Laboratory of Photosynthesis and Bioenergy, Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134, Verona, Italy.
Accademia Nazionale dei Lincei, Palazzo Corsini, Via della Lungara 10, 00165, Rome, Italy.
New Phytol. 2023 Sep;239(5):1567-1583. doi: 10.1111/nph.19064. Epub 2023 Jun 6.
In natural ecosystems, plants compete for space, nutrients and light. The optically dense canopies limit the penetration of photosynthetically active radiation and light often becomes a growth-limiting factor for the understory. The reduced availability of photons in the lower leaf layers is also a major constraint for yield potential in canopies of crop monocultures. Traditionally, crop breeding has selected traits related to plant architecture and nutrient assimilation rather than light use efficiency. Leaf optical density is primarily determined by tissue morphology and by the foliar concentration of photosynthetic pigments (chlorophylls and carotenoids). Most pigment molecules are bound to light-harvesting antenna proteins in the chloroplast thylakoid membranes, where they serve photon capture and excitation energy transfer toward reaction centers of photosystems. Engineering the abundance and composition of antenna proteins has been suggested as a strategy to improve light distribution within canopies and reduce the gap between theoretical and field productivity. Since the assembly of the photosynthetic antennas relies on several coordinated biological processes, many genetic targets are available for modulating cellular chlorophyll levels. In this review, we outline the rationale behind the advantages of developing pale green phenotypes and describe possible approaches toward engineering light-harvesting systems.
在自然生态系统中，植物为了争夺空间、养分和阳光而相互竞争。茂密的树冠限制了光合有效辐射的穿透，光往往成为林下植物生长的限制因素。在作物单一种植的冠层中，较低叶片层中光子的可用性降低也是产量潜力的主要限制因素。传统上，作物育种选择的是与植物结构和养分吸收相关的特性，而不是光利用效率。叶片的光密度主要由组织形态和叶片中光合色素（叶绿素和类胡萝卜素）的浓度决定。大多数色素分子与叶绿体类囊体膜中的光捕获天线蛋白结合，在那里它们进行光子捕获和激发能量向光系统反应中心的转移。增加天线蛋白的丰度和组成被认为是改善冠层内光分布和缩小理论和田间生产力差距的一种策略。由于光合作用天线的组装依赖于几个协调的生物过程，因此有许多遗传靶标可用于调节细胞中的叶绿素水平。在这篇综述中，我们概述了开发淡绿色表型的优势，并描述了工程光捕获系统的可能方法。
