Mangel Nathalie, Fudge Jared B, Gruissem Wilhelm, Fitzpatrick Teresa B, Vanderschuren Hervé
Plant Biotechnology, Department of Biology, ETH Zurich, Zurich, Switzerland.
Vitamin & Environmental Stress Responses in Plants, Department of Botany and Plant Biology, Université de Genève, Geneva, Switzerland.
Front Plant Sci. 2022 Apr 4;13:856880. doi: 10.3389/fpls.2022.856880. eCollection 2022.
Insufficient dietary intake of micronutrients contributes to the onset of deficiencies termed hidden hunger-a global health problem affecting approximately 2 billion people. Vitamin B (thiamine) and vitamin B (pyridoxine) are essential micronutrients because of their roles as enzymatic cofactors in all organisms. Metabolic engineering attempts to biofortify rice endosperm-a poor source of several micronutrients leading to deficiencies when consumed monotonously-have led to only minimal improvements in vitamin B and B contents. To determine if rice germplasm could be exploited for biofortification of rice endosperm, we screened 59 genetically diverse accessions under greenhouse conditions for variation in vitamin B and vitamin B contents across three tissue types (leaves, unpolished and polished grain). Accessions from low, intermediate and high vitamin categories that had similar vitamin levels in two greenhouse experiments were chosen for in-depth vitamer profiling and selected biosynthesis gene expression analyses. Vitamin B and B contents in polished seeds varied almost 4-fold. Genes encoding select vitamin B and B biosynthesis enzymes ( for vitamin B, - and for vitamin B) were differentially expressed in leaves across accessions contrasting in their respective vitamin contents. These expression levels did not correlate with leaf and unpolished seed vitamin contents, except for expression in leaves that was positively correlated with total vitamin B contents in polished seeds. This study expands our knowledge of diversity in micronutrient traits in rice germplasm and provides insights into the expression of genes for vitamin B and B biosynthesis in rice.
膳食中微量营养素摄入不足会导致所谓的隐性饥饿——这是一个影响约20亿人的全球健康问题。维生素B（硫胺素）和维生素B（吡哆醇）是必需的微量营养素，因为它们在所有生物体中作为酶辅因子发挥作用。代谢工程试图对水稻胚乳进行生物强化——水稻胚乳是几种微量营养素的不良来源，长期单调食用会导致缺乏——但仅使维生素B和B的含量有了极小的提高。为了确定水稻种质是否可用于水稻胚乳的生物强化，我们在温室条件下筛选了59个遗传多样的种质，以研究三种组织类型（叶片、糙米和精米）中维生素B和维生素B含量的变化。在两个温室实验中，选择了低、中、高维生素类别中维生素水平相似的种质进行深入的维生素剖析和选定生物合成基因表达分析。精米种子中维生素B和B的含量相差近4倍。编码选定维生素B和B生物合成酶的基因（维生素B的、和维生素B的）在不同种质的叶片中差异表达，这些种质的各自维生素含量形成对比。这些表达水平与叶片和糙米种子中的维生素含量无关，除了叶片中的表达与精米种子中的总维生素B含量呈正相关。这项研究扩展了我们对水稻种质中微量营养素性状多样性的认识，并为水稻中维生素B和B生物合成基因的表达提供了见解。
