here - First Legume Society Conference (LSC1)

Book of Abstracts First Legume Society Conference 2013: A Legume Odyssey Novi Sad, Serbia, 9-11 May 2013
_________________________________________________________________________________________
KEYNOTE LECTURE
Genetic and molecular analysis of sustainable biofuel production from the legume tree
Pongamia pinnata
Peter M. Gresshoff
Centre for Integrative Legume Research, SAFS, The University of Queensland, St Lucia, Brisbane, Australia
Pongamia trees are sourced from tropical and subtropical regions of the world (India, Indonesia,
northern Australia, and other localities in that general region). They are rich with seeds about 1.5-
3.0 gm dry weight after 2 to 4 years. These seeds contain 35-50% plant oil which contains mainly
C18:1 oleic acid (50-55%). Pongamia oil is suitable for both biodiesel as well as aviation fuel
production. Mature trees with 20,000 seeds are not uncommon. The estimated oil yield per
hectare per annum is between 3 to 5 tons. Pongamia, despite its warm weather natural habitat, is
very adaptable. They grow, then have a winter dormancy period of about 3-4 months, and yield
good seed in central Queensland, where winter night temperatures are -5 to -6 degrees C). They
also are deep-rooted and thus very drought-tolerant. Plants grow on salty soil and even next to
the ocean in beach environments. Pongamia is outcrossing with a diploid chromosome number
of 22. Its genome size is about 600-700 Mbp, based on comparison to soybean chromosomes.
Because of the outbreeding the progeny seed are heterogeneous and variable. We have developed
ISSR DNA markers to determine genetic diversity. We have initiated multi-faceted analyses of
Pongamia to facilitate the domestication of elite mother trees. Deep sequencing of its genome
has allowed gene isolation using orthologous soybean genes for fatty acid, nodulation and ureide
metabolism. The chloroplast (152 kbp) and mitochondrial (425 kbp) genomes were sequenced,
assembled and annotated. Great similarity exists to those organelle genomes from Lotus
japonicus. We developed classical clonal propagation procedures by rooted cutting, tissue culture
and grafting to evaluate the genetic versus the environmental influence on traits in different
parent genotypes. We have Life Cycle Analysis data of Pongamia grown in plantation style for 4
years since seed germination. Above ground biomass exceeds 13 kg per tree with 4 m height trees
and 10-15 cm diameter stems. Analysis of nodulation and nitrogen fixation indicated determinate
development progressing to lobed nodules with greater age. Parameters of nodulation appear to
be similar to those seen in other annual legumes such as soybean. We strongly believe that the
use of a high seed number, high oil legume tree is optimal for sustainable production of biofuel
and co-products for the future biofuel industry.
227