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1.
All roads lead to weediness: Patterns of genomic divergence reveal extensive recurrent weedy rice origins from South Asian Oryza
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Zhongyun Huang Nelson D. Young Michael Reagon Katie E. Hyma Kenneth M. Olsen Yulin Jia Ana L. Caicedo 《Molecular ecology》2017,26(12):3151-3167
Weedy rice (Oryza spp.), a weedy relative of cultivated rice (O. sativa), infests and persists in cultivated rice fields worldwide. Many weedy rice populations have evolved similar adaptive traits, considered part of the ‘agricultural weed syndrome’, making this an ideal model to study the genetic basis of parallel evolution. Understanding parallel evolution hinges on accurate knowledge of the genetic background and origins of existing weedy rice groups. Using population structure analyses of South Asian and US weedy rice, we show that weeds in South Asia have highly heterogeneous genetic backgrounds, with ancestry contributions both from cultivated varieties (aus and indica) and wild rice. Moreover, the two main groups of weedy rice in the USA, which are also related to aus and indica cultivars, constitute a separate origin from that of Asian weeds. Weedy rice populations in South Asia largely converge on presence of red pericarps and awns and on ease of shattering. Genomewide divergence scans between weed groups from the USA and South Asia, and their crop relatives are enriched for loci involved in metabolic processes. Some candidate genes related to iconic weedy traits and competitiveness are highly divergent between some weed‐crop pairs, but are not shared among all weed‐crop comparisons. Our results show that weedy rice is an extreme example of recurrent evolution, and suggest that most populations are evolving their weedy traits through different genetic mechanisms. 相似文献
2.
Teresa B. De Leon Elizabeth Karn Kassim Al‐Khatib Luis Espino Timothy Blank Cynthia B. Andaya Virgilio C. Andaya Whitney Brim‐DeForest 《Ecology and evolution》2019,9(10):5835-5848
Control of weeds in cultivated crops is a pivotal component in successful crop production allowing higher yield and higher quality. In rice‐growing regions worldwide, weedy rice (Oryza sativa f. spontanea Rosh.) is a weed related to cultivated rice which infests rice fields. With populations across the globe evolving a suite of phenotypic traits characteristic of weeds and of cultivated rice, varying hypotheses exist on the origin of weedy rice. Here, we investigated the genetic diversity and possible origin of weedy rice in California using 98 simple sequence repeat (SSR) markers and an Rc gene‐specific marker. By employing phylogenetic clustering analysis, we show that four to five genetically distinct biotypes of weedy rice exist in California. Analysis of population structure and genetic distance among individuals reveals diverse evolutionary origins of California weedy rice biotypes, with ancestry derived from indica, aus, and japonica cultivated rice as well as possible contributions from weedy rice from the southern United States and wild rice. Because this diverse parentage primarily consists of weedy, wild, and cultivated rice not found in California, most existing weedy rice biotypes likely originated outside California. 相似文献
3.
Asian cultivated rice(Oryza sativa L.),an important cereal crop worldwide,was domesticated from its wild ancestor 8000 years ago.During its long-term cultivation and evolution under diverse agroecological conditions, Asian cultivated rice has differentiated into indica and japonica subspecies.An effective method is required to identify rice germplasm for its indica and japonica features,which is essential in rice genetic improvements.We developed a protocol that combined DNA extraction from a single rice seed and the insertion/deletion(InDel) molecular fingerprint to determine the indica and japonica features of rice germplasm.We analyzed a set of rice germplasm,including 166 Asian rice varieties,two African rice varieties,30 accessions of wild rice species,and 42 weedy rice accessions,using the single-seeded InDel fingerprints(SSIF).The results show that the SSIF method can efficiently determine the indica and japonica features of the rice germplasm.Further analyses revealed significant indica and japonica differentiation in most Asian rice varieties and weedy rice accessions.In contrast,African rice varieties and nearly all the wild rice accessions did not exhibit such differentiation.The pattern of cultivated and wild rice samples illustrated by the SSIF supports our previous hypothesis that indica and japonica differentiation occurred after rice domestication under different agroecological conditions.In addition,the divergent pattern of rice cultivars and weedy rice accessions suggests the possibility of an endoferal origin(from crop)of the weedy rice included in the present study. 相似文献
4.
H. S. Suh Y. I. Sato H. Morishima 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(3-4):316-321
Weedy rice (Oryza sativa L.) is an important resource for breeding and for studying the evolution of rice. The present study was carried out to identify
the genetic basis of the weedy rices distributed in various countries of the world. One hundred and fifty two strains of weedy
rice collected from Bangladesh, Brazil, Bhutan, China, India, Japan, Korea, Nepal, Thailand and the USA were tested for variations
in six morpho-physiological characteristics and in 14 isozyme loci. Twenty six weedy strains selected from the above materials
were assayed for the Est-10 locus, six RAPD loci of the nuclear genome, and one chloroplast locus. From the results of multivariate analysis based on
the morpho-physiological characteristics and the isozymes, weedy rice strains were classified into indica and japonica types, and each type was further divided into forms resembling cultivated and wild rice. Thus, four groups designated as
I, II, III and IV were identified. Weedy strains of group I (indica-type similar to cultivars) were distributed mostly in temperate countries, group II (indica-type similar to wild rice) in tropical countries, group III (japonica-type similar to cultivars) in Bhutan and Korea, group IV ( japonica-type similar to wild rice) in China and Korea. In group I, classified as indica, several strains showed japonica-specific RAPD markers, while some others had japonica cytoplasm with indica-specific RAPD markers in a heterozygous state at several loci. One weedy strain belonging to group II showed a wild rice-specific
allele at the Est-10 locus. However, in groups III and IV, no variation was ound either for the markers on Est-10 or for the RAPD loci tested. Judging from this study, weedy rice of group I might have originated at least partly from gene
flow between indica and japonica, whereas that of group II most probably originated from gene flow between wild and cultivated indica rice. Weedy rice of group III is thought to have originated from old rice cultivars which had reverted to a weedy form, and
that of group IV from gene flow between japonica cultivars and wild rice having japonica backgrounds.
Received: 2 May 1996 / Accepted: 30 August 1996 相似文献
5.
Population genomics identifies the origin and signatures of selection of Korean weedy rice
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Weedy rice is the same biological species as cultivated rice (Oryza sativa); it is also a noxious weed infesting rice fields worldwide. Its formation and population‐selective or ‐adaptive signatures are poorly understood. In this study, we investigated the phylogenetics, population structure and signatures of selection of Korean weedy rice by determining the whole genomes of 30 weedy rice, 30 landrace rice and ten wild rice samples. The phylogenetic tree and results of ancestry inference study clearly showed that the genetic distance of Korean weedy rice was far from the wild rice and near with cultivated rice. Furthermore, 537 genes showed evidence of recent positive or divergent selection, consistent with some adaptive traits. This study indicates that Korean weedy rice originated from hybridization of modern indica/indica or japonica/japonica rather than wild rice. Moreover, weedy rice is not only a notorious weed in rice fields, but also contains many untapped valuable traits or haplotypes that may be a useful genetic resource for improving cultivated rice. 相似文献
6.
Yong Wang Zheng Zheng Zhong Zhi Gang Zhao Ling Jiang Xiao Feng Bian Wen Wei Zhang Ling Long Liu H. Ikehashi Jian Min Wan 《Planta》2010,231(3):559-570
Weedy rice represents an important resource for rice improvement. The F1 hybrid between the japonica wide compatibility rice cultivar 02428 and a weedy rice accession from Yunnan province (SW China) suffered from pollen sterility.
Pollen abortion in the hybrid occurred at the early bicellular pollen stage, as a result of mitotic failure in the microspore,
although the tapetum developed normally. Genetic mapping in a BC1F1 population (02428//Yunnan weedy rice (YWR)/02428) showed that a major QTL for hybrid pollen sterility (qPS-1) was present on chromosome 1. qPS-1 was fine-mapped to a 110 kb region known to contain the hybrid pollen sterility gene Sa, making it likely that qPS-1 is either identical to, or allelic with Sa. Interestingly, F1 hybrid indicated that Dular and IR36 were assumed to carry the sterility-neutral allele, Sa
n
. Re-sequencing SaM and SaF, the two component genes present at Sa, suggested that variation for IR36 and Dular may be responsible for the loss of male sterility, and the qPS-1 sequence might be derived from wild rice or indica cultivars. A phylogenetic analysis based on microsatellite genotyping suggested that the YWR accession is more closely related
to wild rice and indica type cultivars than to japonica types. Thus it is probable that the YWR accession evolved from a spontaneous hybrid between wild rice and an ancient cultivated
strain of domesticated rice. 相似文献
7.
Jie Qiu Jinwen Zhu Fei Fu Chu-Yu Ye Weidi Wang Linfeng Mao Zhangxiang Lin Li Chen Haiqiang Zhang Longbiao Guo Shen Qiang Yongliang Lu Longjiang Fan 《Planta》2014,240(6):1353-1363
Main conclusion
Whole-genome re-sequencing of weedy rice from southern China reveals that weedy rice can originate from hybridization of domesticated indica and japonica rice.Abstract
Weedy rice (Oryza sativa f. spontanea Rosh.), which harbors phenotypes of both wild and domesticated rice, has become one of the most notorious weeds in rice fields worldwide. While its formation is poorly understood, massive amounts of rice genomic data may provide new insights into this issue. In this study, we determined genomes of three weedy rice samples from the lower Yangtze region, China, and investigated their phylogenetics, population structure and chromosomal admixture patterns. The phylogenetic tree and principle component analysis based on 46,005 SNPs with 126 other Oryza accessions suggested that the three weedy rice accessions were intermediate between japonica and indica rice. An ancestry inference study further demonstrated that weedy rice had two dominant genomic components (temperate japonica and indica). This strongly suggests that weedy rice originated from indica-japonica hybridization. Furthermore, 22,443 novel fixed single nucleotide polymorphisms were detected in the weedy genomes and could have been generated after indica-japonica hybridization for environmental adaptation. 相似文献8.
Yuan Wang Shu‐Da Mo Meng‐Yao Kong Jing Chao Xiao‐Feng Chen Jin‐Ling Yang Yu‐Jiang Yan Zhi‐Hua Shi Sheng Qiang Xiao‐Ling Song Wei‐Min Dai 《植物分类学报:英文版》2019,57(5):519-529
Weeds and crops that grow together often confront similar types of environmental stress, especially drought stress. Weedy rice (Oryza sativa f. spontanea) and cultivated rice (O. sativa L.) provide a unique pair consisting of a weed and a conspecific model crop that can be used to study the drought tolerance of plants across a large distributional range. The investigation on weedy rice's damage to paddy fields showed that it was more serious in dry direct seeding than water direct seeding. Compared with water direct seeding, the seeds of cultivated rice and weedy rice in dry direct seeding will absorb water and germinate under the condition of insufficient soil moisture. Our hypothesis is that weedy rice seeds have evolved stronger germination ability than coexisting cultivated rice under water stress, so that they can obtain more growth space in the early stage in dry direct seeding and thus obtain higher fitness. Seeds of weedy rice populations and coexisting rice cultivars were collected from 61 sites across China and were germinated with 20% polyethylene glycol‐6000 to simulate drought stress. Two drought response indices, which assessed germination rate and germination index, plus one germination stress tolerance index, indicated significantly greater drought tolerance in weedy rice populations than in coexisting rice cultivars (P < 0.01). Drought tolerance for the three indexes were indica weedy rice > indica rice cultivars, japonica weedy rice > japonica rice cultivars, and indica weedy rice > japonica rice cultivars. These results indicate that weedy rice populations show stronger drought stress tolerance than coexisting rice cultivars at various sites, specifically during the seed germination period. Furthermore, Pearson's correlation found that drought response of weedy rice populations and coexisting rice cultivars were significantly different with these environmental factors: latitude, altitude, annual mean precipitation, mean annual temperature, mean precipitation in the sowing month, mean temperature in the sowing month, and sowing methods. Weedy rice shows different patterns of drought tolerance variation across geographical (latitude and altitude) and environmental (precipitation) gradients compared to coexisting rice cultivars. This study suggests that weedy rice might have evolved new drought tolerance and could provide a useful source of genetic resources for improving drought tolerance of crop cultivars and breeding direct seeded cultivars to reduce the usage of seeds in direct seeding. 相似文献
9.
Mapping QTLs for defective female gametophyte development in an inter-subspecific cross in Oryza sativa L. 总被引:3,自引:0,他引:3
Y. S. Liu L. H. Zhu J. S. Sun Y. Chen 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(8):1243-1251
The embryo-sac is an essential structure for angiosperm reproduction. The cytological and genetic characterization of embryo-sac
sterility was examined in a cross between Oryza sativa ssp. indica cv. ZYQ8 and ssp. japonica cultivar, JX17. The arrest of embryo-sac development was manifested following meiosis in the F1 hybrid. When the megaspore carried the lethal genotype, the nucleus either failed to divide or divided only once, and the
immature embryo-sac degenerated. Abortion of the embryo-sac in the indica-japonica hybrid background was not observed in their original parents, and an effect of cytoplasmic gene(s) on embryo-sac sterility
in the reciprocal F1 hybrids was not detected. Using a rice molecular linkage map based on a doubled haploid (DH) population from the cross of
ZYQ8 /JX17, we mapped quantitative trait loci (QTLs) for the defective development of the female gametophyte in backcross
progenies from the DH lines. The result demonstrated that a polygenic system is involved in both megagametogenesis and postzygotic
isolation in inter-subspecific hybrid rice.
Received: 4 May 2000 / Accepted: 20 September 2000 相似文献
10.
Oryza rufipogon Griff. is the ancestor of Asian cultivated rice (O. sativa L.) and possesses valuable genes for rice breeding. Pollen abortion is one of the major causes of indica–japonica hybrid sterility in rice and it happens due to allelic interaction at the pollen sterility gene loci. A total of six loci
(Sa, Sb, Sc, Sd, Se, and Sf) have been found to be associated with F1 pollen sterility between indica and japonica rice, and five of them (all except Sf) have been mapped. Neutral alleles (S
n
) at each locus have the potential to overcome the pollen sterility associated with the respective locus. Therefore, exploitation
and utilization of neutral alleles have significant importance in overcoming indica–japonica hybrid sterility. In this study, an accession (IRW28) of O. rufipogon, native to China, was selected as paternal to cross with typical japonica (Taichung 65) and indica (Guanglu’ai 4) tester lines, and two F2 populations were developed. The simple sequence repeat markers tightly linked to five pollen sterility loci were applied
for genotyping the F2 populations. Chi-squared tests were applied to examine the normal segregation/distortion at each locus. The expected and
observed pollen sterility for each locus were estimated. As a result, the genotypes at five pollen sterility gene loci for
IRW28 were identified as: Sa
i−1/Sa
i−1, Sb
n
/Sb
n
, Sc
i−2/Sc
i−2, Sd
n
/Sd
n
and Se
n
/Se
n
. Our results suggest that IRW28 (O. rufipogon) has the neutral alleles for pollen fertility at the Sb, Sd and Se loci, and these alleles have a good affinity with indica and japonica rice. These neutral alleles provide valuable gene resources to overcome the inter-subspecific hybrid pollen sterility in
rice. 相似文献
11.
Liangming Chen Zhigang Zhao Xi Liu Linglong Liu Ling Jiang Shijia Liu Wenwei Zhang Yihua Wang Yuqiang Liu Jianmin Wan 《Molecular breeding : new strategies in plant improvement》2011,27(2):247-258
The incomplete fertility of japonica × indica rice hybrids has inhibited breeders’ access to the substantial heterotic potential of these hybrids. As hybrid sterility
is caused by an allelic interaction at a small number of loci, it is possible to overcome it by simple introgression at the
major sterility loci. Here we report the use of marker-assisted backcrossing to transfer into the elite japonica cv. Zhendao88 a photoperiod-sensitive male sterility gene from cv. Lunhui422S (indica) and the yellow leaf gene from line Yellow249 (indica). The microsatellite markers RM276, RM455, RM141 and RM185 were used to tag the fertility genes S5, S8, S7 and S9, respectively. Line 509S is a true-breeding photoperiod-sensitive male sterile plant, which morphologically closely resembles
the japonica type. Genotypic analysis showed that the genome of line 509S comprises about 92% japonica DNA. Nevertheless, hybrids between line 509S and japonica varieties suffer from a level of hybrid sterility, although the line is highly cross-compatible with indica types, with the resulting hybrids expressing a significant degree of heterosis. Together, these results suggest that segment
substitution on fertility loci based on known information and marker-assisted selection are an effective approach for utilizing
the heterosis of rice inter-subspecies. 相似文献
12.
13.
Heredity and genetic mapping of domestication-related traits in a temperate japonica weedy rice 总被引:10,自引:0,他引:10
C. Bres-Patry M. Lorieux G. Clément M. Bangratz A. Ghesquière 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,102(1):118-126
Rice is often found as various weedy forms in temperate or newly cultivated rice growing regions throughout the world. The
emergence of these forms in the absence of true wild rice remains unclear. A genetic analysis of domestication-related traits
(weed syndrome) has been conducted to better understand the appearance of these plants in rice fields. A doubled haploid (DH)
population was derived from a cross between a japonica variety and a weedy plant collected in Camargue (France) to set up a genetic linkage map consisting of 68 SSR and 31 AFLP
loci. Five qualitative traits related to pigmentation of different organs and 15 developmental and morphological quantitative
traits were scored for genes and QTLs mapping. Despite a good reactivity in anther culture and a high fertility of the DH
lines, segregation distortions were observed on chromosomal segments bearing gametophytic and sterility genes and corresponded
to various QTLs evidenced in indica×japonica distant crosses. Mapping of the coloration genes was found to be in agreement with the presence of several genes previously
identified and according to the genetic model governing the synthesis and distribution of anthocyan pigment in the plant.
In addition, the main specific traits of weedy forms revealed the same genes/QTLs as progeny derived from a cross between
Oryza sativa and its wild progenitor O. rufipogon. A large variation for most characters was found in the DH population, including transgressive variation. Significant correlations
were observed between morphology and traits related to weeds and corresponded to a distinct colocalization of most of the
QTLs on a limited number of chromosomal regions. The significance of these results on the origin of weedy forms and the de-domestication
process is discussed.
Received: 25 February 2000 / Accepted: 14 April 2000 相似文献
14.
15.
Sweeney MT Thomson MJ Cho YG Park YJ Williamson SH Bustamante CD McCouch SR 《PLoS genetics》2007,3(8):e133
Here we report that the change from the red seeds of wild rice to the white seeds of cultivated rice (Oryza sativa) resulted from the strong selective sweep of a single mutation, a frame-shift deletion within the Rc gene that is found in 97.9% of white rice varieties today. A second mutation, also within Rc, is present in less than 3% of white accessions surveyed. Haplotype analysis revealed that the predominant mutation originated in the japonica subspecies and crossed both geographic and sterility barriers to move into the indica subspecies. A little less than one Mb of japonica DNA hitchhiked with the rc allele into most indica varieties, suggesting that other linked domestication alleles may have been transferred from japonica to indica along with white pericarp color. Our finding provides evidence of active cultural exchange among ancient farmers over the course of rice domestication coupled with very strong, positive selection for a single white allele in both subspecies of O. sativa. 相似文献
16.
Weedy rice is a close relative of domesticated rice (Oryza sativa) that competes aggressively with the crop and limits rice productivity worldwide. Most genetic studies of weedy rice have focused on populations in regions where no reproductively compatible wild Oryza species occur (North America, Europe and northern Asia). Here, we examined the population genetics of weedy rice in Malaysia, where wild rice (O. rufipogon) can be found growing in close proximity to cultivated and weedy rice. Using 375 accessions and a combined analysis of 24 neutral SSR loci and two rice domestication genes (sh4, controlling seed shattering, and Bh4, controlling hull colour), we addressed the following questions: (i) What is the relationship of Malaysian weedy rice to domesticated and wild rice, and to weedy rice strains in the USA? (ii) To what extent does the presence of O. rufipogon influence the genetic and phenotypic diversity of Malaysian weeds? (iii) What do the distributions of sh4 and Bh4 alleles and associated phenotypes reveal about the origin and contemporary evolution of Malaysian weedy rice? Our results reveal the following: independent evolutionary origins for Malaysian weeds and US strains, despite their very close phenotypic resemblance; wild‐to‐weed gene flow in Malaysian weed populations, including apparent adaptive introgression of seed‐shattering alleles; and a prominent role for modern Malaysian cultivars in the origin and recent proliferation of Malaysian weeds. These findings suggest that the genetic complexity and adaptability of weedy crop relatives can be profoundly influenced by proximity to reproductively compatible wild and domesticated populations. 相似文献
17.
Analysis of indica- and japonica-specific markers of Oryza sativa and their applications 总被引:1,自引:0,他引:1
Xiao-Jun Dai Yuan-Zhu Yang Liang Zhou Li-Jun Ou Man-Zhong Liang Wen-Jia Li Gong-Ping Kang Liang-Bi Chen 《Plant Systematics and Evolution》2012,298(2):287-296
Asian rice, Oryza sativa L., is one of the most important crop species. Genetic analysis has established that rice consists of several genetically
differentiated variety groups, with two main groups, namely, O. sativa ssp. japonica kata and ssp. indica
kata. To determine the genetic diversity of indica and japonica rice, 45 rice varieties, including domesticated rice and Asia common wild rice (O. rufipogon Griff.), were analyzed using sequence-related amplified polymorphism, target region amplified polymorphism, simple sequence
repeat, and intersimple sequence repeat marker systems. A total of 90 indica- and japonica-specific bands between typical indica and japonica subspecies were identified, which greatly helped in determining whether domesticated rice is of the indica or japonica type, and in analyzing the consanguinity of hybrid rice with japonica, which were bred from indica and japonica crossed offspring. These specific bands were both located in the coding and non-encoding region, and usually connected with
quantitative trait loci. Utilizing the indica-japonica-specific markers, japonica consanguinity was detected in sterile hybrid rice lines. Many indica-japonica-specific bands were found in O. rufipogon. This result supports the multiple-origin model for domesticated rice. Javanica exhibited a greater number of indica-japonica-specific bands, which indicates that it is a subspecies of O. sativa L. 相似文献
18.
Li W Zeng R Zhang Z Ding X Zhang G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,116(7):915-922
The partial pollen abortion of hybrids between the indica and japonica subspecies of Asian cultivated rice is one of the major barriers in utilizing intersubspecific heterosis in hybrid rice breeding.
Although a single hybrid pollen sterility locus may have little impact on spikelet fertility, the cumulative effect of several
loci usually leads to a serious decrease in spikelet fertility. Isolating of the genes conferring hybrid pollen sterility
is necessary to understand this phenomenon and to overcome the resulting genetic barrier. In this study, a new locus for F1 pollen sterility, S-d, was identified on the short arm of chromosome 1 by analyzing the genetic effect of substituted segments of the near-isogenic
line E11-5 derived from the japonica variety Taichung 65 (recurrent parent) and the indica variety Dee-geo-woo-gen (donor parent). The S-d locus was first mapped to a 0.8 cM interval between SSR markers PSM46 and PSM80 using a F2 population of 125 individuals. The flanking markers were then used to identify recombinants from a population of 2,160 plants
derived from heterozygotes of the primary F2 population. Simultaneously, additional markers were developed from genomic sequence divergence in this region. Analysis of
the recombinants in the region resulted in the successful mapping of the S-d locus to a 67-kb fragment, containing 17 predicted genes. Positional cloning of this gene will contribute to our understanding
of the molecular basis for partial pollen sterility of intersubspecific F1 hybrids in rice. 相似文献
19.
A built-in mechanism to mitigate the spread of insect-resistance and herbicide-tolerance transgenes into weedy rice populations 总被引:2,自引:0,他引:2
Background
The major challenge of cultivating genetically modified (GM) rice (Oryza sativa) at the commercial scale is to prevent the spread of transgenes from GM cultivated rice to its coexisting weedy rice (O. sativa f. spontanea). The strategic development of GM rice with a built-in control mechanism can mitigate transgene spread in weedy rice populations.Methodology/Principal Findings
An RNAi cassette suppressing the expression of the bentazon detoxifying enzyme CYP81A6 was constructed into the T-DNA which contained two tightly linked transgenes expressing the Bt insecticidal protein Cry1Ab and the glyphosate tolerant 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), respectively. GM rice plants developed from this T-DNA were resistant to lepidopteran pests and tolerant to glyphosate, but sensitive to bentazon. The application of bentazon of 2000 mg/L at the rate of 40 mL/m2, which is approximately the recommended dose for the field application to control common rice weeds, killed all F2 plants containing the transgenes generated from the Crop-weed hybrids between a GM rice line (CGH-13) and two weedy rice strains (PI-63 and PI-1401).Conclusions/Significance
Weedy rice plants containing transgenes from GM rice through gene flow can be selectively killed by the spray of bentazon when a non-GM rice variety is cultivated alternately in a few-year interval. The built-in control mechanism in combination of cropping management is likely to mitigate the spread of transgenes into weedy rice populations. 相似文献20.
CARRIE S. THURBER MICHAEL REAGON BRIANA L. GROSS KENNETH M. OLSEN YULIN JIA ANA L. CAICEDO 《Molecular ecology》2010,19(16):3271-3284
Cultivated rice fields worldwide are plagued with weedy rice, a conspecific weed of cultivated rice (Oryza sativa L.). The persistence of weedy rice has been attributed, in part, to its ability to shatter (disperse) seed prior to crop harvesting. In the United States, separately evolved weedy rice groups have been shown to share genomic identity with exotic domesticated cultivars. Here, we investigate the shattering phenotype in a collection of U.S. weedy rice accessions, as well as wild and cultivated relatives. We find that all U.S. weedy rice groups shatter seeds easily, despite multiple origins, and in contrast to a decrease in shattering ability seen in cultivated groups. We assessed allelic identity and diversity at the major shattering locus, sh4, in weedy rice; we find that all cultivated and weedy rice, regardless of population, share similar haplotypes at sh4, and all contain a single derived mutation associated with decreased seed shattering. Our data constitute the strongest evidence to date of an evolution of weeds from domesticated backgrounds. The combination of a shared cultivar sh4 allele and a highly shattering phenotype, suggests that U.S. weedy rice have re‐acquired the shattering trait after divergence from their progenitors through alternative genetic mechanisms. 相似文献