报告题目: Genetic and hormonal control of post-embryonic meristem initiation in maize
报 告 人: Dr.Andrea Gallavotti
Assistant Professor, Waksman Institute of Microbiology
Rutgers, The State University of New Jersey
190 Frelinghuysen Rd. Piscataway, NJ, 08854-8020
报告时间: 3月20日（星期四）上午 10:00-11:00
Plants have the fascinating ability to constantly adapt their development according to changes in the surrounding environment. This plasticity is provided by meristems, small groups of undifferentiated self-regenerating stem cells, continuously formed throughout development. Meristem number, position and activity are a major source of variability in the architecture of different plant species, since they determine if, when and how branches and flowers are formed during both vegetative and reproductive development. Plant architecture, extensively modified during the domestication of crop species, still represents a major target of selection in modern breeding. In particular, in cultivated grasses, the major worldwide food source, vegetative and reproductive branching represents a major component of yield.
Our research is aimed at understanding: i) how pluripotent meristematic cells are formed during development; ii) how meristem fate and organ initiation are regulated; iii) the role of the plant hormone auxin in shaping plant architecture and regulating meristem function (www.auxinevodevo.org); iv) the molecular mechanisms of plant domestication and evolution.
In my laboratory we investigate the molecular mechanisms behind the formation and activity of meristems, by combining the strength of traditional forward and reverse genetics with molecular biology. We use maize mutants affected in branch and flower formation to identify and understand the genes and gene networks controlling plant architecture. We isolated several genes affecting branching in both tassels and ears, the male and female inflorescences of maize. Among these, we identified two transcription factors (BARREN STALK1 and BARREN STALK FASTIGIATE1), an auxin biosynthetic enzyme (SPARSE INFLORESCENCE1) involved in the formation of new meristems, and a transcriptional corepressor (RAMOSA1 ENHANCER LOCUS2) that regulates the decision of meristems to form either a branch or a flower during development. To move towards a systemic understanding of the molecular mechanisms regulating plant architecture, it is essential to achieve a more comprehensive view of the relationships of these genes and pathways, and for this purpose we are using different genomic and proteomic approaches. We also pursue functional comparative analysis, by using different model plant systems (maize and Arabidopsis thaliana) to highlight the similarities and differences at the origin of the variability in plant architectures observed in natural and domesticated environments.
1. Gallavotti, A. 2013. The role of auxin in shaping shoot architecture. Journal of Experimental Botany. 64(9):2593-2608.
2. Gallavotti, A, Malcomber S, Gaines C, Stanfield S, Whipple C, Kellogg E, Schmidt RJ. 2011. BARREN STALK FASTIGIATE1 is an AT-hook Protein Required for the Formation of Maize ears. Plant Cell. 23:1756-1771.
3. Gallavotti, A, Long JA, Stanfield S, Yang X, Jackson D, Vollbrecht E, Schmidt RJ. 2010. The Control of Axillary Meristem fate in the Maize Ramosa Pathway.Development. 137:2849-2856.
4. Skirpan, A, Culler A H, Gallavotti A, Jackson D, Cohen JD, McSteen P. 2009. BARREN INFLORESCENCE2 Interaction with ZmPIN1a Suggests a role in Auxin Transport During Maize Inflorescence Development. Plant Cell Physiol. 50:652-657.
5. Lee, B-ha, Johnston R, Yang Y, Gallavotti A, Kojima M, Travençolo BAN, da Costa LF, Sakakibara H, Jackson D. 2009. Studies of Aberrant Phyllotaxy1 Mutants of Maize Indicate Complex Interactions Between Auxin and Cytokinin Signaling in the Shoot Apical Meristem. Plant Physiol. 150:205-216.
6. Gallavotti, A, Yang Y, Schmidt RJ, Jackson D. 2008. The Relationship Between Auxin Transport and Maize Branching. Plant Physiol. 147:1913-1923.
7. Gallavotti, A, Barazesh S, Malcomber S, Hall D, Jackson D, Schmidt RJ, McSteen P. 2008. Sparse Inflorescence1 Encodes a Monocot-specific YUCCA-like gene Required for Vegetative and Reproductive Development in Maize. Proc Natl Acad Sci U S A. 105:15196-15201. Gallavotti, A, Schmidt RJ. 2007. Two Sides of the same coin. Nat Genet. 39:1425-1426.
8. Gupta, S, Gallavotti A, Stryker GA, Schmidt RJ, Lal SK. 2005. A Novel Class of Helitron-related Transposable Elements in Maize Contain Portions of Multiple Pseudogenes. Plant Mol Biol. 57:115-127.
9. Gallavotti, A, Zhao Q, Kyozuka J, Meeley RB, Ritter MK, Doebley JF, Pè EM, Schmidt RJ. 2004. The role of Barren Stalk1 in the Architecture of Maize. Nature. 432:630-635.