Research On Transcription Factor ABP9 And Its Ability To Enhance Abiotic Stresstolerance Of Maize

Abiotic stresses like drought, salt, waterlogging and so on cause huge decrease of crops every year, which threatens the global crop security. Maize is a important crop that makes up the highest ratio of crops production. Biotechnology is a efficient way to enhance the abiotic stresses tolerance of maize and protects the maize production. In the previous study of our team, a transcription factor ABP9 was isolated from cDNA library of maize inbred line Q319 by G-box motif on maize catalase CAT1 promoter. Researches on ABP9 indicated that ABP9 can be induced by various abiotic stress. Moreover, the transgenic Arabidopsis with over-expressing ABP9 showed enhanced tolerance to drought, salt, freezing and oxidative stresses, high sensitivity of ABA and stomatal responses, and strong ability to scavenge excessive ROS. These evidences proved that ABP9 involved the abiotic stress response pathway of plant and with ability to enhance plant abiotic stress tolerance. At the same time, we had some initial experiment evidences suggested that ABP9 may be edited by a kind of post-transcriptional modification mechanism and there was a kind of ABP9 transcripts with multiple-bases insertion modification.According the known information of ABP9, three questions were raised. First, if a new post-transcriptional modification style exists that not yet have been discovered? Second, if we can take the advantage of ABP9 in maize molecular breeding to enhance maize abiotic tolerance? At last, if ABP9 indeed enhance maize stress tolerance, so what the biological mechanism? It will be significant for both science and practice to verify and clarify the property and function of ABP9. Therefore, this research carry out the following experiments and get primary results and conclusion:1. The existence of ABP9 multiple-bases insertion transcript was verified by several methods. The result indicated that the previous positive result can not be repeated and the conclusion that a special kind of post-transcriptional modification mechanism modified ABP9 transcripts can not be gotten.2. ABP9 transgenic maize lines were created. Moreover, all the transgenic lines were verified to be valid. A field experiment with drought treatment was implemented to those transgenic lines and wild-type lines and proved that the ABP9-overexpressing transgenic lines performed better than wild-type under drought stress, such as increased final production. This result provides a firm base to create new maize varieties with drought resistance using ABP9 gene.3. The ABP9 potential target genes in downstream was determined by next-generation sequencing technology and a group target genes with high confidence were selected. This work initially demonstrated the mechanism of how ABP9 enhancing maize abiotic stress tolerance.