|Medicago truncatula Mutant Database|
Legumes are second only to grasses in their worldwide economic importance. Apart from their importance as food for humans and other animals and as feedstock for industry, legumes play a pivotal role in maintaining our ecosystem by fixing atmospheric nitrogen in symbiotic association with soil bacteria of the family Rhizobiaceae. Deciphering the roles of individual genes in legumes is important not only for a better understanding of the biology of these plants, but also for breeding efforts that aim to improve legume performance and quality for agriculture. This database and the associated biological resources provide tools to facilitate gene function discovery and, ultimately, legume breeding.
Medicago truncatula has been selected as a model species to study biological processes that are unique and/or pertinent to legumes that cannot easily be studied in other model species such as Arabidopsis or rice. Several genomic tools and resources for M. truncatula are now available and a genome sequencing project is in completion. To complement these resources and to enable efficient forward- and reverse-genetics studies with this species, we have generated two mutant resources: (i) a Fast Neutron Bombardment (FNB) deletion mutant population of approximately 80,000 M1 lines; and (ii) a Tnt1 retrotransposon insertion mutant population of over 21,000 lines containing an estimated 520,000 random insertions within the genome. Originally funded by the Noble Foundation, these resources are being expanded and developed further with support from the National Science Foundation Plant Genome Program (DBI 0703285). For example, we are currently expanding the number of Tnt1 mutant lines to 21,000, while at the same time generating Flanking Sequence Tag (FST) information for many of these lines, which is being deposited here. Other Tnt1 mutant lines that are currently being developed by European groups (www.eugrainlegumes.org) will be integrated with our collection to obtain approximately 22,000 mutant lines containing insertions in approximately 90% of all genes.
In collaboration with researchers from various institutions in the United States and Europe we have screened the first 14,700 Tnt1 lines for visible phenotypes in the R1 generation. We identified approximately 30% visible mutants in at least 25 distinct phenotypic classes, including super-nodulating, non-nodulating, non-nitrogen-fixing, late and early flowering, dwarf, altered anthocyanin content, light green, albino, transformed floral organs, and singlet leaves with cauliflower-like reproductive tissue, which are shown on this website.
Phenotypic screening of the FNB mutant population has also begun and this database contains photos and phenotype descriptions for many of these mutants.
Currently this database contains images of Tnt1 and FNB mutants that show significant phenotypes, organized according to line numbers. In addition, FSTs associated with specific Tnt1 lines are contained in a BLAST-able dataset. Functionality of the website is expanding and mutant records will be updated periodically.
Million Tadege, Jiangqi Wen, Ji He, Haidi Tu, Younsig Kwak, Alexis Eschstruth, Anne Cayrel, Gabi Endre, Patrick X. Zhao, Mireille Chabaud, Pascal Ratet and Kirankumar Mysore. Large scale insertional mutagenesis using Tnt1 retrotransposon in the model legume Medicago truncatula. The Plant Journal, 2008, 54 (2), 335-347 doi:10.1111/j.1365-313X.2008.03418.x
[2014-12-15] Tnt1 update: FSTs are updated. 243,544 FSTs in High Confidence and 305,191 FSTs in Low Confidence.
[2014-09-10] Tnt1 update: FSTs are updated. 220,620 FSTs in High Confidence and 279,969 FSTs in Low Confidence.
[2014-07-31] Tnt1 update: FSTs are updated. 197,336 FSTs in High Confidence and 254,026 FSTs in Low Confidence.
[2014-06-05] Tnt1 update: FSTs updated. 157,501 FSTs in High Confidence and 207,781 FSTs in Low Confidence.
[2014-05-01] Tnt1 update: More FSTs are updated. Total 141,360 FSTs in High Confidence and 188,155 FSTs in Low Confidence now.
If you have any questions or suggestions, please contact our curator Dr. Jiangqi Wen at firstname.lastname@example.org or at site administrator. If you are interested in participating in Tnt1 or FNB mutant screening workshops (organized once a year) please contact Dr. Kiran Mysore (for Tnt1 mutant screening) at email@example.com or Dr. Rujin Chen (for FNB mutant screening) at firstname.lastname@example.org, respectively.