Elevated vitamin E content improves all-trans β-carotene accumulation and stability in biofortified sorghum
Elevated vitamin E content improves all-trans β-carotene accumulation and stability in biofortified sorghum
复制标题
DOI：
10.1073/pnas.1605689113
复制
发表时间：
2016-09-27
影响因子：
11.1
通讯作者：
Albertsen, Marc C.
中科院分区：
文献类型：
--
作者：
Che, Ping;Zhao, Zuo-Yu;Albertsen, Marc C.
在人们必须依赖高粱作为主食的地方，营养素缺乏是常见的。高粱谷物严重缺乏维生素原A（β-胡萝卜素）和铁和锌的生物利用度。生物强化是一种改善作物一种或多种微量营养素缺乏的过程。我们已经开发出增加β-胡萝卜素积累的高粱，这将缓解依赖高粱作为主食的人的维生素A缺乏症。然而，随后的β-胡萝卜素在储存过程中的不稳定性会对这种必需微量营养素的充分利用产生负面影响。我们确定氧化是在环境条件下引起β-胡萝卜素降解的主要因素。我们进一步证明，与类胡萝卜素生物合成基因堆叠的尿黑酸香叶基香叶基转移酶（HGGT）的共表达可以减轻β-胡萝卜素的氧化降解，从而增加β-胡萝卜素的积累和稳定性。β-胡萝卜素降解的动力学研究表明，与HGGT共表达的β-胡萝卜素的半衰期从不到4周延长到平均10周。
Micronutrient deficiencies are common in locales where people must rely upon sorghum as their staple diet. Sorghum grain is seriously deficient in provitamin A (beta-carotene) and in the bioavailability of iron and zinc. Biofortification is a process to improve crops for one or more micronutrient deficiencies. We have developed sorghum with increased beta-carotene accumulation that will alleviate vitamin A deficiency among people who rely on sorghum as their dietary staple. However, subsequent beta-carotene instability during storage negatively affects the full utilization of this essential micronutrient. We determined that oxidation is the main factor causing beta-carotene degradation under ambient conditions. We further demonstrated that coexpression of homogentisate geranylgeranyl transferase (HGGT), stacked with carotenoid biosynthesis genes, can mitigate beta-carotene oxidative degradation, resulting in increased beta-carotene accumulation and stability. A kinetic study of beta-carotene degradation showed that the half-life of beta-carotene is extended from less than 4 wk to 10 wk on average with HGGT coexpression.