Abstract Detail



Evolutionary Developmental Biology (Evo-Devo)

Youngstrom, Christopher [1], Geadelmann, Lander [1], Irish, Erin [2], Cheng, Chi-Lien [1].

A Fern WUSCHEL-Related Homeobox Gene Functions in both Gametophyte and Sporophyte Generations.

Stem cells are the ultimate source of all post-embryonic growth in land plants. In vascular plants, stem cells are housed in apical meristems of the root and shoot and in the vascular cambium where their numbers are strictly maintained. A conserved family of WUSCHEL-related homeobox (WOX) transcription factors are required for stem cell maintenance. Phylogenetic analyses of land plant WOX genes group the members into three clades, the ancient, the intermediate, and the modern. All land plants contain members of the ancient clade of WOX transcription factors; however, intermediate and modern clade genes are only present in ferns and are further expanded in gymnosperms and angiosperms. Therefore, the modern and intermediate clades first arose in the fern lineage. Thus, ferns provide a starting point to trace the expansion of the intermediate and modern clades and the roles they play in the evolution of meristem structure and function. Despite their importance, there has been no functional analysis of the three WOX protein clades in any fern. We knocked down the expression of endogenous WOX transcripts in the model fern Ceratopteris richardii by RNAi using Agrobacterium-mediated gametophyte transformation. We found that reduction of the C. richardii intermediate WOX clade protein CrWOXB resulted in defective meristems, which produced fewer and less branched organs of the shoot and root of the sporophyte, and fewer gametophyte cells.


1 - University of Iowa, Biology Department, Department of Biology, 143 BB, U of Iowa,, Iowa City, Iowa, 52242, United States
2 - University of Iowa, Biology Department, 129 E. Jefferson St., Department of Biology 143 BB, Iowa City, IA, 52242, United States

Keywords:
Ceratopteris richardii
gametophyte transformation
WOX genes
RNAi
ferns.

Presentation Type: Oral Paper
Number:
Abstract ID:123
Candidate for Awards:None


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