Vitis vinifera basic helix‐loop‐helix transcription factor enhances plant cell size, vegetative biomass, and reproductive yield
First author: Sung Don Lim; Affiliations: University of Nevada (内华达大学): Reno, USA
Corresponding author: John C. Cushman
Strategies for improving plant size are critical targets for plant biotechnology to increase vegetative biomass or reproductive yield. To improve biomass production, a codon‐optimized helix‐loop‐helix transcription factor (VvCEB1opt) from wine grape (酿酒葡萄) was overexpressed in Arabidopsis thaliana resulting in significantly increased leaf number, leaf and rosette area, fresh weight, and dry weight. Cell size, but typically not cell number, was increased in all tissues resulting in increased vegetative biomass and reproductive organ size, number, and seed yield. Ionomic analysis of leaves revealed the VvCEB1opt‐overexpressing plants had significantly elevated, K, S and Mo content relative to control lines. Increased K content likely drives increased osmotic potential (渗透势) within cells leading to greater cellular growth and expansion. To understand the mechanistic basis of VvCEB1opt action, one transgenic line was genotyped using RNA‐Seq mRNA expression profiling and revealed a novel transcriptional reprogramming network with significant changes in mRNA abundance for genes with functions in delayed flowering, pathogen‐defense responses, iron homeostasis, vesicle‐mediated (囊泡介导的) cell wall formation, and auxin‐mediated signaling and responses. Direct testing of VvCEB1opt‐overexpressing plants showed they had significantly elevated auxin content and a significantly increased number of lateral leaf primordia (侧叶原基) within meristems relative to controls confirming that cell expansion and organ number proliferation was likely an auxin‐mediated process. VvCEB1opt‐overexpression in Nicotiana sylvestnis (林烟草) also showed larger cells, organ size, and biomass demonstrating the potential applicability of this innovative strategy for improving plant biomass and reproductive yield in crops.