RESUMEN
Reactive oxygen species (ROS) are known to be important signal molecules that are involved in biotic and abiotic stress responses as well as in growth regulation. However, the molecular mechanisms by which ROS act as a growth regulator, as well as how ROS-dependent growth regulation relates to its roles in stress responses, are not well understood. We performed a time-course microarray analysis of Arabidopsis root tips upon treatment with hydrogen peroxide, which we named "ROS-map." Using the ROS-map, we identified an MYB transcription factor, MYB30, which showed a strong response to ROS treatment and is the key regulator of a gene network that leads to the hydrogen peroxide-dependent inhibition of root cell elongation. Intriguingly, this network contained multiple genes involved in very-long-chain fatty acid (VLCFA) transport. Finally, we showed that MYB30 is necessary for root growth regulation during defense responses, thus providing a molecular link between these two ROS-associated processes.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/inmunología , Regulación de la Expresión Génica de las Plantas , Meristema/inmunología , Inmunidad de la Planta/genética , Raíces de Plantas/inmunología , Especies Reactivas de Oxígeno/metabolismo , Factores de Transcripción/metabolismo , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Meristema/genética , Meristema/crecimiento & desarrollo , Raíces de Plantas/genética , Raíces de Plantas/crecimiento & desarrollo , Transducción de Señal , Factores de Transcripción/genéticaRESUMEN
Reactive oxygen species (ROS) play important roles as root growth regulators. We previously reported a comprehensive transcriptomic atlas, which we named ROS-map, that revealed ROS-responsible genes in Arabidopsis root tips. By using ROS-map, we have characterised an early ROS response key transcription factor, MYB30, as a regulator of root cell elongation under ROS signals. However, there are other ROS-responsible transcription factors which have the potential to regulate root growth. In the present study, we characterised the function of another early ROS-responsible transcription factor, ANAC032, that was selected from ROS-map. Overexpression of ANAC032 fused with the transcriptional activation domain, VP16, inhibited root growth, especially decreasing cell elongation. By transcriptome analysis, we revealed that ANAC032 regulated many stress-responsible genes in the roots. Intriguingly, ANAC032 upregulated MYB30 and its target genes. The upregulation of MYB30 target genes was completely abolished in the ANAC032-VP16x2 OX and ANAC032 estradiol-inducible line in myb30-2 mutants. Moreover, root growth inhibition was alleviated in ANAC032-OX in myb30-2 mutants. Overall, we characterised an upstream transcription factor, ANAC032, of the MYB30 transcriptional cascade which is a key regulator for root cell elongation under ROS signalling.
Asunto(s)
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Redes Reguladoras de Genes , Meristema/genética , Transactivadores/metabolismo , Factores de Transcripción/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiología , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Meristema/crecimiento & desarrollo , Meristema/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal , Transactivadores/fisiología , Factores de Transcripción/metabolismo , Factores de Transcripción/fisiologíaRESUMEN
Reactive oxygen species (ROS) and plant hormones play important roles in regulating plant growth and stress responses as signaling molecules. Abscisic acid (ABA) is known as the key regulator of both abiotic and biotic stress responses. During stress responses, ABA is known to regulate ROS production, indicating that important crosstalk occurs between ROS and ABA signaling. We recently reported that MYB30, an MYB-type transcription factor, regulates root cell elongation under ROS signaling. In this study, we analyzed the molecular interaction between ROS and ABA signal during for root development, which is mediated through MYB30 transcriptional regulation. We showed that MYB30-regulated root cell elongation was mediated by ROS production under ABA signaling. Our findings will provide one piece of evidence of the complex cross talk between ROS and hormone signaling that regulates root development.