Regulation of Compound Leaf Development in Medicago truncatula by Fused Compound Leaf1, a Class M KNOX Gene  

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.

A KNOTTED1-LIKE HOMEOBOX Protein Regulates Abscission in Tomato by Modulating the Auxin Pathway

“…KD1 is known to modulate boundary separation and proximal-distal axis development in leaves (Kimura et al, 2008;Magnani and Hake, 2008;Peng et al, 2011), and our previous microarray analysis suggested a role for KD1 in leaf and flower abscission (Meir et al, 2010). Manipulating expression of KD1 by silencing or overexpression affects various aspects of plant development.…”

Conserved genetic determinant of motor organ identity in Medicago truncatula and related legumes

“…M. truncatula elp1 mutants were isolated from FN and Tnt1 mutant collections as previously reported (19,36). Pea apu mutants were identified from the pea germplasm collections at The John Innes Centre (http://data.jic.bbsrc.ac.uk/cgi-bin/germplasm/pisum/) and the US Department of Agriculture-Agricultural Research Service Pacific West.…”

“…Jemalong A20. The ELP1 locus was mapped by bulked segregant analysis (BSA) and fine genetic mapping following procedures as previously reported (19,36). For BSA, two bulked pools from 50 F2 mutant plants each were analyzed using 93 SSR markers distributed on the eight chromosomes (37).…”

“…Reverse transcription and cDNA synthesis were carried out with 2 μg of total RNA, using Omniscript RT Kit (Qiagen) and oligo(dT)15 primer. Real-time RT-PCR analysis was carried out as previously described (36). Primer sequences are listed in Table S2.…”

Organogenesis in plants: initiation and elaboration of leaves

“…31,No. 6 numbers and often fused leaflets [64,65]. FCL1 has targets similar to those of class 1 KNOX and is likely to work to extend the organogenic potential in dissected leaves.…”