Location: Hard Winter Wheat Genetics ResearchTitle: Regulation of compound leaf development in Medicago truncatula by Fused Compound Leaf1, a class M KNOX gene Author
Submitted to: The Plant Cell
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2011
Publication Date: 11/20/2011
Publication URL: http://www.plantcell.org/content/23/11/3929.short
Citation: Peng, J., Yu, J., Wang, H., Guo, Y., Li, G., Bai, G., Chen, R. 2011. Regulation of compound leaf development in Medicago truncatula by Fused Compound Leaf1, a class M KNOX gene. The Plant Cell. DOI 10.1105/tpc.111.089128. Interpretive Summary: As the primary organ for photosynthetic carbon fixation, plant leaves play an important role in plant growth, biomass production and survival in environments. Plant leaves show a great difference in their morphology, which contributes to the plant diversity in the natural environment. However, how leaf morphology is determined is not yet understood. Medicago truncatula is a legume plant species and its leaf consists of three blades (leaflets). We cloned a gene called Fused Compound Leaf 1 (FCL1) and demonstrated that FCL1 plays a positive role in boundary separation and proximal-distal axis development of compound leaves. SGL1, a gene regulating single/multiple leaflets development, and FCL1 act additively and both are required for petiole development. The identification of FCL1 may be useful for designing more efficient leaves.
Technical Abstract: Medicago truncatula is a legume species belonging to the inverted repeat lacking clade (IRLC) with trifoliolate compound leaves. However, the regulatory mechanisms underlying development of trifoliolate leaves in legumes remain largely unknown. Here, we report isolation and characterization of fused compound leaf1 (fcl1) mutants of M. truncatula. Phenotypic analysis suggests that FCL1 plays a positive role in boundary separation and proximal-distal axis development of compound leaves. Map-based cloning indicates that FCL1 encodes a class M KNOX protein that harbors the MEINOX domain but lacks the homeodomain. Yeast two-hybrid assays show that FCL1 interacts with a subset of Arabidopsis thaliana BEL1-like proteins with slightly different substrate specificities from the Arabidopsis homolog KNATM-B. Double mutant analyses with M. truncatula single leaflet1 (sgl1) and palmate-like pentafoliata1 (palm1) leaf mutants show that fcl1 is epistatic to palm1 and sgl1 is epistatic to fcl1 in terms of leaf complexity and that SGL1 and FCL1 act additively and are required for petiole development. Previous studies have shown that the canonical KNOX proteins are not involved in compound leaf development in IRLC legumes. The identification of FCL1 supports the role of a truncated KNOX protein in compound leaf development in M. truncatula.