press temperature could be explained with the aid of a simple equation representing the axial flow within the press. The same equation also served to explain the changes in pressure and throughput corresponding to the various seed pretreatments, when changes in viscosity of the oilseed mass were postulated. It was inferred that any seed pretreatment which increased viscosity would also increase throughput of the press. A further examination of the individual components of viscosity might explain the changes in the residual oil content and facilitate the development of improved or novel pretreatments of oilseeds.     

1978 world fats and oils situation

As expected, world oil and meal production and demand this year have been above trend, but the U.S. share of world markets has been greater than projected because of smaller than anticipated oilseed crops in Brazil, the Soviet Union, India, and Senegal. World 1978 fats and oils supplies should be around 53 million metric tons with export markets absorbing about 17 million metric tons. The U.S. 1978 soybean crop may equal or excel the 1977 crop; Canada’s oilseed crops are expected to be up, and Brazil’s 1979 soybean crop is expected to rebound from the 1978 level.     

Recent Progress in Enhancing Fungal Disease Resistance in Ornamental Plants

Fungal diseases pose a major threat to ornamental plants, with an increasing percentage of pathogen-driven host losses. In ornamental plants, management of the majority of fungal diseases primarily depends upon chemical control methods that are often non-specific. Host basal resistance, which is deficient in many ornamental plants, plays a key role in combating diseases. Despite their economic importance, conventional and molecular breeding approaches in ornamental plants to facilitate disease resistance are lagging, and this is predominantly due to their complex genomes, limited availability of gene pools, and degree of heterozygosity. Although genetic engineering in ornamental plants offers feasible methods to overcome the intrinsic barriers of classical breeding, achievements have mainly been reported only in regard to the modification of floral attributes in ornamentals. The unavailability of transformation protocols and candidate gene resources for several ornamental crops presents an obstacle for tackling the functional studies on disease resistance. Recently, multiomics technologies, in combination with genome editing tools, have provided shortcuts to examine the molecular and genetic regulatory mechanisms underlying fungal disease resistance, ultimately leading to the subsequent advances in the development of novel cultivars with desired fungal disease-resistant traits, in ornamental crops. Although fungal diseases constitute the majority of ornamental plant diseases, a comprehensive overview of this highly important fungal disease resistance seems to be insufficient in the field of ornamental horticulture. Hence, in this review, we highlight the representative mechanisms of the fungal infection-related resistance to pathogens in plants, with a focus on ornamental crops. Recent progress in molecular breeding, genetic engineering strategies, and RNAi technologies, such as HIGS and SIGS for the enhancement of fungal disease resistance in various important ornamental crops, is also described.     

Calendula and Coriandrum – New Potential Oilcrops for Industrial Uses

In a two years' field test Calendula officinalis and Coriandrum sativum were shown to be promising candidates for new crops for industrial oil productions. In Calendula seed oil the main fatty acid is calendic acid containing three conjugated double bonds. The mean oil content is 19.4%, and 62.8% of all fatty acids are calendic acid. Seed yield potential of C. officinalis proved to be excellent, but seed shedding is a major problem. Within the species a wide variation was established for genetic differences in, e.g. date of flowering, flower heads per plant, ray and disk flowers and different achene types. For sowing and harvest common farm machinery can be used. In Coriandrum sativum the main fatty acid is petroselinic acid, an isomer of the oleic acid. The agronomic potential of C. sativum appeared to be very good and no special breeding efforts are necessary to initiate first productions. The oil content was 17.1%, and 82% of all fatty acids consisted of oleic and petroselinic acid. In a 2 ha field trial with C. sativum the seed yield was as high as 25 dt/ha. Further breeding work should be directed to increase the oil content of the fruit and to possibly improve disease resistance.     

Breeding for Improved Oil Quality in Winterrape by Means of Haploid Culture Techniques

Farmers growing oilseed rape are facing well defined demands on the quality traits of their product. Therefore their crops are regularly grown from seed with genetically low erucic acid and low glucosinolate content. But well adapted varieties with low linolenic acid content or yellow seed coat would fit further demands of seed crushers. Such genotypes exist, but in general they have poor agricultural habits. Breeders select for genotypes combining quality traits with good adaption to the farmers' need. The breeders' success is limited by genetical influences as segregation within the tested progenies and dominance of the traits, and non-genetical influences on the expression of the traits. To eliminate the genetical influences would require very time consuming conventional breeding methods. The recently developed haploid culture techniques are alternatives to these conventional breeding methods. However, to develop a single testing unit is very expensive. The use of such methods therefore is only justified, if the magnitude of the former mentioned genetic effects hinders the efficient enhancement of the quality traits. Genetic effects estimated by various authors give no expectation of such influences. A clear advantage of the haploid techniques in enhancing the quality traits discussed here, is therefore not anticipated.     

Why is it so difficult to produce high‐quality virgin rapeseed oil for human consumption?

Virgin rapeseed oil becomes increasingly popular for the consumer because of the pleasant seed‐like and nutty taste and smell. The oils are produced in small and medium‐sized facilities by extraction of rapeseed using only a screw press and purifying the oil by sedimentation or filtration. Thus, the producers have no chance to improve the oil quality if the seed quality is bad. Therefore, it is an art to produce high‐quality virgin rapeseed oil that is accepted by the consumer. The most important step in the production chain of virgin rapeseed oil is the period after harvest until the processing, while extraction of the oilseed and purification has only a minor influence on the oil quality. The paper describes the pitfalls during the production of virgin rapeseed oil which primarily wait for the producer during storage of the seeds. Improper storage conditions result in increased metabolic processes in the seeds and an increase of the populations of microorganisms and insects, which finally leads to the degradation of nutrients and the formation of unpleasant aroma compounds.     

Low linolenic soybeans and beyond

Low linolenic soybean oil is the first in a series of modified oilseed products to be introduced to meet food company and consumer needs. Consumer packaged goods and foodservice companies are currently using this oil to successfully replace partially hydrogenated soybean oil, resulting in the reduction of trans fatty acids from the food supply. In addition to meeting consumer demand for healthier foods, many food processors have chosen low linolenic soybean oil based on taste, performance and cost benefits. Seed companies continue to utilize traditional breeding, marker assisted breeding and biotechnology approaches to modify oilseeds that produce oils with health and nutrition benefits. Additional modified oilseeds are at various stages of development. Soybeans with increased levels of stearic acid are being developed as an alternative to partially hydrogenated fats and high saturate fats required to provide solids and structure to food. High stability fry oils with increased levels of oleic acid, reduced levels of linolenic acid as well as a version with lower saturated fat are being developed. Soybeans are also being modified to offer more sustainable sources of omega‐3s including stearidonic acid and eicosapentaenoic acid/docosahexaenoic acid which will result in more efficacious sources of omega‐3s compared to alpha‐linolenic acid‐containing vegetable oil and improved functionality/stability compared to fish and algal oils.     

Characterization of Seed,Oil, and Fatty Acid Methyl Esters of an Ethyl Methanesulfonate Mutant of Camelina sativa with Reduced Seed-Coat Mucilage

Camelina sativa L. Crantz (large-seeded false flax) is a promising oilseed crop for the production of edible oil and biodiesel. An ethyl methanesulfonate (EMS) mutant of C. sativa was identified that lacked seed coat mucilage (SCM) using Ruthenium Red (RR) colorimetric staining. Compared with wild-type (WT) plants, the mucilage-defect mutant line (Cs98) had smaller seeds and seeds with significantly less SCM, but exhibited significantly taller plant height. The seed mass and oil content of the seeds of Cs98 were significantly lower than those of WT plants. However, the seeds of Cs98 had significantly higher crude protein and starch contents, but a significantly lower neutral detergent-soluble fiber (NDSF) fraction (pectin) content. Although Cs98 seed contained significantly higher mineral contents for various macro- and microminerals (e.g., Mg, S, Al, Cu, Mn, Fe, and Zn), these large differences did not prevent the Cs98 seed biodiesel from passing all American Society for Testing and Materials (ASTM) standards for macro- and micromineral content and viscosity, pH, and turbidity. Notably, the oil and biodiesel derived from Cs98 had significantly reduced viscosity compared with WT. Water washes of oil derived from WT and Cs98 seed confirmed that the Cs98 contained only 57% of the mucilage content of the WT oil washes. These significantly lower pectic residues are expected to improve the flow characteristics of the resultant oil and require less washing during biodiesel production.     

Outlook for high‐oleic peanuts and peanut products in 21st century markets

The global oilseed market is dominated by and steadily is becoming more dependent on palm and soybean as major commodity sources to meet growing demand for edible vegetable oil and protein. However, the loss of GRAS status for hydrogenated oils in the U.S., concern for sustainable production practices, debate on dietary saturated fats, and other constraints signal the need for economic alternatives in the oilseed commodity market. Recent technological advances elevate the position of oilseed peanut in such consideration [1]. For example, analysis of the peanut genome sequence has: 1) revealed the chromosomal location of genes that can protect the crop against major diseases (thus reducing need for multiple applications of fungicides), and genes that mediate high‐oleic acid concentration (thus enhancing health benefits, longer product shelf‐life, and improved flavor); 2) generated DNA markers that help breeders track and stack desired genes in hybrid lines; and 3) enabled modern DNA‐sequence driven breeding methods that cut years off the timeline for developing varieties. These capabilities will help reduce cost of production, lead industry transition to high‐oleic products, and ensure an adequate supply of safe, nutritious and healthy peanuts and peanut products.     

Sunflower processing technique

A great deal of interest has recently been shown in sunflower seed as an oilseed erop. The introduction of new Russian seed varieties with higher oil content have helped to stimulate this interest, particularly in the flax and cottonseed growing areas. This paper presents background material pertinent to the subject of sunflower processing. Such things as seed structure, oil and meal quality and certain economic considerations are included. Processing techniques currently used are discussed and comparisons made with the processing of other oilseeds. Brief mention is made of storage and handling of the seeds, meal and oil. Extraction is discussed briefly, but since it is successful only if the seed is properly prepared, seed preparation and handling prior to extraction are stressed. Sunflower seeds are nearly 30% hulls and these hulls are high in crude fiber content. For this reason, dehulling and hull separation practices are important aspects of processing sunflowers. Expeller operating variables are also important where prepressing is part of the process. These processes are stressed. Direct solvent extraction and prepress solvent extraction methods are currently being used successfully. Features of both methods and their applicability are discussed along with seed preparation needed for each method. One of nine papers to be published from the Symposium on Solvent Extraction Techniques for Soybean and Other Seeds, presented at the AOCS Meeting, Minneapolis, October, 1969.     

Die markt- und umweltgerechte Erzeugung von Ölsaaten in Mitteleuropa

Rapeseed Production in Middle Europe-Meeting market and Environment Demands The European oilseed production allows a considerable economical increase in value because of its successful adaptation to the demands of the market during the last decades. Oilseeds are mainly used in highly nutritious products, but mroe and more also for non-food purposes. The most important oilseed crop is rapeseed; its oil is appreciated worldwide with increasing demand because of its dietetic value. Middle Europe has excellent positions for oilseed production. They favour a production, thereby meeting environmental and economical aims, unless the agricultural politics secure the relative preference to the other agricultural market crops. The restriction of the oilseed production in the European Union, forced by the “Blair-House-Compromise”, can lead to supply shortfalls of the demanded quality in the world market.     

How can we genetically engineer oilseed crops to produce high levels of medium‐chain fatty acids?

The end products of fatty acid synthase activities are usually 16‐ and 18‐carbon fatty acids. There are however, several plant species that store 8‐ to 14‐carbon (medium‐chain) fatty acids in their oil seeds. Among the medium‐chain fatty acids (MCFA), caprylic (8:0) and capric (10:0) are minor components of coconut oil, which are used in many industrial, nutritional and pharmaceutical products. Engineering crop plants such as Brassica could provide an economical source of these oils. During the last decade many laboratories have identified, cloned and characterized both the biosynthetic and catabolic enzymes regulating the composition and levels of these unusual fatty acids in seed oil. Among the biosynthetic enzymes thioesterases (TE), β‐ketoacyl‐ACP synthases (KAS) and acyltransferases are best characterized. In fact several independent investigators have shown that combined expression of the medium‐chain specific enzymes, specifically, TE, KAS and lysophosphatidic acid acyltransferase (LPAAT) results in the production of significant levels of MCFA in seed that otherwise do not accumulate any medium‐chain fatty acid. However, any additional increase in the levels of MCFA in transgenic seeds will require further detailed studies, such as possible induction of the medium‐chain specific enzymes in β‐oxidation and the glyoxylate pathways. To examine such a possibility, a number of genes involved in the β‐oxidation cycle among them a novel enzyme now designated as ACX3, a medium‐chain specific acyl‐CoA‐oxidase, has also been cloned. This article is an attempt to summarize our current knowledge and the present status of engineering oilseed crops for production of medium‐chain fatty acids.