The shoot apical and axillary meristems control shoot development, effectively influencing lateral branch and leaf formation. The barley (Hordeum vulgare) uniculm2 (cul2) mutation blocks axillary meristem development, and mutant plants lack lateral branches (tillers) that normally develop from the crown. A genetic screen for cul2 suppressors recovered two recessive alleles of ELIGULUM-A (ELI-A) that partially rescued the cul2 tillering phenotype. Mutations in ELI-A produce shorter plants with fewer tillers and disrupt the leaf blade-sheath boundary, producing liguleless leaves and reduced secondary cell wall development in stems and leaves. ELI-A is predicted to encode an unannotated protein containing an RNaseH-like domain that is conserved in land plants. ELI-A transcripts accumulate at the preligule boundary, the developing ligule, leaf margins, cells destined to develop secondary cell walls, and cells surrounding leaf vascular bundles. Recent studies have identified regulatory similarities between boundary development in leaves and lateral organs. Interestingly, we observed ELI-A transcripts at the preligule boundary, suggesting that ELI-A contributes to boundary formation between the blade and sheath. However, we did not observe ELI-A transcripts at the axillary meristem boundary in leaf axils, suggesting that ELI-A is not involved in boundary development for axillary meristem development. Our results show that ELI-A contributes to leaf and lateral branch development by acting as a boundary gene during ligule development but not during lateral branch development.
Bibliographical noteFunding Information:
1This research was supported by a grant from the United States Department of Agriculture-CSREES-NRI Plant Growth and Development program grant # 2004-03440 and funds received from the Triti-ceae Coordinated Agricultural Project, U.S. Department of Agriculture/National Institute for Food and Agriculture grant number 2011-68002-30029 to G.J.M. 2 Address correspondence to email@example.com.
This research was supported by a grant from the United States Department of Agriculture-CSREES-NRI Plant Growth and Development program grant # 2004-03440 and funds received from the Triticeae Coordinated Agricultural Project, U.S. Department of Agriculture/National Institute for Food and Agriculture grant number 2011-68002-30029 to G.J.M.
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