Flowering Locus T chimeric protein induces floral precocity in edible citrus

• Published in: Plant biotechnology journal 2021-02, Vol.19 (2), p.215-217
• Main Authors: Sinn, Judith P., Held, Jeremy B., Vosburg, Chad, Klee, Sara M., Orbovic, Vladimir, Taylor, Earl L., Gottwald, Tim R., Stover, Ed, Moore, Gloria A., McNellis, Timothy W.
• Format: Article
• Language: English
• Subjects: accelerated breeding; Agriculture; Appropriations; blooming; Brief Communication; Brief Communications; Citrus - genetics; Citrus fruits; Citrus paradisi; Citrus sinensis; early flowering; Flowering; FLOWERING LOCUS T gene; Flowers; Flowers & plants; Flowers - genetics; Fruits; Fusion protein; Gene Expression Regulation, Plant; Genotype & phenotype; Grapefruit; Hybrids; Immunoblotting; juvenility; Leaf blotch; Microbiology; Morphology; Phenotypes; Plant breeding; Plant pathology; Plant reproduction; Pollen; Pollination; Proteins; R&D; Recombinant Fusion Proteins; Reproduction; Research & development; Seed set; Shoots; Tissue culture; Transgenic plants; Trees
• ISSN: 1467-7644; 1467-7652
• DOI: 10.1111/pbi.13463

[...]expression of FT using a Citrus leaf blotch virus (CLBV) vector inoculated into the non‐commercial C. excelsa and hybrids produced as part of a citrus breeding programme resulted in early flowering with minimal effects on growth form (Velázquez et al., 2016). Transgenic ‘Duncan’ grapefruit (Citrus × paradisi) and ‘Hamlin’ sweet orange (C. sinensis) constitutively expressing FT genes produced flower buds in tissue culture and failed to produce shoots or whole plants (Moore et al., 2016). Chimeric PtFT1 fusion protein expression in transgenic grapefruit produces blooming precocity. (a) PtFT1‐scFv constitutive expression cassette. (b) Detection of 47.9 kilodalton (kD) PtFT1‐scFv protein in shoot tip extracts using anti‐cMyc immunoblotting; ‘Duncan’, untransformed grapefruit; and protein loading normalized to tissue weight. (c) Growth form of low‐ (line L), moderate‐ (line J) and high‐expressor (lines H and O) plants. (d) Thorniness in transgenic control (line E), low (line L) and high expressors (lines O and H). (e) Phenotype summary. (f) Precocious flowering in a strongly precocious line. (g) Flower morphology in a strongly precocious line. (h) Germinated pollen grains. (i) Seed set in an immature fruit from a hand‐pollinated flower at 5 months after pollination. (j) Ripe fruit from an unpollinated flower. (k) Flower (arrow) on rooted clone of a mildly precocious line. (l,m) Precious phenotypes of ‘Carrizo’ rootstock and ‘Jackson’ hybrid grapefruit PtFT1‐scFv transformants. Acknowledgements This research was supported by Citrus Research and Development Foundation grants 11‐125‐424 and 18‐016 (T.W.M.) and 573 (E.S. and G.A.M.), Citrus Research Board grant 5200‐146 (G.A.M. and E.S.), a travel grant from the PSU Plant Pathology and Environmental Microbiology Department (S.M.K.), and United States Department of Agriculture National Institute of Food and Agriculture Hatch Appropriations under project no.