Molecular responses and expression analysis of genes in a xerophytic desert shrub <i>Haloxylon ammodendron</i> (Chenopodiaceae) to environmental stresses

Abstract

Haloxylon ammodendron (C.A Mey.) Bunge is a xero-halophytic desert shrub with excellent drought resistance and salt tolerance. To decipher the molecular responses involved in its drought resistance, the cDNA-AFLP (amplified fragment length polymorphism) technique was employed to identify genes expressed differentially in the leaves following drought treatment in the seedlings of H. ammodendron.
Eighty-six non-redundant TDFs (transcript-derived fragments) were identified as drought responsive after verified by reverse northern. Of these, 49 TDFs showed significant homology to genes with known
or predicted function; 6 TDFs were homologous to unknown genes, while 31 TDFs did not show any significant matches. 10 TDFs were selected to further validate the cDNA-AFLP expression patterns by
the semi-quantitative RT-PCR. 57% of TDFs corresponding to proteins of known or putative functions are likely to participate in signal transduction, transcription regulation, protein synthesis, senescence,
transport, cell wall synthesis, stress and defense response, development and growth, photosynthesis, and so on. Moreover, not many functions of these genes have been reported in plants adaptation to unfavorable conditions. The spatial and temporal expression patterns of the tested genes displayed several distinct patterns in response to osmotic stress, desiccation stress and application of exogenous ABA. The results provided general insights into the molecular adaptation mechanisms involved in this desert shrub’s response to desert conditions.