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1.
Leaf senescence constituted the final stage of leaf development and it is always accompanied by the leaf yellowing. The non-yellowing gene (NYE1), initially identified from Arabidopsis in our laboratory, is a key regulatory gene responsible for chlorophyll degradation during senescence. In this study, an orthologue of AtNYE1 was isolated from the bamboo (Bambusa emeiensis cv. Viridiflavus) and tentatively named BeNYE1. The full length sequence of 1 386 bp contains an open reading frame of 801 bp. The protein encoded by BeNYE1 consists of 266 amino acids. Sequence analysis revealed that BeNYE1 had high similarity with other NYE/SGR proteins from various monocotyledon species. BeNYE1 was strongly induced by natural senescence and dark-induced senescence in bamboo. Driven by a 1.5 kb upstream fragment of AtNYE1, BeNYE1 could rescue the stay-green phenotype of nye1-1. The constitutive over-expression of BeNYE1 could accelerate the chlorophyll degradation. These results indicated that BeNYE1 might play an important role in the regulation of chlorophyll degradation during leaf senescence in bamboo. 相似文献
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毛竹中NYE基因的分离及功能分析 总被引:1,自引:0,他引:1
AtNYE1是拟南芥叶片衰老过程中叶绿素降解的重要调控基因,本文用AtNYE1为诱饵基因,通过NCBI tblastn在毛竹的cDNA文库中找到3个与其相似性较高的cDNA全长序列,分别命名为PeNYE1、PeNYE2和PeNYE3。为了验证其是否具有AtNYE1相似的功能,分别将它们的编码区构建到带有花椰菜花叶病毒35S强启动子的植物表达载体上,并通过冻融法将这3个表达载体导入GV3101农杆菌。通过农杆菌介导法,将这3个基因分别在烟草叶片中瞬时表达及在拟南芥植株中稳定表达,结果显示,瞬时过表达和组成型过表达PeNYE1均导致了叶片的黄化,而瞬时或组成型过表达PeNYE2或PeNYE3均未观察到黄化表型。这些结果表明PeNYE1是毛竹中叶绿素降解的重要调控基因。 相似文献
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Identification of a novel chloroplast protein AtNYE1 regulating chlorophyll degradation during leaf senescence in Arabidopsis 总被引:2,自引:0,他引:2
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A dramatic increase of chlorophyll (Chl) degradation occurs during senescence of vegetative plant organs and fruit ripening. Although the biochemical pathway of Chl degradation has long been proposed, little is known about its regulatory mechanism. Identification of Chl degradation-disturbed mutants and subsequently isolation of responsible genes would greatly facilitate the elucidation of the regulation of Chl degradation. Here, we describe a nonyellowing mutant of Arabidopsis (Arabidopsis thaliana), nye1-1, in which 50% Chl was retained, compared to less than 10% in the wild type (Columbia-0), at the end of a 6-d dark incubation. Nevertheless, neither photosynthesis- nor senescence-associated process was significantly affected in nye1-1. Characteristically, a significant reduction in pheophorbide a oxygenase activity was detected in nye1-1. However, no detectable accumulation of either chlorophyllide a or pheophorbide a was observed. Reciprocal crossings revealed that the mutant phenotype was caused by a monogenic semidominant nuclear mutation. We have identified AtNYE1 by positional cloning. Dozens of its putative orthologs, predominantly appearing in higher plant species, were identified, some of which have been associated with Chl degradation in a few crop species. Quantitative polymerase chain reaction analysis showed that AtNYE1 was drastically induced by senescence signals. Constitutive overexpression of AtNYE1 could result in either pale-yellow true leaves or even albino seedlings. These results collectively indicate that NYE1 plays an important regulatory role in Chl degradation during senescence by modulating pheophorbide a oxygenase activity. 相似文献
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Expression of the bacteriophage T4 lysozyme gene in tall fescue confers resistance to gray leaf spot and brown patch diseases 总被引:2,自引:0,他引:2
Tall fescue (Festuca arundinacea Schreb.) is an important turf and forage grass species worldwide. Fungal diseases present a major limitation in the maintenance
of tall fescue lawns, landscapes, and forage fields. Two severe fungal diseases of tall fescue are brown patch, caused by
Rhizoctonia solani, and gray leaf spot, caused by Magnaporthe grisea. These diseases are often major problems of other turfgrass species as well. In efforts to obtain tall fescue plants resistant
to these diseases, we introduced the bacteriophage T4 lysozyme gene into tall fescue through Agrobacterium-mediated genetic transformation. In replicated experiments under controlled environments conducive to disease development,
6 of 13 transgenic events showed high resistance to inoculation of a mixture of two M. grisea isolates from tall fescue. Three of these six resistant plants also displayed significant resistance to an R. solani isolate from tall fescue. Thus, we have demonstrated that the bacteriophage T4 lysozyme gene confers resistance to both gray
leaf spot and brown patch diseases in transgenic tall fescue plants. The gene may have wide applications in engineered fungal
disease resistance in various crops. 相似文献
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The effect of tall fescue turf on growth, flowering, nodulation, and nitrogen fixing potential of Lupinus albifrons Benth. was examined for greenhouse and field grown plants. No allelopathic effect was observed for lupine plants treated with tall fescue leachates. The nitrogen-fixing potential measured by nodule dry weight and acetylene reduction rates was not significantly affected by tall fescue turf.Both the greenhouse and field studies showed that the growth, sexual reproductive allocation and number of inflorescences were significantly reduced when lupine plants were grown with tall fescue. The root-length densities of tall fescue turf and lupine monoculture were measured. The tall fescue turf had 20 times higher root-length density (20 cm cm-3 soil) than the lupine plant monoculture. This suggests that intense competition at the root zone may be a dominant factor which limits the growth of the lupine plants.The flowering characters of the lupine plants were improved by phosphorus fertilization. Transplanting of older lupine plants into the turf substantially alleviated the tall fescue turf competitive effect. 相似文献
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Hiroshi Yamatani Yutaka Sato Yu Masuda Yusuke Kato Ryouhei Morita Kenji Fukunaga Yoshiaki Nagamura Minoru Nishimura Wataru Sakamoto Ayumi Tanaka Makoto Kusaba 《The Plant journal : for cell and molecular biology》2013,74(4):652-662
Yellowing/chlorophyll breakdown is a prominent phenomenon in leaf senescence, and is associated with the degradation of chlorophyll – protein complexes. From a rice mutant population generated by ionizing radiation, we isolated nyc4‐1, a stay‐green mutant with a defect in chlorophyll breakdown during leaf senescence. Using gene mapping, nyc4‐1 was found to be linked to two chromosomal regions. We extracted Os07g0558500 as a candidate for NYC4 via gene expression microarray analysis, and concluded from further evidence that disruption of the gene by a translocation‐related event causes the nyc4 phenotype. Os07g0558500 is thought to be the ortholog of THF1 in Arabidopsis thaliana. The thf1 mutant leaves show variegation in a light intensity‐dependent manner. Surprisingly, the Fv/Fm value remained high in nyc4‐1 during the dark incubation, suggesting that photosystem II retained its function. Western blot analysis revealed that, in nyc4‐1, the PSII core subunits D1 and D2 were significantly retained during leaf senescence in comparison with wild‐type and other non‐functional stay‐green mutants, including sgr‐2, a mutant of the key regulator of chlorophyll degradation SGR. The role of NYC4 in degradation of chlorophyll and chlorophyll – protein complexes during leaf senescence is discussed. 相似文献
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Hand ML Cogan NO Forster JW 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(6):1127-1137
Allohexaploid tall fescue (Festuca arundinacea Schreb. syn. Lolium arundinaceum [Schreb.] Darbysh.) is an agriculturally important grass cultivated for pasture and turf world-wide. Genetic improvement
of tall fescue could benefit from the use of non-domesticated germplasm to diversify breeding populations through the incorporation
of novel and superior allele content. However, such potential germplasm must first be characterised, as three major morphotypes
(Continental, Mediterranean and rhizomatous) with varying degrees of hybrid interfertility are commonly described within this
species. As hexaploid tall fescue is also a member of a polyploid species complex that contains tetraploid, octoploid and
decaploid taxa, it is also possible that germplasm collections may have inadvertently sampled some of these sub-species. In
this study, 1,040 accessions from the publicly available United States Department of Agriculture tall fescue and meadow fescue
germplasm collections were investigated. Sequence of the chloroplast genome-located matK gene and the nuclear ribosomal DNA internal transcribed spacer (rDNA ITS) permitted attribution of accessions to the three
previously known morphotypes and also revealed the presence of tall fescue sub-species of varying ploidy levels, as well as
other closely related species. The majority of accessions were, however, identified as Continental hexaploid tall fescue.
Analysis using 34 simple sequence repeat markers was able to further investigate the level of genetic diversity within each
hexaploid tall fescue morphotype group. At least two genetically distinct sub-groups of Continental hexaploid tall fescue
were identified which are probably associated with palaeogeographic range expansion of this morphotype. This work has comprehensively
characterised a large and complex germplasm collection and has identified genetically diverse accessions which may potentially
contribute valuable alleles at agronomic loci for tall fescue cultivar improvement programs. 相似文献
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Sabine Raab Gabriele Drechsel Maryam Zarepour Wolfram Hartung Tomokazu Koshiba Florian Bittner Stefan Hoth 《The Plant journal : for cell and molecular biology》2009,59(1):39-51
During leaf senescence, resources are recycled by redistribution to younger leaves and reproductive organs. Candidate pathways for the regulation of onset and progression of leaf senescence include ubiquitin‐dependent turnover of key proteins. Here, we identified a novel plant U‐box E3 ubiquitin ligase that prevents premature senescence in Arabidopsis plants, and named it SENESCENCE‐ASSOCIATED E3 UBIQUITIN LIGASE 1 (SAUL1). Using in vitro ubiquitination assays, we show that SAUL1 has E3 ubiquitin ligase activity. We isolated two alleles of saul1 mutants that show premature senescence under low light conditions. The visible yellowing of leaves is accompanied by reduced chlorophyll content, decreased photochemical efficiency of photosystem II and increased expression of senescence genes. In addition, saul1 mutants exhibit enhanced abscisic acid (ABA) biosynthesis. We show that application of ABA to Arabidopsis is sufficient to trigger leaf senescence, and that this response is abolished in the ABA‐insensitive mutants abi1‐1 and abi2‐1, but enhanced in the ABA‐hypersensitive mutant era1‐3. We found that increased ABA levels coincide with enhanced activity of Arabidopsis aldehyde oxidase 3 (AAO3) and accumulation of AAO3 protein in saul1 mutants. Using label transfer experiments, we showed that interactions between SAUL1 and AAO3 occur. This suggests that SAUL1 participates in targeting AAO3 for ubiquitin‐dependent degradation via the 26S proteasome to prevent premature senescence. 相似文献
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B. C. Bastin A. Houser C. P. Bagley K. M. Ely R. R. Payton A. M. Saxton F. N. Schrick J. C. Waller C. J. Kojima 《Animal genetics》2014,45(3):439-441
Fescue toxicosis is a common syndrome of poor growth and reproductive performance of beef cattle grazing endophyte‐infected tall fescue infected with Lolium arundinaceum Schreb. Together with decreased feed intake, decreased growth rates and tissue necrosis due to vasoconstriction, depressed circulating serum prolactin concentrations are typically observed in cattle afflicted with fescue toxicosis. Polymorphisms within the XK, Kell blood group complex subunit‐related family, member 4 (XKR4) gene located on BTA14 have been previously reported to be associated with rump fat thickness, residual feed intake, average daily feed intake and average daily gain in cattle. Associations also have been reported between XKR4 genotype and effectiveness of the dopamine antagonist iloperidone as a treatment of schizophrenia in humans. Domperidone, a related dopamine antagonist, mediates effects of fescue toxicosis on livestock, including restoring depressed concentrations of prolactin. A mixed‐breed population of 592 beef cattle grazing endophyte‐infected tall fescue was used to examine the association between XKR4 genotype and circulating prolactin concentrations. The SNP rs42646708 was significantly (P = 0.0002) associated with serum prolactin concentrations and explained 2.45% of the phenotypic variation. Effect of genotype at the SNP was tested across five breeds, with significant associations within both Angus (P = 0.0275) and Simmental (P = 0.0224) breeds. These results suggest XKR4 may play a role in mediating the negative effects of fescue toxicosis, and polymorphisms within this gene may be useful markers for selection for genetic resistance to the debilitating effects of endophyte‐infected tall fescue. 相似文献
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In plants, chlorophyll is actively synthesized from glutamate in the developmental phase and is degraded into non-fluorescent
chlorophyll catabolites during senescence. The chlorophyll metabolism must be strictly regulated because chlorophylls and
their intermediate molecules generate reactive oxygen species. Many mechanisms have been proposed for the regulation of chlorophyll
synthesis including gene expression, protein stability, and feedback inhibition. However, information on the regulation of
chlorophyll degradation is limited. The conversion of chlorophyll b to chlorophyll a is the first step of chlorophyll degradation. In order to understand the regulatory mechanism of this reaction, we isolated
a mutant which accumulates 7-hydroxymethyl chlorophyll a (HMChl), an intermediate molecule of chlorophyll b to chlorophyll a conversion, and designated the mutant hmc1. In addition to HMChl, hmc1 accumulated pheophorbide a, a chlorophyll degradation product, when chlorophyll degradation was induced by dark incubation. These results indicate that
the activities of HMChl reductase (HAR) and pheophorbide a oxygenase (PaO) are simultaneously down-regulated in this mutant. We identified a mutation in the AtNAP1 gene, which encodes a subunit of the complex for iron–sulfur cluster formation. HAR and PaO use ferredoxin as a reducing
power and PaO has an iron-sulfur center; however, there were no distinct differences in the protein levels of ferredoxin and
PaO between wild type and hmc1. The concerted regulation of chlorophyll degradation is discussed in relation to the function of AtNAP1. 相似文献
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Saha MC Mian MA Eujayl I Zwonitzer JC Wang L May GD 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(4):783-791
Tall fescue (Festuca arundinacea Schreb.) is a major cool season forage and turf grass in the temperate regions of the world. It is also a close relative of other important forage and turf grasses, including meadow fescue and the cultivated ryegrass species. Until now, no SSR markers have been developed from the tall fescue genome. We designed 157 EST-SSR primer pairs from tall fescue ESTs and tested them on 11 genotypes representing seven grass species. Nearly 92% of the primer pairs produced characteristic simple sequence repeat (SSR) bands in at least one species. A large proportion of the primer pairs produced clear reproducible bands in other grass species, with most success in the close taxonomic relatives of tall fescue. A high level of marker polymorphism was observed in the outcrossing species tall fescue and ryegrass (66%). The marker polymorphism in the self-pollinated species rice and wheat was low (43% and 38%, respectively). These SSR markers were useful in the evaluation of genetic relationships among the Festuca and Lolium species. Sequencing of selected PCR bands revealed that the nucleotide sequences of the forage grass genotypes were highly conserved. The two cereal species, particularly rice, had significantly different nucleotide sequences compared to the forage grasses. Our results indicate that the tall fescue EST-SSR markers are valuable genetic markers for the Festuca and Lolium genera. These are also potentially useful markers for comparative genomics among several grass species.Electronic Supplementary Material Supplementary material is available for this article at . 相似文献
19.
Production of transgenic tall fescue and red fescue plants by particle bombardment of mature seed-derived highly regenerative tissues 总被引:29,自引:0,他引:29
Highly regenerative tissues of tall fescue and red fescue produced from mature seed-derived embryogenic callus were induced
and proliferated on medium containing 2,4-dichlorophenoxyacetic acid (4.5 or 9.0 μM), 6-benzylaminopurine (0, 0.044, 0.44
or 2.2 μM) and cupric sulfate (0.1 or 5.0 μM) under dim-light conditions (10 to 30 μE m–2 s–1, 16 h light). Tall fescue tissues were transformed with three plasmids containing the genes for hygromycin phosphotransferase
(hpt), phosphinothricin acetyltransferase (bar) and β-glucuronidase (uidA;gus), and red fescue with three plasmids containing hpt, uidA and a synthetic green fluorescent protein gene [sgfp(S65T)]. DNA from T0 plants of eight independently transformed lines from tall fescue and 11 from red fescue were analyzed by PCR and DNA blot
hybridization. The co-expression frequency of all three transgenes [hpt/bar/uidA or hpt/uidA/sgfp(S65T)] in transgenic tall fescue and red fescue plants was 25–27%; for two transgenes [hpt/bar or hpt/uidA for tall fescue and hpt/uidA or hpt/sgfp(S65T) for red fescue], the co-expression frequency was 50–75%.
Received: 28 September 1999 / Revision received: 13 March 2000 / Accepted: 16 March 2000 相似文献