Search

Peanut allergy is a major cause of food-induced anaphylaxis and subsequent fatality. Food allergies are becoming an increasingly important global health issue. This study was undertaken to verify the effects of peanut sprout extract (PNSE) on the inhibition of allergic and anaphylactic responses using a peanut (PN)-immunized food allergy mouse model. Fresh peanut sprouts were germinated for 0, 3, 5, and 7 days using mature peanuts. Mice were then sensitized to cholera toxin plus PNE or PNSE by intragastric administration on days 0 and 7, and were then challenged with PNE or PNSE on days 21 and 35. After 5 weeks, we examined the mucosal mast cell degranulation, ear swelling, and systemic anaphylaxis stimulated by PNE extract, in comparison with PNSE. Subsequently, Ara h1, a biomarker of PNE allergy; serum levels; and Th1/Th2 cytokine production in supernatants of cultured splenocytes were measured. PNSE treatment significantly attenuated the secretion of anti-Ara h1 antibody, mucosal mast cell degranulation, degree of systemic anaphylaxis, and ear swelling and increased the production of IFN-γ and IL-10, with a decrease in IL-4 secretion. The results of this study show that the allergenicity of PNE could be reduced by germination, which caused downregulation of Th2 lymphocyte activity, systemic anaphylactic response, and mast cell-mediated ear swelling in PNE-sensitized mice.

The popular ornamental plant Petunia is also a valuable model plant in tissue culture. Cellular conversions during differentiation and regeneration have been investigated using various combinations of phytohormones; however, studies on genes for reprogramming toward desired tissue identities have been limited. In this study, we isolated Petunia protoplasts and cultured them in the callus, rooting, or shooting stages, which were used to establish the optimal protoplast culture conditions and to identify genes that epigenetically function as tissue identifiers. The optimal conditions for plasmolysis and enzyme digestion to obtain healthy protoplasts were compared, in which combinations of Viscozyme, Celluclast, and Pectinex (VCP) enzymes were more efficient in isolating protoplasts when followed by 21 to 25% sucrose purification and washing processes. The filtered and washed protoplasts started to divide at 1 day and developed into colonies after 3 weeks of culture, which showed higher efficiency in the Murashige and Skoog (MS) salt culture media compared to that in the Kao and Michayluk (KM) salt media. The pluripotent colonies formed calli on the solid medium supplemented with 3% sucrose after 4 weeks, and were destined to the same cell mass, rooting, or shooting on the regeneration medium. Three epigenetic controllers, ATXR2, ATX4A, and ATX4B, were highly expressed in calli, shoots, and organs of shoots and roots, respectively, confirming that dedifferentiation and regeneration of tissue identity is plastic.

Chinese cabbage is an important dietary source of numerous phytochemicals, including glucosinolates and anthocyanins. The selection and development of elite Chinese cabbage cultivars with favorable traits is hindered by a long breeding cycle, a complex genome structure, and the lack of an efficient plant transformation protocol. Thus, a protoplast transfection-based transformation method may be useful for cell-based breeding and functional studies involving Chinese cabbage plants. In this study, we established an effective method for isolating Chinese cabbage protoplasts, which were then transfected with the pCAMBIA1303 binary vector according to an optimized PEG-based method. More specifically, protoplasts were isolated following a 4 h incubation in a solution comprising 1.5% (v/v) cellulase, 0.25% (v/v) macerozyme, 0.25% (v/v) pectinase, 0.5 M mannitol, 15 mM CaCl2, 25 mM KCl, 0.1% BSA, and 20 mM MES buffer, pH 5.7. This method generated 7.1 × 106 protoplasts, 78% of which were viable. The gfp reporter gene in pCAMBIA1303 was used to determine the transfection efficiency. The Chinese cabbage protoplast transfection rate was highest (68%) when protoplasts were transfected with the 40 μg binary vector for 30 min in a solution containing 40% PEG. The presence of gusA and hptII in the protoplasts was confirmed by PCR. The methods developed in this study would be useful for DNA-free genome editing as well as functional and molecular investigations of Chinese cabbage.

Drought is the primary abiotic stress that limits yield of soybean (Glycine max (L.) Merr.). The study aimed to identify yield-related quantitative trait loci (QTLs) in soybeans using a population of 160 F4-derived lines from ‘Hutcheson’ × PI 471938 crosses, which were cultivated under rain-fed and irrigated conditions. Seed yield was determined based on a total of nine irrigated and five rain-fed environments over two years. Twenty and twenty-seven SSR markers associated with yield (p ≤ 0.05) were identified in the irrigated and rain-fed environments, respectively. Four markers accounted for 22% of the yield variation in the irrigated environments (IR-YLD) and five markers explained 34% of the yield variation in the rain-fed environments (RF-YLD). Two independent IR-YLD and RF-YLD QTLs on chromosome (Chr) 13 (LG-F) were mapped to the Satt395-Sat_074 interval (4.2 cM) and near Sat_375 (3.0 cM), which explained 8% (LOD = 2.6) and 17% (LOD = 5.5) of the yield variation, respectively. The lines homozygous for the Hutcheson allele at the IR-YLD QTL linked to Sat_074 averaged 100 kg ha−1 higher yield than the lines homozygous for the PI 471938 allele. At two independent RF-YLD QTLs on Chr 13 and Chr 17, the lines homozygous for the PI 471938 alleles were 74 to 101 kg ha−1 higher in yield than the lines homozygous for the Hutcheson alleles. Three of the five significant SSR markers associated with RF-YLD were located in a genomic region known for canopy-wilting QTLs, in which the favorable alleles were inherited from PI 471938. The identification of yield-QTLs under the respective rain-fed and irrigated environments provides knowledge regarding differential responses of yield under different irrigation conditions, which will be helpful in developing high-yielding soybean cultivars.

We have developed a cleaved amplified polymorphic sequence (CAPS) marker with the aim of identifying the best species among the different wild Lilium species native to Korea for breeding purpose. The CAPS marker is based on single nucleotide polymorphisms (SNPs) in the nucleotide sequences of the internal transcribed spacer genes, which are widely used in the breeding of angiosperms. We cloned and sequenced the ITS regions of nuclear ribosomal genes from 11 Lilium species and deduced the phylogenetic relationships among them. Phylogenetic analysis based on the maximum likelihood method showed that Lilium species formed a monophyletic clade and were divided into two groups that linked to the two sections, Martagon and Sinomartagon, out of seven sections of Lilium. The lengths of the ITS1 and ITS2 regions in the wild native Lilium species were distinct, and nucleotide polymorphisms were distinguished in these regions. A conserved region in the sequence was found from position 330–340 in all the species. We analyzed the SNP sites and found a suitable restriction endonuclease, Eco52I, having six base pair recognition site, to be suitable for the development of the CAPS marker. Among the 11 Lilium species, only the amplicon from the ITS region of L. hansonii contained the restriction site and produced two distinct bands of around 623 and 268 bp upon digestion with Eco52I. The genotyping of the 11 wild Lilium species by the developed marker can be recommended for breeding programs as it provides an indirect selection of plants and can effectively differentiate wild native lilies. The method using CAPS marker is simple, quick, and highly reliable for identifying the best species for efficient breeding of Lilium.

Camelina [Camelina sativa (L.) Crtz.] of the Brassicaceae family is an annual oilseed crop that has received increasing attention as a biofuel feedstock because of its excellent adaptability to low fertility drylands. Even though moisture is one of the critical factors affecting plant growth and seed yield, genetic studies on response to water deficit in camelina have been limited. This study aimed at identifying camelina genes responding to water deficit and validating their expression pattern. Camelina plants were subjected to 1.9 kPa (well-watered), 4.6 kPa (3 days after water stop), 73.2 kPa (17 days after water stop), and 2.0 kPa (rehydrated) soil water regimes. The transcriptome of test and control plants was analyzed using RNA sequences for de novo sequence assembly followed by gene annotation, which was performed against 39 plant species of the Phytozome database ( http://www.phytozome.net ). Six metabolic novel genes that responded to water deficit in camelina were selected for further analysis: PYRIMIDINE 4, CYP89A9, FASCICLIN-like arabinogalactan, eukaryotic aspartyl protease family protein, photosystem II light harvesting complex gene 2.3, and adenosylmethionine decarboxylase family protein. The expression pattern of these genes obtained by real-time reverse transcription PCR and quantitative reverse transcription PCR analysis were similar to that obtained by transcriptome analysis. The up-regulated genes are known to function in protecting cells against water deficit, whereas the genes with reduced expression were found to be suppressed by lower soil water causing a decrease in their function. The information obtained from the molecular validation of the changes in expression patterns of these six metabolic genes presents insight as to which genes of the camelina may account for actively responding to soil water deficit, which will be target loci for investigating the allelic variations or SNP screening in the camelina germplasm for future breeding program.

Superintendents have used a silicate fertilizer to improve a resistance of turfgrass against several diseases, drought damage and wear stress. This study was conducted to evaluate the effect of liquid fertilizer containing silicate (LFSi) on changes of turfgrass quality and growth by investigating visual quality, chlorophyll content-chlorophyll a, chlorophyll b, and total chlorophyll, root length, shoot length, dry weight of clipping, and nutrient content in leaves tissue. Treatments were designed as follows; control fertilizer (CF), SiF-1 (CF + 1 ml m −2 LFSi), SiF-2 (CF + 2 ml m −2 LFSi), and SiF-3 (CF + 4 ml m −2 LFSi). As compared with CF, soil chemical properties, visual turfgrass quality, chlorophyll content, and dry weight of clipping of LFSi treatments were not significantly. Contrastingly, shoot density, root length, and the content of nitrogen or potassium were increased by application of LFSi. The content of Si in the tissue was positively correlated with potassium content or shoot length, and similarly shoot density positively with chlorophyll content or visual quality, respectively. These results suggested that the application of LFSi improved the turfgrass quality by increasing shoot density or K content in leaf tissue of creeping bentgrass.

The soilborne fungus Fusarium oxysporum f. sp. lilii (Fol) is a serious threat to all lily cultivars, especially infecting bulbs and flowers. It has become increasingly important to develop varieties resistant against the bulb rot disease. Genetic diversity of cultivars and reliable screening methods are required for this purpose. Here, an efficient in vitro screening system for evaluating resistance to Fol in 38 in vitro-grown lily plants was investigated. Various factors including culture conditions of Fol, inoculum density, appropriate plant materials, inoculation method and duration, and incubation period of plant materials after inoculation were combined to optimize the screening method. As a result, we suggest optimal conditions for an in vitro screening system for the selection of Fol-resistant lily cultivars as follows. Fol was grown on potato dextrose agar (PDA) medium for 6 days at 25°C in darkness and used as working inoculation. Spore suspensions were prepared (inoculum density: 1.0 × 10 4 spores‧mL -1 ), and then leaf segments 1.5 × 2.0 cm 2 were inoculated by dipping for 22 hours at 25°C in dark. Later, leaves were cultured on 0.6% agar plates at 25°C and 50% humidity with a photoperiod of 16 hours light/8 hours dark (fluence rate of 40 μmol・m -2 ・s -1 ) to examine the progress of bulb rot. After 7 days, disease levels were classified into indices 1 (no symptom) to 6 (serious bulb rot). Soil inoculation of Fol carried out with resistant or susceptible lily cultivars that had been selected through in vitro screening confirmed the reproducibility of results. Therefore, the in vitro screening method established in this study is efficient and reliable for selection of lily cultivars resistant against bulb rot disease. Additional key words: bulb rot, disease index, disease resistance, Lillium spp. *Corresponding author: hyuns@kribb.re.kr ※ Received 15 May 2015; Revised 6 July 2015; Accepted 16 July 2015. 본 연구는 농림축산식품부・해양수산부・농촌진흥청・산림청 Golden Seed 프로젝트 원예종자사업단의 지원에 의해 이루어진 것임. C 2015 Korean Society for Horticultural Science 서 언 우리나라의 백합은 2013년 통계 기준 전년 대비 7.3% 재 배면적이 감소하였으나 절화 수출액의 32.5%를 차지하는 등 화훼 수출산업에 있어서 중요한 위치를 차지하고 있다 (MAFRA, 2014). 주로 비닐하우스나 온실에서 재배되는 백 합은 그 재배환경으로 인해 뿌리나 구근의 부패병에 많이 노출되어 과다한 농약사용이 문제시되고 있는 것이 현실이 다(Lebiush-Mordechai et al., 2014). 구근으로 번식하는 백 합은 꽃 재배기간뿐만 아니라 구근의 증식, 보관 기간에도 Penicillium sp.와 Fusarium oxysporum f. sp. lilii(Fol)균에 인한 감염으로 절화나 종구의 생산량과 품질에 치명적인 저 하가 발생한다(Loffler and Rumine, 1991). 이 구근부패병은 주로 종구나 지하부 줄기에서 감염이 일어나는데, 연작지 사질토에서 발생이 심하고 주로 토양으로부터 전염이 된다. 구근표면에 갈색 부정형 병반이 생기며, 심하면 구근 전체 Korean J. Hortic. Sci. Technol. 33(6), December 2015 884 가 갈색으로 변하여 썩고, 계속 진전되면 인편이 탈락하게 된다(Komada, 1975). 외관상으로는 아랫잎부터 점차 떨어 져버리고 포기 전체가 죽어가기도 한다. 고사한 줄기의 지 제부위에는 병원체의 균사가 하얗거나 붉은색으로 자라나 있는 것을 볼 수 있다. 주로 정식 전에 토양해충방제를 철저 히 하고 작업 중에 상하지 않도록 하여 상처부위를 통한 침 입을 예방하는 등의 방법으로 피해 정도를 최소화하고 있다. 그러나 이러한 방법보다도 더욱 효율적으로 구근부패병을 방제하기 위해서는 구근부패병에 대한 저항성이 있는 품종 을 선별하여 재배하는 것이 중요하며, 이를 위하여 각 품종 의 구근부패병 저항성 정도를 진단하기 위한 간편하고 민감

Camellia japonica is the most well-known species of the genus Camellia, which is native to Korea, Japan, and China. In this study, the antioxidant and free radical-scavenging activities of petal extracts of Camellia ecotypes with different colors were evaluated. For total phenolic compounds, five ecotypes were grouped into low [(4.8 mg·g−1 of dry weight (DW) GAE (gallic acid equivalent)], medium (6.0–6.2 mg·g−1) and high (19.6 mg·g−1) groups for white, red, and pink colors, respectively. The DPPH radical scavenging activity of the petal extracts, presented as a half maximal inhibitory concentration (IC50), was the greatest (3.8 μg·mL−1) in the pink ecotype and least (43.1 μg·mL−1) in the white ecotype as compared to ascorbic acid (13.6 μg·mL−1). The results demonstrated that the efficient DPPH radical scavenging activity of the pink ecotype was partly due to higher contents of phenolic compounds. Activities of two antioxidant enzymes, catalase and peroxidase, varied among the ecotypes, indicating the presence of ecotype-specific detoxifying processes. Camellia petals had higher amounts of antioxidants as well as excellent reactive oxygen species (ROS) scavenging activities that were dependent on the petal color.

Polymorphic bands of two fine-leaf zoysiagrass mutants (CNU 70-1, CNU 70-2) induced via a gamma-ray irradiation on seeds of Zoysia japonica were obtained by using randomly amplified polymorphic DNA (RAPD) primers. The genotype-specific fragments were then converted into PCR-based sequence characterized amplified region (SCAR) markers, which are now amenable to detecting them among other zoysiagrass species widely noticeable in Korea. The CNU 70-1-specific primer set amplified about 900 bp successfully, while the CNU 70-6 marker produced the expected 1,500 bp band, by which those markers were nominated by CNU 70-1_900 and CNU 70-6_1500 SCARs, respectively. The developed SCAR markers can be an applicable tool in sod industry where illegal appropriation hampers breeder`s right and profits due to the turfgrass plant vegetatively propagating.

About 171 Calanthe species have been reported worldwide. However, only four species and two natural hybrids are known to grow naturally in South Korea. Classification studies of Calanthe orchids using molecular markers have been relatively limited. Therefore, the objectives of this study are to analyze the genetic diversity and relationships of four Calanthe taxa (101 accessions), including C. sieboldii (13 accessions), C. discolor (33), C. × bicolor (54), and C. aristulifera (1), native to South Korea and to identify the potential of each primer combination to discriminate each Calanthe accession using an AFLP technique. Thirty-two AFLP primer pairs produced a total of 2,764 bands, with an average of 86.4 bands per primer pair. Among all bands, 42.3% (1,354 bands), 51.6% (1,652), and 70.0% (2,240) were polymorphic in C. sieboldii, C. discolor, and C. × bicolor, respectively. Calanthe aristulifera was the most distant of the Calanthe taxa, and C. × bicolor, a natural hybrid of C. discolor × C. sieboldii, was more closely related to C. discolor (0.015 of genetic distance) than to C. sieboldii (0.022). Each Calanthe taxon with multiple accessions was divided into two or three groups. Comparisons of gene diversity, polymorphic information content, effective multiplex ratio, marker index, and resolving power proved that resolving power had the best discrimination potential for the 101 Calanthe accessions. These results will help to identify diverse accessions and to develop a breeding program of Calanthe orchids.

Recent development and enlargement of reclaimed lands along the sea shores required to explore alternatives to existing crops, which are suitable to grow well and to declare higher profits. The objectives of this study were to investigate yield-related parameters for development of new leafy vegetables, and to screen some candidates among New Zealand spinach genotypes which were collected in Korea. Initially all the collected genotypes were grown for 7 weeks in a greenhouse of the experiment field in Chungnam National University, and then transplanted into the field to measure morphological or physiological parameters (plant height, branch number, stem diameter, chlorophyll content, and maximum canopy diameter), and yield-related parameters (leaf number, leaf length, leaf width, fresh weight and dry weight). Those parameters were quantitatively measured at 1, 5 or 9 weeks after transplanting (WAT). Parameters exhibiting statistically significant difference among the accessions were plant height, branch number, maximum canopy diameter, chlorophyll content, and leaf length. In contrast to highly correlated parameters with fresh and dry weight obtained in salt-affected soil in the earlier report, fresh weight was correlated significantly with leaf length (r=0.72), leaf width (r=0.64), and canopy diameter(r=0.66), while dry weight was correlated significantly with plant height (r=0.46), leaf length (r=0.72), leaf width (r=0.73), fresh weight (r=0.79), chlorophyll content (r=0.47), and canopy diameter (r=0.87). Based on the significantly correlated with yield parameters, the candidate accessions which were ranked in top statistical groups include CNU06A01, CNU06A13, CNU06A26, CNU06A35, CNU06A38, and CNU06A55. In order to be cultivated in reclaimed lands, it is necessary to screen out salt tolerant accessions among the above high-yielding genotypes.

Rapid establishment by means of seed propagation is cost-effective for Miscanthus species, but the highest biomass-producing Miscanthus used worldwide predominantly is a sterile natural hybrid. Seeded variety and seed propagation will be desirable for extended cultivation of the species, but botanical features and optimal germination conditions of the potential Miscanthus species native to Korea have not been well compared and studied. The ploidy level of M. sinensis, M. sacchariflorus, and M. × giganteus used in this study were estimated to be diploidy, tetraploidy, and triploidy, which can be converted into nuclear DNA contents of 2.75 pg/C, 2.35 pg/C and 2.67 pg/C, respectively. M. sinensis rhizomes are compacted and less branching, while M. sacchariflorus has a broad creeping and thick stemmed rhizomes. Abaxial leaf surface of M. sinensis is densely pilose, but glabrous for M. sacchariflorus, while the leaf sheath of M. sacchariflorus is thickly haired, but hairless for M. sinensis. S pikelets of M. sinensis are awned, but awnless for M. sacchariflorus, which is one remarkable difference between them. When seed germination and seed loss by shattering are considered, the suggested harvest time is at least about 11th week after seed heading initiation. When seeds are not matured enough less than 10 weeks after seed heading, NaOCl treatment seems to damage seeds, resulting in lower seed germination. Compared to immature and less dried Miscanthus seeds, enhanced seed germination with 2% NaOCl, however, was evident for those matured seeds at most of the exposed temperatures ranging from 20 to 35. The greatest germination of 98 and 88% occurred at 30 for M. sinensis and M. sacchariflorus with 2% NaOCl scarification. From the effects of temperature on early growth, seedlings grown at 30 optimized shoot and root length, and fresh and dry weight for both Miscanthus species native to Korea.

This study investigated the effect of exogenous hydrogen peroxide (H₂O₂) on the antioxidant responses and growth of warm-season turfgrass (Zoysia japonica Steud.) and cool-season turfgrass (Poa pratensis L.) subjected to drought stress. Compared with control plants that were not pretreated with H₂O₂, plants pretreated with H₂O₂ had significantly greater fresh and dry weights of shoots and roots, and increased water content. H₂O₂ pretreatments before drought stress significantly decreased the concentrations of malondialdehyde and H₂O₂. DPPH radical scavenging and glutathione activities were significantly increased. The responsive activities of the antioxidant enzymes superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase were also significantly enhanced. Our results suggest that exogenous H₂O₂ could improve the growth of warm-season and cool-season turfgrass under drought stress by increasing the activity of their antioxidant enzymes, while decreasing lipid peroxidation.

Brachypodium, a monocot grass with wide distribution in temperate areas, has been considered a new model plant for many grass species, such as turfgrass or miscanthus, due to its small genome size, self-pollination, rapid life cycle, higher seed yield, and small stature. The objectives of this study were to compare the genetic diversity of natural and artificial populations, and to determine the effects of γ-radiation on genetic variability when evaluated by amplified fragment length polymorphism (AFLP) markers. Two populations used in this study include 66 plant introductions (PI) from the U.S. Department of Agriculture (USDA; POP1), and 43 mutants derived from one of the plant introductions, Bd43 (PI 227011; POP2) treated with a γ-irradiation ranging from 100 to 600 Gy. The highest performance of the phenotypic traits was observed at 200 Gy for germination rate, 100 Gy for height, and 600 Gy for tiller number, implying that the LD50 for determining of optimum dosage depends on the physiological parameters measured. Based on AFLP analysis, POP2 showed higher polymorphism (79.4%), PIC (polymorphism information content; 0.162), and genetic diversity (0.195) than POP1 (59.4%, 0.113, and 0.130, respectively). Those three genetic parameters were evaluated for the mutants derived at various γ-radiation dosages and were found to be the highest when irradiated at 300 Gy. Artificial mutagenesis using γ-radiation improved genetic diversity compared to that of the natural population, and 300 Gy was a useful dosage to enlarge genetic variability in Brachypodium. Results suggest that a dosage maximizing the genetic diversity when evaluated with AFLP markers is an alternative index to LD50 for determining the optimum level for mutation induction.

Among the 400 soybean (Glycine max) landraces, we selected 3 tolerant (KAS150-9, KAS160-15, and KAS170-9) and 3 susceptible lines (KAS160-14, KAS160-20, and KAS201-6-1) by the survival percentage and injury scores. Susceptible lines showed decrease in chlorophyll content and increase in glucose and malondialdehyde (MDA) contents under waterlogging stress, while tolerant lines did not change significantly. For AFLP analysis, 8 EcoRI (+3) and 8 MseI (+3) primers used in 32 primer combinations generated a total of 2 566 bands with a mean of 80 bands per primer combination, of which 1 117 (43.5 %) were clearly polymorphic between the tolerant and susceptible lines. A genetic similarity coefficient, based on cluster analysis using an unweighted pair grouping method of average (UPGMA), was 0.79 for the tolerant group, while the susceptible landraces were genetically less related, with a genetic similarity coefficient of 0.17. The 10 reproducible polymorphic PCR products present in the 3 tolerant or susceptible lines were sequenced and converted into sequence tagged site (STS) markers. These STS primer sets were designated GmWT01-GmWT06 and GmWS01-GmWS04. Two STS primer sets, GmWT06 and GmWS02, generated a single monomorphic PCR product identical in size to the original AFLP fragments. For the broad application of these STS markers in marker-assisted selection (MAS) for soybean genotypes tolerant to waterlogging stress, two developed STS markers are being evaluated with putative waterlogging tolerant mutant lines induced by γ-radiation in soybean mutation breeding programs.

Chrysanthemum (Dendranthema grandiflora) is one of the important cut flowers all over the world as well as in Korea. Dendranthema grandiflora 'Beakma' is a white standard-type cultivar developed in Korea and produces high quality cut flowers throughout the year. However, this cultivar shows hollow stems during high temperature periods in summer. The strength of the stem is decreased and causing extra care in flower handling. The objective of this study was to induce mutations without hollow space in the stem for improvement of quality in Dendranthema grandiflora 'Beakma'. In addition, the effect of radiation was investigated on the survival and growth rate of individuals. A total of 1,679 rooted cuttings were treated with different doses of gamma rays (10-50 Gy). All individuals survived regardless the irradiation-dose but the growth was decreased with an increase of radiation-dose. Particularly, plant height and internode length were remarkably decreased from 2 to 4 times at 40 and 50 Gy. The morphological characteristics of leaves, the leaf length and width were increasingly decreased, and petiole length was increased as increment of dose. The irradiated individuals were repeatedly propagated and one plant was selected as a mutant without hollow space in the stem from a total of 7,109 individual stems. The cuttings from this selected mutant were rooted for propagation and further selection. We conclude that treatment of gamma-ray can be an effective way for indution of exclusive mutations in Dendranthema grandiflora.

In order to evaluate effects of γ-rays on adventitious root formation and ginsenoside production, embryogenic calli induced from cotyledon explants of Panax ginseng C.A. Meyer were treated with γ-rays of 0, 10, 30, 50, 70, and 100 Gy. The highest frequency of adventitious root formation of 75 % occurred at γ-irradiation of 30 Gy, which is considered adequate dosage for selecting mutant cell lines. Five mutated adventitious roots (MAR)3-lines out of the propagation of 142 adventitious root lines treated with 30 Gy were selected based a 100-fold increase in proliferation rate compared to control adventitious roots (CAR) and content of the seven major ginsenosides (Rb1, Rb2, Rc, Rd, Re, Rf, and Rg1) was determined. In the CAR and four of the MAR3-lines (except for MAR3-109), the Rb/Rg ratio was greater than 1.0, thereby indicating altered ginsenoside composition in these root lines. The HPLC analysis of the MAR3-13 and MAR3-26 lines confirmed different ginsenoside profiles, including the three unidentified ginsenoside candidates, Gm1, Gm2, and Gm3. The ginsenosides of the MAR3-13 and MAR3-26 lines showed high hydroxyl and superoxide radical scavenging activities.

5-Methyltryptophan (5MT), a tryptophan analog, resistant M4 rice mutants with high free amino acid contents were obtained through in vitro mutagenesis. To evaluate the 5MT resistance mechanism, a cDNA library was constructed by using the leaves and roots of the 5MT resistant mutant plants. Expressed sequenced tags (ESTs) of 1 019 randomly selected clones were analyzed and then assembled 588 unigens. A total of 389 unigenes had significant homologies with known protein sequences at the NCBI database and the remaining 199 unigenes were designated unidentified genes. These unigens were grouped into 13 categories according to their putative functions. Of the 233 randomly selected clones, 25 were identified as differentially expressed genes between 5MT resistant and 5MT sensitive wild type plants. For further study of the differential expression of the genes, expression patterns of 12 genes related to various biological functions were evaluated in response to 5MT treatment in both the resistant plants and sensitive plants. All of the tested 12 genes exhibited higher expression levels in mutant plants than wild type plants under the 5MT inhibition. These expression patterns of the 12 genes suggested that the genes related to 5MT resistance in the rice mutants have a variety of functions, and yield remarkably diverse expression patterns upon 5MT treatment. Many genes that were identified tend to be related to defense and stress responses, suggesting “cross-talking“ between biotic/abiotic stresses including the 5MT treatment. Therefore, 5MT resistant mutants might be of value for identifying genes related to plant defenses and stresses.

We investigated the structural genes and their transcripts for anthocyanin synthesis inDendranthema grandiflorum ‘Argus’. Color variations in chrysanthemum mutants were obtained through gamm ray irradiation to regenerated plants from anin vitro. Normal florets were pinkish, but the mutants had white or purple ray florets and white, purple, or yellow-green disc florets. Irradiation modified both flower size and the number of ray florets. Compared with the control, levels of total anthocyanins in the mutants ranged from 4 times lower to 6 times higher for the disc florets. This disparity was even more evident, up to 14-fold greater, in the ray florets. Expression of the CHI, F3′H, F3′5′H, DFR, and LDOX genes varied among the mutants, but no dramatic changes were detected in CHS and F3H transcripts in either leaf or floret tissues. Sequence homology to known anthocyanin genes from other plant species was 61 to 84%, 62 to 74%, and 71 to 76% for CHI, F3′H, and LDOX, respectively. Our results support the proposal that such radiation-induced mutations in genes within the anthocyanin pathway are associated with variations in chrysanthemum flower color.

To develop rice (Oryza sativa L.) cultivars to be planted on salt-affected sites, cell lines with enhanced proline content and resistance to growth inhibition by Azetidine-2-carboxylic acid (AZCA), a proline analogue, were screened out among calli irradiated with gamma ray of 50, 70, 90, and 120 Gy. The calli had been derived from embryo culture of the cultivar Donganbyeo. Selected AZCA resistant lines that had high proline accumulation were used as sources for selection of NaCl resistant lines. To determine an optimum concentration for selection of NaCl resistant lines, Donganbyeo seeds were initially cultured on the media containing various NaCl concentrations (0 to 2.5%) for 40 days, and 1.5% NaCl concentration was determined as the optimum concentration. One hundred sixteen salt-tolerant (ST) lines were selected from bulked 20,000 seeds of the AZCA resistant seeds in the medium containing 1.5% NaCl. The putative 33 lines ( generation) considered with salt-tolerance were further analyzed for salt tolerance, amino acid and ion contents, and expression patterns of the salt tolerance-related genes. Out of the 33 lines, 7 lines were confirmed to have superior salt tolerance. Based on growth comparison of the entries, the selected mutant lines exhibited greater shoot length with average 1.5 times, root length with 1.3 times, root numbers with 1.1 times, and fresh weight with 1.5 times than control. Proline contents were increased maximum 20%, 100% and 20% in the leaf, seed and callus, respectively, of the selected lines. Compared to control, amino acid contents of the mutants were 24 to 29%, 49 to 143%, 32 to 60% higher in the leaf, seed and callus, respectively. The ratio of for most of the ST-lines were lower than that of control, ranging from 1.0 to 3.8 for the leaf and 11.5 to 28.5 for the root, while the control had 3.5 and 32.9 in the leaf and root, respectively. The transcription patterns for the P5CS and NHXI genes observed by RT-PCR analysis indicated that these genes were actively expressed under salt stress. The selected mutants will be useful for the development of rice cultivar resistant to salt stress.

This study was to assess selection criteria for salt tolerance in halophytic seashore paspalum (Paspalum vaginatum Swartz) ecotypes, and to determine influence of salinity on water status. Nine seashore paspalums exhibiting the widest range of salinity tolerance were grown in a greenhouse using nutrient/sand culture. Comparative salinity tolerance was determined by measuring shoot, root, and verdure dry weights at six salinity levels (1.2–49.7 dS m−1). Threshold ECw (electrical conductivity of water), ECw50%, ECw25%, and leaf firing (LF50) were also measured. Total water potential (Ψw), solute potential (Ψs), turgor pressure (Ψp), and relative water content (RWC) were determined as measures of water status across salinity levels. Based on the number of times in the top (best) statistical category for growth measurements, SI 93-2 and HI 101 were the most salt-tolerant ecotypes, while Adalayd was least tolerant. Results indicated that comprehensive assessment of salt tolerance using different tissues across salinity levels up to ECw50 were desirable and repeatable in halophytic seashore paspalums. The criteria ECw50%, ECw25%, and LF50 were also useful in ranking of salt tolerance, but threshold ECw was not reliable in halophytic turfgrass. Shoot Ψw and Ψs decreased continuously in all ecotypes as salinity increased. Trends in shoot growth of salt-tolerant SI 93-2 and HI 101 and least tolerant Adalayd paralleled responses of shoot Ψp with the more tolerant ecotypes maintaining more favorable Ψp and growth. Among parameters of water relations, shoot Ψw and Ψp were found to have the largest effects, which accounted for 82% and 22% of variations of shoot and root growth of seashore paspalums, respectively.

Seashore paspalum (Paspalum vaginatum Swartz) is a warm season turfgrass that survives in sand dunes along coastal sites and around brackish ponds or estuaries. The first exposure to salt stress normally occurs in the rhizosphere for persistent turfgrass. Information on diversity in salinity tolerance of seashore paspalums is limited. From Apr. to Oct. 1997, eight seashore paspalum ecotypes (SI 94-1, SI 92, SI 94-2, `Sea Isle 1', `Excalibur', `Sea Isle 2000', `Salam', `Adalayd') and four bermudagrass (Cynodon dactylon × C. transvaalensis Butt-Davy) cultivars (`Tifgreen', `Tifway', `TifSport', `TifEagle') were investigated for levels of salinity tolerance based on root and verdure responses in nutrient/sand culture under greenhouse conditions. Different salt levels (1.1 to 41.1 dS·m-1) were created with sea salt. Measurements were taken for absolute growth at 1.1 (ECw0; electrical conductivity of water), 24.8 (ECw24), 33.1 (ECw 32), and 41.1 dS·m-1 (ECw40), threshold ECw, and ECw for 25% growth reduction from ECw0 growth (ECw25%). Varying levels of salinity tolerance among the 12 entries were observed based on root, verdure, and total plant yield. Ranges of root characteristics were inherent growth (ECw0) = 0.20 to 0.61 g dry weight (DW); growth at ECw24 = 0.11 to 0.47 g; growth at ECw32 = 0.13 to 0.50 g; growth at ECw40 = 0.13 to 0.50 g; threshold ECw = 3.1 to 9.9 dS·m-1; and ECw25% = 23 to 39 dS·m-1. For verdure, ranges were inherent growth at ECw0 = 0.40 to 1.07 g DW; growth at ECw40 = 0.31 to 0.84 g; and ratio of yields at ECw40 to ECw0 = 0.54 to 1.03. Ranges for total growth were inherent growth at ECw0 = 0.72 to 2.66 g DW; growth at ECw24 = 0.55 to 2.23 g; growth at ECw32 = 0.54 to 2.08 g; growth at ECw40 = 0.52 to 1.66 g; threshold ECw = 2.3 to 12.8 dS·m-1; and ECw25% = 16 to 38 dS·m-1. Significant salinity tolerance differences existed among seashore paspalums and bermudagrasses as demonstrated by root, verdure, and total growth measurements. When grasses were ranked across all criteria exhibiting a significant F test based on root, verdure, and total growth, the most tolerant ecotypes were SI 94-1 and SI 92. Salinity tolerance of bermudagrass cultivars was relatively lower than SI 94-1 and SI 92. For assessing salinity tolerance, minimum evaluation criteria must include absolute growth at ECw0 and ECw 40 dS·m-1 for halophytes, but using all significant parameters of root and total yield is recommended for comprehensive evaluation.

Changes in photosynthetic capacity in variable salinity ranges were applied to explore mechanisms of salinity tolerance in seashore paspalum (Paspalum vaginatum Swartz) ecotypes. Nine ecotypes exhibiting a wide range of salinity tolerance were grown in a greenhouse using nutrient/sand culture, with six salinity levels of 1.1–49.7 dS m−1 (denoted as ECw0 to ECw50; electrical conductivity of water). With increasing salinity, chlorophyll concentrations decreased significantly only at ECw50 in comparison with nonsaline control. As salinity increased, initial chlorophyll fluorescence (F0) increased, while maximum fluorescence (Fm) and the variable to maximum fluorescence ratio (Fv/Fm) tended to decrease. As salinity increased, reflectance at visible wavelengths (507–706 nm) was enhanced, whereas it decreased at wavelength ≥760 nm. Compared to Adalayd, more tolerant SI 93-2 and HI 101 exhibited significantly lower reflectance in the photosynthetically active range (PAR), and higher reflectance beyond the PAR. All seashore paspalums maintained active photosynthetic capacity, as indicated by minor reductions in pigments, high light-harvesting capacity, and high maximum photochemical efficiency (high Fv/Fm values of 0.75–0.81) at high salt levels. SI 93-2 and HI 101 were characterized by high Fm and high Fv/Fm at ECw50 with minimal changes with increasing salinity. Also, SI 93-2 and HI 101 exhibited higher density and canopy cover. This resulted in low reflectance, as indicated by significantly higher IR/R (ratio of infrared to red wavelength) and NDVI (normalized difference vegetation index) indexes, and lower stress indexes (Stresses 1 and 2) compared to the least salt-tolerant Adalayd. IR/R and Stress 1 indexes were found to be useful tools for salinity tolerance evaluation, accounting for 85% of shoot and 51% of root growth variations, respectively.

Improving crops through plant breeding, an important approach for sustainable agriculture, has been utilized to increase the yield and quality of foods and other biomaterials for human use. Crops, including cereals, vegetables, ornamental flowers, fruits, and trees, have long been cultivated to produce high-quality products for human consumption. Conventional breeding technologies, such as natural cross-hybridization, mutation induction through physical or chemical mutagenesis, and modern transgenic tools are often used to enhance crop production. However, these breeding methods are sometimes laborious and complicated, especially when attempting to improve desired traits without inducing pleiotropic effects. Recently, targeted genome editing (TGE) technology using engineered nucleases, including meganucleases, zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeat (CRISPR) nucleases, has been used to improve the traits of economically important plants. TGE has emerged as a novel plant-breeding tool that represents an alternative approach to classical breeding, but with higher mutagenic efficiency. Here, we briefly describe the basic principles of TGE and the types of engineered nucleases utilized, along with their advantages and disadvantages. We also discuss their potential use to improve the traits of horticultural crops through genome engineering.