Global warming poses a threat to rice production.Breeding heat-tolerant rice is an effective and economical approach to address this challenge.African rice is a valuable genetic resource for developing heat-tolerant c...Global warming poses a threat to rice production.Breeding heat-tolerant rice is an effective and economical approach to address this challenge.African rice is a valuable genetic resource for developing heat-tolerant crops due to its intricate mechanism for adapting to high temperatures.Oryza longistaminata,a widely distributed wild rice species in Africa,may harbor an even richer gene pool for heat tolerance,which remains untapped.In this study,we identified three heat tolerance QTLs from O.longistaminata at the seedling stage,including novel heat tolerance loci qTT4 and qTT5.Our findings demonstrated that the O.longistaminata alleles for these two QTLs can enhance the heat tolerance of rice seedlings.Remarkably,qTT5 was mapped to a region spanning approximately 287.2 kb,which contains 46 expressing genes.Through the analysis of Gene Ontology and expression differences under heat induction,we identified four candidate genes.Our results lay the foundation for discovering heat tolerance genes underlying O.longistaminata and developing new genetic resources for heat-tolerant rice breeding.展开更多
Influence of a mutation to improve the undesirable traits （shattering, red caryopsis etc.） of wild rice O. longistaminata while preserving its useful genes by radiation 20 Kr gamma rays from 60Co was studied. The mu...Influence of a mutation to improve the undesirable traits （shattering, red caryopsis etc.） of wild rice O. longistaminata while preserving its useful genes by radiation 20 Kr gamma rays from 60Co was studied. The mutants issued this irradiation were crossed with the interspecific variety SIK385-b-42-28-28 （O. glaberrima x O. sativa）. Irradiation followed by crossing with interspecific variety generated a large genetic variability, in the subsequent generations, in plant height, maturity, non-shattering grain, kernel colour, spikelets fertility, panicle length, and grain size. This has resulted in identification of promising mutants which possess all the traits of cultivated rice O. sativa （white kernel, non-shattering grain, secondary branchies etc.）. During 2012 rainy season, nineteen selected mutants from M5 and M7 generations were evaluated for yield potential in replicated trials at Longorola station.展开更多
It is of great importance for the analysis on genetic evolution mechanism, and rice breeding utilization by estimation and protection of genetic diversity of pre- sent DXWR （Oryza rufipogon Griff.）. This study has s...It is of great importance for the analysis on genetic evolution mechanism, and rice breeding utilization by estimation and protection of genetic diversity of pre- sent DXWR （Oryza rufipogon Griff.）. This study has summarized genetic diversity and protection achievements of DXWR from many aspects like varied conservations, years, generations, other species of wild rice and cultivated rice. In this study, a u- nified and scientific evaluation system of genetic diversity is encouraged to be built and suggestions on research prospect and ecological conservation of DXWR genetic diversity have been proposed.展开更多
The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hybridization are in three respects, that is, breeding monosomic alien addition lines （MAALs）...The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hybridization are in three respects, that is, breeding monosomic alien addition lines （MAALs）, constructing introgression lines （ILs） and analyzing the heredity of the characters and mapping the related genes. There are serious reproductive barriers, mainly incrossability and hybrid sterility, in the interspecific hybridization of O. sativa with non-AA genome wild rice. These are the ＇bottleneck＇ for transferring elite genes from wild rice to O. sativa. Combining traditional crossing method with biotechnique is a reliable way to overcome the reproductive barriers and to improve the utilizing efficiency of non-AA genome wild rice.展开更多
Two populations of Dongxiang wild rice （Oryza rufipogon）, Shuitaoshu and Dongtangshang, were crossed with five male sterile rice lines with different cytoplasmic backgrounds （B06S, Zhenshan 97A, Xieqingzao A, Zhong...Two populations of Dongxiang wild rice （Oryza rufipogon）, Shuitaoshu and Dongtangshang, were crossed with five male sterile rice lines with different cytoplasmic backgrounds （B06S, Zhenshan 97A, Xieqingzao A, Zhong 9A, and Yuetai A）, and the seed setting rate of the F1 was used to judge the fertility restoration ability in the Dongxiang wild rice. With P1, F1, P2, and F2 populations as materials, the Akaike＇s Information Criterion （AIC） was used to identify the major genes affecting quantitative traits, and when the major genes existed, the genetic effects of the major gene and the polygene and their genetic variance were estimated through segregation analysis. The seed setting rates of the F1 generation varied from 45.98% to 76.57%, suggesting that the Dongxiang wild rice had the fertility restoration ability. One major gene plus polygene mixed inheritance model was the most fitted genetic model for this trait in all the F2 populations. The heritability values of the major genes varied from 56.63% to 88.29% and those of the polygenes from 2.74% to 30.97%, and the total heritability values were from 63.17% to 94.01%. The major gene inheritance of the combination Zhong 9A/Dongtangshang was controlled by the additive effect without dominant effect, and the other nine combinatfons were by the completely dominant inheritance.展开更多
This study was conducted to develop and characterize a novel cytoplasmic male sterile （CMS） source which was identified from Dongxiang wild rice （Oryza rufipogon） by crossing Dongxiang wild rice as female with Zho...This study was conducted to develop and characterize a novel cytoplasmic male sterile （CMS） source which was identified from Dongxiang wild rice （Oryza rufipogon） by crossing Dongxiang wild rice as female with Zhongzao 35, an indica inbred variety, as male and continuous backcrossing with Zhongzao 35. Observation under optical microscope manifested that this novel CMS belonged to typical abortion type with less pollen compared with wild abortive type cytoplasm （CMS-WA）. Sequential planting showed that this novel CMS has complete and stable male sterility. Testcross experiment showed that all the 24 tested materials including maintainer and restorer lines of CMS-WA and Honglian type cytoplasm （CMS-HL） and other indica inbred varieties are the maintainers with complete maintaining ability, suggesting that this novel CMS has fertility restoration totally different from CMS-WA and CMS-HL and belongs to a novel type of CMS. So far, we only discovered a unique fertility restoration source for this novel CMS. Inheritance analysis showed that the fertility restoration of this CMS was governed by three pairs of independent dominant genes. Prospect for application of this novel CMS system in hybrid rice breeding was also discussed.展开更多
Although great accomplishments of in situ conservation have been made during the last decade throughout the world, there is an urgent need to conduct more targeted research to explore many basic questions about crop w...Although great accomplishments of in situ conservation have been made during the last decade throughout the world, there is an urgent need to conduct more targeted research to explore many basic questions about crop wild relatives (CWR) in situ conservation such as how to better identify and manage the target in situ conservation populations of CWR. In this study, we performed an extensive field investigation of 201 natural populations or habitats of O. rufipogon, a seriously endangered wild progenitor of cultivated rice in China. Our updated information suggests that: 1) the majority of the natural populations have been extinct throughout China, which leads to serious fragmentation of the population system as a whole;and 2) the survived populations have become small in size and thus fragmented within the population as a result of the loss of subpopulations. To assess the relationships between the biodiversity education and conservation of wild rice, we employed participatory approaches in the field investigation. Our data indicate that the continuous rapid decline of biodiversity education seemed closely related to the extinction of wild rice germplasm. These findings imply the potential necessity and huge challenge for making in situ conservation plans in the future. By means of our understanding of ecogeography, sociology and culture, and population genetics of the species, we propose a strategy for selecting in situ conservation locations as well as priority sites for establishing in situ conservation practices in China.展开更多
Domestication of crops is one of the greatest inventions of the human race and has played a vital role in the progress of human civilization.Understanding the genetic mechanisms of crop domestication could shed light ...Domestication of crops is one of the greatest inventions of the human race and has played a vital role in the progress of human civilization.Understanding the genetic mechanisms of crop domestication could shed light on its history and would advance crop breeding.Cultivated rice species,which were domesticated from wild rice species,are important food crops worldwide.Morphological traits,physiological characteristics,and ecological adaptability of cultivated rice are very different from those characters of wild rice.In this review,we summarize current knowledge of the genetic mechanisms underlying these differences between wild and cultivated rice and discuss the application of wild rice species in modern breeding.展开更多
The wild rice species in the genus Oryza harbor a large amount of genetic diversity that has been untapped for rice improvement.Pan-genomics has revolutionized genomic research in plants.However,rice pan-genomic studi...The wild rice species in the genus Oryza harbor a large amount of genetic diversity that has been untapped for rice improvement.Pan-genomics has revolutionized genomic research in plants.However,rice pan-genomic studies so far have been limited mostly to cultivated accessions,with only a few close wild relatives.Advances in sequencing technologies have permitted the assembly of highquality rice genome sequences at low cost,making it possible to construct genus-level pan-genomes across all species.In this review,we summarize progress in current research on genetic and genomic resources in Oryza,and in sequencing and computational technologies used for rice genome and pangenome construction.For future work,we discuss the approaches and challenges in the construction of,and data access to,Oryza pan-genomes based on representative high-quality genome assemblies.The Oryza pan-genomes will provide a basis for the exploration and use of the extensive genetic diversity present in both cultivated and wild rice populations.展开更多
Photosynthetic efficiency,a key trait that determines yield potential in rice,is quantitatively regulated by multiple genes.Utilization of valuable genetic resources hidden in wild rice is an effective way to improve ...Photosynthetic efficiency,a key trait that determines yield potential in rice,is quantitatively regulated by multiple genes.Utilization of valuable genetic resources hidden in wild rice is an effective way to improve rice photosynthesis and yield potential.In this study,152 backcross inbred lines derived from wild rice Oryza longistaminata were explored for QTL mapping of photosynthetic rate(Pn)and biomass(BM)in natural fields.Five novel QTLs for Pn and seven QTLs for BM or daily biomass(DBM)derived from O.longistaminata were identified.One of these QTLs,qPn8.1,could significantly improve Pn and was located in a 68-kb region containing only 11 candidate genes.Meanwhile,qBM1.1 and qDBM1.1 for BM and DBM on chromosome 1 were overlapped with qPn1.1 for Pn from 9311,and could affect both Pn and BM in natural fields.These QTLs identified in O.longistaminata may provide a novel alternative to explore new genes and resources for yield potentiality,highlighting the important role of wild rice in rice breeding programs.展开更多
Low temperature and sparse light in early spring is one of the factors causing reduction for rice production. So it is important to develop cold tolerance cultivars. In the present study, cold tolerance characters of ...Low temperature and sparse light in early spring is one of the factors causing reduction for rice production. So it is important to develop cold tolerance cultivars. In the present study, cold tolerance characters of 36 parents and 423 rice lines from 68 hybrid groups were investigated at seedling stage under low tempera- ture and sparse light conditions in field. There were 10 parent accessions with strong cold tolerance of level 1. Among them, 3 were common wild rice accessions; 4 were japonica rice cultivars; 2 were indica rice; 1 was offspring from hybrid be- tween indica and japonica.There were 33 lines with strong cold tolerance of level 1 from the hybrid groups of common wild rice,and 15 from the hybrid groups of IRBB5, and only 3 from the hybrid groups of BPHR96. There were abundant cold tolerance resources in rice germplasm. It was feasible to develop cold tolerance cul- tivars from the hybrids among common wild rice, japonica cultivars and indica culti- vars.展开更多
As maternal parents, diploid （L202-2x） and autotetraploid （L202-4x） of Oryza sativa cv. L2O2 were crossed with O. officinalis. Embryo development and fertilization in these two crosses were comparatively studied. ...As maternal parents, diploid （L202-2x） and autotetraploid （L202-4x） of Oryza sativa cv. L2O2 were crossed with O. officinalis. Embryo development and fertilization in these two crosses were comparatively studied. There were no mature hybrid seeds obtained because all the hybridized spikelets died 30 days after pollination. The main reasons for no seed set were abnormal fertilization and development of the embryos and endosperms in the interspecific hybrids. There were doublefertilization, egg cell single-fertilization and non-fertilization in these crosses. Although 59.45% and 54.87% of hybrid embryos produced in the crosses of L202-2x/O. officinalis and L202-4x/O. officinalis, respectively, hybrid embryos ceased to develop or degenerated and plenty of free endosperm nuclei were in disaggregating state without developing cellular endosperms three days after pollination. Besides, some embryological differences in these two crosses were found, that is, the rate of double-fertilization and total rate of doubleand single-fertilization in L202-2x/O. officinalis were higher than those in L202-4x/O. officinalis. The embryo and endosperm of hybrids developed more slowly, and embryos and free endosperm nuclei were more severely degenerated in L202-4x/O. officinalis than in L202-2x/O. officinalis. Five days after pollination, a few of embryos in L202-2x/O. officinalis developed into pear-shaped ones, however, embryos in L202-4x/O. officinalis were all degenerated. Therefore, it is more difficult to obtain interspecific hybrids by wide crosses between autotetraploid of O. sativa and O. officinalis.展开更多
The African rice midge, Orseolia oryzivora H. & G., is an important insect pest in Burkina Faso. Our study was conducted from 2017 to 2019 in three irrigated rice schemes including Banzon, Karfiguéla and Vall...The African rice midge, Orseolia oryzivora H. & G., is an important insect pest in Burkina Faso. Our study was conducted from 2017 to 2019 in three irrigated rice schemes including Banzon, Karfiguéla and Vallée du Kou in Western Burkina Faso. The objective of this study was to investigate the ecology of the insect pest. In each rice scheme, four plots of 500 m2 each, spread 50 m apart were randomly selected in farmers’ fields and used for the study. In each plot, a light trap was implemented along one of the diagonals of the plot. Each light trap consisted of a yellow plastic round bowl containing soapy water almost at half the bowl and a torch. The bowl had a capacity of 4.5 l, a diameter of 28 cm and a height of 10.5 cm. The torch had 3 batteries of 1.5 V each, 30 cm long and 1 cm diameter. The torches were lit every night at 6 pm and off at 6 am. Four hundred tillers were collected per month from the cultivated rice and from each of the alternative hosts of the rice midge in order to evaluate the monthly gall count, pre-imaginal populations and parasitism associated with O. oryzivora and its cousin, O. bonzii that is hosted by Paspalum scrobiculatum. The number of O. oryzivora’s adults caught in the light traps was higher during the wet season than the dry season. The level of larval parasitism ranged from 6.16% (Banzon) to 14.29% (Vallée du Kou). The highest level of pupal parasitism (13.73%) was recorded in Vallée du Kou. The damage of O. oryzivora was observed on the wild rice species, O. longistaminata in all three sites. The highest levels of parasitism associated with O. bonzii were recorded in Karfiguéla (20.08% and 25.21% for larval parasitism and pupal parasitism, respectively). These findings are useful in the development of a sustainable control strategy of O. oryzivora.展开更多
In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice （Oryza sativa L.）. In the present study, hybrids between O. sativa （AA genome） a...In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice （Oryza sativa L.）. In the present study, hybrids between O. sativa （AA genome） and three Chinese wild rices, namely O. rufipogon （AA genome）, O. officinalis （CC genome）, and O. meyeriana （GG genome）, were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid, the other F1 hybrids were completely sterile. Genomic in situ hybridization （GISH） was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4＇,6＇-Diamidino- 2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatin compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.展开更多
The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era...The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era, centromeres represent the last frontiers of higher eukaryotic genomes because of their densely methylated, highly repetitive and, heterochromatic DNA （Hall et al., 2004）. Although these functions are conserved among all eukaryotes, centromeric DNA sequences are evolving rapidly （Jiang et al., 2003）.展开更多
基金partly granted from the National Natural Science Foundation of China(Grant No.U20A2023)the Joint Open Competitive Project of the Yazhou Bay Laboratory and the China National Seed Company Limitedhe Hubei Hongshan Laboratory,China(Grant No.2021hszd010)。
文摘Global warming poses a threat to rice production.Breeding heat-tolerant rice is an effective and economical approach to address this challenge.African rice is a valuable genetic resource for developing heat-tolerant crops due to its intricate mechanism for adapting to high temperatures.Oryza longistaminata,a widely distributed wild rice species in Africa,may harbor an even richer gene pool for heat tolerance,which remains untapped.In this study,we identified three heat tolerance QTLs from O.longistaminata at the seedling stage,including novel heat tolerance loci qTT4 and qTT5.Our findings demonstrated that the O.longistaminata alleles for these two QTLs can enhance the heat tolerance of rice seedlings.Remarkably,qTT5 was mapped to a region spanning approximately 287.2 kb,which contains 46 expressing genes.Through the analysis of Gene Ontology and expression differences under heat induction,we identified four candidate genes.Our results lay the foundation for discovering heat tolerance genes underlying O.longistaminata and developing new genetic resources for heat-tolerant rice breeding.
文摘Influence of a mutation to improve the undesirable traits （shattering, red caryopsis etc.） of wild rice O. longistaminata while preserving its useful genes by radiation 20 Kr gamma rays from 60Co was studied. The mutants issued this irradiation were crossed with the interspecific variety SIK385-b-42-28-28 （O. glaberrima x O. sativa）. Irradiation followed by crossing with interspecific variety generated a large genetic variability, in the subsequent generations, in plant height, maturity, non-shattering grain, kernel colour, spikelets fertility, panicle length, and grain size. This has resulted in identification of promising mutants which possess all the traits of cultivated rice O. sativa （white kernel, non-shattering grain, secondary branchies etc.）. During 2012 rainy season, nineteen selected mutants from M5 and M7 generations were evaluated for yield potential in replicated trials at Longorola station.
基金Supported by National Natural Science Foundation of China(30960189)the National Public Benefit(Agricultural)Research Foundation of China(201103007)+1 种基金Special Funds for Establishment of Modern Agricultural and Industrial Technology System(NXCYTY-01)Project supported by Jiangxi Academy of Agricultural Science for Innovation(2010CQN008)~~
文摘It is of great importance for the analysis on genetic evolution mechanism, and rice breeding utilization by estimation and protection of genetic diversity of pre- sent DXWR （Oryza rufipogon Griff.）. This study has summarized genetic diversity and protection achievements of DXWR from many aspects like varied conservations, years, generations, other species of wild rice and cultivated rice. In this study, a u- nified and scientific evaluation system of genetic diversity is encouraged to be built and suggestions on research prospect and ecological conservation of DXWR genetic diversity have been proposed.
文摘The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hybridization are in three respects, that is, breeding monosomic alien addition lines （MAALs）, constructing introgression lines （ILs） and analyzing the heredity of the characters and mapping the related genes. There are serious reproductive barriers, mainly incrossability and hybrid sterility, in the interspecific hybridization of O. sativa with non-AA genome wild rice. These are the ＇bottleneck＇ for transferring elite genes from wild rice to O. sativa. Combining traditional crossing method with biotechnique is a reliable way to overcome the reproductive barriers and to improve the utilizing efficiency of non-AA genome wild rice.
文摘Two populations of Dongxiang wild rice （Oryza rufipogon）, Shuitaoshu and Dongtangshang, were crossed with five male sterile rice lines with different cytoplasmic backgrounds （B06S, Zhenshan 97A, Xieqingzao A, Zhong 9A, and Yuetai A）, and the seed setting rate of the F1 was used to judge the fertility restoration ability in the Dongxiang wild rice. With P1, F1, P2, and F2 populations as materials, the Akaike＇s Information Criterion （AIC） was used to identify the major genes affecting quantitative traits, and when the major genes existed, the genetic effects of the major gene and the polygene and their genetic variance were estimated through segregation analysis. The seed setting rates of the F1 generation varied from 45.98% to 76.57%, suggesting that the Dongxiang wild rice had the fertility restoration ability. One major gene plus polygene mixed inheritance model was the most fitted genetic model for this trait in all the F2 populations. The heritability values of the major genes varied from 56.63% to 88.29% and those of the polygenes from 2.74% to 30.97%, and the total heritability values were from 63.17% to 94.01%. The major gene inheritance of the combination Zhong 9A/Dongtangshang was controlled by the additive effect without dominant effect, and the other nine combinatfons were by the completely dominant inheritance.
基金supported by the Key Program for Scienceand Technology of Jiangxi ProvinceChina(Grant No.20114ABF03101)+1 种基金the Program of Advantage Group forInnovation of Science and Technology of Jiangxi ProvinceChina(Grant No.20115BCB29019)
文摘This study was conducted to develop and characterize a novel cytoplasmic male sterile （CMS） source which was identified from Dongxiang wild rice （Oryza rufipogon） by crossing Dongxiang wild rice as female with Zhongzao 35, an indica inbred variety, as male and continuous backcrossing with Zhongzao 35. Observation under optical microscope manifested that this novel CMS belonged to typical abortion type with less pollen compared with wild abortive type cytoplasm （CMS-WA）. Sequential planting showed that this novel CMS has complete and stable male sterility. Testcross experiment showed that all the 24 tested materials including maintainer and restorer lines of CMS-WA and Honglian type cytoplasm （CMS-HL） and other indica inbred varieties are the maintainers with complete maintaining ability, suggesting that this novel CMS has fertility restoration totally different from CMS-WA and CMS-HL and belongs to a novel type of CMS. So far, we only discovered a unique fertility restoration source for this novel CMS. Inheritance analysis showed that the fertility restoration of this CMS was governed by three pairs of independent dominant genes. Prospect for application of this novel CMS system in hybrid rice breeding was also discussed.
文摘Although great accomplishments of in situ conservation have been made during the last decade throughout the world, there is an urgent need to conduct more targeted research to explore many basic questions about crop wild relatives (CWR) in situ conservation such as how to better identify and manage the target in situ conservation populations of CWR. In this study, we performed an extensive field investigation of 201 natural populations or habitats of O. rufipogon, a seriously endangered wild progenitor of cultivated rice in China. Our updated information suggests that: 1) the majority of the natural populations have been extinct throughout China, which leads to serious fragmentation of the population system as a whole;and 2) the survived populations have become small in size and thus fragmented within the population as a result of the loss of subpopulations. To assess the relationships between the biodiversity education and conservation of wild rice, we employed participatory approaches in the field investigation. Our data indicate that the continuous rapid decline of biodiversity education seemed closely related to the extinction of wild rice germplasm. These findings imply the potential necessity and huge challenge for making in situ conservation plans in the future. By means of our understanding of ecogeography, sociology and culture, and population genetics of the species, we propose a strategy for selecting in situ conservation locations as well as priority sites for establishing in situ conservation practices in China.
基金supported by the National Natural Science Foundation of China(31830065 and 31960159)。
文摘Domestication of crops is one of the greatest inventions of the human race and has played a vital role in the progress of human civilization.Understanding the genetic mechanisms of crop domestication could shed light on its history and would advance crop breeding.Cultivated rice species,which were domesticated from wild rice species,are important food crops worldwide.Morphological traits,physiological characteristics,and ecological adaptability of cultivated rice are very different from those characters of wild rice.In this review,we summarize current knowledge of the genetic mechanisms underlying these differences between wild and cultivated rice and discuss the application of wild rice species in modern breeding.
基金supported by Chinese Academy of Sciences"Strategic Priority Research Program"(XDA24040201)National Key Research and Development Program of China(2020YFE0202300)State Key Laboratory of Plant Genomics。
文摘The wild rice species in the genus Oryza harbor a large amount of genetic diversity that has been untapped for rice improvement.Pan-genomics has revolutionized genomic research in plants.However,rice pan-genomic studies so far have been limited mostly to cultivated accessions,with only a few close wild relatives.Advances in sequencing technologies have permitted the assembly of highquality rice genome sequences at low cost,making it possible to construct genus-level pan-genomes across all species.In this review,we summarize progress in current research on genetic and genomic resources in Oryza,and in sequencing and computational technologies used for rice genome and pangenome construction.For future work,we discuss the approaches and challenges in the construction of,and data access to,Oryza pan-genomes based on representative high-quality genome assemblies.The Oryza pan-genomes will provide a basis for the exploration and use of the extensive genetic diversity present in both cultivated and wild rice populations.
基金partly granted from the National Natural Science Foundation of China (Grant Nos. U20A2023 and 32172074)the Creative Research Groups of the Natural Science Foundation of Hubei Province,China (Grant No. 2020CFA009)the earmarked fund for China Agriculture Research System (Grant No. CARS-01-08)
文摘Photosynthetic efficiency,a key trait that determines yield potential in rice,is quantitatively regulated by multiple genes.Utilization of valuable genetic resources hidden in wild rice is an effective way to improve rice photosynthesis and yield potential.In this study,152 backcross inbred lines derived from wild rice Oryza longistaminata were explored for QTL mapping of photosynthetic rate(Pn)and biomass(BM)in natural fields.Five novel QTLs for Pn and seven QTLs for BM or daily biomass(DBM)derived from O.longistaminata were identified.One of these QTLs,qPn8.1,could significantly improve Pn and was located in a 68-kb region containing only 11 candidate genes.Meanwhile,qBM1.1 and qDBM1.1 for BM and DBM on chromosome 1 were overlapped with qPn1.1 for Pn from 9311,and could affect both Pn and BM in natural fields.These QTLs identified in O.longistaminata may provide a novel alternative to explore new genes and resources for yield potentiality,highlighting the important role of wild rice in rice breeding programs.
基金Supported by Guangxi Natural Science Foundation Item,China(2013GXNSFBA019-066)Guangxi Science Research and Technology Development Project,China(Guikezhong14121001-2-4)Nanning Municipal Science Research and Technology Development Plan Item,China(20132304)~~
文摘Low temperature and sparse light in early spring is one of the factors causing reduction for rice production. So it is important to develop cold tolerance cultivars. In the present study, cold tolerance characters of 36 parents and 423 rice lines from 68 hybrid groups were investigated at seedling stage under low tempera- ture and sparse light conditions in field. There were 10 parent accessions with strong cold tolerance of level 1. Among them, 3 were common wild rice accessions; 4 were japonica rice cultivars; 2 were indica rice; 1 was offspring from hybrid be- tween indica and japonica.There were 33 lines with strong cold tolerance of level 1 from the hybrid groups of common wild rice,and 15 from the hybrid groups of IRBB5, and only 3 from the hybrid groups of BPHR96. There were abundant cold tolerance resources in rice germplasm. It was feasible to develop cold tolerance cul- tivars from the hybrids among common wild rice, japonica cultivars and indica culti- vars.
基金supported by the Guangdong Provincial Key Project of Natural Science Foundation, China (Grant No. 021037)Guangdong Province Natural Science Foundation, China (Grant No. 7301008)+1 种基金South China Agricultural University President Foundation, China (Grant No. 2007K036)The Confocal Laser Scanning Microscope was provided by the Testing Center of South China Agricultural University, Guangzhou, China
文摘As maternal parents, diploid （L202-2x） and autotetraploid （L202-4x） of Oryza sativa cv. L2O2 were crossed with O. officinalis. Embryo development and fertilization in these two crosses were comparatively studied. There were no mature hybrid seeds obtained because all the hybridized spikelets died 30 days after pollination. The main reasons for no seed set were abnormal fertilization and development of the embryos and endosperms in the interspecific hybrids. There were doublefertilization, egg cell single-fertilization and non-fertilization in these crosses. Although 59.45% and 54.87% of hybrid embryos produced in the crosses of L202-2x/O. officinalis and L202-4x/O. officinalis, respectively, hybrid embryos ceased to develop or degenerated and plenty of free endosperm nuclei were in disaggregating state without developing cellular endosperms three days after pollination. Besides, some embryological differences in these two crosses were found, that is, the rate of double-fertilization and total rate of doubleand single-fertilization in L202-2x/O. officinalis were higher than those in L202-4x/O. officinalis. The embryo and endosperm of hybrids developed more slowly, and embryos and free endosperm nuclei were more severely degenerated in L202-4x/O. officinalis than in L202-2x/O. officinalis. Five days after pollination, a few of embryos in L202-2x/O. officinalis developed into pear-shaped ones, however, embryos in L202-4x/O. officinalis were all degenerated. Therefore, it is more difficult to obtain interspecific hybrids by wide crosses between autotetraploid of O. sativa and O. officinalis.
文摘The African rice midge, Orseolia oryzivora H. & G., is an important insect pest in Burkina Faso. Our study was conducted from 2017 to 2019 in three irrigated rice schemes including Banzon, Karfiguéla and Vallée du Kou in Western Burkina Faso. The objective of this study was to investigate the ecology of the insect pest. In each rice scheme, four plots of 500 m2 each, spread 50 m apart were randomly selected in farmers’ fields and used for the study. In each plot, a light trap was implemented along one of the diagonals of the plot. Each light trap consisted of a yellow plastic round bowl containing soapy water almost at half the bowl and a torch. The bowl had a capacity of 4.5 l, a diameter of 28 cm and a height of 10.5 cm. The torch had 3 batteries of 1.5 V each, 30 cm long and 1 cm diameter. The torches were lit every night at 6 pm and off at 6 am. Four hundred tillers were collected per month from the cultivated rice and from each of the alternative hosts of the rice midge in order to evaluate the monthly gall count, pre-imaginal populations and parasitism associated with O. oryzivora and its cousin, O. bonzii that is hosted by Paspalum scrobiculatum. The number of O. oryzivora’s adults caught in the light traps was higher during the wet season than the dry season. The level of larval parasitism ranged from 6.16% (Banzon) to 14.29% (Vallée du Kou). The highest level of pupal parasitism (13.73%) was recorded in Vallée du Kou. The damage of O. oryzivora was observed on the wild rice species, O. longistaminata in all three sites. The highest levels of parasitism associated with O. bonzii were recorded in Karfiguéla (20.08% and 25.21% for larval parasitism and pupal parasitism, respectively). These findings are useful in the development of a sustainable control strategy of O. oryzivora.
文摘In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice （Oryza sativa L.）. In the present study, hybrids between O. sativa （AA genome） and three Chinese wild rices, namely O. rufipogon （AA genome）, O. officinalis （CC genome）, and O. meyeriana （GG genome）, were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid, the other F1 hybrids were completely sterile. Genomic in situ hybridization （GISH） was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4＇,6＇-Diamidino- 2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatin compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.
基金supported by the grants from the National Natural Science Foundation of China(Nos.31576124,31071382 and 30771210)the National Basic Research Program of China(973 Program,Nos.2010CB125904 and 2013CBA01405)
文摘The centromere of eukaryotic chromosomes is the crucial locus responsible for sister chromatid cohesion and for correct segregation of chromosomes to daughter cells during cell division. In the structural genomics era, centromeres represent the last frontiers of higher eukaryotic genomes because of their densely methylated, highly repetitive and, heterochromatic DNA （Hall et al., 2004）. Although these functions are conserved among all eukaryotes, centromeric DNA sequences are evolving rapidly （Jiang et al., 2003）.
