| Plants have developed mutualistic symbiosis with diverse fungal endophytes increasing fitness by conferring abiotic and biotic stress tolerance. However, the molecular regulation mechanisms involved in stress resistance remain largely unknown. Drunken horse grass (Achnatherum inebrians), an important perennial bunchgrass in China, is naturally occurring symbiosis with an asexual fungus Neotyphodium gansuense. The effect of temperature on seed germination was determined for drunken horse grass infected (E+) vs. non-infected (E-) by N. gansuense. Our results indicated that E+ seeds showed a higher germination rate under low temperature (10℃) condition compared with E- seeds, whereas under relatively higher temperature (15,20 and 25℃) conditions, no obviously difference were detected between the E+ and E- seeds. To gain insight into the molecular mechanisms involved in the low temperature resistance of E+ grass. Solexa deep-sequencing and proteomics were used to identify candidate genes and proteins showing differential expressed level. Firstly.152 differentially expressed tags with a log2 ratio>2 or<-2 (P<0.001) were identified, representing 109 up-regulated and 43 down-regulated genes, which were classified into 8 functional categories. Many genes were found to be association with low temperature response, such as genes participating in biosynthesis of alkaloids and unsaturated fatty acids etc. In turn, RT-PCR analysis showed that the expression patterns of six genes are agreement with the Solexa analysis. Secondly, about 10 differently expressed proteins were sueeessfully identified in our research. Those proteins mainly involved in the energy metabolism and stress response. In conclusion, this study provides comprehensive gene expression changes induced by Neotyphodium endophyte infection response to low temperature which are essential for understanding the molecular basis of endophyte-enhanced plant improvements. |
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