共查询到20条相似文献,搜索用时 15 毫秒
1.
Osakabe K Abe K Yamanouchi H Takyuu T Yoshioka T Ito Y Kato T Tabata S Kurei S Yoshioka Y Machida Y Seki M Kobayashi M Shinozaki K Ichikawa H Toki S 《Plant molecular biology》2005,57(6):819-833
Rad51 paralogs belong to the Rad52 epistasis group of proteins and are involved in homologous recombination (HR), especially the assembly and stabilization of Rad51, which is a homolog of RecA in eukaryotes. We previously cloned and characterized two RAD51 paralogous genes in Arabidopsis, named AtRAD51C and AtXRCC3, which are considered the counterparts of human RAD51C and XRCC3, respectively. Here we describe the identification of RAD51B homologue in Arabidopsis, AtRAD51B. We found a higher expression of AtRAD51B in flower buds and roots. Expression of AtRAD51B was induced by genotoxic stresses such as ionizing irradiation and treatment with a cross-linking reagent, cisplatin. Yeast two-hybrid analysis showed that AtRad51B interacted with AtRad51C. We also found and characterized T-DNA insertion mutant lines. The mutant lines were devoid of AtRAD51B expression, viable and fertile. The mutants were moderately sensitive to γ-ray and hypersensitive to cisplatin. Our results suggest that AtRAD51B gene product is involved in the repair of double-strand DNA breaks (DSBs) via HRAccession numbers: AB194809 (AtRAD51Bα), AB194810 (AtRAD51Bβ), AB194811 (AtRAD51D). 相似文献
2.
The cellular roles of RAD51 paralogs in somatic and reproductive growth have been extensively described in a wide range of animal systems and, to a lesser extent, in Arabidopsis, a dicot model plant. Here, the OsRAD51D gene was identified and characterized in rice (Oryza sativa L.), a monocot model crop. In the rice genome, three alternative OsRAD51D mRNA splicing variants, OsRAD51D.1, OsRAD51D.2, and OsRAD51D.3, were predicted. Yeast two‐hybrid studies, however, showed that only OsRAD51D.1 interacted with OsRAD51B and OsRAD51C paralogs, suggesting that OsRAD51D.1 is a functional OsRAD51D protein in rice. Loss‐of‐function osrad51d mutant rice plants displayed normal vegetative growth. However, the mutant plants were defective in reproductive growth, resulting in sterile flowers. Homozygous osrad51d mutant flowers exhibited impaired development of lemma and palea and contained unusual numbers of stamens and stigmas. During early meiosis, osrad51d pollen mother cells (PMCs) failed to form normal homologous chromosome pairings. In subsequent meiotic progression, mutant PMCs represented fragmented chromosomes. The osrad51d pollen cells contained numerous abnormal micro‐nuclei that resulted in malfunctioning pollen. The abnormalities of heterozygous mutant and T2 Ubi:RNAi‐OsRAD51D RNAi‐knock‐down transgenic plants were intermediate between those of wild type and homozygous mutant plants. The osrad51d and Ubi:RNAi‐OsRAD51D plants contained longer telomeres compared with wild type plants, indicating that OsRAD51D is a negative factor for telomere lengthening. Overall, these results suggest that OsRAD51D plays a critical role in reproductive growth in rice. This essential function of OsRAD51D is distinct from Arabidopsis, in which AtRAD51D is not an essential factor for meiosis or reproductive development. 相似文献
3.
Bego?a Garc��a-Sogo Benito Pineda Lourdes Castelblanque Teresa Ant��n M��nica Medina Edel��n Roque Claudia Torresi Jos�� P��o Beltr��n Vicente Moreno Luis Antonio Ca?as 《Plant cell reports》2010,29(1):61-77
Engineered male sterility in ornamental plants has many applications such as facilitate hybrid seed production, eliminate
pollen allergens, reduce the need for deadheading to extend the flowering period, redirect resources from seeds to vegetative
growth, increase flower longevity and prevent gene flow between genetically modified and related native plants. We have developed
a reliable and efficient Agrobacterium-mediated protocol for the genetic transformation of different Kalanchoe
blossfeldiana commercial cultivars. Transformation efficiency for cv. ‘Hillary’ was 55.3% whereas that of cv. ‘Tenorio’ reached 75.8%. Selection was carried
out with the nptII gene and increasing the kanamycin concentration from 25 to 100 mg l−1 allowed to reduced escapes from 50 to 60% to virtually 0%. This method was used to produce male-sterile plants through engineered
anther ablation. In our approach, we tested a male sterility chimaeric gene construct (PsEND1::barnase) to evaluate its effectiveness and effect on phenotype. No significant differences were found in the growth patterns between
the transgenic lines and the wild-type plants. No viable pollen grains were observed in the ablated anthers of any of the
lines carrying the PsEND1::barnase construct, indicating that the male sterility was complete. In addition, seed set was completely abolished in all the transgenic
plants obtained. Our engineered male-sterile approach could be used, alone or in combination with a female-sterility system,
to reduce the invasive potential of new ornamentals, which has become an important environmental problem in many countries. 相似文献
4.
5.
The Interplay of RecA-related Proteins and the MND1–HOP2 Complex during Meiosis in Arabidopsis thaliana
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Julien Vignard Tanja Siwiec Liudmila Chelysheva Nathalie Vrielynck Florine Gonord Susan J Armstrong Peter Schlgelhofer Raphael Mercier 《PLoS genetics》2007,3(10)
During meiosis, homologous chromosomes recognize each other, align, and exchange genetic information. This process requires the action of RecA-related proteins Rad51 and Dmc1 to catalyze DNA strand exchanges. The Mnd1–Hop2 complex has been shown to assist in Dmc1-dependent processes. Furthermore, higher eukaryotes possess additional RecA-related proteins, like XRCC3, which are involved in meiotic recombination. However, little is known about the functional interplay between these proteins during meiosis. We investigated the functional relationship between AtMND1, AtDMC1, AtRAD51, and AtXRCC3 during meiosis in Arabidopsis thaliana. We demonstrate the localization of AtMND1 to meiotic chromosomes, even in the absence of recombination, and show that AtMND1 loading depends exclusively on AHP2, the Arabidopsis Hop2 homolog. We provide evidence of genetic interaction between AtMND1, AtDMC1, AtRAD51, and AtXRCC3. In vitro assays suggest that this functional link is due to direct interaction of the AtMND1–AHP2 complex with AtRAD51 and AtDMC1. We show that AtDMC1 foci accumulate in the Atmnd1 mutant, but are reduced in number in Atrad51 and Atxrcc3 mutants. This study provides the first insights into the functional differences of AtRAD51 and AtXRCC3 during meiosis, demonstrating that AtXRCC3 is dispensable for AtDMC1 focus formation in an Atmnd1 mutant background, whereas AtRAD51 is not. These results clarify the functional interactions between key players in the strand exchange processes during meiotic recombination. Furthermore, they highlight a direct interaction between MND1 and RAD51 and show a functional divergence between RAD51 and XRCC3. 相似文献
6.
Late-acting self-incompatibility in tea plant (<Emphasis Type="Italic">Camellia sinensis</Emphasis>)
The self-incompatibility of tea plant (Camellia sinensis (L.) O. Kuntze) was studied with the methods of aniline blue fluorescence assay and paraffin sections. The characteristics
of pollen tube elongation after hand pollination was analyzed in 4 tea cultivars, including ‘Keemenzhong’, ‘Longjing-changye’,
‘Fuding-dabaicha’ and ‘Yabukita’, under self-pollination and cross-pollination, respectively. Although there were some difference
among cultivars, pollen tubes elongated through the style and reach the ovary successfully at 48 h after pollination for both
cross- and self-pollen tubes in all the four cultivars of tea. Pollen tubes entered into the ovule micropyles, however, only
for cross-pollination, but not for self-pollination. Pollen tubes of selfing plants, failed in fertilizing, seemed have some
difficulties to enter the ovule. All of which indicated that the self-incompatibility of tea plant is a late-acting self-incompatibility
system (LSI) or an ovarian sterility (OS), in which the self incompatibility was due to none self pollen tube penetrating
into the ovule and no fertilization. 相似文献
7.
8.
Abe K Osakabe K Nakayama S Endo M Tagiri A Todoriki S Ichikawa H Toki S 《Plant physiology》2005,139(2):896-908
Rad51 is a homolog of the bacterial RecA recombinase, and a key factor in homologous recombination in eukaryotes. Rad51 paralogs have been identified from yeast to vertebrates. Rad51 paralogs are thought to play an important role in the assembly or stabilization of Rad51 that promotes homologous pairing and strand exchange reactions. We previously characterized two RAD51 paralogous genes in Arabidopsis (Arabidopsis thaliana) named AtRAD51C and AtXRCC3, which are homologs of human RAD51C and XRCC3, respectively, and described the interaction of their products in a yeast two-hybrid system. Recent studies showed the involvement of AtXrcc3 in DNA repair and functional role in meiosis. To determine the role of RAD51C in meiotic and mitotic recombination in higher plants, we characterized a T-DNA insertion mutant of AtRAD51C. Although the atrad51C mutant grew normally during vegetative developmental stage, the mutant produced aborted siliques, and their anthers did not contain mature pollen grains. Crossing of the mutant with wild-type plants showed defective male and female gametogeneses as evidenced by lack of seed production. Furthermore, meiosis was severely disturbed in the mutant. The atrad51C mutant also showed increased sensitivity to gamma-irradiation and cisplatin, which are known to induce double-strand DNA breaks. The efficiency of homologous recombination in somatic cells in the mutant was markedly reduced relative to that in wild-type plants. 相似文献
9.
Brca2 is involved in meiosis in Arabidopsis thaliana as suggested by its interaction with Dmc1
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Two BRCA2-like sequences are present in the Arabidopsis genome. Both genes are expressed in flower buds and encode nearly identical proteins, which contain four BRC motifs. In a yeast two-hybrid assay, the Arabidopsis Brca2 proteins interact with Rad51 and Dmc1. RNAi constructs aimed at silencing the BRCA2 genes at meiosis triggered a reproducible sterility phenotype, which was associated with dramatic meiosis alterations. We obtained the same phenotype upon introduction of RNAi constructs aimed at silencing the RAD51 gene at meiosis in dmc1 mutant plants. The meiotic figures we observed strongly suggest that homologous recombination is highly disturbed in these meiotic cells, leaving aberrant recombination events to repair the meiotic double-strand breaks. The 'brca2' meiotic phenotype was eliminated in spo11 mutant plants. Our experiments point to an essential role of Brca2 at meiosis in Arabidopsis. We also propose a role for Rad51 in the dmc1 context. 相似文献
10.
Pradillo M López E Linacero R Romero C Cuñado N Sánchez-Morán E Santos JL 《The Plant journal : for cell and molecular biology》2012,69(6):921-933
The eukaryotic recombinases RAD51 and DMC1 are essential for DNA strand-exchange between homologous chromosomes during meiosis. RAD51 is also expressed during mitosis, and mediates homologous recombination (HR) between sister chromatids. It has been suggested that DMC1 might be involved in the switch from intersister chromatid recombination in somatic cells to interhomolog meiotic recombination. At meiosis, the Arabidopsis Atrad51 null mutant fails to synapse and has extensive chromosome fragmentation. The Atdmc1 null mutant is also asynaptic, but in this case chromosome fragmentation is absent. Thus in plants, AtDMC1 appears to be indispensable for interhomolog homologous recombination, whereas AtRAD51 seems to be more involved in intersister recombination. In this work, we have studied a new AtRAD51 knock-down mutant, Atrad51-2, which expresses only a small quantity of RAD51 protein. Atrad51-2 mutant plants are sterile and hypersensitive to DNA double-strand break induction, but their vegetative development is apparently normal. The meiotic phenotype of the mutant consists of partial synapsis, an elevated frequency of univalents, a low incidence of chromosome fragmentation and multivalent chromosome associations. Surprisingly, non-homologous chromosomes are involved in 51% of bivalents. The depletion of AtDMC1 in the Atrad51-2 background results in the loss of bivalents and in an increase of chromosome fragmentation. Our results suggest that a critical level of AtRAD51 is required to ensure the fidelity of HR during interchromosomal exchanges. Assuming the existence of asymmetrical DNA strand invasion during the initial steps of recombination, we have developed a working model in which the initial step of strand invasion is mediated by AtDMC1, with AtRAD51 required to check the fidelity of this process. 相似文献
11.
Yimei Gan Yupeng Fan Yehua Yang Baosheng Dai Dayu Gao Xuekui Wang Kunbo Wang Mingjing Yao Heyang Wen Wenzhao Yu 《Molecular breeding : new strategies in plant improvement》2010,26(1):77-89
A transgenic male sterile line of upland cotton was generated by the ectopic expression of the monooxygenase (MNX) gene from Arabidopsis thaliana via Agrobacterium-mediated transformation. The bacterium harbored a plasmid pBinplus carrying a 1.25-kb MNX coding sequence together with a GUS reporter gene; the former was driven by the MS2 promoter of a male sterility gene in Arabidopsis, and the latter was under the control of CaMV 35S promoter. Twenty-seven putative transgenic plants (T0) were obtained, all of which showed GUS activity and positive signals of NPTII and MNX genes by PCR analysis, and also showed male sterility to some extent. It was further confirmed by Southern blotting that
one copy of the NPTII and MNX gene was integrated in the genome of the plants which expressed male sterility to a higher degree. Northern blotting assay
also demonstrated that the transgenes stably transcribed in the genome of the transgenic plants in F4 generation. The male sterile plants usually display lower plant height, shortened internodes, shrunken anthers without pollen
grains or with some abortive pollen grains, and unusual leaves with deeper multi-lobes. Microscope observations on the meiosis
processes of pollen mother cells (PMCs) showed that the abortion of pollen grains mainly resulted from abnormalities of meiosis
such as direct degeneration of PMCs, degenerations of dyad and tetrads, amitosis, lagging chromosomes, and the multi-polar
segregations of chromosomes and so on. This study indicates a method of developing novel cotton male sterile materials for
potential application in agriculture and for engineering of male sterility in other important crops. 相似文献
12.
Citrus FT (CiFT) cDNA, which promoted the transition from the vegetative to the reproductive phase in Arabidopsis thaliana, when constitutively expressed was introduced into trifoliate orange (Poncirus trifoliata L. Raf.). The transgenic plants in which CiFT was expressed constitutively showed early flowering, fruiting, and characteristic morphological changes. They started to
flower as early as 12 weeks after transfer to a greenhouse, whereas wild-type plants usually have a long juvenile period of
several years. Most of the transgenic flowers developed on leafy inflorescences, apparently in place of thorns; however, wild-type
adult trifoliate orange usually develops solitary flowers in the axils of leaves. All of the transgenic lines accumulated
CiFT mRNA in their shoots, but there were variations in the accumulation level. The transgenic lines showed variation in phenotypes,
such as time to first flowering and tree shape. In F1 progeny obtained by crossing ‘Kiyomi’ tangor (C. unshiu × sinensis) with the pollen of one transgenic line, extremely early flowering immediately after germination was observed. The transgene
segregated in F1 progeny in a Mendelian fashion, with complete co-segregation of the transgene and the early flowering phenotype. These results
showed that constitutive expression of CiFT can reduce the generation time in trifoliate orange. 相似文献
13.
Márta Molnár-Láng András Cseh Éva Szakács István Molnár 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,120(8):1535-1545
The main objective of the present work was to develop a wheat genotype containing both the recessive crossability alleles
(kr1kr1kr2kr2), allowing high crossability between 6x wheat and diploid rye, and the 1BL.1RS wheat/rye translocation chromosome. This wheat
genotype could be used as a recipient partner in wheat–rye crosses for the efficient introduction of new allelic variation
into 1RS in translocation wheats. After crossing the wheat cultivars ‘Mv Magdaléna’ and ‘Mv Béres’, which carry the 1BL.1RS
translocation involving the 1RS chromosome arm from ‘Petkus’, with the line ‘Mv9 kr1’, 117 F2 plants were analysed for crossability, ten of which had higher than 50% seed set with rye and thus presumably carried the
kr1kr1kr2kr2 alleles. Four of the ten plants contained the 1BL.1RS translocation in the disomic condition as detected by genomic in situ
hybridization (GISH). The wheat × rye F1 hybrids produced between these lines and the rye cultivar ‘Kriszta’ were analysed in meiosis using GISH. 1BL.1RS/1R chromosome
pairing was detected in 62.4% of the pollen mother cells. The use of fluorescent in situ hybridization (FISH) with the repetitive
DNA probes pSc119.2, Afa family and pTa71 allowed the 1R and 1BL.1RS chromosomes to be identified. The presence of the 1RS
arm from ‘Kriszta’ besides that of ‘Petkus’ was demonstrated in the F1 hybrids using the rye SSR markers RMS13 and SCM9. In four of the 22 BC1 progenies analysed, only ‘Kriszta’-specific bands were observed with these markers, though the presence of the 1BL.1RS translocation
was detected using GISH. It can be concluded that recombination occurred between the ‘Petkus’ and ‘Kriszta’ 1RS chromosome
arms in the translocated chromosome in these plants. 相似文献
14.
15.
A breakthrough in transgenic Arabidopsis thaliana research was the development of the floral dip transformation protocol, a simple and reliable method of obtaining transformants,
T1 transgenic lines, at high efficiency while avoiding the use of tissue culture. However, the traditional protocol (a “sterile”
method) of obtaining T2 transgenic lines has not evolved along with improvements in transformation technology as it continues to be laborious and
time-consuming. In this study, we report on the development of an improved protocol (a “nonsterile” method) for selecting
and growing A. thaliana transformants (T2 transgenic lines) resistant to kanamycin under nonsterile conditions. This protocol involves the use of a simple yet specialized
device that will aid in solium selection of T2 transgenic lines that can be rapidly grown in a hydroponic system. The “nonsterile” method reduces labor and time involved
as compared to the “sterile” method; moreover, it is easy to set up and maintain. This method may also be applicable to other
selecting agents, and perhaps to other plants. 相似文献
16.
Information on the development of the male reproductive structures in willow will help advance our understanding of its reproductive behavior and contribute to our ability to work towards its improvement. Willow also offers the opportunity to study male sterility, a subject matter which is not typically dealt with in woody plants. As compared to the three willow species examined (Salix eriocephala, S. exigua, and S. purpurea), pollen development in S. discolor S365 showed several abnormalities starting with the delay in meiosis. This lasted for about 10 days and meiosis eventually occurred as manifested by the formation of microspores. However, most of the resulting microspores collapsed, while only a few developed into pollen grains. The large number of undeveloped and disintegrated microspores appeared to make the few pollen grains sticky, preventing them from being dispersed. Histochemical analysis showed that meiosis in most species of willow was associated with the presence of large amounts of insoluble polysaccharides in the anther wall layers, but only very few of these were observed in S. discolor. Also, a 32-kDa protein which is the most abundant protein in the reproductive structures of willow, was absent in S. discolor S365. Proteomic analysis showed that this is similar to the storage proteins in Populus x canadensis and P. deltoides. Therefore, male sterility in S. discolor may be due to some genetic defects affecting the accumulation of essential reserves in its reproductive structures. The mechanism behind this is unknown, but this study has established the nature of sterility in S. discolor S365. 相似文献
17.
The rice RAD51C gene is required for the meiosis of both female and male gametocytes and the DNA repair of somatic cells 总被引:1,自引:0,他引:1
The RecA/RAD51 family of rice (Oryza sativa) consists of at least 13 members. However, the functions of most of these members are unknown. Here the functional characterization of one member of this family, RAD51C, is reported. Knockout (KO) of RAD51C resulted in both female and male sterility in rice. Transferring RAD51C to the RAD51C-KO line restored fertility. Cytological analyses showed that the sterility of RAD51C-KO plants was associated with abnormal early meiotic processes in both megasporocytes and pollen mother cells (PMCs). PMCs had an absence of normal pachytene chromosomes and had abnormal chromosome fragments. The RAD51C-KO line showed no obvious difference from wild-type plants in mitosis in the anther wall cells, which was consistent with the observation that the RAD51C-KO line did not have obviously abnormal morphology during vegetative development. However, the RAD51C-KO line was sensitive to different DNA-damaging agents. These results suggest that RAD51C is essential for reproductive development by regulating meiosis as well as for DNA damage repair in somatic cells. 相似文献
18.
To explore a new approach to generating reproductive sterility in transgenic plants, the barnase gene from Bacillus amyloliquefaciens was placed under the control of an 1853-bp nucleotide sequence from the 3′end of the second intron of Arabidopsis
AGAMOUS and CaMV 35S (−60) minimal promoter [AG-I-35S (−60)::Barnase], and was introduced into tobacco through transformation mediated by Agrobacterium tumefaciens. All AG-I-35S (−60)::Barnase transgenic plants showed normal vegetative growth and 28% of the transgenic lines displayed complete ablation of flowering.
Two transgenic lines, Bar-5 and Bar-15, were 98.1 and 98.4% sterile, respectively, as determined by seed production and germination.
When controlled by AG-I-35S (−60) chimeric promoter, barnase mRNA was detected in the reproductive tissues of transgenic tobacco plants, but not in vegetative parts. This study presents
the first application of an AG intron sequence in the engineered ablation of sexual reproduction in plants. The AG-I-35S (−60)::Barnase construct can be useful in diminishing pollen and seed formation in plants, providing a novel bisexual sterility strategy
for interception of transgene escape and has other potentially commercial use for transgenic engineering. 相似文献
19.
Summary Creeping bentgrass is a very important turfgrass species used extensively on golf course greens, fairways, and tees. One of
the challenges of creeping bentgrass management is the control of grassy weeds, most of which respond to herbicides in a similar
manner to that of creeping bentgrass. As part of a weed management program for golf courses, Roundup?-tolerant creeping bentgrass will be simple to employ and more effective in controlling problem weeds than currently available
methods. The goal of this research was to evaluate fitness-related reproductive traits in four transgenic creeping bentgrass
events modified to express a Roundup?-tolerant gene, cp4 epsps, to determine if these creeping bentgrass events had gained an unexpected reproductive fitness advantage. We compared transgenic
events ASR 333, ASR801 with their nontransformed tissue culture line, C99056L and transgenic events ASR365, ASR368 with their
non-transformed tissue culture line, B99061R. Populations of plants from three conventional cultivars were also included for
comparison to determine whether significant variations, if present in transgenic events, were novel to the non-transformed
organism, Agrostis stolonifera L. Our results showed that none of the four transgenic events surveyed were significantly different from the respective non-transformed
tissue culture line plants for the following characteristics: first heading date, anthesis duration, inflorescence length,
number of florets per inflorescence, pollen size, and seed-set capacity through open-pollination. One of the transgenic events,
ASR333, needed significantly more days for anthesis initiation than the nontransformed tissue culture line, C99056L; while
another transgenic event, ASR801, exhibited significantly shorter pollen longevity than plants of the tissue culture line,
C99056L. However, ASR801 was not significantly different from the conventional cultivars ‘Penn A-4’ and ‘Penncross’ for pollen
longevity. Plants of both transgenic events ASR365 and ASR368 did not differ significantly from plants of the tissue culture
line, B99061R, for all characters measured. 相似文献
20.
Hanchen Chen Chengpeng He Chongyang Wang Xuanpeng Wang Fengyin Ruan Junjie Yan Ping Yin Yingxiang Wang Shunping Yan 《The Plant cell》2021,33(8):2869
Meiosis is a fundamental process for sexual reproduction in most eukaryotes and the evolutionarily conserved recombinases RADiation sensitive51 (RAD51) and Disrupted Meiotic cDNA1 (DMC1) are essential for meiosis and thus fertility. The mitotic function of RAD51 is clear, but the meiotic function of RAD51 remains largely unknown. Here we show that RAD51 functions as an interacting protein to restrain the Structural Maintenance of Chromosomes5/6 (SMC5/6) complex from inhibiting DMC1. We unexpectedly found that loss of the SMC5/6 partially suppresses the rad51 knockout mutant in terms of sterility, pollen inviability, and meiotic chromosome fragmentation in a DMC1-dependent manner in Arabidopsis thaliana. Biochemical and cytological studies revealed that the DMC1 localization in meiotic chromosomes is inhibited by the SMC5/6 complex, which is attenuated by RAD51 through physical interactions. This study not only identified the long-sought-after function of RAD51 in meiosis but also discovered the inhibition of SMC5/6 on DMC1 as a control mechanism during meiotic recombination. RAD51 functions as an interacting protein to restrain the SMC5/6 complex from inhibiting DMC1 during meiosis. 相似文献