One hundred and thirty-eight rice accessions were screened for resistance to the small brown planthopper （SBPH） （Laodelphax striatellus Fallen） by the modified seedbox screening test. Twenty-five rice accessions w...One hundred and thirty-eight rice accessions were screened for resistance to the small brown planthopper （SBPH） （Laodelphax striatellus Fallen） by the modified seedbox screening test. Twenty-five rice accessions with different levels of resistance to SBPH were detected, accounting for 18.1% of the total accessions, which included 2 highly resistant, 9 resistant and 14 moderately resistant varieties. Compared with indica rice, japonica rice was more susceptible to SBPH. Antixenosis test, antibiosis test and correlation analysis were performed to elucidate the resistance mechanism. The resistant check Rathu Heenati （RHT）, highly resistant varieties Mudgo and Kasalath, and resistant variety IR36 expressed strong antixenosis and antibiosis against SBPH, indicating the close relationship between resistance level and these two resistance mechanisms in the four rice varieties. Antibiosis was the dominant resistance pattern in the resistant varieties Daorenqiao and Yangmaogu due to their high antibiosis but low antixenosis. Dular, ASD7 and Milyang 23 had relatively strong antixenosis and antibiosis, indicating the two resistance mechanisms were significant in these three varieties. The resistant DV85 expressed relatively high level of antixenosis but low antibiosis, whereas Zhaiyeqing 8 and Guiyigu conferred only moderate antibiosis and antixenosis to SBPH, suggesting tolerance in these three varieties. Antibiosis and antixenosis governed the resistance to SBPH in the moderately resistant accession 9311. Antixenosis was the main resistance type in V20A. Tolerance was considered to be an important resistance mechanism in Minghui 63 and Yangjing 9538 due to their poor antibiosis and antixenosis resistance. The above accessions with strong antibiosis or antixenosis were the ideal materials for the resistance breeding.展开更多
Rice panicle apical abortion(PAA)is a detrimental agronomic trait resulting in spikelet number reduction and yield loss.To understand its underlying molecular mechanism,we identified one recessive PAA mutant tutou2 fr...Rice panicle apical abortion(PAA)is a detrimental agronomic trait resulting in spikelet number reduction and yield loss.To understand its underlying molecular mechanism,we identified one recessive PAA mutant tutou2 from the offspring of tissue cultures.The mutation locus was finely mapped to a 75-kb interval on the long arm of chromosome 10.Sequence analysis revealed a single nucleotide substitution of A to T at the 941 position of LOC_Os10g31910 in tutou2,resulting in an amino acid change from isoleucine to phenylalanine.Complementation analysis showed that the degenerated panicle phenotype in tutou2 was rescued in the transgenic lines.A phenotype similar to tutou2 can also be obtained by LOC_Os10g31910 knockout in wild-type rice.These results suggested that LOC_Os10 g31910 is the causative locus TUTOU2 responsible for the tutou2 PAA phenotype and probably also the locus of DEL1,previously documented as a leaf senescence gene.The significant phenotypic differences between del1 and tutou2 suggest that the locus DEL1/TUTOU2 plays roles in both leaf and panicle development which were not considered fully in previous studies.展开更多
Understanding the genetic mechanism underlying folate biosynthesis and accumulation in rice would be beneficial for breeding high folate content varieties as a cost-effective approach to addressing widespread folate d...Understanding the genetic mechanism underlying folate biosynthesis and accumulation in rice would be beneficial for breeding high folate content varieties as a cost-effective approach to addressing widespread folate deficiency in developing countries. In this study, the inheritance of rice grain folate content was investigated in the Lemont/Teqing recombinant inbred lines and the Koshihikari/Kasalath//Koshihikari backcross inbred lines. 264 F12 recombinant inbred lines（RILs） and 182 BC1F10 backcross inbred lines（BILs） with their parents planted in randomized complete blocks with two replicates in 2010, and RILs harvested in 2008 were used for QTL detection using inclusive composite interval mapping（ICIM） method. In the RIL population, two QTLs, denoted by qQTF-3-1 and qQTF-3-2（QTF, quantitative total folate）, explaining 7.8% and 11.1-15.8% of the folate content variation were detected in one or two years, respectively. In the BIL population, a QTL, denoted by qQTF-3-3, was detected, explaining 25.3% of the variation in folate content. All the positive alleles for higher folate content were from the high-folate parents, i.e., Teqing and Kasalath. The known putative folate biosynthesis genes do not underlie the QTLs detected in this study and therefore may be novel loci affecting folate content in milled rice. QTLs identified in this study have potential value for marker assisted breeding for high-folate rice variety.展开更多
Plant cell walls constitute the skeletal structures of plant bodies,and thus confer lodging resistance for grain crops.While the basic cell wall synthesis machinery is relatively well established now,our understanding...Plant cell walls constitute the skeletal structures of plant bodies,and thus confer lodging resistance for grain crops.While the basic cell wall synthesis machinery is relatively well established now,our understanding of how the process is regulated remains limited and fragmented.In this study,we report the identification and characterization of the novel rice（Oryza sativa L.）brittle culm16（brittle node;bc16）mutant.The brittle node phenotype of the bc16 mutant appears exclusively at nodes,and resembles the previously reported bc5 mutant.Combined histochemical staining and electron microscopy assays revealed that in the bc16 mutant,the secondary cell wall formation and thickening of node sclerenchyma tissues are seriously affected after heading.Furthermore,cell wall composition assays revealed that the bc16 mutation led to a significant reduction in cellulose and lignin contents.Using a map-based cloning approach,the bc16 locus is mapped to an approximately 1.7-Mb region of chromosome 4.Together,our findings strengthen evidence for discretely spatial differences in the secondary cell wall formation within plant bodies.展开更多
Voltage-gated sodium channels play an important role in the generation and propagation of action potentials in excitable cells. They are composed of a pore-forming α subunit and auxiliary β subunits. To date, nine s...Voltage-gated sodium channels play an important role in the generation and propagation of action potentials in excitable cells. They are composed of a pore-forming α subunit and auxiliary β subunits. To date, nine subtypes of the α subunit, designated Nav1.1 to Nav1.9, have been shown to form functional sodium channels. In addition, four different mammalian subunits （β1-β4） isoforms have been cloned from the nervous system. The β subunits are structurally homologous and form single transmembrane glycoproteins with short intracellular loops and immunoglobulin-like extracellular segments. The association of the various α subtypes with different combinations of auxiliary β subunits creates the possibility of additional molecular and functional complexity for neuronal sodium channels.展开更多
文摘One hundred and thirty-eight rice accessions were screened for resistance to the small brown planthopper （SBPH） （Laodelphax striatellus Fallen） by the modified seedbox screening test. Twenty-five rice accessions with different levels of resistance to SBPH were detected, accounting for 18.1% of the total accessions, which included 2 highly resistant, 9 resistant and 14 moderately resistant varieties. Compared with indica rice, japonica rice was more susceptible to SBPH. Antixenosis test, antibiosis test and correlation analysis were performed to elucidate the resistance mechanism. The resistant check Rathu Heenati （RHT）, highly resistant varieties Mudgo and Kasalath, and resistant variety IR36 expressed strong antixenosis and antibiosis against SBPH, indicating the close relationship between resistance level and these two resistance mechanisms in the four rice varieties. Antibiosis was the dominant resistance pattern in the resistant varieties Daorenqiao and Yangmaogu due to their high antibiosis but low antixenosis. Dular, ASD7 and Milyang 23 had relatively strong antixenosis and antibiosis, indicating the two resistance mechanisms were significant in these three varieties. The resistant DV85 expressed relatively high level of antixenosis but low antibiosis, whereas Zhaiyeqing 8 and Guiyigu conferred only moderate antibiosis and antixenosis to SBPH, suggesting tolerance in these three varieties. Antibiosis and antixenosis governed the resistance to SBPH in the moderately resistant accession 9311. Antixenosis was the main resistance type in V20A. Tolerance was considered to be an important resistance mechanism in Minghui 63 and Yangjing 9538 due to their poor antibiosis and antixenosis resistance. The above accessions with strong antibiosis or antixenosis were the ideal materials for the resistance breeding.
基金supported by grants from the National Transgenic Science and Technology Program,China(2016ZX08009003-003)the National Key Research and Development Program of China(2016YFD0101100)+1 种基金the Youth Innovation Team Program of Chongqing Academy of Agricultural Sciences,China(NKY-2018QC03)the National Natural Science Foundation of China(31960401)。
文摘Rice panicle apical abortion(PAA)is a detrimental agronomic trait resulting in spikelet number reduction and yield loss.To understand its underlying molecular mechanism,we identified one recessive PAA mutant tutou2 from the offspring of tissue cultures.The mutation locus was finely mapped to a 75-kb interval on the long arm of chromosome 10.Sequence analysis revealed a single nucleotide substitution of A to T at the 941 position of LOC_Os10g31910 in tutou2,resulting in an amino acid change from isoleucine to phenylalanine.Complementation analysis showed that the degenerated panicle phenotype in tutou2 was rescued in the transgenic lines.A phenotype similar to tutou2 can also be obtained by LOC_Os10g31910 knockout in wild-type rice.These results suggested that LOC_Os10 g31910 is the causative locus TUTOU2 responsible for the tutou2 PAA phenotype and probably also the locus of DEL1,previously documented as a leaf senescence gene.The significant phenotypic differences between del1 and tutou2 suggest that the locus DEL1/TUTOU2 plays roles in both leaf and panicle development which were not considered fully in previous studies.
基金supported by grants from the National Basic Research Program of China(2007CB10880-1,2013CB127000)
文摘Understanding the genetic mechanism underlying folate biosynthesis and accumulation in rice would be beneficial for breeding high folate content varieties as a cost-effective approach to addressing widespread folate deficiency in developing countries. In this study, the inheritance of rice grain folate content was investigated in the Lemont/Teqing recombinant inbred lines and the Koshihikari/Kasalath//Koshihikari backcross inbred lines. 264 F12 recombinant inbred lines（RILs） and 182 BC1F10 backcross inbred lines（BILs） with their parents planted in randomized complete blocks with two replicates in 2010, and RILs harvested in 2008 were used for QTL detection using inclusive composite interval mapping（ICIM） method. In the RIL population, two QTLs, denoted by qQTF-3-1 and qQTF-3-2（QTF, quantitative total folate）, explaining 7.8% and 11.1-15.8% of the folate content variation were detected in one or two years, respectively. In the BIL population, a QTL, denoted by qQTF-3-3, was detected, explaining 25.3% of the variation in folate content. All the positive alleles for higher folate content were from the high-folate parents, i.e., Teqing and Kasalath. The known putative folate biosynthesis genes do not underlie the QTLs detected in this study and therefore may be novel loci affecting folate content in milled rice. QTLs identified in this study have potential value for marker assisted breeding for high-folate rice variety.
基金supported by the Fundamental Research Funds for Excellent Young Scientists of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (Grant to YR, 2014JB04-009, 1610092015003-08)the National Transgenic Science and Technology Program, China (2016ZX08009003-003)
文摘Plant cell walls constitute the skeletal structures of plant bodies,and thus confer lodging resistance for grain crops.While the basic cell wall synthesis machinery is relatively well established now,our understanding of how the process is regulated remains limited and fragmented.In this study,we report the identification and characterization of the novel rice（Oryza sativa L.）brittle culm16（brittle node;bc16）mutant.The brittle node phenotype of the bc16 mutant appears exclusively at nodes,and resembles the previously reported bc5 mutant.Combined histochemical staining and electron microscopy assays revealed that in the bc16 mutant,the secondary cell wall formation and thickening of node sclerenchyma tissues are seriously affected after heading.Furthermore,cell wall composition assays revealed that the bc16 mutation led to a significant reduction in cellulose and lignin contents.Using a map-based cloning approach,the bc16 locus is mapped to an approximately 1.7-Mb region of chromosome 4.Together,our findings strengthen evidence for discretely spatial differences in the secondary cell wall formation within plant bodies.
基金grants from the National Natural Science Foundation of China(No.30300330)Qimingxing program of Shanghai(No.05QMX1431)
文摘Voltage-gated sodium channels play an important role in the generation and propagation of action potentials in excitable cells. They are composed of a pore-forming α subunit and auxiliary β subunits. To date, nine subtypes of the α subunit, designated Nav1.1 to Nav1.9, have been shown to form functional sodium channels. In addition, four different mammalian subunits （β1-β4） isoforms have been cloned from the nervous system. The β subunits are structurally homologous and form single transmembrane glycoproteins with short intracellular loops and immunoglobulin-like extracellular segments. The association of the various α subtypes with different combinations of auxiliary β subunits creates the possibility of additional molecular and functional complexity for neuronal sodium channels.
