Transcriptome analysis of Leucaena leucocephala and identification of highly expressed genes in roots and shoots

Abstract

Leucaena leucocephala (leucaena) is a fast-growing tree legume highly tolerant to various abiotic and biotic stresses. Because of its abilities to withstand high temperature and prolonged drought and to grow as a disease-free plant, it is an interesting model plant to investigate genetics of stress resistance. The high-level stress resistance may be correlated with higher expression of certain genes in the root, which is the primary site for nutrient and water uptake and also infection by soil-borne pathogens. The objectives of this study were to characterize the transcriptome of leucaena and to identify root-specific genes that may be involved in drought tolerance and disease resistance. Transcriptomes of leucaena were analyzed through Illumina-based sequencing and de novo assembly, which generated 62,299 and 61,591 unigenes (≥500 bp) from the root and shoot, respectively. Through a 4 x 180k microarray analysis, the expression of 10,435 unigenes were compared between the root and shoot. Upregulated sequences in the root were mostly represented by unigenes that were related to secondary metabolism, while in the shoot, upregulated sequences were mostly represented by unigenes that were involved in carbohydrate and lipid metabolism. The unigenes sharing homology with terpenoid biosynthesis genes and a nicotianamine synthase gene were upregulated more than 100-fold in the root, which indicates that these genes may have important roles in high stress tolerance of leucaena. Cataloging of actively transcribed sequences in the root and shoot will lead to identification of genes for drought tolerance and disease resistance in leucaena.

Transcriptomic resources for the medicinal legume Mucuna pruriens: de novo transcriptome assembly, annotation, identification and validation of EST-SSR markers

“…A similar result was found for comparison of root and shoot tissues in Leucaena leucocephala (Lam.) de Wit [ 77 ]. In our study, the most highly upregulated gene involved in secondary metabolism in the root transcriptome was isoflavone reductase which exhibits a ~6-fold increase relative to pods and leaves (unigene MP60067 in Fig.…”

Phytochemical and comparative transcriptome analyses reveal different regulatory mechanisms in the terpenoid biosynthesis pathways between Matricaria recutita L. and Chamaemelum nobile L.

“…Transcriptomic analyses can be used to identify functional elements in the genome, metabolic pathways, and differentially expressed genes in model and non-model organisms [17][18][19][20]. The transcriptomes of many important medicinal plants and their individual tissues such as leaves, roots, and stems have been reported [21][22][23][24][25].…”