Study On Expression And Regulation Of Drought-Induced Genes In Haloxylon Ammodendron

Haloxylon ammodendron (C.A.Mey) Bunge is an important desert plant with the characteristics of good drought-resistance and salt-tolerance in northwest of China. It's one of the best ways to cultivate more drought-resistance plants by studying the mechanism of H. ammodendron in drought resistance, discovering its interested genes, and then by the combination of cross breeding and molecular breeding, transforming interested gene into target plants to improve directly the properties of plants. It's the first time for this article to study the drought-responsive genes of H. ammodendron subjected to drought stress by cDNA-AFLP(amplified fragment length polymorphism); to compare with the genome of model plants; in further, to study in detail the expression of some regulation- and senesensce-relative genes under the conditions of PEG, dehydration and exogenous ABA. The main conclusions are as follows:(1) H. ammodendron possessed of the same stress-metabolism pathways compared to other plants. Among the eighty-six genes of differently expressed, there were fourty-eight genes with significant homology to function-known and function-putative genes including signal transduction, transcription regulation, transcription factors, defense, senescense, transporters, cell wall, development and photosynthesis genes, which were 56% of the total obtained genes, and it was vital for most of plants to fight with various stresses.(2) In the function-known and function-putative genes, there were sixteen regulation- relative genes, including seven signal transduction, six transcription regulation and three transcription factors, with the percentage of 33%. The results indicated large amounts of regulation-relative genes were induced and upstream-regulation mechanism was initiated rapidly to adapt to adversity conditions when H. ammodendron suffered from drought stress.(3) Compared to the seedlings irrigated normally, the height of young seedlings decreased 31.6%, the eight of liginification increased 34.7%, the content of ABA enhanced 141.9%, however, Fv/Fm had on significant effect when stopping water for 25d in H. ammodendron seedlings. Moreover, higher holding water capacity could be maintained in detached leaves. The results showed H.