Colorectal cancer cell dormancy:An insight into pathways

Cancer cell dormancy(CCD)in colorectal cancer(CRC)poses a significant challenge to effective treatment.In CRC,CCD contributes to tumour recurrence,drug resistance,and amplifying the disease's burden.The molecular mechanisms governing CCD and strategies for eliminating dormant cancer cells remain largely unexplored.Therefore,understanding the molecular mechanisms governing dormancy is crucial for improving patient outcomes and developing targeted therapies.This editorial highlights the complex interplay of signalling pathways and factors involved in colorectal CCD,emphasizing the roles of Hippo/YAP,pluripotent transcription factors such as NANOG,HIF-1αsignalling,and Notch signalling pathways.Additionally,ERK/p38α/β/MAPK pathways,AKT signalling pathway,and Extracellular Matrix Metalloproteinase Inducer,along with some potential less explored pathways such as STAT/p53 switch and canonical and non-canonical Wnt and SMAD signalling,are also involved in promoting colorectal CCD.Highlighting their clinical significance,these findings may offer the potential for identifying key dormancy regulator pathways,improving treatment strategies,surmounting drug resistance,and advancing personalized medicine approaches.Moreover,insights into dormancy mechanisms could lead to the development of predictive biomarkers for identifying patients at risk of recurrence and the tailoring of targeted therapies based on individual dormancy profiles.It is essential to conduct further research into these pathways and their modulation to fully comprehend CRC dormancy mechanisms and enhance patient outcomes.

Whole-genome characterization of CKX genes in Prunus persica and their role in bud dormancy and regrowth

Bud dormancy is a complex physiological process of perennial woody plants living in temperate regions,and it can be affected by various phytohormones.Cytokinin oxidase/dehydrogenases(CKXs)are a group of enzymes essential for maintaining cytokinin homeostasis,yet a comprehensive analysis of these enzymes in peach remains lacking.Here,a total of 51 CKX members from different species,including six from peach,eleven from apple,nine from poplar,seven from Arabidopsis,eight from strawberry,and ten from rice,were identified using the Simple HMM Search tool of TBtools and a BLASTP program and classified into four groups using phylogenetic analysis.Conserved motif and gene structure analysis of these 51 CKX members showed that 10 conserved motifs were identified,and each CKX gene contained at least two introns.Cis-element analysis of PpCKXs showed that all PpCKX genes have light-responsive elements and at least one hormone-responsive element.The changed relative expression levels of six PpCKX genes in peach buds from endodormancy to bud-break were observed by qRT-PCR.Among them,the expression trend of PpCKX6 was almost opposite that of PpEBB1,a positive bud-break regulator in woody plants,around the bud-break stage.Y1H,EMSA,and dual-luciferase assays indicated that PpEBB1negatively regulated PpCKX6 through direct binding to a GCC box-like element located in the promoter region of PpCKX6.In addition,a transient assay showed that overexpression of PpCKX6 delayed the bud-break of peach.These results indicate that the PpCKX genes play an essential role in the dormancy-regrowth process,and Pp CKX6may act downstream of PpEBB1 directly to regulate the bud-break process,which further improves the hormoneregulatory network of dormancy-regrowth of woody plants,and provides new insights for molecular breeding and genetic engineering of peach.

Identification of P-type plasma membrane H^(+)-ATPases in common wheat and characterization of TaHA7 associated with seed dormancy and germination

The P-type plasma membrane(PM)H^(+)-ATPases(HAs)are crucial for plant development,growth,and defense.The HAs have been thoroughly characterized in many different plants.However,despite their importance,the functions of HAs in germination and seed dormancy(SD)have not been validated in wheat.Here,we identified 28 TaHA genes(TaHA1-28)in common wheat,which were divided into five subfamilies.An examination of gene expression in strong-and weak-SD wheat varieties led to the discovery of six candidate genes(TaHA7/-12/-14/-16/-18/-20).Based on a single nucleotide polymorphism(SNP)mutation(C/T)in the TaHA7 coding region,a CAPS marker(HA7)was developed and validated in 168 wheat varieties and 171 Chinese mini-core collections that exhibit diverse germination and SD phenotypes.We further verified the roles of the two allelic variations of TaHA7 in germination and SD using wheat mutants mutagenized with ethyl methane sulphonate(EMS)in‘Jimai 22’and‘Jing 411’backgrounds,and in transgenic Arabidopsis lines.TaHA7 appears to regulate germination and SD by mediating gibberellic acid(GA)and abscisic acid(ABA)signaling,metabolism,and biosynthesis.The results presented here will enable future research regarding the TaHAs in wheat.

Peculiarity of transcriptional and H3K27me3 dynamics during peach bud dormancy

Bud dormancy facilitates the survival of meristems under harsh environmental conditions.To elucidate how molecular responses to chilling accumulation controlling dormancy in peach buds,chromatin immunoprecipitation sequencing to identify the H3K27me3 modifications and RNA sequencing of two peach cultivars with pronounced differences in chilling requirement were carried out,the results showed that genes associated with abscisic acid and gibberellic acid signal pathways play key roles in dormancy regulation.The results demonstrated that peach flower bud differentiation occurred continuously in both cultivars during chilling accumulation,which was correlated with the transcript abundance of key genes involved in phytohormone metabolism and flower bud development under adverse conditions.The more increased strength in high chillingrequirement cultivar along with the chilling accumulation at the genome-wide level.The function of the dormancy-associated MADS-box gene PpDAM6 was identified,which is involved in leaf bud break in peach and flower development in transgenic Nicotiana tabacum(NC89).In addition,PpDAM6 was positively regulated by PpCBF,and the genes of putative dormancy-related and associated with metabolic pathways were proposed.Taken together,these results constituted a theoretical basis for elucidating the regulation of peach bud dormancy transition.

Dormancy of Amaranthus retroflexus L. Seeds and Physiological Response Seedlings to Acifluorfen Sodium

Amaranthus retroflexus L. is a serious and widespread malignant weed in soybean fields in Heilongjiang Province. Exploring the dormancy characteristics of A. retroflexus L. seeds and the physiological response of its seedlings to acifluorfen sodium can provide a basis for further researches on its resistance mechanism. Using newly harvested and stored A. retroflexus L. seeds for one year as experimental materials, the effects of different concentrations of HCl, NaOH, water temperature, gibberellic acid(GA) and polyethylene glycol(PEG) on the dormancy and germination of A. retroflexus L. seeds were studied. The sensitivity of A. retroflexus L.to acifluorfen sodium was determined using bioassay. The effects on leaf chlorophyll content and target enzyme activity were studied at a normal dosage of 360 g a.i. hm^(-2) and a doubling dosage of 720 g a.i. hm^(-2) of acifluorfen sodium. Newly harvested seeds exhibiting dormancy were soaked in water of various temperatures and in different concentrations of NaOH and HCl, which were ineffective in breaking the seed dormancy. GA could break seed dormancy, and the highest seed germination rate reached 93.33% when they were soaked at 3 000 mg·L^(-1) for 72 h and 4 000 mg·L^(-1) for 48 h. The drought stress was simulated with a 15%-25% polyethylene glycol solution, which had no significant effect on the seed germination rate. The GR_(50) value of acifluorfen sodium for A. retroflexus L. was 705.7 g a.i. hm^(-2), which was 1.96 times the recommended dose in the field. After the application of different doses of acifluorfen sodium, the chlorophyll content of A. retroflexus L. reached its minimum value 3 days after treatment(DAT), and then gradually increased. The activity of the target enzyme protoporphyrinogen oxidase(PPO) reached the highest value at 7 DAT under different dosages, and gradually returned to normal levels thereafter. Soaking with gibberellin was an effective method to break seed dormancy. A. retroflexus L. seeds had certain drought resistance during the germination process. A. retroflexus L. was not sensitive to acifluorfen sodium and acifluorfen sodium ether, and could not effectively inhibit the PPO activity, indicating that A. retroflexus L. had target resistance to acifluorfen sodium.

Effect of Different Soak Treatments on Breaking Seed Dormancy in Soil Seed Bank from Different Degraded Grasslands

[Objective] The aim was to study the effect of different soak treatments on breaking seed dormancy in soil seed bank from different degraded grasslands. [Method] Different concentrations of H2SO4,GA3 and KNO3 were used for soaking the seeds in the soil seed bank from different degraded grasslands,and the germination number of seeds was detected. [Result] When the seeds from soil seed bank were soaked with 60%,70%,80% and 90% H2SO4,the germination number of seeds was 0,indicating that the germination of seeds was inhibited; when the seeds were soaked with GA3,the germination number of seeds increased with the concentration of GA3 increasing. When the concentration of GA3 increased to 0.10%,the germination of seeds was inhibited; when the seeds were soaked with 0.2% KNO3,the germination number of seeds was greater than the blank control. [Conclusion] The number of remaining seeds was more in the soil seed banks collected from moderately degraded grassland and heavily degraded grassland; while the number of remaining seeds was small in the soil seed banks collected from lightly degraded grassland and extremely degraded grassland.

Overcoming seed dormancy of mooseer(Allium hirtifolium) through cold stratification,gibberellic acid,and acid scarification

Mooseer （Allium hirtifolium Boiss.） is bulbous perennial herb widely used in pharmaceutical and food industry in Iran. We studied germination of mooseer seeds in two separate experiments. In the first experiment, we evaluated four treatments： sulfuric acid scarification, sandpaper scarification, cold stratification, and gibberellic acid （GA3） application. In the second experiment, we evaluated combinations of these treatments. All treatments in the first experiment had no effect on seed germination, suggesting that mooseer seeds have physical and physiological dormancy. In the second experiment, the highest germina- tion percentage （86.6%） was observed after five minutes scarification with sulfuric acid （75% v/v）, followed by 60 days of cold stratification. Duration of sulfuric acid scarification （5, 10, and 20 min） did not affect germination rates, but increasing duration of cold stratification （from 15 to 60 days）, increased germination from 28.3% to 86.6%. Our study showed that mooseer seeds have both physical and physiological dormancy.

Roles of abscisic acid and gibberellins in maintaining primary and secondary dormancy of Korean pine seeds

Primary dormancy of seeds of Korean pine(Pinus koraiensis Sieb.et Zucc.)after dispersal in the autumn and the induction of secondary dormancy the fi rst summer following seed dispersal limit the regeneration of mixed broadleaved Korean pine forests in Northeast China.This study was to determine how changes in the levels of abscisic acid(ABA)and gibberellic acid(GA)maintain primary and secondary dormancy of Korean pine seeds under germination conditions.We transferred seeds with one of fi ve primary dormancy states or three secondary dormancy states to germination conditions and measured changes in the levels of ABA,GA 1+3(GA 1 and GA 3)and GA 4+7(GA 4 and GA 7)in the seed coat,megagametophyte and embryo during incubation.Seed coat ABA levels in primary dormant seeds(PDS)and ABA levels in various parts of secondary dormant seeds(SDS)gradually declined during incubation but were still higher than in seeds for which dormancy was progressively released.GA 4+7 and GA 1+3 levels in embryos greatly decreased 35%and 24%,respectively,during incubation of SDS,and thus,the ratio of ABA to GA 4+7 in embryos and megagametophytes signifi cantly increased.The ratio of ABA to GA 1+3 in various parts of SDS increased slightly during incubation.In contrast,in seeds for which secondary dormancy was already released,GA 4+7 and GA 1+3 levels in the embryo,GA 4+7/ABA ratio in the embryo and seed coat,and the GA 1+3/ABA in the embryo and megagametophyte signifi cantly increased during incubation.There was no trend in the changes in the levels of ABA,GA 4+7 or GA 1+3 in embryos and megagametophytes of PDS or the levels of GA 4+7 or GA 1+3 in megagametophytes of SDS during incubation.The results suggest that high ABA levels in the seed coat maintain primary dormancy of Korean pine seeds.Maintenance of secondary dormancy involves a reduction of GA 4+7,GA 1+3,GA 4+7/ABA,and GA 1+3/ABA and the retention of high ABA levels.

Insights into Seasonal Dormancy of Perennial Herbaceous Forages

Seasonal dormancy is an adaptive mechanism where plants suspend growth and become physiologically inactive to avoid extreme environmental conditions. Environmental factors like temperature, photoperiod, nutrients, and soil moisture control plant growth and development through various complex molecular mechanisms. Crown and seed dormancy of plants are mostly influenced by day length and temperature. Genes and physiological pathways triggered by these two factors along with genotype variability are some targets to manipulate seasonal dormancy. There is genetic variation in the depth and duration of seasonal dormancy. Therefore, their genetic manipulation is possible. Manipulations of summer and fall dormancy are relatively easier compared to winter dormancy because plants require protection of their apical meristem from freezing temperatures and limited water supply. Genetic factors that regulate seed dormancy may also have regulatory role for seasonal dormancy of the maternal plants. Limited genetic and genomic information are available for seasonal dormancy in herbaceous perennial species. Knowledge of genes controlling seasonal dormancy of eudicots, forest trees, and horticultural crops could be interpolated to explore possible dormancy mechanisms in perennial forages. This study reviews current knowledge of seasonal dormancy of herbaceous forages emphasizing the genetic and physiological context that would be valuable to breeders and plant biologists to expand the production season of perennial species by developing non-dormant and semi-dormant cultivars.

Study on Characters of Hard Seeds of Amphicarpaea edgeworthii Benth. (Leguminosae) and Methods for Breaking Dormancy

[Objective] This study aimed to understand the characters of hard seeds of Amphicarpaea edgeworthii Benth. （Leguminosae） and explore the methods for break- ing dormancy. [Method] For both aerial and subterranean seeds of A. edgeworthii, the morphological characteristics were observed and the appropriate temperature for germination was explored. For aerial seeds of A. edgeworthii, the characters of hard seeds were studied, and concentrated sulfuric acid treatment, hot water soak treat- ment and mechanical damage treatment were compared to explore the methods for breaking seed dormancy. [Result] The aerial seeds were oblate and averaged 3.38 mm in length, 3.02 mm in width, 1.88 mm in thickness, 15.32 g in thousand grain weight, with a hard seed rate after of up to 98% natural maturation. The subter- ranean seeds were approximately oblate with a maximum diameter of 15 mm and a hundred grain weight of （50.08-58.26 g）; among all the treatments for breaking hardseededness, cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods, whereas hot water soak treatment was the least effective method; constant temperature between 20 and 30 ℃ was optimum for the germination of aerial seeds, and alternative temperature of 30/20 ℃ was most appropriate for the germination of subterranean seeds. [Conclusion] Cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods to break the hardseededness of A. edgeworthii.

Analysis of QTL for Seed Dormancy and Their Response to Dry Heat Treatment in Rice (Oryza sativa L.)

Quantitative trait loci (QTL) controlling seed dormancy in rice were identified usingrecombinant inbred lines (RILs) population derived from the cross between a japonicavariety Kinmaze and an indica variety DV85. Seeds of two parental cultivars and each RILwere harvested in 35d after heading. The germination percentage of these seeds at 30℃for 7 days were measured as the degree of seed dormancy. QTL analysis was performed withWindows QTL Cartographer 1.13a program by composite interval mapping. A total of four QTLfor seed dormancy were detected on chromosome 2 (two regions), 5 and 11, respectively.Phenotypic variation explained by each QTL ranged from 8.37 to 17.40%. Responses of suchloci to a dormancy-breaking treatment with dry heat were further detected. The resultsshowed that two alleles of qDOR-2-1 and qDOR-5 from DV85 as well as the allele of qDOR-11 from Kinmaze increased the seed dormancy, which seemed to be easily broken by dry heattreatment. Such loci of seed dormancy may be applied to rice genetic improvement. Theallele of qDOR-2-2 from DV85 increased the seed dormancy, which could not be broken bydry heat treatment.

Development of the Relationship between Angiogenesis and Tumor Dormancy

Tumor dormancy, a complex and still poorly understood phenomenon, has been defined by the long-term persistence of occult can- cer cells during tumor progression. Recurrence and metastasis may occur just because of an activation of a small portion of the tumor cells. In our view, sustained angiogenesis is considered essential in triggering invasive tumor growth. Here we analyze the correlation between angiogenesis and tumor dormancy, the establishment of tumor dormancy models, the imaging strategies and the new biomarkers for dececting microscopic tumors before or during the angiogenic switch. It imperative to understand the role of an- giogenesis in tumor dormancy, as this will accelerate the development of anti-angiogenesis techniques to induce dormancy and/or eradicate dormant disease.

Research Progress of Molecular Regulation Mechanism of Seed Dormancy

Dormancy is the biological adaptation behavior for seed, and it is regulated by many factors. A lot of studies have been done on various aspects of seed dormancy, and the breadth and width of these studies are in constant expanding and deepening. With the wide application of means of quantitative genetics method and mutant in the study on seed dormancy, a large number of quantitative trait loci（QTL） and mutant genes related with dormancy have been identified, which is of great significance for the further revelation of the detail mechanisms of plant seed dormancy and germination. This paper briefly introduced the genetic variation of seed dormancy in recent years, described the inductive formation of plant seed dormancy from the four aspects of dormancy specific gene, chromatin, seed growth development and hormone, and stated the action mechanism of environmental factors on seed dormancy from genetic and molecular levels, as well as the regulation and control mechanism of dormancy release, with the aim to provide certain references for the study on seed dormancy.

OsVP1 activates Sdr4 expression to control rice seed dormancy via the ABA signaling pathway

Pre-harvest sprouting(PHS)is a disadvantageous trait in cereal production worldwide,causing large economic losses each year.Its regulation mechanism is still unclear.We generated the Oryza sativa Viviparous1(OsVP1)mutant using gene editing technique,which shows increased PHS compared with that of the wild type Nipponbare.OsVP1 is localized mainly in the nucleus and expressed in various tissues and organs.Expression of Seed dormancy 4(Sdr4),a key gene controlling PHS,was sharply reduced in OsVP1 mutants.OsVP1 bound to the specific motif CACCTG in the promoter of Sdr4 and activated its expression in rice protoplasts.Overexpression of Sdr4 reduced the high seed germination rate of OsVP1 mutant cr-osvp1-1,showing that Sdr4 acts as a downstream target of OsVP1.Both OsVP1 and Sdr4 loss-of-function mutants were insensitive to exogenous ABA and employed the ABA signaling pathway in regulating seed dormancy.These findings shed light on the control of seed dormancy aimed at preventing PHS in rice.

Changes in the biochemical composition and enzyme activity during dormancy release of Cyclocarya paliurus seeds

Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes in biochemical composition and enzyme activity were investigated during dormancy release. The activities of all the studied enzymes in the stratified seeds increased significantly, compared to those in the control samples. Of the enzymes examined, the activities of protease increased the most （413.8%）, followed by peroxidase （278.7%）, lipase （161.0%）, glucose-6-phosphate dehydrognase （149.1%） and amylase （60.6%） after 8 months of stratification. Crude fat and protein constituted the bulk of the storage reserves in mature seeds of C. pal# urus. Compared with the seeds before stratification, about 45% of the starch, 46% of the protein and 11% of the crude fat were depleted during dormancy release of C. paliurus seeds, while the soluble sugar content was enhanced by 101.5% in the germinating seeds. Correlation analysis showed, during dormancy release of C. paliurus seeds, a close positive relationship between POD and G6PDH activity as well as soluble sugar content and amylase activity, while there was a significant negative relationship between storage substances and their related enzyme activities.

Seed dormancy and germination characteristics of two Rheum species in the Himalaya-Hengduan Mountains

Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the characteristics of seed dormancy and germination in two endemic Rheum species(Rheum nobile and Rheum alexandrae) in the Himalaya-Hengduan Mountains. To determine the type of dormancy,fresh seeds of the two species(one population each) were incubated in light at 25/15 and 15/5℃, and then dry after-ripening(DAR) seeds were incubated on water agar substrate with or without GA_3. To determine the effect of temperature and light on germination, DAR seeds of the two species(two populations each) were incubated both in the light and in the dark at several temperatures, including constant and alternating temperatures. Base temperature(T_b) and thermal times for 50% germination(θ_(50)) were calculated. DAR released physiological dormancy(PD), increasing final germination at 15/5℃ and widening the range of germination temperatures from higher to lower, indicative of type 2 non-deep PD for the two Rheum species. Light had no significant effect on germination of seeds from the two species(two populations each). Seeds of the two species germinated significantly better(>80%) at medium temperatures(10-25℃) than at extreme low(5℃) or high(35℃) temperatures. Alternating temperatures(25/15 and 15/5℃) did not significantly increase the final germination of the two species either in the light and in the dark, but it promoted seed germination more quickly than corresponding constant temperatures in the light in both Rh. alexandrae populations, especially at 15/5℃. Germination in response to temperature was well described by the thermal-time model at suboptimal temperatures. The estimated Tbvalues were 1 and 0.9℃, respectively, in two Rh. nobile populations; 4 and 4.1℃,respectively, in two Rh. alexandrae populations; θ_(50)(thermal time) were 100 and 125℃d, respectively in two Rh. nobile populations; 76.92 and 83.33℃d, respectively in two Rh. alexandrae populations. The dormancy type, and germination responses to temperature and light condition does not explain why the two Rheum species are distributed in contrasting habitats. However, these findings reflect an advantageous germination strategy of these two Rheum species to adapt to the same alpine environments.

An electron microscopic-cytochemical localization of plasma membrane Ca^(2+)-ATPase activity in poplar apical bud cells during the induction of dormancy by short-day photoperiods

Plasma membrane （PM） Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day （SD）-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activity, indicated by the status of cerium phosphate precipitated grains, was localized mainly on the interior face （cytoplasmic side） of the PM when plants were grown under long days and reached a deep dormancy. A few reaction products were also observed on the nuclear envelope.When plant buds were developing dormancy after 28 to 42 d of SD exposure, almost no reaction products were present on the interior face of the PM. In contrast, a large number of cerium phosphate precipitated grains were distributed on the exterior face of the PM. After 70 d of SD exposure, when buds had developed a deep dormancy, the reaction products of Ca2+-ATPase activity again appeared on the interior face of the PM. The results seemed suggesting that two kinds of Ca2+-ATPases may be present on the PM during the SD-induced dormancy in poplar.One is the Ca2+-punlping ATPase, which is located on the interior face of the PM, for maintaining and restoring the Ca2+homeostasis. The other might be an ecto-Ca2+-ATPase, which is located on the exterior face of the PM, for the exocytosis of cell wall materials as suggested by the fact of the cell wall thickening during the dormancy developlnent in poplar.

Effect of different seed treatments on dormancy breaking and germination in three species in arid and semi-arid lands

Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless ,specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of scarification treatments on seed dormancy and germination of Acacia nilotica （L.） Willd. ex Del., Prosopis juliflora （Sw.） DC. ：and Dodonaea viscosa （L.） Jacq. The following treatments were applied： T1, untreated seed （control）; T2, sulphuric acid （97%） for 45 min; T3, boiling water for 5 min. The seeds were cultured on a Murashige and Skoog （MS） medium after sterilization. The responses of seeds to treatments were compared with each other and with the control treatment. Germination was observed daily for a 30-day period. Results indicated positive responses to treatments, while impermeable Seed coats may be responsible for low germination rates in intact seeds as seen experimentally in the untreated control. The highest germination was obtained for P. juliflora and D. viscosa acid-scarified seeds （80.8%-90.8%） and for scarified seeds of A. nilotica （50.2%） boiled in water. The germination indices, i.e., final germination percentage （FG）, mean daily germination （MDG） and germination rate （GR）, were significantly affected by treatments and species （p 〈 0.01）.

Photoperiod-and temperature-mediated control of the ethylene response and winter dormancy induction in Prunus mume

Plant dormancy is essential for perennial plant survival.Different genotypes of Prunus mume,including Eumume group and Apricot Mei group,undergo leaf senescence and dormancy at different times.In order to verify the cold resistance of P.mume,freeze resistance evaluation was carried out.Our results showed that Apricot Mei group had a stronger freezing tolerance than Eumume group and that leaf senescence and dormancy of Apricot Mei group occurred at an earlier period before winter.Based on phenotypic data in response to seasonal climate change,the significant candidate regions were selected using GWAS.Furthermore,through KEGG pathway and qRT-PCR analyses,we found that the ethylene-related genes,including PmEIL(Pm002057)and PmERF(Pm004265),were significantly upregulated in‘Songchun’Mei(Apricot Mei group)and downregulated in‘Zaohua Lve’Mei(Eumume group).Ethylene-related genes expression models showed that ethylene may be indirectly involved in the induction of dormancy.The PmEIL and PmERF genes were the core genes of the ethylene signal transduction pathway and were regulated by the exogenous ACC or PZA compounds.For non-dormant or weekly dormant perennial plants,application of ACC was able to induce plant dormancy and thus enhance cold/freeze tolerance.Overall,the expression of the major ethylene genes played a significant role in dormancy induction and freezing tolerance in P.mume;accordingly,application of ACC and PZA compounds were an effective approach for enhancing cold/freeze of tolerance of woody plant.

Increased BnaMFT-transcript level is associated with secondary dormancy in oilseed rape (Brassica napus L.)

Brassica napus cultivars have little or no primary dormancy;however,they are prone to sec on dary dorma ncy in ducti on.Secondary dormant seeds can produce volunteer plants,which can result in genetic contamination,reduced quality and biosafety issues.However,informati on regarding the molecular mecha nism un derlyi ng sec on dary dormancy is limited.The MOTHER OF FT AND TFL1(MFT)gene,which is evolutionarily conserved in the plant kingdom,acts in a complex gene network in the seed dormancy or germination processes.In this study,we identified four B.napus genes that share high homology with AtMFT,named as BnaMFT.Analyses of c/s-acting elements showed that BnaMFT promoters contain multiple seed-specific regulatory elements,and various stress-and hormone-responsive elements.Further experiments validated that BnaMFTs were specifically expressed during seed maturation and in the dry seed,with peaks at 35-42 days after pollination.BnaMFTs were not sufficient for primary dormancy;however,they were significantly enhanced by secondary dormancy induction with PEG6000 treatment.Moreover,BnaMFTtranscripts were elevated by treatment with abscisic acid(ABA),which is known to be accumulated duri ng sec on dary dorma ncy.These results collectively suggest that increased BnaMFT tra nscription levels are associated with sec on dary dorma ncy inducti on in an ABA-depe ndent mariner in B.napus.