Fatty acid desaturases modulated octadecanoid pathway in Sesame

Omega 3 fatty acid desaturases are involved in the production of α-linolenic acid (LNA) an essential omega 3 fatty acid, which is present in only traces in sesame seeds. LNA is the precursor for jasmonic acid which is the end product of octadecanoid pathway. This study was undertaken to analyze the key components of octadecanoid pathway and its relationship with fatty acid content in sesame. Fatty acid desaturation and membrane fluidity are modulated differentially in various stresses. Sesame seedlings were subjected to transient stress to analyse the octadecanoid pathway and its impact on fatty acid desaturation.  The mRNA levels of omega 3 desaturases and LNA content were higher in cold stressed sesame seedlings than heat, drought and salinity stresses. The LOX activity and MDA content were higher in heat stressed sesame seedlings. Jasmonic acid content was higher in salinity stressed seedlings while abscisic acid registered the highest in drought stressed seedlings. Chloroplast fatty acid desaturase genes expression was found to increase the LNA content in cold stressed seedlings. The level of membrane damage measured by lipid peroxidation in terms of LOX activity and MDA content were found to be minimal in cold stressed seedling. This suggests a possible role of LNA in membrane fluidity and cold acclimation in sesame. A synergistic role of JA and ABA is also suspected in abiotic stress tolerance in sesame

Genetic Potential and Possible Improvement of <em>Sesamum indicum</em> L.

Sesame (Sesamum indicum L.) is one of the traditional oil seed crop widely cultivated in many countries. The top producers of sesame seeds are mainly Tanzania, Myanmar, India, China and Japan. Sesame oil contains high level of unsaturated fatty acids (80%) and low levels of saturated fatty acids (20%). The main fatty acids are palmitic, stearic, oleic, linoleic and trace amounts of linolenic fatty acids. Sesame seed contains 50–60% of high-quality oil rich in natural antioxidants such as sesamin, sesamolin, sesaminol and sesamol it enhances the stability and keeping quality of sesame oil. Sesame seeds have good sources of dietary fibre, fats, vitamins, minerals, proteins and rich in anti-oxidants. Polyunsaturated fatty acids in sesame will reduce the risk of high blood pressure, cardiac disorders and blood sugar levels. Sesame is believed to have been originated in India where maximum variability of genetic resources is available. High yielding varieties available to date have reached the yield plateau even with the advanced cultivation practices. The area under oilseed crops cultivation also reducing every year. Hence, there is an urgent need to increase the oil content and yield of Indian sesame varieties. Understanding the available germplasm and novel interventions to develop high yielding varieties warrant both molecular and phenotypic data which is meagre in case of sesame

Genetic Engineering for Oil Modification

Genetic manipulation is a strong tool for modifying crops to produce a considerably wider range of valuable products which gratifies human health benefits and industrial needs. Oilseed crops can be modified both for improving the existing lipid products and engineering novel lipid products. Global demand for vegetable oils is rising as a result of rising per capita consumption of oil in our dietary habits and its use in biofuels. There are numerous potential markets for renewable, carbon-neutral, ‘eco-friendly’ oil-based compounds produced by crops as substitutes for non-renewable petroleum products. Existing oil crops, on the other hand, have limited fatty acid compositions, making them unsuitable for use as industrial feedstocks. As a result, increasing oil output is necessary to fulfill rising demand. Increasing the oil content of oilseed crops is one way to increase oil yield without expanding the area under cultivation. Besides, the pharmaceutical and nutraceutical values of oilseed crops are being improved by genetic engineering techniques. This chapter addresses the current state of the art gene manipulation strategies followed in oilseed crops for oil modification to fulfill the growing human needs.</jats:p

Genetic Engineering for Oil Modification

Genetic manipulation is a strong tool for modifying crops to produce a considerably wider range of valuable products which gratifies human health benefits and industrial needs. Oilseed crops can be modified both for improving the existing lipid products and engineering novel lipid products. Global demand for vegetable oils is rising as a result of rising per capita consumption of oil in our dietary habits and its use in biofuels. There are numerous potential markets for renewable, carbon-neutral, ‘eco-friendly’ oil-based compounds produced by crops as substitutes for non-renewable petroleum products. Existing oil crops, on the other hand, have limited fatty acid compositions, making them unsuitable for use as industrial feedstocks. As a result, increasing oil output is necessary to fulfill rising demand. Increasing the oil content of oilseed crops is one way to increase oil yield without expanding the area under cultivation. Besides, the pharmaceutical and nutraceutical values of oilseed crops are being improved by genetic engineering techniques. This chapter addresses the current state of the art gene manipulation strategies followed in oilseed crops for oil modification to fulfill the growing human needs

Fatty acid desaturases modulated octadecanoid pathway in Sesame

Omega 3 fatty acid desaturases are involved in the production of α-linolenic acid (LNA) an essential omega 3 fatty acid, which is present in only traces in sesame seeds. LNA is the precursor for jasmonic acid which is the end product of octadecanoid pathway. This study was undertaken to analyze the key components of octadecanoid pathway and its relationship with fatty acid content in sesame. Fatty acid desaturation and membrane fluidity are modulated differentially in various stresses. Sesame seedlings were subjected to transient stress to analyse the octadecanoid pathway and its impact on fatty acid desaturation.  The mRNA levels of omega 3 desaturases and LNA content were higher in cold stressed sesame seedlings than heat, drought and salinity stresses. The LOX activity and MDA content were higher in heat stressed sesame seedlings. Jasmonic acid content was higher in salinity stressed seedlings while abscisic acid registered the highest in drought stressed seedlings. Chloroplast fatty acid desaturase genes expression was found to increase the LNA content in cold stressed seedlings. The level of membrane damage measured by lipid peroxidation in terms of LOX activity and MDA content were found to be minimal in cold stressed seedling. This suggests a possible role of LNA in membrane fluidity and cold acclimation in sesame. A synergistic role of JA and ABA is also suspected in abiotic stress tolerance in sesame.</jats:p