87 research outputs found
Sensing, signaLling, and CONTROL of phosphate starvation in plants: molecular players and applications
No full textSensing, Signalling, and Control of Phosphate Starvation in Plants: Molecular Players and Applications
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MicroRNA399 is a long-distance signal for the regulation of plant phosphate homeostasis
Get PDFThe presence of microRNA species in plant phloem sap suggests potential signaling roles by long-distance lregulation of gene expression. Proof for such a role for a phloem-mobile microRNA is lacking. Here we show lthat phosphate (Pi) starvation-induced microRNA399 (miR399) is present in the phloem sap of two diverse lplant species, rapeseed and pumpkin, and levels are strongly and specifically increased in phloem sap during Pi ldeprivation. By performing micro-grafting experiments using Arabidopsis, we further show that chimeric lplants constitutively over-expressing miR399 in the shoot accumulate mature miR399 species to very high llevels in their wild-type roots, while corresponding primary transcripts are virtually absent in roots, ldemonstrating shoot-to-root transport. The chimeric plants exhibit (i) down-regulation of the miR399 target ltranscript (PHO2), which encodes a critical component for maintenance of Pi homeostasis, in the wild-type lroot, and (ii) Pi accumulation in the shoot, which is the phenotype of pho2 mutants, miR399 over-expressers or lchimeric plants with a genetic knock-out of PHO2 in the root. Hence the transported miR399 molecules retain lbiological activity. This is a demonstration of systemic control of a biological process, i.e. maintenance of plant lPi homeostasis, by a phloem-mobile microRNA
Reading the Mahāvaṃsa: The Literary Aims of a Theravāda Buddhist History, by Kristin Scheible
No full textA quantitative RT-PCR platform for high-throughput expression profiling of 2500 rice transcription factors
Get PDFAbstract Background Quantitative reverse transcription – polymerase chain reaction (qRT-PCR) has been demonstrated to be particularly suitable for the analysis of weakly expressed genes, such as those encoding transcription factors. Rice (Oryza sativa L.) is an important crop and the most advanced model for monocotyledonous species; its nuclear genome has been sequenced and molecular tools are being developed for functional analyses. However, high-throughput methods for rice research are still limited and a large-scale qRT-PCR platform for gene expression analyses has not been reported. Results We established a qRT-PCR platform enabling the multi-parallel determination of the expression levels of more than 2500 rice transcription factor genes. Additionally, using different rice cultivars, tissues and physiological conditions, we evaluated the expression stability of seven reference genes. We demonstrate this resource allows specific and reliable detection of the expression of transcription factor genes in rice. Conclusion Multi-parallel qRT-PCR allows the versatile and sensitive transcriptome profiling of large numbers of rice transcription factor genes. The new platform complements existing microarray-based expression profiling techniques, by allowing the analysis of lowly expressed transcription factor genes to determine their involvement in developmental or physiological processes. We expect that this resource will be of broad utility to the scientific community in the further development of rice as an important model for plant science.</p
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