Camelina sativa (L.) Crantz is an important Brassicaceae oil crop with a number of excellent agronomic traits including low water and fertilizer input, strong adaptation and resistance. Furthermore, its short life cycle and easy genetic transformation, combined with available data of genome and other “-omics” have enabled camelina as a model oil plant to study lipid metabolism regulation and genetic improvement. Particularly, camelina is capable of rapid metabolic engineering to synthesize and accumulate high levels of unusual fatty acids and modified oils in seeds, which are more stable and environmentally friendly. Such engineered camelina oils have been increasingly used as the super resource for edible oil, health-promoting food and medicine, biofuel oil and high-valued chemical production. In this review, we mainly highlight the latest advance in metabolic engineering towards the predictive manipulation of metabolism for commercial production of desirable bio-based products using camelina as an ideal platform. Moreover, we deeply analysis camelina seed metabolic engineering strategy and its promising achievements by describing the metabolic assembly of biosynthesis pathways for acetyl glycerides, hydroxylated fatty acids, medium-chain fatty acids, ω-3 long-chain polyunsaturated fatty acids, palmitoleic acid (ω-7) and other high-value oils. Future prospects are discussed, with a focus on the cutting-edge techniques in camelina such as genome editing application, fine directed manipulation of metabolism and future outlook for camelina industry development.

Drought is an important environmental constraint limiting the productivity of many crops worldwide. Seedling tolerance to drought is crucial for crop growth and development through the whole season under water-limited condition. Experiments were conducted to investigate the effects of seed pretreatment by hydrogen peroxide (H2O2) on drought tolerance in wheat (Triticum aestivum L.) seedlings. H2O2-pretreated seeds exhibited 56% higher in germination rate than the water-pretreated seeds (control) under PGE-induced drought condition. Level of H2O2 in seedlings arising from H2O2-treated seeds grown under drought stress was markedly lower than the controls, indicating the operation of antioxidant system in them. These seedlings exhibited increased growth characteristics including higher net photosynthetic rate, leaf area and dry weight. Moreover, H2O2 treatment improved water use efficiency (WUE) and proline level. H2O2 pretreatment enhanced the membrane stability, as revealed from greatly reduced membrane damage rate (MDA) and malondialdehyde (MDA) content. The seedlings showed the higher expression of antioxidative enzyme such as catalase (CAT) and ascorbate peroxidase (APX). The present data suggest that H2O2, a stress signal, could trigger the activation of antioxidants in seeds, which persists in the seedlings to alleviate the oxidative damage, leading to improvements in physiological attributes for the seedling growth under drought. Key words: wheat (Triticum aestivum L.), seed pretreatment, H2O2, signaling, drought tolerance, membrane permeability, antioxidative system.