Frittelli Arianna, Botticella Ermelinda, Palombieri Samuela, Masci Stefania, Celletti Silvia, Fontanella Maria Chiara, Astolfi Stefania, De Vita Pasquale, Volpato Mirko, Sestili Francesco
Department of Agriculture and Forest Science (DAFNE), University of Tuscia, Viterbo, Italy.
Institute of Sciences of Food Production (ISPA), National Research Council (CNR), Lecce, Italy.
Front Plant Sci. 2023 Jan 18;14:1079559. doi: 10.3389/fpls.2023.1079559. eCollection 2023.
Micronutrient malnutrition affects more than half of the world population. Reduced bioavailability of microelements in the raw materials is considered one of the main causes of mineral deficiency in populations whose diet is largely based on the consumption of staple crops. In this context, the production of low phytic acid () cereals is a main goal of the breeding programs, as phytic acid (PA) binds essential mineral cations such as iron (Fe), zinc (Zn), manganese (Mn), potassium (K), calcium (Ca) and magnesium (Mg) precipitating in the form of phytate salts poorly digested by monogastric animals, including humans, due to the lack of phytases in the digestive tract. Since PA limits the bioavailability of microelements, it is widely recognized as an anti-nutritional compound. A Targeting Induced Local Lesions IN Genomes (TILLING) approach has been undertaken to silence the genes encoding the TdABCC13 proteins, known as Multidrug-Resistance associated Proteins 3 (TdMRP3), transporters involved in the accumulation of PA inside the vacuole in durum wheat. The TdMRP3 complete null genotypes showed a significant reduction in the content of PA and were able to accumulate a higher amount of essential micronutrients (Fe, Zn, Mn) compared to the control. The number of spikelets and seeds per spike, traits associated with the agronomic performances, were reduced compared to the control, but the negative effect was in part balanced by the increased grain weight. The TdMRP3 mutant lines showed morphological differences in the root apparatus such as a significant decrease in the number of root tips, root length, volume and surface area and an increase in root average diameter compared to the control plants. These materials represent a promising basis for obtaining new commercial durum wheats with higher nutritional value.
微量营养素营养不良影响着全球一半以上的人口。原材料中微量元素生物利用率的降低被认为是导致以食用主食作物为主的人群矿物质缺乏的主要原因之一。在这种背景下，培育低植酸谷物是育种计划的主要目标，因为植酸（PA）会结合铁（Fe）、锌（Zn）、锰（Mn）、钾（K）、钙（Ca）和镁（Mg）等必需矿物质阳离子，以植酸盐的形式沉淀，由于包括人类在内的单胃动物消化道中缺乏植酸酶，因而难以消化。由于植酸限制了微量元素的生物利用率，它被广泛认为是一种抗营养化合物。人们采用了靶向基因组诱导局部损伤（TILLING）方法来使编码TdABCC13蛋白（即多药耐药相关蛋白3，TdMRP3）的基因沉默，该蛋白是参与硬粒小麦液泡内植酸积累的转运蛋白。与对照相比，TdMRP3完全无效基因型的植酸含量显著降低，并且能够积累更多的必需微量元素（铁、锌、锰）。与农艺性能相关的每穗小穗数和种子数与对照相比有所减少，但粒重增加在一定程度上抵消了负面影响。与对照植株相比，TdMRP3突变系在根系结构上表现出形态差异，例如根尖数量、根长、根体积和根表面积显著减少，而根平均直径增加。这些材料是培育具有更高营养价值的新型商业硬粒小麦的良好基础。
