RESUMEN
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 in Arabidopsis thaliana. Dipping the flowers of CARK3 T-DNA mutants in ABA solution, led to less reduction of pollen fertility than in the wild type plants (Col-0). We demonstrated that PMEIL, a gene located downstream of CARK3, directly affects pollen fertility. Due to the close arrangement of CARK3 and PMEIL, CARK3 expression represses transcription of PMEIL in 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.
Asunto(s)
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Reguladores del Crecimiento de las Plantas/fisiología , Infertilidad Vegetal/genética , Polen/genética , Proteínas Serina-Treonina Quinasas/genética , Arabidopsis/fisiología , Proteínas de Arabidopsis/fisiología , Orden Génico/genética , Orden Génico/fisiología , Germinación , Péptidos y Proteínas de Señalización Intracelular/fisiología , Reguladores del Crecimiento de las Plantas/metabolismo , Infertilidad Vegetal/fisiología , Polen/fisiología , Proteínas Serina-Treonina Quinasas/fisiologíaRESUMEN
Perception of pathogen (or microbe)-associated molecular patterns (PAMPs/MAMPs) by pattern recognition receptors (PRRs) is a key component of plant innate immunity. The Arabidopsis PRR EF-Tu receptor (EFR) recognizes the bacterial PAMP elongation factor Tu (EF-Tu) and its derived peptide elf18. Previous work revealed that transgenic expression of AtEFR in Solanaceae confers elf18 responsiveness and broad-spectrum bacterial disease resistance. In this study, we developed a set of bioassays to study the activation of PAMP-triggered immunity (PTI) in wheat. We generated transgenic wheat (Triticum aestivum) plants expressing AtEFR driven by the constitutive rice actin promoter and tested their response to elf18. We show that transgenic expression of AtEFR in wheat confers recognition of elf18, as measured by the induction of immune marker genes and callose deposition. When challenged with the cereal bacterial pathogen Pseudomonas syringae pv. oryzae, transgenic EFR wheat lines had reduced lesion size and bacterial multiplication. These results demonstrate that AtEFR can be transferred successfully from dicot to monocot species, further revealing that immune signalling pathways are conserved across these distant phyla. As novel PRRs are identified, their transfer between plant families represents a useful strategy for enhancing resistance to pathogens in crops.