Close arrangement of CARK3 and PMEIL affects ABA-mediated pollen sterility in Arabidopsis thaliana.

Abscisic acid (ABA) signaling is a vital plant signaling pathway for plant responses to stress conditions. ABA treatment can alter global gene expression patterns and cause significant phenotypic changes. We investigated the responses to ABA treatment during flowering inArabidopsis thaliana.Dipping the flowers ofCARK3T-DNA mutants in ABA solution, led to less reduction of pollen fertility than in the wild type plants (Col-0). We demonstrated thatPMEIL, a gene located downstream ofCARK3, directly affects pollen fertility. Due to the close arrangement ofCARK3andPMEIL,CARK3expression represses transcription ofPMEILin an ABA-dependent manner through transcriptional interference. Our study uncovers a molecular mechanism underlying ABA-mediated pollen sterility and provides an example of how transcriptional interference caused by close arrangement of genes may mediate stress responses during plant reproduction.