Abstract
BackgroundPlant architecture and the timing and distribution of reproductive structures are fundamental agronomic traits shaped by patterns of determinate and indeterminate growth. Florigen, encoded by FLOWERING LOCUS T (FT) in Arabidopsis and SINGLE FLOWER TRUSS (SFT) in tomato, acts as a general growth hormone, advancing determinate growth. Domestication of upland cotton (Gossypium hirsutum) converted it from a lanky photoperiodic perennial to a highly inbred, compact day-neutral plant that is managed as an annual row-crop. This dramatic change in plant architecture provides a unique opportunity to analyze the transition from perennial to annual growth.Methodology/Principal FindingsTo explore these architectural changes, we addressed the role of day-length upon flowering in an ancestral, perennial accession and in a domesticated variety of cotton. Using a disarmed Cotton leaf crumple virus (CLCrV) as a transient expression system, we delivered FT to both cotton accessions. Ectopic expression of FT in ancestral cotton mimicked the effects of day-length, promoting photoperiod-independent flowering, precocious determinate architecture, and lanceolate leaf shape. Domesticated cotton infected with FT demonstrated more synchronized fruiting and enhanced “annualization”. Transient expression of FT also facilitated simple crosses between wild photoperiodic and domesticated day-neutral accessions, effectively demonstrating a mechanism to increase genetic diversity among cultivated lines of cotton. Virus was not detected in the F1 progeny, indicating that crosses made by this approach do not harbor recombinant DNA molecules.ConclusionsThese findings extend our understanding of FT as a general growth hormone that regulates shoot architecture by advancing organ-specific and age-related determinate growth. Judicious manipulation of FT could benefit cotton architecture to improve crop management.
Highlights
Plant architecture is fundamental to agricultural productivity and artificial selection of desired growth habits is prominent in the earliest domestication of exotics into crops, the yield enhancements of the ‘‘green revolution’’, and in modern crop improvement
These findings extend our understanding of FLOWERING LOCUS T (FT) as a general growth hormone that regulates shoot architecture by advancing organ-specific and age-related determinate growth
We demonstrate that day-length affects flowering, plant architecture, and leaf shape in a coordinated and reversible manner, leading us to hypothesize that these changes are florigen-dependent
Summary
Plant architecture is fundamental to agricultural productivity and artificial selection of desired growth habits is prominent in the earliest domestication of exotics into crops, the yield enhancements of the ‘‘green revolution’’, and in modern crop improvement. Indeterminate shoot apical meristems retain a population of vegetative stem cells indefinitely with tissue and organ differentiation occurring below and on the flanks. Because of this single point of continued growth, shoots derived from indeterminate apical meristems are said to be monopodial. Domestication of upland cotton (Gossypium hirsutum) converted it from a lanky photoperiodic perennial to a highly inbred, compact day-neutral plant that is managed as an annual row-crop. This dramatic change in plant architecture provides a unique opportunity to analyze the transition from perennial to annual growth
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
