Radially arranged cortical microtubules are a prominent feature of guard cells. We observed guard cells expressing GFP-tubulin （GFP-TUA6） with confocal microscopy and found recognizable changes in the appearance of ...Radially arranged cortical microtubules are a prominent feature of guard cells. We observed guard cells expressing GFP-tubulin （GFP-TUA6） with confocal microscopy and found recognizable changes in the appearance of micro- tubules when stomata open or close （Eisinger et al., 2012）. In the present study, analysis of fluorescence distribution showed a dramatic increase in peak intensities of microtubule bundles within guard cells as stomata open. This increase was correlated with an increase in the total fluorescence that could be attributed to polymerized tubulin, Adjacent pave- ment cells did not show similar changes in peak intensities or integrated fluorescence when stomatal apertures changed. Imaging of RFP-tagged end binding protein 1 （EB1） and YFP-tagged ^-tubulin expressed in the same cell revealed that the number of microtubules with growing ends remained constant, although the total amount of polymerized tubulin was higher in open than in closed guard cells. Taken together, these results indicate that the changes in microtubule array organization that are correlated with and required for normal guard cell function are characterized by changes in micro- tubule clustering or bundling.展开更多
The anther is the male reproductive organ in flowering plants. Although some genes were reported to be involved in anther development, the molecular mechanisms underlying the transcriptional regulation of these genes ...The anther is the male reproductive organ in flowering plants. Although some genes were reported to be involved in anther development, the molecular mechanisms underlying the transcriptional regulation of these genes is unclear. Ifr-2 （leaf and flower related-2）, the null allele of Arabidopsis thaliana LFR （LEAF AND FLOWER RELATED）, was male-sterile. The anthers of Ifr-2 plants were defective in sporogenous cell formation, tapetum development, and pollen development. In agreement with these phenotypes, expression studies showed that LFR was expressed in all cell layers of the anther, and that expression was particularly strong in the tapetal cells and pollen grains, Quantitative RT-PCR analysis revealed that LFR is required for the normal transcription of some anther development-related genes, such as AMS, CALS5, and DYT1, MS1 and MS2, and ROXY2. Genetic analysis showed that SPL was epistatic to LFR while LFR was epistatic to DYT1. We propose that LFR may be a crucial component in the regulation of a genetic network that modulates anther development.展开更多
Reactive Oxygen Species （ROS） are continuously produced as a result of aerobic metabolism or in response to biotic and abiotic stresses. ROS are not only toxic by-products of aerobic metabolism, but are also signali...Reactive Oxygen Species （ROS） are continuously produced as a result of aerobic metabolism or in response to biotic and abiotic stresses. ROS are not only toxic by-products of aerobic metabolism, but are also signaling molecules involved in plant growth and environmental adaptation. Antioxidants can protect the cell from oxidative damage by scavenging the ROS. Thus, they play an important role in optimizing cell function by regulating cellular redox state and modifying gene expression. This article aims to review recent studies highlighting the role of redox signals in establishing and maintaining symbiosis between rhizobia and legumes.展开更多
文摘Radially arranged cortical microtubules are a prominent feature of guard cells. We observed guard cells expressing GFP-tubulin （GFP-TUA6） with confocal microscopy and found recognizable changes in the appearance of micro- tubules when stomata open or close （Eisinger et al., 2012）. In the present study, analysis of fluorescence distribution showed a dramatic increase in peak intensities of microtubule bundles within guard cells as stomata open. This increase was correlated with an increase in the total fluorescence that could be attributed to polymerized tubulin, Adjacent pave- ment cells did not show similar changes in peak intensities or integrated fluorescence when stomatal apertures changed. Imaging of RFP-tagged end binding protein 1 （EB1） and YFP-tagged ^-tubulin expressed in the same cell revealed that the number of microtubules with growing ends remained constant, although the total amount of polymerized tubulin was higher in open than in closed guard cells. Taken together, these results indicate that the changes in microtubule array organization that are correlated with and required for normal guard cell function are characterized by changes in micro- tubule clustering or bundling.
文摘The anther is the male reproductive organ in flowering plants. Although some genes were reported to be involved in anther development, the molecular mechanisms underlying the transcriptional regulation of these genes is unclear. Ifr-2 （leaf and flower related-2）, the null allele of Arabidopsis thaliana LFR （LEAF AND FLOWER RELATED）, was male-sterile. The anthers of Ifr-2 plants were defective in sporogenous cell formation, tapetum development, and pollen development. In agreement with these phenotypes, expression studies showed that LFR was expressed in all cell layers of the anther, and that expression was particularly strong in the tapetal cells and pollen grains, Quantitative RT-PCR analysis revealed that LFR is required for the normal transcription of some anther development-related genes, such as AMS, CALS5, and DYT1, MS1 and MS2, and ROXY2. Genetic analysis showed that SPL was epistatic to LFR while LFR was epistatic to DYT1. We propose that LFR may be a crucial component in the regulation of a genetic network that modulates anther development.
文摘Reactive Oxygen Species （ROS） are continuously produced as a result of aerobic metabolism or in response to biotic and abiotic stresses. ROS are not only toxic by-products of aerobic metabolism, but are also signaling molecules involved in plant growth and environmental adaptation. Antioxidants can protect the cell from oxidative damage by scavenging the ROS. Thus, they play an important role in optimizing cell function by regulating cellular redox state and modifying gene expression. This article aims to review recent studies highlighting the role of redox signals in establishing and maintaining symbiosis between rhizobia and legumes.
