The Study Of Alternative Splicing Of ABA Receptor In Maize And Its Function In The Drought Resistance

Maize has been the first crops in our country, which are challenged by the drought stess.ABA is called stress phytohormone, it is significant to study the ABA-related genes’ function in maize. There exit alternative splicing phenomenon in the core ABA signaling component PYL-PP2C-SnRK2, which modulate the transcripts of these genes. Our results showed:1. For the first time, we confirmed and cloned the13PYLs and its16transcripts in maize B73inbred line, in which2genes experienced alternative splicing. Phylogeny analysis show these genes were divided3clades with Arabidopsis and rice homologues.2. We cloned14type A PP2C genes and its19transcripts in B73, in which4genes experienced alternative splicing, we also cloned12SnRK2genes and its32transcripts in B73, in which10genes experienced alternative splicing.3. In ABA-deficient mutant vp14, the expression levels of ZmVP14, ZmPYLA/B、 ZmPYLC/D were down-regulated, while those of ZmPP2C11/12、ZmPP2Cl3/14/15、 ZmPP2C16/17、ZmPP2C18/19were up-regulated.4. The proteins of ZmPYLB、ZmPYLD and ZmPYLR have no interaction with all proteins of type A PP2C with or without ABA. The ZmPYLA can interact with ZmPP2C5/7/9/20/23/13/17independent of ABA, with ZmPP2C10/24/12dependent of ABA. The ZmPYLC can interact with ZmPP2C5/7/22/23/17independent of ABA, with ZmPP2C9/20/13/19dependent of ABA.5. The affinity of ZmPYLC for ABA is remarkably higher than ZmPYLD for ABA through ITC experiments.6. The transgenic Arabidopsis of ZmPYLC showed high resistance with drought, and the water loss rate of transgenic plants was lower than those of WT, the germination of transgenic plant seeds showed supersensitive to ABA.7. The transgenic maize experiments showed that over-expression of ZmPYLC resulted down-regulated of ZmPYLD; while over-expression of ZmPYLD resulted down-regulated of ZmPYLC, the two isoforms of one gene antagonized each other.