Developing transcriptomic resources for the mimosoid legume genus Leucaena (Leguminosae)

Leucaena includes 19 diploid and five allotetraploid species of neotropical trees and shrubs classified within the Mimosoideae subfamily of legumes. Leucaena, especially L. leucocephala, have been co-opted into multipurpose agriculture throughout the tropics. These semi-domesticates provide protein-rich leaves for green manure and animal fodder as well as wood for construction and biofuels. However, they have also become noxious invasive weeds in many tropical regions. Despite interest in the evolutionary history as well as the economic and agro-ecological importance of the genus, few genomic resources are available for mimosoids in general or Leucaena specifically. RNA-seq analyses were carried out on three seedlings from the same maternal lineage for each species of Leucaena. The resulting Illumina 100bp PE reads were de novo assembled into transcriptomes using the software suite Trinity. The number of transcripts recovered, projected number of genes, as well as full-length orthologs matching TRAPID were comparable across species. The results from TRAPID categorized over 96.0 % of transcripts into known gene families. Furthermore, analysis with CEGMA identified 97.5-99.2 % “complete hits”, suggesting that these whole seedling transcriptomes have deeply sampled gene space. These resources, as well as future analyses of the data, serve as a primary platform to investigate questions relevant to the evolution of Leucaena genomes while also being useful in plant breeding research.