Plants coordinate their development using long-distance signaling. The vascular system provides a route for long-distance movement, and specifically the xylem for root-to-shoot signaling. Root-to-shoot signals play ro...Plants coordinate their development using long-distance signaling. The vascular system provides a route for long-distance movement, and specifically the xylem for root-to-shoot signaling. Root-to-shoot signals play roles communicating soil conditions, and these signals are important for agricultural water conservation. Using genetic approaches, the Arabidopsis bypass1 （bpsl） mutant, which over-produces a root-derived signal, was identified. Although bpsl mutants have both root and shoot defects, the shoot can develop normally if the roots are removed, and the mutant root is sufficient to induce arrest of the wild-type shoot. BYPASS1 encodes a protein with no functionally characterized domains, and BPSl-like genes are found in plant genomes, but not the genomes of animals. Analyses of hormone pathways indicate that the mobile compound that arises in bpsl roots requires carotenoid biosynthesis, but it is neither abscisic acid nor strigolactone. The current model suggests that BPS1 is required to prevent the synthesis of a novel substance that moves from the root to the shoot, where it modifies shoot growth by interfering with auxin signaling.展开更多
Root-to-shoot signaling is used by plants to coordinate shoot development with the conditions experienced by the roots. A mobile and biologically active compound, the bps signal, is over-produced in roots of an Arabid...Root-to-shoot signaling is used by plants to coordinate shoot development with the conditions experienced by the roots. A mobile and biologically active compound, the bps signal, is over-produced in roots of an Arabidopsis thaliana mutant called bypass1 （bpsl）, and might also be a normally produced signaling molecule in wild-type plants. Our goal is to identify the bps signal chemically, which will then allow us to assess its production in normal plants. To identify any signaling molecule, a bioassay is required, and here we describe the development of a robust, simple, and quantitative bioassay for the bps signal. The developed bioassay follows the growth-reducing activity of the bps signal using the pCYCB1;I：：GUS cell cycle marker. Wild-type plants carrying this marker, and provided the bps signal through either grafts or metabolite extracts, showed reduced cell division. By contrast, control grafts and treatment with control extracts showed no change in pCYCB1;I：：GUS expression. To determine the chemical nature of the bps signal, extracts were treated with RNase A, Proteinase K, or heat. None of these treatments diminished the activity of bpsl extracts, sug- gesting that the active molecule might be a metabolite. This bioassay will be useful for future biochemical fractionation and analysis directed toward bps signal identification.展开更多
基金the USDA and the NSF for awards to LES that supported this work (NSF IOS 0922288 and USDA award 20083530404488)
文摘Plants coordinate their development using long-distance signaling. The vascular system provides a route for long-distance movement, and specifically the xylem for root-to-shoot signaling. Root-to-shoot signals play roles communicating soil conditions, and these signals are important for agricultural water conservation. Using genetic approaches, the Arabidopsis bypass1 （bpsl） mutant, which over-produces a root-derived signal, was identified. Although bpsl mutants have both root and shoot defects, the shoot can develop normally if the roots are removed, and the mutant root is sufficient to induce arrest of the wild-type shoot. BYPASS1 encodes a protein with no functionally characterized domains, and BPSl-like genes are found in plant genomes, but not the genomes of animals. Analyses of hormone pathways indicate that the mobile compound that arises in bpsl roots requires carotenoid biosynthesis, but it is neither abscisic acid nor strigolactone. The current model suggests that BPS1 is required to prevent the synthesis of a novel substance that moves from the root to the shoot, where it modifies shoot growth by interfering with auxin signaling.
文摘Root-to-shoot signaling is used by plants to coordinate shoot development with the conditions experienced by the roots. A mobile and biologically active compound, the bps signal, is over-produced in roots of an Arabidopsis thaliana mutant called bypass1 （bpsl）, and might also be a normally produced signaling molecule in wild-type plants. Our goal is to identify the bps signal chemically, which will then allow us to assess its production in normal plants. To identify any signaling molecule, a bioassay is required, and here we describe the development of a robust, simple, and quantitative bioassay for the bps signal. The developed bioassay follows the growth-reducing activity of the bps signal using the pCYCB1;I：：GUS cell cycle marker. Wild-type plants carrying this marker, and provided the bps signal through either grafts or metabolite extracts, showed reduced cell division. By contrast, control grafts and treatment with control extracts showed no change in pCYCB1;I：：GUS expression. To determine the chemical nature of the bps signal, extracts were treated with RNase A, Proteinase K, or heat. None of these treatments diminished the activity of bpsl extracts, sug- gesting that the active molecule might be a metabolite. This bioassay will be useful for future biochemical fractionation and analysis directed toward bps signal identification.
