DNA synthesis in osmoprimed leek (<i>Allium porrum</i>L.) seeds and evidence for repair and replication

Ashraf, Muhammad; Bray, Clifford M.

doi:10.1017/s0960258500001525

Cited by 58 publications

(30 citation statements)

References 30 publications

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“…Priming has been shown to be both beneficial (Georghiou et al, 1987;Probert et al, 1991;Wechsberg, 1994) and detrimental Tarquis and Bradford, 1992) to subsequent longevity. Increases in the rate of germination through priming have been attributed to the advancement of germination metabolism (Lanteri et al, 1993;Sarocco et al, 1995;Soeda et al, 2005), enhanced antioxidant activity (Bailly et al, 2000) and, particularly where longevity is improved, repair processes (Burgass and Powell, 1984;Ashraf and Bray, 1993;Bray et al, 1993;Sivritepe and Dourado, 1995). Negative effects of priming have been explained as the consequence of germination sensu strictu having advanced to a state where seeds have lost desiccation tolerance (Ś liwińska and Jendrzejczak, 2002) or are less able to resist damage during air-dry storage (Powell et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Priming and re-drying improve the survival of mature seeds of Digitalis purpurea during storage

et al. 2009

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† Background and Aims Most priming studies have been conducted on commercial seed lots of unspecified uniformity and maturity, and subsequent seed longevity has been reported to both increase and decrease. Here a seed lot of Digitalis purpurea L. with relatively uniform maturity and known history was used to analyse the effects of priming on seed longevity in air-dry storage. † Methods Seeds collected close to natural dispersal and dried at 15 % relative humidity (RH), 15 8C, were placed into experimental storage (60 % RH, 45 8C) for 14 or 28 d, primed for 48 h at 0, 21, 22, 25, 210 or 215 MPa, re-equilibrated (47 % RH, 20 8C) and then returned to storage. Further seed samples were primed for 2 or 48 h at 21 MPa and either dried at 15 % RH, 15 8C or immediately re-equilibrated for experimental storage. Finally, some seeds were given up to three cycles of experimental storage and priming (48 h at 21 MPa). † Key Results Priming at 21 MPa had a variable effect on subsequent survival during experimental storage. The shortest lived seeds in the control population showed slightly increased life spans; the longer lived seeds showed reduced life spans. In contrast, seeds first stored for 14 or 28 d before priming had substantially increased life spans. The increase tended to be greatest in the shortest lived fraction of the seed population. Both the period of rehydration and the subsequent drying conditions had significant effects on longevity. Interrupting air-dry storage with additional cycles of priming also increased longevity. † Conclusions The extent of prior deterioration and the post-priming desiccation environment affect the benefits of priming to the subsequent survival of mature seeds. Rehydration-dehydration treatments may have potential as an adjunct or alternative to the regeneration of seed accessions maintained in gene banks for plant biodiversity conservation or plant breeding.

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Section: Introductionmentioning

confidence: 99%

Priming and re-drying improve the survival of mature seeds of Digitalis purpurea during storage

et al. 2009

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“…Using [^H]thymidine pulse labelling. Bray et al (1989) and Ashraf and Bray (1993) showed that during priming of leek seeds, a low level of both replicative and repair-type DNA synthesis occurred in the absence of any cell division. Upon germination of these primed seeds, DNA synthesis was greatly enhanced compared with nonprimed seeds.…”

Section: Introductionmentioning

confidence: 99%

Effects of osmotic preconditioning on nuclear replication activity in seeds of pepper (Capsicum annuum)

Lanteri¹,

Kraak²,

Vos³

et al. 1993

Physiol Plant

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Effects of osmotic preconditioning on nuclear replication activity in seeds of pepper {Capsicum annuum). -Physiol. Plant. 89: 433-440.Flow cytometric determination of nuclear DNA contents in embryos of dry, fully matured pepper seeds revealed only 2C signals. Therefore, pepper belongs to those species in which the quiescent embryo arrests nuclear division in the presynthetic G, phase. In whole seeds, two other peaks were observed which corresponded with the 3C and 6C DNA content and originated from the triploid endosperm. After 36 to 48 h of imbibition in water (48 to 60 h before visible germination), a rise in the 4C signal was observed in the root tip of the embryo. Osmotic preconditioning (priming) of pepper seeds for 7, 14 or 21 days in polyethylene glycol (PEG) or KNO3 + K3PO4 considerably reduced the time to 50% germination (t^,,) and the mean germination time, and the effect was proportional to the duration of the priming treatments. An induction of the 4C signal was firstly observed after 10 days osmopriming in either PEG or KNO3 + K3PO4. For both priming methods, a positive correlation was found between the efficiency of the treatment to reduce the mean germination time, and the induction of DNA synthesis, measured as the amount of 4C versus 2C, at 12 h before radicle protrusion. Apart from the quantitative effect, there was also a temporal influence of priming on DNA synthetic activity. When primed seeds were subsequently imbibed in water,'the induction of DNA synthesis started about 12 h earlier than in untreated seeds. This was also found for seeds primed for 7 days, when no induction of DNA synthesis had yet occurred. Apparently, during priming of pepper seeds there is a lag period of 9 days in which physiological processes other than DNA synthesis can take place. These processes sustain a rapid inception of nuclear replicative activity upon imbibition. By comparing the relative nuclear DNA contents of dry, imbibed and primed seeds, we provide information about the relation between the percentage of cells in seeds which have entered the replication stage of nuclear division, and germination performance. >>

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“…This is observed as high levels of de novo DNA synthesis several hours before entry of cells into S phase and completion of germination, marked by the emergence of the young root (radicle) from the seed coat (17,18). Seeds also can remain in a dormant state in the soil seed bank, often experiencing cycles of hydration and dehydration.…”

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confidence: 99%

DNA damage checkpoint kinase ATM regulates germination and maintains genome stability in seeds

Waterworth

Footitt

Bray

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

113

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Genome integrity is crucial for cellular survival and the faithful transmission of genetic information. The eukaryotic cellular response to DNA damage is orchestrated by the DNA damage checkpoint kinases ATAXIA TELANGIECTASIA MUTATED (ATM) and ATM AND RAD3-RELATED (ATR). Here we identify important physiological roles for these sensor kinases in control of seed germination. We demonstrate that double-strand breaks (DSBs) are rate-limiting for germination. We identify that desiccation tolerant seeds exhibit a striking transcriptional DSB damage response during germination, indicative of high levels of genotoxic stress, which is induced following maturation drying and quiescence. Mutant atr and atm seeds are highly resistant to aging, establishing ATM and ATR as determinants of seed viability. In response to aging, ATM delays germination, whereas atm mutant seeds germinate with extensive chromosomal abnormalities. This identifies ATM as a major factor that controls germination in aged seeds, integrating progression through germination with surveillance of genome integrity. Mechanistically, ATM functions through control of DNA replication in imbibing seeds. ATM signaling is mediated by transcriptional control of the cell cycle inhibitor SIAMESE-RELATED 5, an essential factor required for the aging-induced delay to germination. In the soil seed bank, seeds exhibit increased transcript levels of ATM and ATR, with changes in dormancy and germination potential modulated by environmental signals, including temperature and soil moisture. Collectively, our findings reveal physiological functions for these sensor kinases in linking genome integrity to germination, thereby influencing seed quality, crucial for plant survival in the natural environment and sustainable crop production.DNA repair | seed vigor | DNA damage response | dormancy cycling | soil seed bank M aintenance of genome integrity is indispensable for cellular survival and transmission of genetic information to the next generation; however, constant exposure of DNA to environmental and cellular oxidative stresses results in damage that can arrest growth and result in mutagenesis or cell death. Consequently, organisms have evolved powerful DNA repair and DNA damage signaling mechanisms. In plants, as in other eukaryotes, the cellular response to DNA damage is orchestrated by the phosphoinositide-3-kinase-related protein kinases (PIKKs) ATAXIA TELANGIECTASIA MUTATED (ATM) and ATM AND RAD3-RELATED (ATR) (1). In response to genotoxic stresses, these checkpoint kinases activate DNA repair factors, delay or halt cell cycle progression, and promote endocycles or programmed cell death (1-4). ATM is activated by double-strand DNA breaks (DSBs), a highly toxic form of DNA damage that results in chromosome fragmentation (1, 5), and plants mutated in ATM display hypersensitivity to DSBs induced by gamma radiation or radiomimetics (6). ATM also mediates a strong transcriptional up-regulation of hundreds of genes, including the SIAMESE/SIAMESE-RELATED cell cycle inhibitors ...

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DNA synthesis in osmoprimed leek (Allium porrumL.) seeds and evidence for repair and replication

Cited by 58 publications

References 30 publications

Priming and re-drying improve the survival of mature seeds of Digitalis purpurea during storage

Priming and re-drying improve the survival of mature seeds of Digitalis purpurea during storage

Effects of osmotic preconditioning on nuclear replication activity in seeds of pepper (Capsicum annuum)

DNA damage checkpoint kinase ATM regulates germination and maintains genome stability in seeds

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