Red Pepper Plants Research Articles

Regulation of Ethylene Biosynthesis Under Salt Stress in Red Pepper (Capsicum annuum L.) by 1-Aminocyclopropane-1-Carboxylic Acid (ACC) Deaminase-producing Halotolerant Bacteria

The present study was carried out to understand the mechanism of salt stress amelioration in red pepper plants by inoculation of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-producing halotolerant bacteria. In general, ethylene production, ACC concentration, ACC synthase (ACS), and ACC oxidase (ACO) enzyme activities increased with increasing levels of salt stress. Treatment with halotolerant bacteria reduced ethylene production by 47–64%, ACC concentration by 47–55% and ACO activity by 18–19% in salt-stressed (150 mmol NaCl) red pepper seedlings compared to uninoculated controls. ACS activity was lower in red pepper seedlings treated with Bacillus aryabhattai RS341 but higher in seedlings treated with Brevibacterium epidermidis RS15 (44%) and Micrococcus yunnanensis RS222 (23%) under salt-stressed conditions as compared to uninoculated controls. A significant increase was recorded in red pepper plant growth under salt stress when treated with ACC deaminase-producing halotolerant bacteria as compared to uninoculated controls. The results of this study collectively suggest that salt stress enhanced ethylene production by increasing enzyme activities of the ethylene biosynthetic pathway. Inoculation with ACC deaminase-producing halotolerant bacteria plays an important role in ethylene metabolism, particularly by reducing the ACC concentration, although a direct effect on reducing ACO activity was also observed. It is suggested that growth promotion in inoculated red pepper plants under inhibitory levels of salt stress is due to ACC deaminase activity present in the halotolerant bacteria.

2007-2008년도 경북 북부지역 고추산지의 병해 발생상황

경상북도 북부지역의 주요 고추 산지를 대상으로 생육기별 발병상황을 조사하고, 수확기 발병상황을 기상 환경 및 재배 방식과 관련하여 분석하였다. 2007년과 2008년에 가장 피해가 심하였던 병은 모자이크병과 탄저병, 역병이었다. 2008년에는 2007년에 비하여 모자이크병 발생이 심하였으며, 그 외의 병 발생은 2007년에 비하여 적었다. 수확기 모자이크병 발생 정도는 5월의 강수량과 부의 상관이 인정되었으며, 8월의 강수량과 9월의 역병 발생 사이에 정의 상관이 인정되었다. 비가림 시설재배 고추에서는 노지재배에 비하여 탄저병과 역병, 모자이크병에 의한 피해가 적었다. 그러나 비가림 시설재배를 하는 고추 재배 농가는 5%에 불과하였다. The disease occurrence on red-pepper plants in relation to cultivation methods of the farmers and to the precipitation was investigated in northern Kyungbuk Province. The major diseases were mosaic, anthracnose and Phytophthora blight in 2007 and 2008. In 2008, mosaic was more severe than that in 2007, but the other diseases were milder than those in 2007. A negative correlation between the mosaic incidence in the harvesting season and the precipitation during May was recognized. On the other hand, there was a positive correlation between the severity of Phytophthora blight in September and the precipitation during August. The occurrence of anthracnose, Phytophthora blight and mosaic in the surveyed pepper plants grown in plastic houses were milder than those in fields, although the farmers cultivating red-pepper plants in the plastic houses were less than 5% in the northern Kyungbuk Province.

고추의 생장에 미치는 Azospirillum brasilense 및 Methylobacterium oryzae 접종 효과

BACKGROUND: Rhizosphere bacteria may improve plant growth and productivity both by supply nutrients and hormonal stimulation. Although many experiments have shown improvements in plant growth with inoculation of bacterial cultures to the rhizosphere, the main obstacle in the applications of plant growth promoting rhizobacteria in a large scale is the inconsistency of the results. We tested the growth promoting effects of Azospirillum and Methylobacterium strains on red pepper plant. METHODS AND RESULTS: Red pepper seedlings were grown for 25 days in a growth media inoculated with A. brasilense CW903 or M. oryzae CBMB20. The seedlings were transplanted and grown for 45 days in pots with soil in a greenhouse, at half the recommended level of fertilizer. Bacterial culture, <TEX>$4.0{\times}10^9$</TEX> for A. brasilense CW903 and <TEX>$5.8{\times}10^8$</TEX> CFU for M. oryzae CBMB20, was applied in root zone soil periodically every 10 days during the experiment. Inoculation of M. oryzae CBMB20 significantly increased the red pepper plant growth in terms of leaf number, height and mass of shoot, or root mass compared to uninoculated control plants. Although beneficial effects of A. brasilense on plant growth of many crops were observed, the growthpromoting effect of A. brasilense CW903 on red pepper plant was not found in this study. CONCLUSION(s): The factors responsible for the irregularities in plant growth promoting of rhizobacteria are difficult to elucidate. Extensive inoculation experiments in the greenhouse and in the field should enable us to define the factors critical to obtain successful application of plant growth promoting rhizobacteria.

Foliar Colonization and Growth Promotion of Red Pepper (Capsicum annuum L.) by Methylobacterium oryzae CBMB20

In order to exploit Methylobacterium oryzae CBMB20 as of plant growth promoting agent, different inoculation methods have been evaluated. The present study aimed to evaluate soil, foliar, and soil+foliar inoculations of M. oryzae CBMB20 to improve the growth, fruit yield, and nutrient uptake of red pepper (Capsicum annuum L.) under greenhouse conditions. The population range of green fluorescent protein (gfp)-tagged M. oryzae CBMB20 using the three inoculation methods was 2.5-2.9 <TEX>${\log}_{10}$</TEX> cfu/g in the rhizosphere and 4.5-6.0 <TEX>${\log}_{10}$</TEX> cfu/g in the phyllosphere of red pepper plants. Confocal laser scanning microscopy results confirmed the colonization of M. oryzae CBMB20 endophytically on leaf surface. Plant height, fruit dry weight, and total biomass were significantly higher (<TEX>$p{\leq}0.05$</TEX>) in all M. oryzae CBMB20 inoculation methods as compared to non-inoculated control. Furthermore, uptake of mineral nutrients such as N, P, K, Ca, and Mg in red pepper plants in all M. oryzae CBMB20 inoculation methods was higher than in non-inoculated control. Comparative results of inoculation methods clearly demonstrated that soil+foliar inoculation of M. oryzae CBMB20 lead to the highest biomass accumulation and nutrient uptake which may be due to its efficient colonization in the red pepper rhizosphere and phyllosphere.

Bacillus subtilis S54 균주를 이용한 고추 역병과 탄저병의 생물학적 방제

Phytophthora blight and anthracnose disease caused by Phytophthora capsici and Collectotrichum gloeosporioides are the most important devastating diseases of red pepper plants, worldwide. Five different bacterial isolates were isolated from the red pepper rhizosphere and non-rhizosphere soil and subsequently tested for antagonistic activity against P. capsisi and C. gloeosporioides. The area of the inhibition zone was taken as a measure for antagonistic activity. Among the 5 isolates tested, S54 exhibited a maximum antagonistic activity under in vitro and in vivo conditions. In greenhouse studies the isolate has successfully reduced the disease symptom. Protect value was 80.8% (Phytophthora blight) and 81.9% (Anthrancnose disease), whereas the infection rate of control plants was 21.3% and 23.2%. Based on the 16S rDNA sequence and API 50CHB Kit analysis the most effective isolate was identified as Bacillus subtilis. The results of the study indicate that the stratin S54 could be used as an potential biological control of Phytophthora blight and anthracnose disease of red pepper.

Enhancement of growth and salt tolerance of red pepper seedlings (Capsicum annuum L.) by regulating stress ethylene synthesis with halotolerant bacteria containing 1-aminocyclopropane-1-carboxylic acid deaminase activity

Three 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-producing halotolerant bacteria were isolated from West Coast soil of Yellow Sea, Incheon, South Korea and evaluated for their efficiency in improving red pepper plant growth under salt stress. The strains RS16, RS656 and RS111 were identified by 16S rRNA gene sequencing as Brevibacterium iodinum, Bacillus licheniformis and Zhihengliuela alba, respectively. Two hour exposure of 100, 150 and 200 mM NaCl stress on 8 day old red pepper seedlings caused 44, 64 and 74% increase ethylene production, while at 150 mM NaCl stress, inoculation of B. licheniformis RS656, Z. alba RS111, and Br. iodinum RS16 reduces ethylene production by 44, 53 and 57%, respectively. Similarly, 3 week old red pepper plants were subjected to salt stress for two weeks and approximately ∼50% reduction in growth recorded at 150 mM NaCl stress compared to negative control whereas bacteria inoculation significantly increase the growth compared to positive control. Salt stress also caused 1.3-fold reduction in the root/shoot dry weight ratio compared to the absence of salt while bacteria inoculation retained the biomass allocation similar to control plants. The salt tolerance index (ratio of biomass of salt stressed to non-stressed plant) was also significantly increased in inoculated plants compared to non-inoculated. Increase nutrient uptakes under salt stress by red pepper further evident that bacteria inoculation ameliorates salt stress effect. In summary, this study indicates that the use of ACC deaminase-producing halotolerant bacteria mitigates the salt stress by reducing salt stress-induced ethylene production on growth of red pepper plants.

Short communication. Phytophthora nicotianae, the causal agent of root and crown rot (Tristeza disease) of red pepper in La Vera region (Cáceres, Spain)

Root and crown rot (Tristeza disease) is an increasing problem for red pepper crop in La Vera region (Cáceres, western Spain). Field surveys were carried on in 2006 and 2007 to identify the causal agents of this disease. A Phytophthora species was isolated from diseased plants in most of the surveyed fields (27 of 36 in 2006 and 15 of 16 in 2007), while Verticillium spp. were not detected. Fifteen Phytophthora isolates were examined and identified as P. nicotianae, all of them were heterothalic isolates of mating type A2. Pathogenicity tests conducted on 'Jaranda' red pepper plants developed symptoms of wilt and root and crown rot, although disease severity differed significantly (P &lt; 0.001) among isolates. Results indicate that P. nicotianae is the principal causal agent of the Tristeza disease of red pepper plants in La Vera region and this has several implications for the development of future disease management strategies. The host range of isolates from red pepper plants should be studied in order to establish suitable crop rotation in this region.

Xenorhabdus nematophilla 유래물질 벤질리덴아세톤의 고추 병해 방제 효과

벤질리덴아세톤은 모노테르펜 화합물로 곤충병원세균인 Xenorhabdus nematophilla K1의 대사물질이다. 본 연구는 벤질리덴아세톤을 이용하여 고추의 두 가지 주요 병해에 대한 방제 가능성이 조사되었다. 벤질리덴아세톤은 역병균 Phytophthora capsici와 탄저병균 Colletotrichum acutatum에 대해 강력한 억제능력을 가지고 있었다. 이러한 벤질리덴아세톤의 항균력은 태양이 비치는 자연조건에서 60일 이상 유지되었으며, 토양수 내에서도 상실되지 않았다. 벤질리덴아세톤을 혼합한 토양에 심겨진 고추 근권토양에 Phytophthora capsici 현탁액을 관주하였을 때, 역병 발생이 크게 감소되었다. 또한 Colletotrichum acutatum에 오염된 고추 열매 표면에 벤질리덴아세톤 용액을 살포하여 탄저병 발생을 억제할 수 있었다. 이러한 결과는 벤질리덴아세톤을 고추 역병과 탄저병 방제용 농약으로 개발할 수 있음을 제시하고 있다. A monoterpenoid benzylideneacetone (BZA) is a bacterial metabolite isolated from culture broth of an entomopathogenic bacterium, Xenorhabdus nematophila K1. It was tested in this study the control efficacy of the metabolite against two major fungal diseases occurring in red-pepper plants. BZA exhibited significant antifungal activities against Phytophthora capsici and Colletotrichum acutatum. Under natural light conditions, the antifungal activity of BZA was maintained for more than sixty days. The antifungal activity of BZA was not lost even in soil because the incidence of Phytophthora blight against red-pepper plants was significantly reduced when the suspensions of P. capsici were poured to the rhizosphere soils mixed with BZA. Application of the BZA suspension spray to the fruit surface infected with C. acutatum significantly suppressed the disease occurrence of anthracnose on the red-pepper plants. These results suggest that BZA can be used to develop a promising agrochemical to control phytophthora blight and anthracnose of redpepper plants.

Potential Use of Elicitors from Trichoderma in Induced Systemic Resistance for the Management of Phytophthora capsici in Red Pepper

Eleven isolates of Trichoderma harzianum were screened for their potential to induce systemic resistance against Phytophthora capsici in red pepper plants. The effect of talc formulations of these eleven isolates on induction of glucanase activity and phenol content was studied. There was a significant increase in glucanase activity in plants treated with Th8 and Th1 (94 and 90 μg glucose released min -1 g -1 ) compared to control (77 μg). Similarly phenol content also increased in plants treated with Th4, Th7 and Th10 (48-59 μg g-1) compared to control (34 μg g -1 ). Cell wall glucan elicitors were extracted from T. harzianum isolate Th10 that had been reported earlier as an efficient biocontrol agent. Treatment with elicitor preparations also induced high glucanase activity (40 μg glucose released min-1 g-1) and increased phenol content (42 μg g -1 ) compared to control where the glucanase activity was 33 μg glucose released min -1 g -1 while phenol content was 27 μg g -1 . Similarly the elicitor treatment as seedling dip reduced P. capsici infection to 23% compared to control (93%). The potential use of ISR eliciting isolates in the biocontrol of P. capsici in red pepper is discussed.

Synergistic Plant Growth Promotion by the Indigenous Auxins-producing PGPR Bacillus subtilis AH18 and Bacillus licheniforims K11

In this study, we invested the synergistic plant promotion ability of red-pepper and tomato by the selected multi-functional PGPR: Bacillus subtilis AH18 and Bacillus licheniformis K11. The both strains of PGPR B. licheniformis K11 and B. subtilis AH18 produced the auxins, antifungal β-glucannase, and siderophores, and were capable of solubilizing insoluble phosphates. The auxins produced by B. subtilis AH18 and B. licheniformis K11 were purified and identified from culture filtrates using PVP column, Sephadex LH-20 column chromatography, HPLC, GC-MS, and 1H-NMR. The purified auxinAH18 was confirmed to have derivatives composed with IAA of MW 175, IBA of MW 203, and IPA of MW 189. The amount ratio of auxinAH18 producing was as follows: IAA:IBA:IPA=1:1.5:2.6. The purified auxinK11 consisted of an IBA of MW 203. B. licheniformis K11 and B. subtilis AH18 stimulated seed germination and root growth of red-pepper, tomato, green onions, and spinach. In particular, red-pepper and tomato plants displayed up to 20% increased root, stem, and leaf growth. When the pots were simultaneously treated with a combination of auxinAH18 and auxinK11, the growth rates of red pepper and tomato plants were over 20% greater than observed with treatment with either auxin alone.

다기능 PGPR 균주들의 기작별 상호보완형 컨소시엄 구성을 통한 고추역병 방제 및 고추생장촉진

본 연구에서는 생물농약용으로 연구 개발된 길항미생물의 균주들을 이용하여 친환경농업용 길항미생물 컨소시엄을 개발하고자 하였으며, 개별 길항미생물의 항생능력, 항진균성 siderophore 및 <TEX>${\beta}$</TEX>-glucannase 생산능, auxin생산능, 인산가용능 등 각 기작별 상호 보완형 미생물균주의 컨소시엄 후보군을 구성하였다. 구성된 컨소시엄 후보군 중 컨소시엄 No. 11이 in vivo pot test에서 가장 좋은 고추생장촉진능과 교추역병 방제능을 발휘하였다. 최적 컨소시엄인 No. 11 컨소시엄내 두 길항미생물인 B. subtilis AH18과 B. licheniformis K11은 기작별 상호보완형으로 모두 auxin생산능, 항진균성siderophore 및 <TEX>${\beta}$</TEX>-glucannase생산능을 가지며, 특히 B. licheniformis K11는 고추역병을 길항하는 항생물질인 iturin을 생산한다. 고추역병방제용 최적컨소시엄 구성균주들간의 상호 비경쟁적 상리공생 여부를 조사하기 위하여 개별균주인 B. subtilis AH18과 B. licheniformis K11을 각각 단독으로 배양한 것과 두 균주를 동시에 접종하여 배양한 것 그리고, 각각 단독으로 배양한 것을 접종시에 혼용하는 것의 3가지 처리를 실시하였다. 그 결과 동시 배양한 것은 각각을 단독을 배양한 것과 비교하였을 때 방제능과 생육촉진능 모두 시너지 효과를 나타내지 않았다. 하지만, 단독배양 후 혼용한 처리구에서는 시너지 효과를 크게 나타내었는데 방제능도 가지면서 뿌리, 줄기, 잎의 생장촉진효과에서 모두 개별 단독배양 후 처리 또는 동시배양 후 처리에서 보다 50% 이상 시너지 효과를 발휘하였다. We found out the new method of the consortium for the environmental friendly agriculture by 8 kinds of the selected antagonistic rhizobacteria. This research involved composition of mutual complementary consortium by each antagonistic function such as production of antibiotic, siderophore, antifungal cellulase and insoluble phosphate solubilization. The consortium No.11 among composed consortium candidates showed the most pepper growth promoting activity and Phytophthora blight suppression on the in vivo pot test of red-pepper plant. The consortium No. 11 is combination of PGPR Bacillus subtilis AH18 and Bacillus licheniformis K11. B. subtilis AH18 and B. licheniformis K11 both could produce the auxin, antifungal <TEX>${\beta}$</TEX>-glucannase and siderophore. Also, they had mechanism for solubilization of insoluble phosphate. But, B. licheniformis K11 could produce the antibiotic of iturin which was able to inhibit Phytophthora capsici. We confirmed complementary noncompetitive mutualism between B. subtilis AH18 and B. licheniformis K11 of the consortium No.11. The results came out through treatment of two strains co-culture, treatment of individual culture and co-treatment of two individual cultures for the growth and Phytophthora blight suppression of red-pepper. The treatment of two strains co-culture didn't show a synergic effect in comparing sole treatment on the pepper growth promotion and Phytophthora blight suppression. But, when the pots were treated simultaneously with co-treatment of two individual cultures, an synergic effect was seen in the growth promotion of roots, stem, leaves and suppressed Phytophthora blight on red-pepper in vivo pot test.

Synergistic effects of inoculating arbuscular mycorrhizal fungi and Methylobacterium oryzae strains on growth and nutrient uptake of red pepper (Capsicum annuum L.)

A greenhouse experiment was conducted to examine the effects of inoculation with two Methylobacterium oryzae strains (CBMB20 and CBMB110) and a consortium of three arbuscular mycorrhizal (AM) fungi on the growth of red pepper (Capsicum annum L.). Inoculation of red pepper plants with the M. oryzae strains resulted in a significant increase in root length and root fresh weight compared to untreated control plants. The combined inoculation of M. oryzae strains and AM fungi significantly increased various plant growth parameters and chlorophyll content compared to uninoculated controls. Mycorrhizal colonisation and the number of AM fungal spores were higher in co-inoculation treatments. In addition, the combined inoculation of M. oryzae strains and AM fungi resulted in significantly higher nitrogen (N) accumulation in the roots and shoots of red pepper plants compared to uninoculated controls. The combined inoculation of M. oryzae strain CBMB110 and AM fungi increased the phosphorus (P) content by 23.3% compared to untreated controls. The micronutrient content of the red pepper plants also increased in most of the inoculation treatments. A perfect mutualism among CBMB100-AMF was found which was attributed to the improved macro- and micronutrient uptake along with higher chlorophyll content in red pepper. Further research on in-depth understanding of the co-operative microbial interactions will facilitate the successful application of Methylobacterium-AM fungi products in biotechnology.

Biological control of Phytophthora blight in red pepper (Capsicum annuum L.) using Bacillus subtilis

Phytophthora blight is one of the most important devastating diseases of red pepper plants. Forty-one bacterial isolates were obtained from rhizosphere soil and subsequently tested for antagonistic activity under in vitro and in vivo conditions. Among the 41 isolates tested, 12 exhibited a maximum antagonistic activity in dual culture assay. These 12 isolates were further screened for disease suppression on red pepper plants in both natural and greenhouse conditions. All the antagonists showed varying levels of antagonism, whereas the isolates R33 and R13 exhibited the maximum (86.8 and 71%) ability to reduce the disease severity in in vivo conditions. Based on the 16S rDNA sequencing, the most effective isolates were identified as Bacillussubtilis. In addition, the isolates were also screened for siderophores, hydrogen cyanide and hydrolytic enzymes. Further, the isolates increased the root and shoot length of the red pepper, which is an added advantage of the isolates while performing the desired function.

Alleviation of low-temperature photoinhibition in gamma-irradiated red pepper (Capsicum annuum L.) plants

We studied the radiation-induced stress resistance in red pepper leaves under conditions of low-temperature photoinhibition or artificially induced photo-oxidative stress. Plants irradiated with 4, 8, or 16-Gy gamma rays were more resistant to both stress factors than were the controls. However, exposure to a low temperature for 12 h with illumination or photo-oxidative treatment for 1 h differentially affected the irradiated leaves, although they had similar stress intensities as defined by their maximal photochemical efficiencies (Fv/Fm). Decreases in Fv/Fm induced by the two stress factors were instead alleviated, dose-dependently, by as much as 22 to 41% (low temperature) or 14 to 29% (photo-oxidation) in the irradiated groups. In contrast, non-photochemical quenching (NPQ) and the de-epoxidation state of xanthophyll cycle pigments could not be correlated with this enhanced stress resistance in the irradiated groups. These results suggest that the adaptive response of plants exposed to gamma radiation is more effective in protecting against low-temperature photoinhibition than against photo-oxidative stress. We also discuss here the involvement of antioxidative defense systems for increased resistance against low-temperature photoinhibition in irradiated red pepper.

Effects ofin Planta gamma-irradiation on growth, photosynthesis, and antioxidative capacity of red pepper (Capsicum annuum L.) plants

We investigated the effects of low-dose inplanta irradiation on red pepper plants treated with gamma rays of 2, 4, 8, and 16 Gy. Growth was stimulated at 2 and 4 Gy but inhibited at 8 and 16 Gy. Photochemical quenching (qP) increased slightly in all treatment groups for 1 d after irradiation (DAl), whereas non-photochemical quenching (NPQ) decreased more noticeably. These changes in qP and NPQ were transient and had almost recovered to the control level by 2 DAl. Although carotenoid pigments also fluctuated during the experimental period, chlorophylls were almost entirely insensitive to the gamma rays. Irradiation also partially protected leaves from a decrease in photochemical efficiency (Fv/Fm) under conditions of UV-B (2.2 W m-2) and high light intensity (800 μmol m-2 s-1). This enhanced stress resistance could be partly explained by higher levels of SOD and APX activities, as well as ascorbate content. Our results demonstrate for the first time that the carotenoid pigments are the most radio-sensitive and fastest recovering compounds in plants, and that SOD, APX, and ascorbate are important inducible factors for improving stress resistance through the use ofin planta gamma-irradiation.

고추 탄저병균의 배양형 변이 그리고 병원성 차이

The dominant isolates of Colletotrichum gloeosporioides from the red pepper anthracnose(both of the diseased plants and debris) was more pathogenic than the isolates of Colletotrichum acutatum of minorly isolated from Gyeong-buk, Korea. There were both of the G and R strains of cultural variants of Colletotrichum gloeosporioides, the G strain was more pathogenic than R strain. The cultivars of red-pepper, cv. `Kumsegi` was the most susceptible and cv. `papet` was the least susceptible in the pathogenicity test. The isolates of Colletotrichum gloeosporioides from other host plant such on sesame, safflower, yam, strawberry could infect to the red pepper plant also.

고추 플러그묘 초기 생육을 촉진시키는 Bacillus amyloliquefaciens MJ-3의 분리 및 상토내 처리 효과

본 연구에서는 가지과 작물의 근권에서 유용한 균주를 분리하고 근권ㆍ길항ㆍ생육촉진미생물을 선별ㆍ제제화하고 상토에 첨가하여 미생물제제 혼입 상토를 제조한 후 고추 플러그묘의 초기 생장에 미치는 영향을 조사하였다. 근권미생물로는 가지과 작물의 뿌리 및 재배 토양 등 385점의 균원시료로부터 540여점을 분리한 후, 가지과 작물에 공통적으로 발생되는 Alternaria solani, Botrytis cinerea, Fusarium oxysporium, Phytophthora capsici, Sclerotinia sclerotiorum 등의 병원균에 높은 길항력을 가진 미생물 20여종을 선발하고, 이들 길항미생물 중에서 고추의 초기 생육을 촉진시키는 MJ-3균주를 최종 선발하였다. 근권ㆍ길항ㆍ생육촉진미생물인 분리주 MJ-3은 Bergey's manual of systematic bacteriology의 방법과 16S rDNA sequence법 등으로 조사하여 Bacillus amyloliquefaciens동정하였다. 제제화한 B. amyloliquefaciens를 상토에 첨하여 미생물 혼입 상토를 제조하였고, 이를 이용하여 재배한 고추 플러그 묘는 초장과 경경, 뿌리길이, 생체중량 등이 모두 대조구에 비해 소량 증가되었으나, 특히 뿌리의 생체중량이 대조구가 0.61g/plant인데 비해 시험구는 0.88g/plant로 44.3% 증가하였다. 미생물제제 첨가 상토에서 재배한 고추의 gib-berellin (GA<TEX>$_1$</TEX>) 함량은 0.559ng/g(건조중량)이었다. The effect of useful rhizobacterium added in bed soil on the early growth promotion of red pepper plug seedlings was investigated. Total 540 colonies of rhizobacteria from 385 samples of eggplant family roots were isolated. Among these, 5 isolates were selected for antifungal activity against pathogenic fungi such as Alternaria solani, Botrytis cinerea, Fusarium oxysporium, Phytophthora capsici, and Sclerotia sclerotiorum. Of all the isolates, MJ-3 having the most pronounced growth-promoting ability for red pepper was finally selected and identified as Bacillus amyloliquefaciens through characterization of biochemical and bacteriological aspects and 16S rDNA sequence. The plant height, stem diameter, root length and fresh weight of red pepper plants which were grown with inoculation of B. amyloliquefaciens MJ-3 were higher than those without inoculation. Especially the root weight of the inoculated red pepper plant increased by 44.3%, the content of endogenous plant hormone (CA<TEX>$_1$</TEX>) being 0.556 ng/g (dry weight).

방사선과 자외선에 대한 고추 식물체 및 배양세포의 생장반응과 Capsidiol 생합성 유전자의 발현 차이

Differential responses of red pepper plant and cultured cells to enhanced <TEX>${\gamma}$</TEX>-ray(<TEX>$^{60}$</TEX> Co) and ultraviolet(UV) stress were investigated. In seed treatment, 1 Gy of <TEX>${\gamma}$</TEX>-ray increased seedling dry weight up to 19.1%, but 50 Gy treatment markedly ingibited seed germination and subsequent growth of seedling. UV treatment to seed did not change the germination ability of seeds and the growth of seedlings regardless of duration of UV treatment until 24 hrs. In case of UV treatment to seedlings, plant injury was seriously progressed even after the seedlings were returned to no UV condition, and eventually all the leaves showed chlorosis by the stress. However, progress of plant injury by <TEX>${\gamma}$</TEX>-ray stress slower than that caused by UV stress, and even at the high dose of <TEX>${\gamma}$</TEX>-ray 50 Gy, did not caused the cholrosis of stressed plant leaf. Amount of electrolytes leakage from plant leaf by UV treatment for 24hrs was increased up to 28.8 folds in comparison with untreated control, whereas that of 50 Gy of <TEX>${\gamma}$</TEX>-ray was increased only 1.2 folds. UV stress induced the production of capsidiol, antimicrobial phytoalexin, by activation of gene expression involved in capsidiol biosynthesis, such as sesquiterpene cyclase and cyclase and cytochrome P450 hydroxylase in the leaf and cultured cell, but <TEX>${\gamma}$</TEX>-ray stress induced neither the production of capsidiol nor expression of the genes.

저선량 γ선 조사가 고추의 광합성과 광 스트레스 경감에 미치는 효과

고추 종자에 저선량 <TEX>$\gamma$</TEX>선을 조사시킨 고추 식물체의 생육과 광합성 능 및 광 스트레스 반응에 미치는 영향을 조사하였다. 저선량 4 Gy가 조사된 고추 식물체에서 광합성에 의한 산소발생이 대조구에 비해 1.5배정도 높은 것으로 나타났다. 고추 잎에 900 <TEX>${\mu}mol/m^2/s$</TEX>의 빛의 세기로 광저해를 4시간 유도하였을 때 최대 광합성능 (Pmax)이 대조구의 경우 20%정도 감소되는 반면 4 Gy 조사구는 3% 정도의 감소를 보였다. Fv/Fm는 광저해가 진행됨에 따라 감소되는 경향을 보이며 대조구의 경우 4시간 처리시 Fv/Fm 값이 50% 정도 감소되는 것을 볼 수 있었다. 반면 4 Gy 조사구는 Fv/Fm값이 대략 37%정도 감소되어 대조구에 비해 광 스트레스에 대해 덜 민감한 것으로 나타났다. Fo는 광저해가 진행됨에 따라 거의 변화가 없었으며 대조구나 4 Gy조사구 사이의 차이도 거의 없는 것으로 나타났다. 광계II의 광양자 수율인 <TEX>$\Phi_{PSII}$</TEX>과 광계II 반응중심에 의한 여기 포획률을 나타내주는 1/Fo-1/Fm 또한 광저해가 진행됨에 따라 감소되었으며 4시간을 처리했을 경우 각각 대조구는 47%, 4 Gy 조사구는 30%의 감소를 볼 수 있었다. 비광화학적 소멸인 NPQ는 광저해가 진행됨에 따라 감소되는 경향을 보였으나 대조구와 4 Gy 조사구간에 차이는 없는 것으로 나타났다. 이러한 결과를 볼 때 종자의 종피를 투과한 저선량의 <TEX>$\gamma$</TEX>선이 식물의 광합성을 증대시키고 동시에 광 스트레스에 대한 저해를 감소시키는 것으로 보인다. The effect of low dose <TEX>$\gamma$</TEX> radiation on photosynthesis and the reduction of photoinhibition in red pepper plant was investigated. The seedling height leaf width and leaf length of pepper were stimulated in plants grown from seeds irradiated with the low dose of 4 Gy. The <TEX>$O_2$</TEX> evolution in the 4 Gy irradiation group was 1.5 times greater than in the control. To investigate the effect of low dose <TEX>$\gamma$</TEX> radiation on response to high light stress, photoinhibition was induced in leaves of pepper by illumination of high light (900 <TEX>$\mu mol/m^2/s$</TEX>). Pmax was decreased with increasing illumination time by 20% in the control, while hardly decreased in the 4 Gy irradiation group. The photochemical yield of PSII, estimated as Fv/Fm, was decreased with increasing illumination time by 50% after 4 hours while Fo did not change. However, Fv/Fm in the 4 Gy irradiation group was decreased by 37% of inhibition, indicating that the photoinhibition was decreased by the low dose <TEX>$\gamma$</TEX> radiation. Changes in the effective quantum yield of PSII, <TEX>$\Phi_{PSII}$</TEX>, and 1/Fo-1/Fm, a measure of the rate constant of excitation trapping by the PSII reaction center, showed similar pattern to Fv/Fm. And NPQ was decreased after photoinhibitory treatment showing no difference between the control and the 4 Gy irradiation group. These results showed the positive effect of low dose <TEX>$\gamma$</TEX> radiation on the seedling growth and the reduction of photoinhibition.

Crop drying programme in Turkey

The present status of agricultural crop drying practices in Turkey is investigated in this study. The emphasis of drying on market value, annual production and export values of some commercially important crops is given in a broad perspective. In the recent years, developing international market conditions in Europe, Middle East, and Central Asia has been encouraging to Turkey's fresh and dry agricultural crop export due to the rapidly increasing internal and external market demands. Grapes, apricots, black tea, figs, red pepper, and l and aromatic plants are the major exported agricultural crops, contributing annually 35 to 40 l of USD$ to Turkey's economics. From the view point of dried crop quality, drying of special crops are still an important topic for the agricultural sector. Traditionally used drying methods have many drawbacks. High air temperatures and relative humidity during the drying season promote the insect and mold development in harvested crops. Furthermore, the intensive solar radiation causes several quality reductions like vitamin losses or color changes in dried crops. Thus, the conventional drying methods do not meet the particular requirements of the related standards. To overcome these problems, producers should be made aware of the fact that the high quality of dried products can be sold to three or four fold prices and directed to the dryer investments. Moreover, the introduction of low cost and locally manufactured dryer offers a promising alternative to reduce the excessive postharvest losses and also improve the economical situation of the farmers.