次级代谢产物,也被称为植物化学物质,代表植物分子的一大子集,包括具有促进健康作用的化合物。的确,许多流行病学研究表明,当定期服用并以足够的数量服用时,这些分子可以对人类健康产生长期有益的影响,通过减少退行性疾病的发病率,比如心血管疾病,肥胖,糖尿病,和癌症。由于这些植物化学物质的饮食摄入量往往不足,正在使用各种策略来提高其在主要作物中的含量,及其最终产品。最有效的策略之一是通过遗传方法改良作物,因为这是产生新品种的唯一方法,其中给定的植物化学物质的高积累是稳定固定的。基因改善品质性状的努力正在迅速发展,从经典育种到分子辅助方法;这些需要对性状的分子基础有充分的了解,确定控制它们的基因/等位基因。这可以通过对负责植物化学物质积累的代谢途径的整体分析来实现,确定植物化学物质含量与调节代谢途径的关键酶活性之间的联系,以及关键酶及其编码基因/等位基因之间。一旦这些被识别出来,它们可以用作通过生物技术方法选择新的改良基因型的标记。这篇综述概述了与植物化学物质的饮食摄入有关的主要健康促进特性,并描述了分子方法如何为改善食用作物的健康质量提供手段。最后,举例说明了一个案例研究,在硬粒小麦中鉴定出控制粗面粉食品中最终类胡萝卜素含量的脂氧合酶-B1基因,如面食产品。
Secondary metabolites, also known as phytochemicals, represent a large subset of plant molecules that include compounds with health-promoting effects. Indeed, a number of epidemiological studies have shown that, when taken regularly and in adequate amounts, these molecules can have long-term beneficial effects on human health, through reduction of the incidence of degenerative diseases, such as cardiovascular diseases, obesity, diabetes, and cancer. As the dietary intake of these phytochemicals is often inadequate, various strategies are in use to improve their content in staple crops, and the end-products thereof. One of the most effective strategies is crop improvement through genetic approaches, as this is the only way to generate new cultivars in which the high accumulation of a given phytochemical is stably fixed. Efforts to genetically improve quality traits are rapidly evolving, from classical breeding to molecular-assisted approaches; these require sound understanding of the molecular bases underlying the traits, to identify the genes/alleles that control them. This can be achieved through global analysis of the metabolic pathway responsible for phytochemical accumulation, to identify the link between phytochemical content and the activities of key enzymes that regulate the metabolic pathway, and between the key enzymes and their encoding genes/alleles. Once these have been identified, they can be used as markers for selection of new improved genotypes through biotechnological approaches. This review provides an overview of the major health-promoting properties shown to be associated with the dietary intake of phytochemicals, and describes how molecular approaches provide means for improving the health quality of edible crops. Finally, a
case study is illustrated, of the identification in durum wheat of the Lipoxygenase-B1 genes that control the final carotenoid content in semolina-based foods, such as pasta products.