Analysis of expressed sequence tags in developing secondary xylem and shoot of Acacia mangium

Abstract

Acacia mangium is a fast-growing tree widely planted in tropical countries because of its rapid growth, high wood density, high fiber quality, and good adaptability. Despite its importance as a fiber source in the pulp and paper industry, a large-scale analysis of expressed sequence tags (ESTs) has not been performed in A. mangium. In this study, we sequenced 10 752 clones of a normalized complementary DNA (cDNA) library prepared from A. mangium developing secondary xylem and shoot, and obtained a total of 8963 ESTs. The ESTs were assembled into 6220 unigenes comprising 1614 contigs and 4606 singletons. The unigene set was then subjected to various bioinformatic analyses. BlastN searches of the unigene set against the Gene Index Databases of soybean, Medicago truncatula, Lotus japonicus, grape, poplar, spruce, and pine demonstrated that the largest number of unigenes shared homologies with the soybean Gene Indices. BlastX searches against the TAIR9 peptide database enabled us to annotate the unigenes. Based on the annotation, we discussed whether the unigenes involved in the cell cycle, cell growth, shoot apical meristem development, and cell wall biosynthesis were present. This new genomic resource will accelerate the functional genomics of wood formation and molecular breeding to improve the wood properties of A. mangium. © 2010 The Japan Wood Research Society.