Downregulation of the CpSRP43 gene expression confers a truncated light-harvesting antenna (TLA) and enhances biomass and leaf-to-stem ratio in Nicotiana tabacum canopies

• Published in: Planta 2018-07, Vol.248 (1), p.139-154
• Main Authors: Kirst, Henning, Shen, Yanxin, Vamvaka, Evangelia, Betterle, Nico, Xu, Dongmei, Warek, Ujwala, Strickland, James A., Melis, Anastasios
• Format: Article
• Language: English
• Subjects: Accumulation; Agriculture; Agronomy; Antenna arrays; Antennae; Biomass; Biomedical and Life Sciences; Canopies; Chlorophyll; Chloroplast Proteins - genetics; Chloroplast Proteins - metabolism; Crop yield; Crops; Cultivation; Down-Regulation; Ecology; Forestry; Gene expression; Irradiance; Leaves; Life Sciences; Light; Light-Harvesting Protein Complexes - metabolism; Monoculture; Nicotiana - anatomy & histology; Nicotiana - genetics; Nicotiana - growth & development; Nicotiana - metabolism; Nicotiana tabacum; ORIGINAL ARTICLE; Photosynthesis; Plant Leaves - anatomy & histology; Plant Sciences; Plant Stems - anatomy & histology; Planting density; Plants; Plants (botany); Productivity; Recognition; Reverse Transcriptase Polymerase Chain Reaction; Ribonucleic acid; RNA; RNA Interference; RNA-mediated interference; Signal recognition particle; Signal Recognition Particle - genetics; Signal Recognition Particle - metabolism; Signal Recognition Particle - physiology; Sunlight; Tobacco; Transgenic plants
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-018-2889-7

Evolution of sizable arrays of light-harvesting antennae in all photosynthetic systems confers a survival advantage for the organism in the wild, where sunlight is often the growth-limiting factor. In crop monocultures, however, this property is strongly counterproductive, when growth takes place under direct and excess sunlight. The large arrays of light-harvesting antennae in crop plants cause the surface of the canopies to over-absorb solar irradiance, far in excess of what is needed to saturate photosynthesis and forcing them to engage in wasteful dissipation of the excess energy. Evidence in this work showed that downregulation by RNA-interference approaches of the Nicotiana tabacum signal recognition particle 43 (SRP43), a nuclear gene encoding a chloroplast-localized component of the photosynthetic light-harvesting assembly pathway, caused a decrease in the light-harvesting antenna size of the photosystems, a corresponding increase in the photosynthetic productivity of chlorophyll in the leaves, and improved tobacco plant canopy biomass accumulation under high-density cultivation conditions. Importantly, the resulting TLA transgenic plants had a substantially greater leaf-to-stem biomass ratio, compared to those of the wild type, grown under identical agronomic conditions. The results are discussed in terms of the potential benefit that could accrue to agriculture upon application of the TLA-technology to crop plants, entailing higher density planting with plants having a greater biomass and leaf-to-stem ratio, translating into greater crop yields per plant with canopies in a novel agronomic configuration.