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Title: A key to totipotency: Wuschel‐like homeobox 2a unlocks embryogenic culture response in maize ( Zea mays L.)
Summary

The ability of plant somatic cells to dedifferentiate, form somatic embryos and regenerate whole plantsin vitrohas been harnessed for both clonal propagation and as a key component of plant genetic engineering systems. Embryogenic culture response is significantly limited, however, by plant genotype in most species. This impedes advancements in both plant transformation‐based functional genomics research and crop improvement efforts. We utilized natural variation among maize inbred lines to genetically map somatic embryo generation potential in tissue culture and identify candidate genes underlying totipotency. Using a series of maize lines derived from crosses involving the culturable parent A188 and the non‐responsive parent B73, we identified a region on chromosome 3 associated with embryogenic culture response and focused on three candidate genes within the region based on genetic position and expression pattern. Two candidate genes showed no effect when ectopically expressed in B73, but the geneWox2awas found to induce somatic embryogenesis and embryogenic callus proliferation. Transgenic B73 cells with strong constitutive expression of the B73 and A188 coding sequences ofWox2awere found to produce somatic embryos at similar frequencies, demonstrating that sufficient expression of either allele could rescue the embryogenic culture phenotype. Transgenic B73 plants were regenerated from the somatic embryos without chemical selection and no pleiotropic effects were observed in theWox2aoverexpression lines in the regenerated T0 plants or in the two independent events which produced T1 progeny. In addition to linking natural variation in tissue culture response toWox2a, our data support the utility ofWox2ain enabling transformation of recalcitrant genotypes.

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Award ID(s):
1917138
NSF-PAR ID:
10425867
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Plant Biotechnology Journal
Volume:
21
Issue:
9
ISSN:
1467-7644
Page Range / eLocation ID:
p. 1860-1872
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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