RESUMEN
Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes found throughout the phylogenetic tree. The ß-class carbonic anhydrases (ß-CAs) are the predominating class of CAs in plants. Growing evidence underscores the importance of ß-CAs in plant immunity and environmental adaptation in addition to their roles in photosynthesis. However, many fundamental problems in Arabidopsis ßCAs expression remain unsolved. Here we examined the transcript abundance of AtßCAs in different tissues of Arabidopsis thaliana, and the accumulation of mRNA in response to CO2 and darkness. Histochemical analysis was performed to study the promoter activity of AtßCAs during post-germination seedling growth and in mature plants. All six members of the AtßCA subfamily showed a response to changed CO2 level and darkness, but each member showed a specific dynamic pattern. Although expression of each AtßCA was unique, in general most AtßCAs were synchronously expressed in green leaves since 5 days after germination until flowering. AtßCA1 and AtßCA2 were most highly expressed in leaves but AtßCA2 displayed weaker expression in roots. The level of AtßCA3 transcripts was highest in flowers, while AtßCA5 was most widely expressed and might be involved in more processes than other members. AtßCA6 was unique for increased expression in darkness and no expression in either the anther or pistil. The present study provides useful information for further functional investigation.
Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Anhidrasas Carbónicas/genética , Flores/genética , Regulación de la Expresión Génica de las Plantas , Hojas de la Planta/genética , Raíces de Plantas/genética , Arabidopsis/enzimología , Proteínas de Arabidopsis/metabolismo , Dióxido de Carbono/metabolismo , Anhidrasas Carbónicas/metabolismo , Oscuridad , Flores/enzimología , Isoenzimas/genética , Isoenzimas/metabolismo , Especificidad de Órganos , Hojas de la Planta/enzimología , Raíces de Plantas/enzimología , Regiones Promotoras Genéticas , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
Auxin has been regarded as the main signal molecule coordinating the growth and ripening of fruits in strawberry, the reference genomic system for Rosaceae. The mechanisms regulating auxin biosynthesis in strawberry are largely elusive. Recently, we demonstrated that two YUCCA genes are involved in flower and fruit development in cultivated strawberry. Here, we show that the woodland strawberry (Fragaria vesca L.) genome harbors nine loci for YUCCA genes and eight of them encode functional proteins. Transcription pattern in different plant organs was different for all eight FvYUCs. Functionality of the FvYUC6 gene was studied in transgenic strawberry overexpressing FvYUC6, which showed typical high-auxin phenotypes. Overexpression of FvYUC6 also delayed flowering and led to complete male sterility in F. vesca. Additionally, specific repression of FvYUC6 expression by RNA interference significantly inhibited vegetative growth and reduced plant fertility. The development of leaves, roots, flowers, and fruits was greatly affected in FvYUC6-repressed plants. Expression of a subset of auxin-responsive genes was well correlated with the changes of FvYUC6 transcript levels and free indole-3-acetic acid levels in transgenic strawberry. These observations are consistent with an important role of FvYUC6 in auxin synthesis, and support a main role of the gene product in vegetative and reproductive development in woodland strawberry.
