Mutants with abnormal leaf coloration are good genetic materials for understanding the mechanism of chloroplast development and chlorophyll biosynthesis. In this study, a rice mutant st2 （stripe2） with stripe leaves...Mutants with abnormal leaf coloration are good genetic materials for understanding the mechanism of chloroplast development and chlorophyll biosynthesis. In this study, a rice mutant st2 （stripe2） with stripe leaves was identified from the ＂y-ray irradiated mutant pool. The st2 mutant exhibited decreased accumulation of chlorophyll and aberrant chloroplasts. Genetic analysis indicated that the st2 mutant was controlled by a single recessive locus. The ST2 gene was finely confined to a 27-kb region on chromosome 1 by the map-based cloning strategy and a 5-bp deletion in Os01g0765000 was identified by sequence analysis. The deletion happened in the joint of exon 3 and intron 3 and led to new spliced products of mRNA. Genetic comptementation confirmed that Os01g0765000 is the ST2 gene. We found that the ST2 gene was expressed ubiquitously. Subcellular localization assay showed that the ST2 protein was located in mitochondria. ST2 belongs to the cytidine deaminase-like family and possibly functions as the dCMP deaminase, which catalyzes the formation of dUMP from dCMP by deamination. Additionally, exogenous application of dUMP could partially rescue the st2 phenotype. Therefore, our study identified a putative dCMP deaminase as a novel regulator in chloroplast development for the first time.展开更多
InGaN/GaN multiple quantum-well(MQW) structures with a wavelength range of green were successfully grown on a c-plane GaN template with SiO_2 stripe patterns along the [11-20] and [1-100] directions as a mask. The sur...InGaN/GaN multiple quantum-well(MQW) structures with a wavelength range of green were successfully grown on a c-plane GaN template with SiO_2 stripe patterns along the [11-20] and [1-100] directions as a mask. The surface morphologies of both samples were investigated using scanning electron microscopy and demonstrated anisotropic growth characteristics of GaN. The optical characteristics were investigated using Raman spectra and photoluminescence(PL). The InGaN/GaN MQW structure grown on the GaN template with SiO_2 stripes along the [1-100] orientation exhibited less stress and higher PL intensity.Transmission electron microscopy results indicated that portions of MQWs were grown on an inclined semipolar plane, and air voids occurred only when the direction of the mask stripe was along the [1-100] orientation. The enhancement of the optical characteristic was due to the air-void structure and inclined semipolar quantum-well sidewalls.展开更多
基金supported by the grant from the Ministry of Science and Technology of China (No. 2012AA10A302-2)
文摘Mutants with abnormal leaf coloration are good genetic materials for understanding the mechanism of chloroplast development and chlorophyll biosynthesis. In this study, a rice mutant st2 （stripe2） with stripe leaves was identified from the ＂y-ray irradiated mutant pool. The st2 mutant exhibited decreased accumulation of chlorophyll and aberrant chloroplasts. Genetic analysis indicated that the st2 mutant was controlled by a single recessive locus. The ST2 gene was finely confined to a 27-kb region on chromosome 1 by the map-based cloning strategy and a 5-bp deletion in Os01g0765000 was identified by sequence analysis. The deletion happened in the joint of exon 3 and intron 3 and led to new spliced products of mRNA. Genetic comptementation confirmed that Os01g0765000 is the ST2 gene. We found that the ST2 gene was expressed ubiquitously. Subcellular localization assay showed that the ST2 protein was located in mitochondria. ST2 belongs to the cytidine deaminase-like family and possibly functions as the dCMP deaminase, which catalyzes the formation of dUMP from dCMP by deamination. Additionally, exogenous application of dUMP could partially rescue the st2 phenotype. Therefore, our study identified a putative dCMP deaminase as a novel regulator in chloroplast development for the first time.
基金supported by the Key Research and Development Program in Shaanxi Province (Grant Nos. 2018ZDCXL-GY-01-02-02 and 2018ZDCXLGY-01-07)Wuhu and Xidian University Special Fund for Industry University Research Cooperation (Grant No. XWYCXY-012020007)+2 种基金the National Natural Science Foundation of China (Grant No. 62074120)the Fundamental Research Funds for the Central Universitiesthe Innovation Fund of Xidian University。
文摘InGaN/GaN multiple quantum-well(MQW) structures with a wavelength range of green were successfully grown on a c-plane GaN template with SiO_2 stripe patterns along the [11-20] and [1-100] directions as a mask. The surface morphologies of both samples were investigated using scanning electron microscopy and demonstrated anisotropic growth characteristics of GaN. The optical characteristics were investigated using Raman spectra and photoluminescence(PL). The InGaN/GaN MQW structure grown on the GaN template with SiO_2 stripes along the [1-100] orientation exhibited less stress and higher PL intensity.Transmission electron microscopy results indicated that portions of MQWs were grown on an inclined semipolar plane, and air voids occurred only when the direction of the mask stripe was along the [1-100] orientation. The enhancement of the optical characteristic was due to the air-void structure and inclined semipolar quantum-well sidewalls.
