The hotABA-deficiency suppressor2 （has2） mutation increases drought tolerance and the ABA sensitivity of stomata closure and seed germination. Here we report that the HAS2 locus encodes the MITOCHONDRIAL EDITING FAC...The hotABA-deficiency suppressor2 （has2） mutation increases drought tolerance and the ABA sensitivity of stomata closure and seed germination. Here we report that the HAS2 locus encodes the MITOCHONDRIAL EDITING FACTOR11 （MEF11）, also known as LOVASTATIN INSENSITIVE1. has21mef11 mutants exhibited phenotypes very similar to the ABA-hypersensitive mutant, hail-1 pp2ca-1 hab 1-1 abil-2, which is impaired in four genes encoding type 2C protein phosphatases （PP2C） that act as upstream negative regulators of the ABA signaling cascade. Like pp2c, mef11 plants were more resistant to progressive water stress and seed germination was more sensitive to paclobutrazol （a gibberellin biosynthesis inhibitor） as well as mannitol and NaCI, compared with the wild-type plants. Phenotypic alterations in mef11 were associated with the lack of editing of transcripts for the mitochondrial cytochrome c maturation FN2 （cCmFN2） gene, which encodes a cytochrome c-heme lyase subunit involved in cytochrome c biogenesis. Although the abundance of electron transfer chain complexes was not affected, their dysfunction could be deduced from increased respiration and altered production of hydrogen peroxide and nitric oxide in reef11 seeds. As minor defects in mitochondrial respiration affect ABA signaling, this suggests an essential role for ABA in mitochondrial retrograde regulation.展开更多
Light and temperature are key external factors in the control of Arabidopsis thaliana seed germination and dormancy mechanisms. Perception and response to these stimuli have to ensure that seedling emergence and growt...Light and temperature are key external factors in the control of Arabidopsis thaliana seed germination and dormancy mechanisms. Perception and response to these stimuli have to ensure that seedling emergence and growth occur at the most advantageous time for correct establishment. Analysis of over 300 Arabidopsis accessions identified 14, from 12 different geographical locations, that were able to germinate to greater than 20% at 6℃ in the dark. This natural variation was exploited to identify genetic loci responsible for cold-tolerant, dark germination. A quantitative trait loci approach was used on recombinant inbred line progeny of a cross between Bay-0 and Shahdara. Six distinct quantitative trait loci were identified, three of which were major loci, each responsible for 17-25% of the phenotypic variability in this trait. Parental phenotypes indicated that the majority of the cold-tolerant, dark-germination characteristics are related to light responses. Validation of the three major loci using heterogeneous inbred families confirmed the feasibility of fine mapping and cloning the genes at the quantitative trait loci responsible for cold-tolerant, dark germination.展开更多
文摘The hotABA-deficiency suppressor2 （has2） mutation increases drought tolerance and the ABA sensitivity of stomata closure and seed germination. Here we report that the HAS2 locus encodes the MITOCHONDRIAL EDITING FACTOR11 （MEF11）, also known as LOVASTATIN INSENSITIVE1. has21mef11 mutants exhibited phenotypes very similar to the ABA-hypersensitive mutant, hail-1 pp2ca-1 hab 1-1 abil-2, which is impaired in four genes encoding type 2C protein phosphatases （PP2C） that act as upstream negative regulators of the ABA signaling cascade. Like pp2c, mef11 plants were more resistant to progressive water stress and seed germination was more sensitive to paclobutrazol （a gibberellin biosynthesis inhibitor） as well as mannitol and NaCI, compared with the wild-type plants. Phenotypic alterations in mef11 were associated with the lack of editing of transcripts for the mitochondrial cytochrome c maturation FN2 （cCmFN2） gene, which encodes a cytochrome c-heme lyase subunit involved in cytochrome c biogenesis. Although the abundance of electron transfer chain complexes was not affected, their dysfunction could be deduced from increased respiration and altered production of hydrogen peroxide and nitric oxide in reef11 seeds. As minor defects in mitochondrial respiration affect ABA signaling, this suggests an essential role for ABA in mitochondrial retrograde regulation.
文摘Light and temperature are key external factors in the control of Arabidopsis thaliana seed germination and dormancy mechanisms. Perception and response to these stimuli have to ensure that seedling emergence and growth occur at the most advantageous time for correct establishment. Analysis of over 300 Arabidopsis accessions identified 14, from 12 different geographical locations, that were able to germinate to greater than 20% at 6℃ in the dark. This natural variation was exploited to identify genetic loci responsible for cold-tolerant, dark germination. A quantitative trait loci approach was used on recombinant inbred line progeny of a cross between Bay-0 and Shahdara. Six distinct quantitative trait loci were identified, three of which were major loci, each responsible for 17-25% of the phenotypic variability in this trait. Parental phenotypes indicated that the majority of the cold-tolerant, dark-germination characteristics are related to light responses. Validation of the three major loci using heterogeneous inbred families confirmed the feasibility of fine mapping and cloning the genes at the quantitative trait loci responsible for cold-tolerant, dark germination.
