Genetic engineering of higher leaf vein density in rice towards improved yield

通过基因工程提高水稻叶脉密度以提高产量

• 批准号: RGPIN-2014-05998
• 负责人: Mattsson, Jim
• 金额: $ 2.48万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611965
• 关键词: Genetic; engineering; higher; leaf; vein

The world’s population will reach an estimated 9.1 billion by the year 2050. How will we feed this population when currently 1 billion people already are chronically hungry? Rice and wheat provide more food than any other crops. Big production increases in these crops will be hard to achieve for several reasons. Both species, utilizing the most common variant of photosynthesis known as C3, have reduced photosynthetic yield due to a process known as photorespiration especially in environments with high temperatures and reduced access to water. Global warming is already exacerbating these problems. There is a world-wide effort underway to explore the possibility of reducing photorespiration in rice and wheat by engineering traits typical of plants utilizing C4 photosynthesis. A conversion to C4 traits could increase yields to levels approaching that of maize, a C4 plant, whose photosynthetic yield at higher temperatures is 50% higher than rice. C4 plants concentrate CO2 in bundle sheath cells surrounding leaf veins, thereby avoiding photorespiration. Since C4 photosynthesis is associated with leaf veins, C4 plants require a high vein density for a high yield of photosynthates. While considerable advances have been made in the understanding of the molecular genetic basis of C4 photosynthesis, the fundamental requirement of a high vein density is unresolved. We have pioneered work demonstrating that higher vein density can be obtained in dicot plants by manipulating transport and distribution of the plant hormone auxin. We have now obtained similar evidence for monocots, including wheat and rice. We have also demonstrated that access to undetermined ground cells strongly influences the response to auxin and the formation of higher vein density. Taken together, this puts my laboratory in an excellent position to generate rice plants with genetically induced higher leaf vein density. We propose to approach this problem from four parallel directions; to increase levels of inductive auxin, to increase to the perception of auxin, to reduce canalization of auxin and finally, to provide a larger number of immature ground cells that can respond to auxin by vein formation. We also seek to identify genes involved in the differentiation of the enhanced bundle-sheath layer typical of C4 leaf veins. This program will allow us to generate a basic understanding of the parameters that regulate vein patterning in monocot plants. More important, present data together with the parallel approaches that we are taking provide high chance of success in enhancing leaf vein density on rice. This will allow us to collaborate with and potentially get funded by international efforts to engineer C4 rice and ultimately also C4 wheat to increase food production. There are several potential long-term benefits of this program to Canada. First, it may become a substantial contribution to addressing future food security in the world, which is of interest to Canada from humanitarian, economical and political perspectives. Second, the outcomes of this program can also be applied to Canadian crops, primarily wheat and canola, grown in large scale in Canada. These crops experience high temperatures as well as periodic drought, leading to reduced yield in large part due to photorespiration.

到 2050 年，世界人口预计将达到 91 亿。目前已有 10 亿人长期处于饥饿之中，我们将如何养活这些人口？稻米和小麦提供的粮食比任何其他作物都多。这些作物的产量大幅增长将十分困难。这两个物种都利用最常见的光合作用（C3），由于光呼吸过程而降低了光合作用产量，特别是在高温和全球变暖的环境中。加剧这些问题。 世界范围内正在努力探索通过改造利用 C4 光合作用的植物的典型性状来减少水稻和小麦光呼吸的可能性，将其转化为 C4 性状可以将产量提高到接近玉米（一种 C4 植物，其光合作用）的水平。 C4 植物在较高温度下的产量比水稻高 50%，因此 C4 植物将二氧化碳集中在叶脉周围的束鞘细胞中，从而避免了光呼吸。高叶脉密度带来高产量的光合产物虽然在理解 C4 光合作用的分子遗传基础方面已经取得了相当大的进展，但高叶脉密度的基本要求尚未得到解决。 我们的开创性工作表明，通过操纵植物激素生长素的运输和分布，可以在双子叶植物中获得更高的叶脉密度。我们现在已经获得了单子叶植物（包括小麦和水稻）的类似证据，我们还证明了对未确定的地面细胞的访问。强烈影响生长素的反应和更高叶脉密度的形成，这使我的实验室处于有利地位，可以从四个平行方向来解决这个问题。增加诱导生长素的水平，增加生长素的感知，减少生长素的管化，最后，提供大量可以通过静脉形成对生长素做出反应的未成熟地面细胞。 C4 叶脉典型的增强束鞘层。 该程序将使我们能够对调节单子叶植物叶脉图案的参数有一个基本的了解，更重要的是，提供的数据以及我们正在采取的并行方法为提高水稻叶脉密度提供了很大的成功机会。使我们能够与国际努力合作并可能获得资金，以改造 C4 水稻并最终改造 C4 小麦以增加粮食产量。 该计划对加拿大有几个潜在的长期好处，首先，它可能对解决世界未来的粮食安全问题做出重大贡献，从人道主义、经济和政治角度来看，这对加拿大有利。该计划也适用于在加拿大大规模种植的加拿大作物，主要是小麦和油菜籽，这些作物经历高温和周期性干旱，导致产量下降，很大程度上是由于光呼吸作用。