Progress 01/15/11 to 01/14/16
Outputs
Target Audience:The target audiences for this project were academic scientists, who are interested in crop genetics, and yield traits, and industry scientists and breeders working to improve maize productivity. Changes/Problems:One of the parts of Aim 1 of the proposal was to generate inducible ABPHYL1 maize lines, to test direct interactions with auxin signaling. Inducible constructs in maize are problematic, and in fact have only been reported once in the literature- by a company, who have much bigger resources for generation of transgenic lines. We have used a similar strategy to the one reported, but the analysis of the lines showed that none of them were inducible. This meant that the profiling part of Aim 1 could not be completed, nonetheless this was more than compensated for by the profiling of FEA4, which functions in the ABPHYL2 pathway, as described earlier in this report. What opportunities for training and professional development has the project provided?Fang Yang, a post doc, was responsible for the major aims of the proposal. She has now taken a faculty position in China, and is continuing to use her training in maize development to establish her research program there. Huyen Bui, also worked on the project as a post doc, and was trained in plant genetics and genomics. Huyen left last year to take a post doc position at Univ. Utah. Tara Skopelitis, lab manager, assisted with propagation of transgenic maize reporter lines. How have the results been disseminated to communities of interest?At seminars and conferences, and in publications, listed elsewhere in this report. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The goals of this research were to characterize plant hormone regulatory networks by study of maize mutations with specific phenotypes in phyllotaxy, or leaf patterning. The underlying mechanisms were to be elucidated by the study of transcriptional and proteomic regulatory networks. The project was based on resources already developed in the Jackson lab, which includeded mutants that perturb maize development through effects on hormone signal transduction, and reporters for auxin and cytokinin signaling. These tools were to be used in developmental and transcript profiling studies to understand hormone regulatory networks. In addition, map based cloning was proposed to identify the ABPHYL2 locus of maize. The overall project was highly succesful, resulting in 6 publications, and training of 2 postdoctoral scholars (one now in a faculty position and the second continuing in maize genetics research) and one undergraduate (now in graduate school). As described below, some parts of Aim 1 could not be completed, due to problems in generating maize inducible constructs. However, Aim 3 progressed extremely well, and the Abph2 locus was cloned, and found to encode a glutaredoxin, the first time such an enzyme has been found to control shoot meristem size and phyllotaxy. A putative target of this enzyme was also identified, as the FASCIATED EAR4 bZIP transcription factor. Therefore we focused our profiling experiments and network analysis (Aim 2) on this newly discovered pathway, resulting in 2 publications in The Plant Cell. In the first, we described a new locus controlling phyllotaxy, the geometric arrangement of leaves important for plant productivity. Auxin was well known to regulate phyllotactic patterns via PIN1-dependent auxin polar transport, and our previous studies of Zea mays (maize) aberrant phyllotaxy 1 (abph1) mutants suggested the importance of auxin and cytokinin signaling for control of phyllotaxy. However, whether additional regulators control these patterns was not known. We reported the new dominant maize mutant, Aberrant phyllotaxy 2 (Abph2), in which the shoot meristems are enlarged and the phyllotactic pattern switches from alternate to decussate. Map-based cloning revealed that the Abph2 mutation was caused by transposition of a glutaredoxin gene, MALE STERILE CONVERTED ANTHER1 (MSCA1), which gained an altered expression pattern in Abph2 mutant embryos. msca1 loss-of-function mutants had reduced meristem size and revealed a novel function of glutaredoxins in meristem growth. In addition, we found that MSCA1 interacted with the TGA transcription factor, FASCIATED EAR 4 (FEA4), suggesting a novel regulatory module for regulating shoot meristem size. In the second publication, we described fea4 as a semi-dwarfed mutant with fasciated ears and tassels, and greatly enlarged vegetative and inflorescence meristems. We identified FEA4 as a bZIP transcription factor, orthologous to Arabidopsis PERIANTHIA. FEA4 was expressed in the peripheral zone of the SAM and in the vasculature of immature leaves, and conspicuously excluded from the stem cell niche at the tip of the SAM and from incipient leaf primordia. Following the transition to reproductive fate, FEA4 was expressed throughout the entire inflorescence and floral meristems. Native expression of a functional YFP:FEA4 fusion recapitulated this pattern of expression. We used Chromatin Immunoprecipitation-sequencing (ChIP-seq) to identify 4,060 genes proximal to FEA4 binding sites, including ones that were potentially bound and modulated by FEA4 based on transcriptional changes in fea4 mutant ears. Our results suggested that FEA4 promotes differentiation in the meristem periphery by regulating auxin-based responses and genes associated with leaf differentiation and polarity, potentially in opposition to factors such as KNOTTED1 and WUSCHEL. Our project aimed to develop a knowledgebase of how plants grow and develop, to identify important genes in the process and figure out how they work. Such basic research is often translated by others into more practical outcomes. For the current project, a better understanding of how leaves are initiated and develop could lead to increases in biomass production, for biofuels, or could help in designing more productive crop plants.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Yang, F., Bui, H.T., Pautler, M., Llaca, V., Johnston, R., Lee, B., Kolbe, A., Sakai, H., and Jackson, D., (2015). A maize glutaredoxin gene, Abphyl2, regulates shoot meristem size and phyllotaxy. Plant Cell.27(1):121-31.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Pautler, M., Eveland, A.L., LaRue, T., Yang, F., Weeks, R., Lunde, C., Je, B.I., Meeley, R., Komatsu, M., Vollbrecht, E., Sakai, H., and Jackson, D. (2015). FASCIATED EAR4 encodes a bZIP transcription factor that regulates shoot meristem size in maize. Plant Cell
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Krishnakumar, V, Choi, Y, Beck, E, Wu, Q, Luo, A, Sylvester, A, Jackson, D, Chan, AP. (2015). A maize database resource that captures tissue-specific and subcellular-localized gene expression, via fluorescent tags and confocal imaging (Maize Cell Genomics Database). Plant Cell Physiol. 56(1):e12.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Lituiev, D.S., Krohn, D.G., M�ller, B., Jackson, D., Hellriegel, B., Dresselhaus, T. and Grossniklaus, U. (2013). Theoretical and experimental evidence indicates that there is no auxin gradient patterning the angiosperm female gametophyte. Development. 140(22): 4544-53.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Pautler M, Tanaka W, Hirano HY, Jackson D. (2013)Grass Meristems I: Shoot apical meristem maintenance, axillary meristem determinacy, and the floral transition. Plant Cell Physiol. 54(3): 302-12.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Jiang F, Guo M, Yang F, Duncan K, Jackson D, et al. (2012) Mutations in an AP2 Transcription Factor-Like Gene Affect Internode Length and Leaf Shape in Maize. PLoS ONE 7(5): e37040.
|
Progress 01/15/11 to 01/14/12
Outputs
Target Audience: This research is mosty aimed at academic scientists, as well as those who could apply the research knowledge in creating improvements to agriculture. As secondary target audience would be students and Professors who could use the research as a teaching tool. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? A former post doc, Fang Yang, was trained in maize geneics and imaging. She has taken a position in China, and a new post doc, Huyen Bui, is now being trained in plant genetics and plant biology, her former training was in yeast cell biology. How have the results been disseminated to communities of interest? Oral presentations have been made at the Maize Genetics Conference (Portland, OR, March 2012) and at a Banbury Meeting (CSHL, NY, Sept 2011). What do you plan to do during the next reporting period to accomplish the goals? We will omplete the analysis of Abphyl2 mutants and gene and submit for publication. Analysis will continue for the abphyl1 inducible constructs, and the mRNAseq analyses.
Impacts
What was accomplished under these goals?
Several goals towards this project have been accomplished. Maize lines carrying an inducible ABPHYL1 transgene have been generated and their testing is in progress.If succesful, this will be the first demonstration of a maize inducible protein construct. Analysis of abph1 mutants by mRNAseq has ben completed, and analysis is in progress. TheAbph2 locus has been cloned, and found to encode a glutaredoxin, the first time such an enzyme has been found to control shoot meristem size and phyllotaxy. A putative target of this enzyme has also been identified. Lastly, fluorescent protein reporters have been made and used to characterize the ABPHYL mutants.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Pautler M, Tanaka W, Hirano HY, Jackson D. Grass Meristems I: Shoot apical meristem maintenance, axillary meristem determinacy, and the floral transition. Plant Cell Physiol. 2013 Feb 14. [Epub ahead of print]
|