A developmentally retarded mutant (drm1) was identified from ethyl methanesulfonate (EMS)-mutagenized M2 seedsin Columbia (Col-0) genetic background. The drm1 flowers 109 d after sowing, with a whole life cycle of abo...A developmentally retarded mutant (drm1) was identified from ethyl methanesulfonate (EMS)-mutagenized M2 seedsin Columbia (Col-0) genetic background. The drm1 flowers 109 d after sowing, with a whole life cycle of about 160 d.It also shows a pleiotropic phenotype, e.g., slow germination and lower germination rate, lower growth rate, curlingleaves and abnormal floral organs. The drm1 mutation was a single recessive nuclear mutation, which was mapped tothe bottom of chromosome 5 and located within a region of 20-30 kb around MXK3.1. There have been no mutantswith similar phenotypes reported in the literature, suggesting that DRM1 is a novel flowering promoting locus. Thefindings that the drm1 flowered lately under all photoperiod conditions and its late flowering phenotype was significantlyrestored by vernalization treatment suggest that the drm1 is a typical late flowering mutant and most likely associatedwith the autonomous flowering pathway. The conclusion was further confirmed by the revelation that the transcriptlevel of FLC was constantly upregulated in the drm1 at all the developmental phases examined, except for a very earlystage. Moreover, the transcript levels of two other important repressors, EMF and TFL1, were also upregulated in thedrm1, implying that the two repressors, along with FLC, seems to act in parallel pathways in the drm1 to regulateflowering as well as other aspects of floral development in a negatively additive way. This helps to explain why the drm1exhibits a much more severe late-flowering phenotype than most late-flowering mutants reported. It also implies that theDRM1 might act upstream of these repressors.展开更多
谷子(Setaria italica P. Beauv.)作为C4模式植物,具有较强的抗旱性,但干旱仍是制约其生长和产量的重要因素。为探究谷子耐旱性突变体(Drought-resistant mutant)的抗旱生理机制,以野生型‘豫谷28’和其耐旱性突变体(drm1-1)为材料,采...谷子(Setaria italica P. Beauv.)作为C4模式植物,具有较强的抗旱性,但干旱仍是制约其生长和产量的重要因素。为探究谷子耐旱性突变体(Drought-resistant mutant)的抗旱生理机制,以野生型‘豫谷28’和其耐旱性突变体(drm1-1)为材料,采用盆栽法分析了干旱胁迫下野生型与drm1-1在孕穗期和花后10 d的光合特性和抗旱性。结果显示,在正常条件下,drm1-1诱导了谷子光合作用相关的磷酸烯醇式丙酮酸羧化酶基因pepc、丙酮酸磷酸双激酶基因ppdk以及苹果酸酶基因nadp-me的表达,显著提高了相应酶的活性,也使得drm1-1的光合速率较野生型显著提高。在干旱胁迫条件下,drm1-1的光合速率和叶绿素荧光参数与正常条件相比,下降幅度显著小于野生型,具有显著的光合优势,同时drm1-1叶片的相对含水量与正常条件相比,下降的幅度显著小于野生型,而渗透调节物含量及抗氧化物酶活性均较野生型显著增加;且drm1-1的持水能力及抗旱性能更强。产量性状分析表明,干旱胁迫条件下drm1-1具有突出的产量优势。展开更多
文摘A developmentally retarded mutant (drm1) was identified from ethyl methanesulfonate (EMS)-mutagenized M2 seedsin Columbia (Col-0) genetic background. The drm1 flowers 109 d after sowing, with a whole life cycle of about 160 d.It also shows a pleiotropic phenotype, e.g., slow germination and lower germination rate, lower growth rate, curlingleaves and abnormal floral organs. The drm1 mutation was a single recessive nuclear mutation, which was mapped tothe bottom of chromosome 5 and located within a region of 20-30 kb around MXK3.1. There have been no mutantswith similar phenotypes reported in the literature, suggesting that DRM1 is a novel flowering promoting locus. Thefindings that the drm1 flowered lately under all photoperiod conditions and its late flowering phenotype was significantlyrestored by vernalization treatment suggest that the drm1 is a typical late flowering mutant and most likely associatedwith the autonomous flowering pathway. The conclusion was further confirmed by the revelation that the transcriptlevel of FLC was constantly upregulated in the drm1 at all the developmental phases examined, except for a very earlystage. Moreover, the transcript levels of two other important repressors, EMF and TFL1, were also upregulated in thedrm1, implying that the two repressors, along with FLC, seems to act in parallel pathways in the drm1 to regulateflowering as well as other aspects of floral development in a negatively additive way. This helps to explain why the drm1exhibits a much more severe late-flowering phenotype than most late-flowering mutants reported. It also implies that theDRM1 might act upstream of these repressors.
文摘谷子(Setaria italica P. Beauv.)作为C4模式植物,具有较强的抗旱性,但干旱仍是制约其生长和产量的重要因素。为探究谷子耐旱性突变体(Drought-resistant mutant)的抗旱生理机制,以野生型‘豫谷28’和其耐旱性突变体(drm1-1)为材料,采用盆栽法分析了干旱胁迫下野生型与drm1-1在孕穗期和花后10 d的光合特性和抗旱性。结果显示,在正常条件下,drm1-1诱导了谷子光合作用相关的磷酸烯醇式丙酮酸羧化酶基因pepc、丙酮酸磷酸双激酶基因ppdk以及苹果酸酶基因nadp-me的表达,显著提高了相应酶的活性,也使得drm1-1的光合速率较野生型显著提高。在干旱胁迫条件下,drm1-1的光合速率和叶绿素荧光参数与正常条件相比,下降幅度显著小于野生型,具有显著的光合优势,同时drm1-1叶片的相对含水量与正常条件相比,下降的幅度显著小于野生型,而渗透调节物含量及抗氧化物酶活性均较野生型显著增加;且drm1-1的持水能力及抗旱性能更强。产量性状分析表明,干旱胁迫条件下drm1-1具有突出的产量优势。
