Impact of climate on the genetic diversity of native species using Microlaena stipoides as a model – Progress Report

Progress report on the grant:

Prof R.J. Henry1, Dr F. M. Shapter1, Dr I.Chivers2 , Dr D.L.E. Waters1 and S. McDonald1
1 Centre for Plant Conservation Genetics, Southern Cross University.
2 Native Seeds Pty Ltd, Melbourne.

17 December 2009

Project Scope
To characterise the genetic variation which occurs in wild populations of Microlaena stipoidesacross a range of environmental and climatic conditions. The change in average rainfall, temperature and altitude from coastal to alpine areas of Victoria can be used as a reference for how this species varies genetically and phenotypically with changes in the environment. Analysis of these adaptations in conjunction with climatic data will enable hypotheses about the genetic potential of native grasses to tolerate climate change.

Plant collection
Live plant specimens have been collected at 36 sites along a transect from Melbourne to Paynesville. These plants have been established in two common gardens, one at the Native seeds Research site in Dumbalk Victoria and the other at Southern Cross University in Northern NSW.   Leaf specimens were harvested for 10 individuals at six sites along the transect to use for analysis of the genomic variation within a site compared with that between each of the sites. Leaf samples were also harvested for the 36 whole plants and DNA has been extracted for all leaf specimens. Seed has been harvested from 30 of the plants in the common garden and stored for future breeding work. Herbarium specimens representing the 36 plants in the common garden experiment will pressed and delivered to a Herbarium early in the new year when the new growth is optimal and leaf samples, for DNA extraction and lodgement in the Australian Plant DNA Bank, will be harvested in conjunction with this.

Initial phenotypic evaluation of the common garden experiment has identified significant variation to plant size, seed quantity, colour and size, tiller number, plant architecture, leaf shape and colour, and, dry matter and grain yield.

Environmental data
Average Rainfall and temperature, along with soil type and altitude have been tabulated for all 37 sites (the site at the highest altitude was above the snowline and had no M. stipoidespresent) for comparison with the genetic analysis.

Genomic characterisation
The isa gene has been used in previous studies looking at the impact of climatic change on genetic variability in wild barleys. The homologue of this gene has been characterised in M. stipoides and primers for PCR amplification have been optimised. Of the 96 DNA samples the first 8 have been analysed for sequence variability.

Student progress
The project successfully recruited a Masters student in April 2009, It was determined that the breadth of this project would support the development of a Masters thesis, rather than Honours as originally planned, without significant alteration of the project scope. The student is progressing well and has almost completed the experimental section of the work and has commenced writing his thesis.

It is currently envisaged that the Masters thesis will be published as two journal articles, one focussing on the relationships between the genetic variation and climatic changes and a second paper analysing the amount of phenotypic variation found in the different environments. New DNA sequencing technology has been applied to the analysis of this species in related work at the CPCG. We will explore the potential of this new technology to contribute to plant conservation genetics using this grass as a model system and publish this work separately if successful.