Molecular Evidence Of Drought Tolerance Mechanism Of Zygophyllum Xanthoxylum (Buage) Maxim And Isolation Of Drought Related Genes

Drought is one of the major abiotic stresses that adversely affect plant growth and crop yield worldwide. Lots of genes are thought to be involved in responses to abiotic stress. However, only a few genes have been known precisely until recently and moreover most of the studied genes originated from a few annual herbaceous plants like Arabidopsis, tobacco and rice. Information on drought-resistant genes of perennial trees is scare, even though drought stress constitutes a major challenge to forestry development in the future.Zygophyllum xanthoxylum (Buage) Maxim, belonging, to Zygophyllacea family, is a xerophyte plant species originated from Africa and mainly distributed in desert areas in northern Africa, central Asia and North America. In China, it is mainly distributed in desert areas and desertificated grassland in the northwestern region. Z. Xanthoxylum is a strong drought tolerant shrub; the annual rainfall of its natural range is between 50 and 200mm. To understand the molecular mechanism of water stress and the role of differential gene expression in drought tolerance of the trees, using xerophytic frutex Z. Xanthoxylum as material, we studied its transcriptome during drought stress by suppression subtractive hybridization (SSH) method. Based on structural analysis of leaves and physiological change of the plants, we analyzed the mechanism of drought tolerance of Z Xanthoxylum. At the same time, we isolated five drought related genes from Z. Xanthoxylum with RACE method. The functions of new genes were studied primarily. Main results as follows:1. Constructed a SSH cDNA library from the drought treated Z. Xanthoxylum's leaves and analyzed the expression profiles of part of the genes. Using mixed cDNAs prepared from drought treated leaves as testers and cDNAs from unstressed as drivers. A forward subtractive cDNA library was constructed, from which 4 000 recombinant clones were picked and amplified. Through differential screening of the subtractive cDNA library, 400 clones were randomly sequenced. By blast analysis of the obtained expressed sequence tags (ESTs), we...