Plasma membrane intrinsic proteins （PIPs） are a subfamily ofaquaporins that enable fast and controlled translocation of water across the membrane. In this study, we systematically identified and cloned ten PIP genes...Plasma membrane intrinsic proteins （PIPs） are a subfamily ofaquaporins that enable fast and controlled translocation of water across the membrane. In this study, we systematically identified and cloned ten PIP genes from rice. Based on the similarity of the amino acid sequences they encoded, these rice PIP genes were classified into two groups and designated as OsPIP1-1 to OsPIP1-3 and OsPIP2-1 to OsPIP2-7 following the nomenclature of PIP genes in maize. Quantitative RT-PCR analysis identified three root-specific and one leaf-specific OsPIP genes. Furthermore, the expression profile of each OsPIP gene in response to salt, drought and ABA treatment was examined in detail. Analysis on transgenic plants over-expressing of either OsPIP1 （OsPIP1-1） or OsPIP2 （OsPIP2-2） in wild-type Arabidopsis, showed enhanced tolerance to salt （100 mM of NaCl） and drought （200 mM ofmannitol）, but not to salt treatment of higher concentration （150 mM of NaCl）. Taken together, these data suggest a distinct role of each OsPIP gene in response to different stresses, and should add a new layer to the understanding of the physiological function of rice PIP genes.展开更多
Wild-type （Zhonghua 11） and mutant rice （Oryza sativa L.） plants were used to investigate the effect of cadmium （Cd） application on biomass production, to characterize the influx of Cd from roots to shoots, and ...Wild-type （Zhonghua 11） and mutant rice （Oryza sativa L.） plants were used to investigate the effect of cadmium （Cd） application on biomass production, to characterize the influx of Cd from roots to shoots, and to determine the form, content, and subcellular distribution of Cd in the roots, leaf sheaths, and leaves of the rice plants. Seedlings were cultivated in a nutrient solution and were treated with 0.5 mmol L^-1 of Cd^2＋ for 14 d. The sensitivity of rice plants to Cd toxicity was tested by studying the changes in biomass production and by observing the onset of toxicity symptoms in the plants. Both the wild-type and mutant rice plants developed symptoms of Cd stress. In addition, Cd application significantly （P ≤ 0.01） decreased dry matter production of roots, leaf sheaths, and leaves of both types, especially the mutant. The Cd content in roots of the mutant was significantly （P ≤0.05） higher than that of the wild-type rice. However, there was no significant difference in the Cd content of roots, leaf sheaths, and leaves between the wild-type and mutant rice. Most of the Cd was bound to the cell wall of the roots, leaf sheaths, and leaves, and the mutant had greater Cd content in cell organelles than the wild type. The uneven subcellular distribution could be responsible for the Cd sensitivity of the mutant rice. Furthermore, different chemical forms of Cd were found to occur in the roots, leaf sheaths, and leaves of both types of rice plants. Ethanol-, water-, and NaCl-extractable Cd had greater toxicity than the other forms of Cd and induced stunted growth and chlorosis in the plants. The high Cd content of the toxic forms of Cd in the cell organelles could seriously damage the cells and the metabolic processes in mutant rice plants.展开更多
Magnesium （Mg） deficiency in plant affects photosynthesis and many other metabolic processes. Rice （Oryza sativa L. cv. ＇Wuyunjing 7＇） plants were grown in hydroponics culture at three Mg and two potassium （K）...Magnesium （Mg） deficiency in plant affects photosynthesis and many other metabolic processes. Rice （Oryza sativa L. cv. ＇Wuyunjing 7＇） plants were grown in hydroponics culture at three Mg and two potassium （K） levels under greenhouse conditions to examine the induction of oxidative stress and consequent antioxidant responses in rice leaves due to Mg deficiency. At low Mg （0.2 mmol L 1 Mg supply for two weeks after transplanting） and high K （6 mmol L^-1） for 21 days, the rice plants showed severe Mg deficiency and a significant decreases in the dry matter production. The Mg deficiency in leaves decreased chlorophyll concentrations, photosynthetic activity, and soluble protein, but significantly increased the concentrations of soluble sugars and malondialdchyde （MDA） and the activities of superoxide dismutase （SOLD, EC 1.15.1.1）, catalase （CAT, EC 1.11.1.6） and peroxidase （POD, EC 1.11.1.7）. In addition, Mg concentrations in the leaves and in the shoot biomass were negatively related to the activities of the three antioxidative enzymes and the concentration of MDA in leaves. There were very significant interactive effects between Mg and K supplied in the culture solution on shoot biomass yield, chlorophyll content, photosynthesis rate, the activities of SOD, CAT and POD, and MDA content in the leaves of rice. It is suggested that the high K level in the nutrient solution aggravated the effect of low Mg supply-induced Mg deficiency and created the oxidative damage in rice plants.展开更多
Drought is the most important factor limiting rice yields in the rainfed areas of Asia. To overcome the problem, we developed a new strategy 'designed QTL pyramiding' to more effi ciently develop drought toler...Drought is the most important factor limiting rice yields in the rainfed areas of Asia. To overcome the problem, we developed a new strategy 'designed QTL pyramiding' to more effi ciently develop drought tolerant (DT)展开更多
During vegetative development, higher plants continuously form new leaves in regular spatial and temporal patterns. Mutants with abnormal leaf developmental patterns not only provide a great insight into understanding...During vegetative development, higher plants continuously form new leaves in regular spatial and temporal patterns. Mutants with abnormal leaf developmental patterns not only provide a great insight into understanding the regulatory mechanism of plant architecture, but also enrich the ways to its modification by which crop yield could be improved. Here, we reported the characterization of the rice leafy-head2 （lhd2） mutant that exhibits shortened plastochron, dwarfism, reduced tiller number, and failure of phase transition from vegetative to reproductive growth. Anatomical and histological study revealed that the rapid emergence of leaves in lhd2 was resulted from the rapid initiation of leaf primordia whereas the reduced tiller number was a consequence of the suppression of the tiller bud outgrowth. The molecular and genetic analysis showed that LHD2 encodes a putative RNA binding protein with 67% similarity to maize TEl. Comparison of genome-scale expression profiles between wild-type and lhd2 plants suggested that LHD2 may regulate rice shoot development through KNOXand hormone-related genes. The similar phenotypes caused by LHD2 mutation and the conserved expression pattern of LHD2 indicated a conserved mechanism in controlling the temporal leaf initiation in grass.展开更多
Pollen sterility is commonly found in the intra-specific hybrids of indica and japonica rice,which is one of the main constrains for the utilization of heterosis between indica and japonica.Six loci controlling the po...Pollen sterility is commonly found in the intra-specific hybrids of indica and japonica rice,which is one of the main constrains for the utilization of heterosis between indica and japonica.Six loci controlling the pollen sterility of F1 between indica and japonica have been identified from previous studies.Neutral alleles at each locus are potential to overcome the F1 pollen sterility associated with the locus.Therefore,exploitation and utilization of neutral alleles are of significant importance.The present research was based on fine mapping of the F1 pollen-sterility gene Sb and the abundant genetic diversity of Oryza rufipogon Griff.indigenous to Gaozhou,Guangdong Province(referred to as Gaozhou wild rice).Crosses were made using Taichung65(with the genotype of SbjSbj and referred to as E1) and its near-isogenic line of F1 pollen sterility gene Sb(with the genotype of SbiSbi,E2) as female parents,and 12 different accessions of Gaozhou wild rice as male parents.F1 pollen fertility was examined to identify the materials having the neutral alleles at the F1 pollen-sterility locus.Segregation of 4 molecular markers tightly linked with the Sb locus was analyzed in the F2 populations derived from the F1s carrying the neutral gene.The pollen fertility related to the 3 genotypes of the molecular markers was also checked by statistical test to determine whether it was consistent with the hypothesis.The results showed that the pollen fertility of two F1s from one accession of Gaozhou wild rice(GZW099) with E1 and E2 was(89.22±1.07)% and(85.65±1.05)%,respectively.Both of them were fertile and showed no significant difference by t-test.Segregation of the 3 genotypes of the 4 molecular markers followed the expected Mendelian ratio(1:2:1) in the F2 populations.There was no significant difference for the averaged pollen fertility of the plants related to the 3 genotypes,suggesting that no interaction exists between the alleles at the Sb locus in GZW099 and Taichung65 or E2.Evidentially,GZW099 carried the neutral gene(name展开更多
The continuous growth of lowland rice (LR) in paddy fields supplied with enough water over the years, and of upland rice (UR) in naturally rain-fed soils, has resulted in greater resistance to drought stress in UR com...The continuous growth of lowland rice (LR) in paddy fields supplied with enough water over the years, and of upland rice (UR) in naturally rain-fed soils, has resulted in greater resistance to drought stress in UR compared to LR. To elucidate their differential regulation mechanisms of drought-resistance, genome-wide transcript regulation under drought stress in UR and LR was investigated using cDNA-AFLP. The results indicated that over 90% of gene expression was not affected by drought stress in the two rice genotypes, more than 8% was regulated by drought stress in both, and less than 1% was specifically expressed in UR or LR. Fifty-seven genes were specifically expressed in UR and thirty-eight specifically in LR. Genes specifically expressed in UR included cell rescue and defence genes functioning in drought-resistance, signal transduction molecules, nucleotides and amino acid biosynthesis genes required for plant growth, and the regulatory genes for growth and development. In LR, genes specifically expressed were related to protein and nucleotide degradation. Some genes were upregulated earlier in UR, and downregulated genes were inclined to be downregulated earlier in UR compared to LR, implying that more rapid regulation mechanisms caused earlier responses of UR to drought stress. Expression levels of upregulated genes in UR were higher than those in LR. The differences in gene expression between UR and LR could account for stronger regulation ability, more drought-resistance and superior growth of UR under drought stress compared to LR.展开更多
Through the efforts of the International Rice Genome Sequencing Project, the whole genome sequence of rice has been decoded (International Rice Genome Sequencing Project, 2005). This sequence information has
Asian rice gall midge (GM) is a major rice pest in South China. Breeding resistance varieties has been a viable and ecologically acceptable approach for managing the pest. This paper reports that the progress of
Development of cytoplasmic male sterile (CMS) lines with elongated uppermost internode (EUI) trait provides a genetic option to eliminate the use of GA 3 in hybrid rice. During the past two decades, extensive work
文摘Plasma membrane intrinsic proteins （PIPs） are a subfamily ofaquaporins that enable fast and controlled translocation of water across the membrane. In this study, we systematically identified and cloned ten PIP genes from rice. Based on the similarity of the amino acid sequences they encoded, these rice PIP genes were classified into two groups and designated as OsPIP1-1 to OsPIP1-3 and OsPIP2-1 to OsPIP2-7 following the nomenclature of PIP genes in maize. Quantitative RT-PCR analysis identified three root-specific and one leaf-specific OsPIP genes. Furthermore, the expression profile of each OsPIP gene in response to salt, drought and ABA treatment was examined in detail. Analysis on transgenic plants over-expressing of either OsPIP1 （OsPIP1-1） or OsPIP2 （OsPIP2-2） in wild-type Arabidopsis, showed enhanced tolerance to salt （100 mM of NaCl） and drought （200 mM ofmannitol）, but not to salt treatment of higher concentration （150 mM of NaCl）. Taken together, these data suggest a distinct role of each OsPIP gene in response to different stresses, and should add a new layer to the understanding of the physiological function of rice PIP genes.
基金the National Natural Science Foundation of China (No30671255)the National Key Technologies R&D Program of China during the 11th Five-Year Plan Period (No2006BAK02A18)the National Basic Research Program (973) of China (No2002CB410804)
文摘Wild-type （Zhonghua 11） and mutant rice （Oryza sativa L.） plants were used to investigate the effect of cadmium （Cd） application on biomass production, to characterize the influx of Cd from roots to shoots, and to determine the form, content, and subcellular distribution of Cd in the roots, leaf sheaths, and leaves of the rice plants. Seedlings were cultivated in a nutrient solution and were treated with 0.5 mmol L^-1 of Cd^2＋ for 14 d. The sensitivity of rice plants to Cd toxicity was tested by studying the changes in biomass production and by observing the onset of toxicity symptoms in the plants. Both the wild-type and mutant rice plants developed symptoms of Cd stress. In addition, Cd application significantly （P ≤ 0.01） decreased dry matter production of roots, leaf sheaths, and leaves of both types, especially the mutant. The Cd content in roots of the mutant was significantly （P ≤0.05） higher than that of the wild-type rice. However, there was no significant difference in the Cd content of roots, leaf sheaths, and leaves between the wild-type and mutant rice. Most of the Cd was bound to the cell wall of the roots, leaf sheaths, and leaves, and the mutant had greater Cd content in cell organelles than the wild type. The uneven subcellular distribution could be responsible for the Cd sensitivity of the mutant rice. Furthermore, different chemical forms of Cd were found to occur in the roots, leaf sheaths, and leaves of both types of rice plants. Ethanol-, water-, and NaCl-extractable Cd had greater toxicity than the other forms of Cd and induced stunted growth and chlorosis in the plants. The high Cd content of the toxic forms of Cd in the cell organelles could seriously damage the cells and the metabolic processes in mutant rice plants.
文摘Magnesium （Mg） deficiency in plant affects photosynthesis and many other metabolic processes. Rice （Oryza sativa L. cv. ＇Wuyunjing 7＇） plants were grown in hydroponics culture at three Mg and two potassium （K） levels under greenhouse conditions to examine the induction of oxidative stress and consequent antioxidant responses in rice leaves due to Mg deficiency. At low Mg （0.2 mmol L 1 Mg supply for two weeks after transplanting） and high K （6 mmol L^-1） for 21 days, the rice plants showed severe Mg deficiency and a significant decreases in the dry matter production. The Mg deficiency in leaves decreased chlorophyll concentrations, photosynthetic activity, and soluble protein, but significantly increased the concentrations of soluble sugars and malondialdchyde （MDA） and the activities of superoxide dismutase （SOLD, EC 1.15.1.1）, catalase （CAT, EC 1.11.1.6） and peroxidase （POD, EC 1.11.1.7）. In addition, Mg concentrations in the leaves and in the shoot biomass were negatively related to the activities of the three antioxidative enzymes and the concentration of MDA in leaves. There were very significant interactive effects between Mg and K supplied in the culture solution on shoot biomass yield, chlorophyll content, photosynthesis rate, the activities of SOD, CAT and POD, and MDA content in the leaves of rice. It is suggested that the high K level in the nutrient solution aggravated the effect of low Mg supply-induced Mg deficiency and created the oxidative damage in rice plants.
文摘Drought is the most important factor limiting rice yields in the rainfed areas of Asia. To overcome the problem, we developed a new strategy 'designed QTL pyramiding' to more effi ciently develop drought tolerant (DT)
文摘During vegetative development, higher plants continuously form new leaves in regular spatial and temporal patterns. Mutants with abnormal leaf developmental patterns not only provide a great insight into understanding the regulatory mechanism of plant architecture, but also enrich the ways to its modification by which crop yield could be improved. Here, we reported the characterization of the rice leafy-head2 （lhd2） mutant that exhibits shortened plastochron, dwarfism, reduced tiller number, and failure of phase transition from vegetative to reproductive growth. Anatomical and histological study revealed that the rapid emergence of leaves in lhd2 was resulted from the rapid initiation of leaf primordia whereas the reduced tiller number was a consequence of the suppression of the tiller bud outgrowth. The molecular and genetic analysis showed that LHD2 encodes a putative RNA binding protein with 67% similarity to maize TEl. Comparison of genome-scale expression profiles between wild-type and lhd2 plants suggested that LHD2 may regulate rice shoot development through KNOXand hormone-related genes. The similar phenotypes caused by LHD2 mutation and the conserved expression pattern of LHD2 indicated a conserved mechanism in controlling the temporal leaf initiation in grass.
基金Supported by the Joint Funds of the National Natural Science Foundation of ChinaGuangdong Province(Grant No.U0631003)Natural Science Foundation of Guangdong Province(Grant No.5300831)
文摘Pollen sterility is commonly found in the intra-specific hybrids of indica and japonica rice,which is one of the main constrains for the utilization of heterosis between indica and japonica.Six loci controlling the pollen sterility of F1 between indica and japonica have been identified from previous studies.Neutral alleles at each locus are potential to overcome the F1 pollen sterility associated with the locus.Therefore,exploitation and utilization of neutral alleles are of significant importance.The present research was based on fine mapping of the F1 pollen-sterility gene Sb and the abundant genetic diversity of Oryza rufipogon Griff.indigenous to Gaozhou,Guangdong Province(referred to as Gaozhou wild rice).Crosses were made using Taichung65(with the genotype of SbjSbj and referred to as E1) and its near-isogenic line of F1 pollen sterility gene Sb(with the genotype of SbiSbi,E2) as female parents,and 12 different accessions of Gaozhou wild rice as male parents.F1 pollen fertility was examined to identify the materials having the neutral alleles at the F1 pollen-sterility locus.Segregation of 4 molecular markers tightly linked with the Sb locus was analyzed in the F2 populations derived from the F1s carrying the neutral gene.The pollen fertility related to the 3 genotypes of the molecular markers was also checked by statistical test to determine whether it was consistent with the hypothesis.The results showed that the pollen fertility of two F1s from one accession of Gaozhou wild rice(GZW099) with E1 and E2 was(89.22±1.07)% and(85.65±1.05)%,respectively.Both of them were fertile and showed no significant difference by t-test.Segregation of the 3 genotypes of the 4 molecular markers followed the expected Mendelian ratio(1:2:1) in the F2 populations.There was no significant difference for the averaged pollen fertility of the plants related to the 3 genotypes,suggesting that no interaction exists between the alleles at the Sb locus in GZW099 and Taichung65 or E2.Evidentially,GZW099 carried the neutral gene(name
基金Supported by the National Key Basic Research and Development Program of China (Grant No. 2004CB117201)Specialized Research Fund for Doctoral Program of Higher Education of Ministry of Education of China (Grant No. 200800190017)Key Project of Transgenic Crop Improvement in China (Grant No. 2009ZX08- 009-073B)
文摘The continuous growth of lowland rice (LR) in paddy fields supplied with enough water over the years, and of upland rice (UR) in naturally rain-fed soils, has resulted in greater resistance to drought stress in UR compared to LR. To elucidate their differential regulation mechanisms of drought-resistance, genome-wide transcript regulation under drought stress in UR and LR was investigated using cDNA-AFLP. The results indicated that over 90% of gene expression was not affected by drought stress in the two rice genotypes, more than 8% was regulated by drought stress in both, and less than 1% was specifically expressed in UR or LR. Fifty-seven genes were specifically expressed in UR and thirty-eight specifically in LR. Genes specifically expressed in UR included cell rescue and defence genes functioning in drought-resistance, signal transduction molecules, nucleotides and amino acid biosynthesis genes required for plant growth, and the regulatory genes for growth and development. In LR, genes specifically expressed were related to protein and nucleotide degradation. Some genes were upregulated earlier in UR, and downregulated genes were inclined to be downregulated earlier in UR compared to LR, implying that more rapid regulation mechanisms caused earlier responses of UR to drought stress. Expression levels of upregulated genes in UR were higher than those in LR. The differences in gene expression between UR and LR could account for stronger regulation ability, more drought-resistance and superior growth of UR under drought stress compared to LR.
文摘Through the efforts of the International Rice Genome Sequencing Project, the whole genome sequence of rice has been decoded (International Rice Genome Sequencing Project, 2005). This sequence information has
文摘Asian rice gall midge (GM) is a major rice pest in South China. Breeding resistance varieties has been a viable and ecologically acceptable approach for managing the pest. This paper reports that the progress of
文摘Development of cytoplasmic male sterile (CMS) lines with elongated uppermost internode (EUI) trait provides a genetic option to eliminate the use of GA 3 in hybrid rice. During the past two decades, extensive work
