Chinese Cabbage Seedlings Research Articles

알팔파바구미 성충의 밭작물 유식물에 대한 기주선호성

자운영 포장에서 알팔파바구미 성충의 발생양상과 1세대 성충의 밭작물 유식물에 대한 기주선호성을 조사하였다. 자운영 포장에서 포충망에 의한 알팔파바구미의 월동 성충은 3월 하순부터 발생하기 시작하여 4월 중순에 피크를 나타내었으며, 1세대 성충은 4월 하순부터 발생하기 시작하여 5월 하순에 피크를 나타내었다. 하지만 월동 성충의 발생량은 매우 적었고, 1세대 성충의 발생량은 매우 많았으나, 연차간 변이가 심하였다. 온실에서 배추 및 콩 등 11종의 유식물에 대한 알팔파바구미 1세대 성충의 7일 차 발생충수는 배추>콩>케일 순으로 유의하게 많았으며, 조, 땅콩, 기장, 가지 및 상추에서 매우 적었고, 옥수수, 쑥갓, 수수에서는 전혀 발생하지 않았다. 7일 차 유식물의 피해주율도 배추(60.0%)>콩(50.0%)>케일(30.0%)>조(16.7%), 기장(13.3%)>상추(3.3%) 순으로 유의하게 심하였다. 한편, 자운영포장에서 11종의 유식물에 대한 7일 차 피해주율은 배추(46.7%), 콩(43.3%)>케일(23.3%)>조(13.3%), 기장(13.3%) 순으로 유의하게 심하여 온실에서의 결과와 같은 경향을 나타내었다. 따라서 알팔파바구미의 기주선호성은 녹비작물포장 주변에서 밭작물의 안전한 재배를 위한 작물선택의 참고자료로 활용될 수 있을 것이다. Occurrence of adult alfalfa weevil, Hypera postica Gyllenhal, was observed at Chinese milk vetch field, and host plant preference of its <TEX>$1^{st}$</TEX> generation adult was observed at greenhouse and Chinese milk vetch field. The over-wintered adult of the weevil appeared from late March and peaked in mid April while the <TEX>$1^{st}$</TEX> generation adult appeared from late April and peaked in late May. However, the occurrence of over-wintered adult was very low contrary to the <TEX>$1^{st}$</TEX> generation adult which was very high with some variations among observed years. In greenhouse, host plant preference of <TEX>$1^{st}$</TEX> adult generation of H. postica was evaluated with 11 different seedlings. H. postica was found to occur in significantly higher number on Chinese cabbage seedling followed by soybean, and kale at 7 days after releasing(DAR). Corn, crown daisy and sorghum were found to be the least preferred with nil occurrence of the weevil. Seedlings damage rate by H. postica feeding at 7DAR was the most severe on Chinese cabbage(60.0%) followed by soybean(50.0%), kale(30.0%), foxtail millet(16.7%), proso millet(13.3%) and lettuce(3.3%) significantly. Also, seedlings damage rate by H. postica at 7DAR in Chinese milk vetch field had shown the similar trend with Chinese cabbage(46.7%), soybean(43.3%), kale(23.3%), foxtail millet(13.3%) and proso millet(13.3%) in greenhouse significantly. Accordingly, results on host plant preference of H. postica from this study can be used as a basic information for safe cultivation of upland crops at near or around green manure crop field.

LED 광원의 다양한 광질이 배추 유묘의 유전자 발현에 미치는 영향

광은 모든 살아 있는 세포에 있어서 매우 중요한 신호이며 생물체에게 이익이 되면서 동시에 해가 되기도 하는데, 광 환경에 잘 적응한 유기체는 자연에서의 경쟁에서 더 잘 살아남을 수 있다. 광질과 식물 생육에 대한 정보는 LED와 같은 인공광을 효율적으로 사용하게 하여 경제적인 손실을 줄일 수 있다. 초기 1주 동안 단일 광파장에 노출된 배추 유묘의 생장을 보면 백색광 조건에서 생장한 묘와 비교했을 때 적색광과 청색광 조건에서는 유묘의 발달과 생육이 정상이었다. 암조건에서 자란 유묘는 하배축이 길고 황화된 반면, 초적외광 조건에서 자란 유묘는 황화되었으나 하배축이 거의 신장하지 않았다. 마이크로어레이를 이용하여 유전자 대량 발현분석 실험을 수행한 결과, 청색광 조건에서 유묘의 생육이 가장 왕성하였으며 적색광 조건과 비교하여 발현변화를 보인 유전자의 수가 2배 많았다. 각각의 광질 조건에서 발현 증가 된 유전자들을 기능별로 분류해 보면(GO 분석) 적색광과 청색광은 생물학적 과정(biological process)과 관련된 유전자의 발현에 영향을 많이 주었다. 특히 대사과정(metabolic process)과 발달과정(developmental process) 그리고 세포 요소(cellular component) 중 색소체(plastid)나 엽록체(chloroplast)관련 유전자들의 발현이 청색광 조건에서 더 많이 증가하였다. 또한 초적외광 조건에서도 다양한 유전자들이 발현 변화를 보였다. 본 논문은 다양한 배추 유묘의 생장에 대한 광질의 영향을 분자생물학적으로 증명하기 위해 수행되었으며 유묘의 배양에 LED 광원이 효율적으로 이용될 수 있음을 보여 주었다. Light with two faces, beneficial and harmful effects is an important signal for every living cell. Optimal adaptation to light environment enhances the fitness of an organism and survival in nature. Understandings of light quality and plant growth provide with the economical guides for artificial light sources like LEDs. Compared with those under white light, the 1 week seedlings of Chinese cabbage (Brassica rapa) under monochromic red and blue light showed normal development and growth. In contrast to extremely long and etiolated hypocotyls of the seedlings under dark, those under far-red etiolated were extremely short. Based on the microarray analysis, blue light induced the vigorous development and growth and two fold changes of transcripts than red light condition. To have insight of gene products under different light qualities conditions, GO term enrichments were calculated and each gene according to their GO terms were categorized. The blue and red lights affected the expressions of genes related to biological process. Especially, the genes related to metabolic process and developmental process and plastid and chloroplast in the cellular component category were induced under blue light. This study provided the molecular biological evidence for various light qualities on the growing process of B. rapa.

The maturation zone is an important target of Piriformospora indica in Chinese cabbage roots

The mutualistic symbiont Piriformospora indica exhibits a great potential in agriculture. The interaction between P. indica and Chinese cabbage (Brassica campestris cv. Chinensis) results in growth and biomass promotion of the host plant and in particular in root hair development. The resulting highly bushy root phenotype of colonized Chinese cabbage seedlings differs substantially from reports of other plant species, which prompted the more detailed study of this symbiosis. A large-scale expressed sequence tag (EST) data set was obtained from a double-subtractive EST library, by subtracting the cDNAs of Chinese cabbage root tissue and of P. indica mycelium from those of P. indica-colonized root tissue. The analysis revealed ~700 unique genes rooted in 141 clusters and 559 singles. A total of 66% of the sequences could be annotated in the NCBI GenBank. Genes which are stimulated by P. indica are involved in various types of transport, carbohydrate metabolism, auxin signalling, cell wall metabolism, and root development, including the root hair-forming phosphoinositide phosphatase 4. For 20 key genes, induction by fungal colonization was confirmed kinetically during the interaction by real-time reverse transcription–PCR. Moreover, the auxin concentration increases transiently after exposure of the roots to P. indica. Microscopic analyses demonstrated that the development of the root maturation zone is the major target of P. indica in Chinese cabbage. Taken together, the symbiotic interaction between Chinese cabbage and P. indica is a novel model to study root growth promotion which, in turn, is important for agriculture and plant biotechnology.

CHARACTERIZATION AND DISTRIBUTION OF DILATED CISTERNAE OF THE ENDOPLASMIC RETICULUM IN INTACT PLANTS, PROTOPLASTS, AND CALLI OF BRASSICACEAE

ABSTRACT The characteristics, occurrence, arid distribution of dilated cisternae (DC) of the rough endoplasmic reticulum (r-ER) in different plant organs of 24 species from three Rhoeadales families were examined by transmission electron microscopy. A typical cisterna originates from a dilation of the r-ER and contains a homogeneous, moderately dense material. The appearance of the cisternal content varies with the development of the cell and ranges from an electron-dense homogeneous matrix, via accumulations consisting of tightly packed longitudinally oriented rods or tubules, to vacuolar-like inclusions which eventually lose the attached ribosomes. The occurrence of DC was followed up in detail in different parts of the seedlings of Chinese cabbage (Brassica chinensis L.) 24 h, 48 h, and 72 h after germination. DC were not found in meristematic cells or cells undergoing differentiation, but appeared in more mature cells. Their number and size increased with the age and the development of the cell. DC we...

English

This study demonstrates the isolation and characterization of cDNA encoding a phosphoinositide phosphatase (PIP) from a stem cell cDNA library of Chinese cabbage ( Brassica rapa ) seedling. The full length gene ( BrSAC1 ; GenBank accession no., GU434275) contained 1999 base pairs (bp), with an open reading frame of 1785 bp, encoding a polypeptide of 594 amino acids with a predicted molecular weight of 65 kDa, including a putative N-terminal signal peptide (the signal peptide counted within the 594 residues). Other regions found within the sequence include a conserved KXKXX COPI-binding motif and a consensus Cx5R (T/S) catalytic motif. BrSAC1 protein shares 92% identity with AtSac1B, and 86% identity with AtRHD4 at the amino acid level. Gene expression analyses revealed that BrsSAC1 was constitutively expressed at high levels in the pistil, stamen and flower bud, whereas it was expressed at low levels in the leaf and stem. In addition to injury, BrSAC1 expression was also induced in response to different types of stress condition, namely cold, desiccation, salt, submergence, abscisic acid and heavy metals. Overexpression of BrSAC1 in transgenic tobacco conferred tolerance to cold, dehydration, and salt stress at the seed germination/seedling stage as reflected by the percentage of germination/green seedlings, the fresh weight of seedlings and their development pattern. Our data suggest that BrSAC1 is an important stress response determinant in plants. Keywords: Abiotic stress, Brassica rapa , phosphoinositide phosphatase, transgenic plant African Journal of Biotechnology Vol. 12(15), pp. 1782-1792

Produção agroecológica de mudas e desenvolvimento a campo de couve-chinesa

O trabalho foi desenvolvido em duas etapas: a produção de mudas de couve-chinesa em bandejas e posterior transplante para o campo, objetivando avaliar o desempenho de diferentes substratos sobre o desenvolvimento da cultura. Para isso determinou-se, tanto na fase de formação das mudas, quanto nas plantas adultas, o comprimento da parte aérea, número de folhas, comprimento da raiz, massa seca da parte aérea, massa seca da raiz e diâmetro do coleto. A etapa de produção de mudas foi conduzida em ambiente protegido, com os seguintes tratamentos: T0 substrato comercial Plantmax® (HA); T1: 100% composto; T2: 95% composto + 2,5% areia + 2,5% pó de rocha; T3: 90% composto + 3% areia + 7% de pó de rocha e T4: 85% composto + 6% areia + 9% pó de rocha. Na produção de mudas, os substratos orgânicos, formulados com 100% e 85% composto, apresentaram melhores resultados, aos 15 e 28 DAS, respectivamente. Os resultados de campo demonstraram que adição de pó de rocha é um fator determinante no desempenho das mudas, sendo os melhores resultados obtidos nas parcelas cultivadas com mudas obtidas nos substratos formulados com 7 e 9% de pó de basalto.

Influence of stress hormones on the auxin homeostasis in Brassica rapa seedlings

KEY MESSAGE : Stress hormones, particularly jasmonic acid, influenced root growth, auxin levels, and transcription of auxin amidohydrolase BrIAR3 in Brassica rapa seedlings, while auxin conjugate synthetases BrGH3.1 and BrGH3.9 were down-regulated by all treatments. The influence of stress hormones: jasmonic acid (JA), salicylic acid (SA), and abscisic acid (ABA) on 1-day-old seedlings of Chinese cabbage (Brassica rapa L. ssp. pekinensis) was investigated with particular focus on auxin levels and the regulation of reversible auxin conjugation as a mechanism of auxin homeostasis. At the physiological level, stress hormones inhibited root growth, where JA was the most prominent inhibitor with an IC50 value 3.1μM, which is one and two orders of magnitude lower than that found for ABA and SA, respectively. JA treatment significantly increased the total auxin content, by induction of free and conjugated forms. Also, the stress hormones affected the transcription of genes involved in the process of the reversible auxin conjugation: auxin amidohydrolases BrIAR3 and BrILL2, and auxin conjugate synthetases BrGH3.1 and BrGH3.9. JA treatment increased the transcript level of BrIAR3 two-fold, while it did not affect the transcription of BrILL2. SA and ABA down-regulated the transcription of both auxin amidohydrolase genes by 30%. Transcription of both auxin conjugate synthetases was significantly down-regulated by all treatments by 30-70%. Among the investigated biochemical stress markers, glutathione along with protein carbonylation appeared the most affected upon treatments. The redox status of the seedlings was shifted to the more oxidized state upon JA and ABA treatments, whereas SA caused more reduced redox state in comparison to the control. The principal component analysis visualized relationship among auxin and stress parameters upon treatments. Accordingly, the role of auxin in stress response of Brassica seedlings was discussed.

Pseudosigmoidea ibarakiensis sp. nov., a dark septate endophytic fungus from a cedar forest in Ibaraki, Japan.

A dark septate fungus of Pseudosigmoidea, Hyphomycetes, was recovered from forest soil in Ibaraki prefecture, Japan. The isolate is characterized by pale to brown conidia with up to 8 septa measuring 68–132 × 4–7.9 μm. It is also unique in producing conidia borne by long conidogenious cells in agar medium with or without water, compared to P. cranei, which must be immersed in water to sporulate. Morphological analysis indicated that the isolate is distinct from P. cranei and is described as a new species, P. ibarakiensis sp. nov. Pathogenicity tests of Chinese cabbage and cucumber seedlings indicated that the fungus grows as an endophyte and colonizes, inter and intracellularly, the root epidermal and cortical layers without causing apparent disease symptoms in the host. This endophyte showed the ability to support cucumber plant growth under conditions where NaNO3 was replaced by organic nitrogen but also conferred to Chinese cabbage the ability to grow at low pH. It also became successfully established in six other plants, including the Brassicae, Solanaceae, Poaceae, and Liliacea families, suggesting its adaptability to a broad range of host plants.

Isolation and functional characterization of BrUGT gene encoding a UDP-glycosyltransferase from Chinese cabbage (Brassica rapa)

Glycosyltransferases are enzymes (EC 2.4) that catalyze the transfer of monosaccharide moieties from activated nucleotide sugar to a glycosyl acceptor molecule which can be a carbohydrate, glycoside, oligosaccharide, or a polysaccharide. In this study, a UDP-glucosyltransferase cDNA was isolated from Brassica rapa using a rapid amplification of cDNA ends (RACE) and subsequently named BrUGT. It has a full-length cDNA of 1,236 bp with 119 bp 5'-untranslated region (UTR), a complete ORF of 834 bp encoding a polypeptide of 277 amino acids (31.19 kDa) and a 3'-UTR of 283 bp. BLASTX analysis hits a catalytic domain of Glycos_transf_1 super family (cl12012) that belongs to the Glycosyltransferases group 1 with tetratricopeptide (TPR) regions located between 165 to 350 bp. Expression analysis showed high mRNA transcripts in pistil, followed by petal, seed and calyx of flower. Moreover, expression analysis of BrUGT in Chinese cabbage seedlings under stresses of cold, salt, PEG, <TEX>$H_2O_2$</TEX>, drought and ABA showed elevated mRNA transcript. Furthermore, when BrUGT gene was transformed into rice using pUbi-1 promoter, overexpression was evident among the <TEX>$T_1$</TEX> plants. This study provides insights into the function of BrUGT in plants.

Flavobacterium hercynium EPB-C313 균주를 이용한 배추 뿌리혹병 생물적 방제

Plasmodiophora brassicae에 의한 배추 뿌리혹병은 배추뿐만 아니라 순무, 양배추에 발병하여 큰 피해를 주는 병원균이다. 배추 뿌리혹병균에 길항효과가 있는 미생물을 선발하기 위하여 배추 조직에서 분리한 Flavobacterium hercynium EPB-C313 균주의 항균활성 검정을 하였고, 포장시험을 통하여 배추 뿌리혹병에 대한 방제효과를 조사하였다. F. hercynium EPB-C313의 균체, 배양액, 배양여액를 배추 뿌리혹병 휴면포자와 혼합 처리하여 24시간 후 조사하였을 때 각각 90.4%, 36.8% 및 26.0%의 휴면포자가 불활성화 되었다. 온실 포트검정에서는 배추의 어린묘를 F. hercynium EPB-C313 배양액에 침지한 후 정식하면 뿌리혹 형성 억제율이 100%로 대조약제 fluazinam액상수 화제의 91.7%보다 우수한 효과를 나타내었다. 배추 뿌리혹병이 50% 이상 발병되었던 재배포장에 F. hercynium EPB-C313 혼합펠렛을 토양혼화 하고, F. hercynium EPBC313 배양액의 유묘관주 및 정식 10일 후 1회 토양관주하면 63.7%의 방제효과를 보였다. 이상의 결과로 볼 때 F. hercynium EPB-C313 균주는 매우 유용한 배추 뿌리혹병 생물적 방제제로 판단된다. Clubroot of Chinese cabbage by Plasmodiophora brassicae, was found to be high virulent to the Chinese cabbage, turnips and cabbage. It this study, the endophytic bacteria Flavobacterium hercynium EPB-C313, which was isolated from tissues of Chinese cabbage, was investigated the antimicrobial activity on the inactivation of resting spores and its control effect on clubroot disease by bioassay. The bacterial cells, culture solutions, and culture filtrates of F. hercynium EPB-C313 inactivate the resting spores of P. brassicae with 90.4, 36.8, and 26.0%, respectively. The clubroot was inhibited with 100% by dipping the seedlings of Chinese cabbage in culture solutions of F. hercynium EPB-C313 before planting, however the chemmical 'fluazinam' was 91.7% in pot tests. Complex treatment were highly enhanced control efficacy with 63.7% at field of 50% diseased plants by soil incorporation with the pellet contains organic matter and F. hercynium EPB-C313, seedling drench of culture solution of F. hercynium EPB-C313 and soil drench with 10 days after planting. These results imply that the F. hercynium EPB-C313 is a very useful biological control agent of clubroot disease of Chinese cabbage.

First Report of Damping-off Caused by Alternaria japonica on Chinese Cabbage Seedlings in China.

In May 2011, samples of Chinese cabbage (Brassica campestris L. subsp. chinensis Markino) seedlings at the two-to four-leaf stage with damping-off symptoms were collected from greenhouses in the Tibet Autonomous Region of China. Infected stems of the seedlings were constricted at or near the soil surface. On diseased stems, a light to dark brown coloration was demarcated from healthy tissue. Damping-off and death of seedlings occurred as the lesions enlarged, resulting in a significant reduction of seedlings. Diseased stems were cut into 3-mm-long segments, surface-sterilized with 3.5% sodium hypochlorite for 1 min, and rinsed in sterilized water three times before being placed on water agar. A fungus frequently isolated from diseased plants was hyphal tipped under a dissecting microscope and transferred onto potato dextrose agar (PDA) to obtain a pure culture. The isolate grew slowly on PDA at 25°C with a 12-h photoperiod. The colony was white at first and gradually turned gray or grayish-green. No conidia or chlamydospores developed. However, conidia were produced on potato-carrot agar. Conidia were yellow-brown, obpyriform or obpyriform with beaks, had two to eight transverse septa, one to three vertical or oblique septa, and were produced solitarily or often in chains of two or three and measured 43.5 to 85.2 × 21.5 to 28.0 μm. A few conidia without beaks were also present and were nearly round and slightly smaller than the conidia with beaks. Several adjacent chlamydospores with thickened walls were often intercalary. The isolate was tentatively identified as Alternaria japonica based on its morphological characteristics (1,2). For molecular analyses, the internal transcribed spacer (ITS) regions of ribosomal DNA from the isolate were amplified with universal primers ITS1 and ITS4. The resulting sequence (Accession No. JN654465) submitted to GenBank had a 99% identity to that of A. japonica (Accession No. AY154703.1) isolated from leaves of Raphanus sativus. To confirm the pathogenicity of A. japonica, nine healthy 10-day-old Chinese cabbage seedlings were inoculated at the stem base with one PDA plug from a 6-day-old culture, with nine noninoculated (PDA plus only) seedlings serving as controls. Two days after inoculation, symptoms similar to those on the naturally infected plants developed on the inoculated seedlings. No symptoms developed on the controls. The pathogen was reisolated from the stems of inoculated and diseased seedlings. To our knowledge, this is the first report of A. japonica leading to damping off on Chinese cabbage seedlings in China.

Effects of Different Light Sources on the Growth of Non-heading Chinese Cabbage (Brassica campestris L.)

To date, little is known about the effects of different light sources on the growth and quality of non-heading Chinese cabbage (Brassica campestris L.). The objective of present study was to evaluate the effects of light-emitting diodes (LEDs) light sources (blue, blue plus red, red), fluorescent lamps and sunlight on growth and vitamin C, soluble protein, sucrose, soluble sugar, starch and pigment concentrations in non-heading Chinese cabbage seedlings. The dry mass of shoots and the fresh and dry masses of roots were highest in seedlings grown under red LEDs with weak lights. The fresh mass of roots and starch concentration were highest under red LEDs despite of the altered photosynthetic photo flux density (PPFD) levels. The concentrations of chlorophylls and vitamin C were greatest under blue LEDs with altered PPFD levels. The numbers of flower buds and open flowers were highest under red LEDs and blue plus red LEDs and were higher under LEDs than fluorescent lamps. The duration of flowering was highest under red LEDs and blue plus red LEDs. The present results demonstrate that LED light sources are more effective than fluorescent lamps for vegetative and reproductive growth of non-heading Chinese cabbage. Moreover, blue LEDs benefit vegetative growth, while red LEDs and blue plus red LEDs support reproductive growth in non-heading Chinese cabbage. In the artificial cultivation and subsequent transplanting of the life cycle of plants, the light source can be selected to meet the requirements of different growth stages of plants and be used to promote the subsequent process in the industrial production of non-heading Chinese cabbage.

First Report of a Root and Crown Disease of the Invasive Weed Lepidium draba Caused by Phoma macrostoma.

The exotic rangeland perennial Lepidium draba occurs as a noxious weed in 22 states, mostly in the western United States. Because chemical control measures against this invasive perennial, a member of the Brassicaceae, have not achieved adequate results, biological control is being pursued. While inventories of arthropods that feed on L. draba have been established, little is known of soilborne pathogens for possible use as biological control agents. To address this deficiency, we have surveyed for diseases of L. draba in the United States and Eurasia to identify and test potential biocontrol agents. In intensive surveys for soilborne diseases in a single infestation that is >20 years old in a cattle pasture in south-central Montana, several chlorotic, stunted plants were noted. Roots of chlorotic plants that exhibited elongated fissures from which other soilborne fungi were isolated also had numerous prominent pycnidia embedded in the crown tissue above the lesions. Examination with a dissecting microscope revealed large ostioles made evident by the wide concave inversions in the short necks of the pycnidia. Culture of root tissue on potato dextrose agar resulted in whitish, becoming pale gray colonies, with a dull peach-to-reddish tinge at the margins, with abundant single pycnidia. Conidia in vitro were mainly unicellular, variable shape, subglobose to ellipsoidal, with several guttules averaging 6 × 2.5 μm. These morphological traits are characteristic of Phoma macrostoma, which is regarded as a weak or wound pathogen. The internal transcribed spacer region of rDNA was amplified using primers ITS1 and ITS4 and sequenced. BLAST analysis of the 575-bp fragment showed a 100% homology with the sequence of an isolate of P. macrostoma that has been investigated extensively for commercialization as a biological control agent of various agricultural weeds (1), including wild mustard (GenBank No. DQ474091). The nucleotide sequence has been assigned GenBank No. HM755951. Pathogenicity tests consisted of making four 1.4-mm-diameter holes in five NaOCl (0.1%)-sterilized root sections of L. draba and pipetting ~50 to 100 μl of a 106 CFU/ml conidial suspension into the incisions, incubating the inoculated roots at 20 to 25°C overnight and planting the root sections, one per pot, in an artificial greenhouse potting mix and placing the pots in the greenhouse at 20 to 25°C. Controls were five root sections that were treated similarly except that sterile water was injected. The experiment was repeated. After 10 days, shoots that grew from inoculated roots were chlorotic and shorter than those produced from control roots. P. macrostoma was isolated from tissue of inoculated roots that became blackened distal to the inoculation points. To examine the host range of P. macrostoma on other brassica species, crowns of 2-week-old seedlings of radish, broccoli, cauliflower, broccoli raab, turnip, kohlrabi, cabbage, Chinese cabbage, mustard greens, and canola were injected with 0.5 ml of a 106 CFU/ml conidial suspension. Plants were grown in the greenhouse at 20 to 25°C for 4 weeks after inoculation and examined for symptoms. The experiment was repeated twice. Blackened root tissue with slight chlorosis occurred only on roots of radish and crowns of broccoli, from which P. macrostoma was reisolated. To our knowledge, this the first report of a disease of L. draba caused by P. macrostoma. Reference: (1) K. L. Bailey et al. U.S. Patent Application Serial No. 60/294,475, Filed May 20, 2001.

Molecular diversity of binucleate Rhizoctonia AG-A in China

AG-A belongs to the binucleate Rhizoctonia (BNR) anastomosis group (AG) of the Ceratobasidium teleomorph, which parasitizes the roots of many plant species. Ninety nine isolate species of AG-A were obtained from Tibet, Sichuan, and Yunnan Province in China. All isolates were divided into three types based on their cultural characteristics. Type I: abundant aerial mycelia, dense hyphae, loose sclerotia; Type II: abundant aerial mycelia, no sclerotia. Type III: sparse aerial mycelium and no sclerotia. All of the isolates infected the seedlings of Chinese mustard and Chinese cabbage, causing the formation of lesions on the stem and a brown discoloration of the roots. Sequence analysis of the 5.8S rDNA-ITS showed a similarity of 98–100% among the isolates. Inter Simple Sequence Repeat (ISSR) was used to detect genetic variation in binucleate Rhizoctonia spp. Forty two AG-A isolates were amplified using 15 random primers. From a total of 164 bands, 144 bands (87.8%) were polymorphic in the 42 tested isolates. A dendrogram showing genetic relationships between the isolates was constructed using unweighted pair-group averages based on genetic distances. According to the dendrogram, the 42 tested isolates could be aligned into three clusters with a genetic similarity coefficient of 0.29, the first clusters including 27 isolates with III of culture characteristics on PDA; the second clusters included eight isolates with I of cultural characteristics on PDA; the third cluster included seven isolates with II of cultural characteristics on PDA. The results of ISSR analysis showed an association between the hosts of these isolates. Our results showed that ISSR analysis can reveal more molecular variation among isolates of AG-A than sequence analysis using the 5.8S rDNA-ITS.

Growth Promotion of Chinese Cabbage and Arabidopsis by Piriformospora indica Is Not Stimulated by Mycelium-Synthesized Auxin

Piriformospora indica, an endophytic fungus of the order Sebacinales, interacts with the roots of a large variety of plant species. We compared the interaction of this fungus with Chinese cabbage (Brassica campestris subsp. chinensis) and Arabidopsis seedlings. The development of shoots and roots of Chinese cabbage seedlings was strongly promoted by P. indica and the fresh weight of the seedlings increased approximately twofold. The strong stimulation of root hair development resulted in a bushy root phenotype. The auxin level in the infected Chinese cabbage roots was twofold higher compared with the uncolonized controls. Three classes of auxin-related genes, which were upregulated by P. indica in Chinese cabbage roots, were isolated from a double-subtractive expressed sequence tag library: genes for proteins related to cell wall acidification, intercellular auxin transport carrier proteins such as AUX1, and auxin signal proteins. Overexpression of B. campestris BcAUX1 in Arabidopsis strongly promoted growth and biomass production of Arabidopsis seedlings and plants; the roots were highly branched but not bushy when compared with colonized Chinese cabbage roots. This suggests that BcAUX1 is a target of P. indica in Chinese cabbage. P. indica also promoted growth of Arabidopsis seedlings but the auxin levels were not higher and auxin genes were not upregulated, implying that auxin signaling is a more important target of P. indica in Chinese cabbage than in Arabidopsis. The fungus also stimulated growth of Arabidopsis aux1 and aux1/axr4 and rhd6 seedlings. Furthermore, a component in an exudate fraction from P. indica but not auxin stimulated growth of Chinese cabbage and Arabidopsis seedlings. We propose that activation of auxin biosynthesis and signaling in the roots might be the cause for the P. indica-mediated growth phenotype in Chinese cabbage.

Isolation and characterization of Bradh1 gene encoding alcohol dehydrogenase from Chinese cabbage (Brassica rapa)

Alcohol dehydrogenase (E.C.1.1.1.1) is an enzyme present in higher plants involved in the anaerobic fermentation pathway that catalyzes the reduction of pyruvate to ethanol, resulting in continuous <TEX>$NAD^+$</TEX> regeneration. It also plays an important role in many plant developments including tolerance to anoxia condition. Here, a cDNA clone encoding alcohol dehydrogenase (ADH) was isolated from Chinese cabbage (Brassica rapa) seedlings. The gene named Bradh1 had a total length of 1,326 bp that contains a single open reading frame of 1,140 bp. The predicted protein consists of 379 amino acid residues with a calculated molecular mass of 41.17 kDa. Expression pattern analysis revealed a tissue-specific expressing gene in different tissues and strongly expressed in the shoot, roots and seeds of Chinese cabbage. Agrobacterium transformation of full-length cDNA Bradh1 into rice Gopumbyeo showed high efficiency. Furthermore, induction of ADH in transgenic rice enhanced tolerance to anaerobiosis stresses and elevated mRNA transcripts. The overexpression of Bradh1 in rice increases germination under anaerobiosis stresses, implying the possibility of developing new varieties suited for direct seeding or flood-prone rice field.

배추 무사마귀병 발병 억제 및 생육증진을 위한 달걀껍질 토양혼화처리 효과

무사마귀병이 상습적으로 발생하는 농가포장에 달걀껍질을 토양혼화 처리한 후 배추를 정식하고 <TEX>$10{\sim}13$</TEX>일 간격으로 4회에 걸쳐 배추를 수확하여 무사마귀병 발병과 배추생육, 토양 pH 변화 등을 조사한 결과 지상부 생육에 있어서 난막을 제거한 달걀껍질 처리구의 배추들이 시험중기부터 다른 처리구들에 비하여 빠른 생육을 보였으며, 무사마귀병 발병도도 가장 낮았다. 난막이 있는 달걀껍질 처리구는 무처리 대조구보다는 생육이 좋았으나 난막 없는 달걀껍질 처리구보다는 낮았다. 토양 pH는 처리 3주 이후부터 차이가 커지기 시작하여, 난막 없는 달걀껍질 처리구에서는 8.0 이상으로 상승한 반면 무처리구에서는 6.8 정도에 머물렀다. 달걀껍질과 기타 칼슘화합물의 효과를 비교한 시험에서는 <TEX>$CaCO_3$</TEX> 처리구의 발병도가 1.7로 가장 낮았고, 무사마귀병 방제용 살균제인 플루설파마이드 처리구와 무사마귀병 저항성 품종인 CR그린배추의 발병도가 모두 1.9인 반면, 달걀껍질 처리구의 발병도는 2.7로 높은 편이었다. 무처리 대조구의 발병도는 3.4였다. 그러나 배추 생육은 발병도와는 다른 양상을 보여, 달걀껍질 처리구의 배추 생육이 약 2.1kg으로 가장 좋았던 반면 무사마귀병 저항성 품종인 CR그린배추의 생육은 약 2.0 kg, 무사마귀병 방제용 살균제인 플루설파마이드 처리구에서는 약 1.7 kg, 그리고 무처리 대조구에서는 약 1.3 kg에 머물렀다. 달걀껍질은 무사마귀병을 크게 억제하지는 못하여도 배추의 생육을 증진시키는 효과는 매우 컸다. 따라서, 배추를 정식하기 전에 토양에 달걀껍질을 혼화한다면 무사마귀병 발생에 관계없이 배추를 재배가 가능할 것이다. Before transplanting Chinese cabbage seedlings, two kinds of eggshell powder were blended into the soil of cabbage field where the club root pathogen, Plasmodiophora brassicae, was infested. The incidence of clubroot disease, the shoot and root growth of cabbages, and soil pH were examined four times at 10 to 13 days interval from transplanting Chinese cabbage. As results, the cabbages treated with eggshell powder without membrane showed the fastest growth in above ground part, and the lowest disease index for clubroot disease. The cabbages treated with eggshell powder with membrane showed better growth than the cabbages of non-treated check, but lower growth than those treated with eggshell powder without membrane. Soil pH started to increase from 3 weeks after soil blending of eggshell powder, and it reached to above 8.0. However, the soil pH of non-treated check stayed at around 6.8. In the experiment to compare the effect of eggshell powder with other calcium compounds, soil-blending of <TEX>$CaCO_3$</TEX> resulted the lowest disease incidence of 1.7 and the registered fungicide, 'flusulfamide', and the resistant variety 'CR Green cabbage' followed with the incidence of 1.9. Cabbages of non-treated check scored the highest disease incidence, 3.4, and that of eggshell powder without membrane was as high as 2.7. However, the growth of Chinese cabbage showed the different pattern to the disease incidence. Chinese cabbages treated with eggshell without membrane recorded the highest average growth, around 2.1 kg. On the other hand, the average growth of CR Green Chinese cabbage was about 2.0 kg, that of flusulfamide-treatment plot was 1.7, and that of non-treated check was as low as 1.3 kg. Soil blending of eggshell powder without membrane did not inhibit the development of clubroot, but increased the growth of cabbage to a great extent. Therefore, it was confirmed that soil blending of eggshell powder before transplanting makes the Chinese cabbage culture possible even in the field infested with club root pathogen.

하수처리수 및 폐양액의 재이용이 배추 유묘 생장에 미치는 영향

기후변화로 인해 발생될 수 있는 물 부족 현상에 대응하기 위하여 기존 농업용수에 대한 대체용수로 하수처리수 및 폐양액의 재이용이 유식물 생장에 미치는 영향을 평가하였다. 하수처리수와 폐양액에 대한 수질분석결과 유기배지로부터의 폐양액은 무기배지로부터의 폐양액 및 하수처리수와 비교해서 보다 많은 양분을 함유하고 있었으며 하수처리수에서는 <TEX>$Na^+$</TEX>과 <TEX>$Cl^-$</TEX> 함량이 다른 용수보다 높은 것으로 나타났다. 배추묘의 생육은 폐양액 처리구에서 대조구인 지하수 처리구에 비해 유사하거나 촉진되었고 하수처리수 처리구에서는 대조구와 비슷하게 나타났다. 육묘기간 동안 배추묘가 흡수한 질소는 관행재배에서 5.47 mg/plant 이었으며, 유기배지와 무기배지로부터의 폐양액 처리구에서 각각 10.02 mg/plant, 5.20 mg/plant인 것으로 나타났다. 하수처리수 처리구에서는 배추의 질소함량이 4.59 mg/plant으로 나타났다. 관행의 1/2 수준으로 시비하고 유기배지로부터의 폐양액을 처리한 배추의 질소 흡수량은 8.34 mg/plant으로 관행재배보다 높은 것으로 나타나 폐양액 이용 시 육묘에 이용되는 비료의 시용을 줄여야 할 것으로 판단된다. 한편 배추의 인 함량은 관행재배에서 8.9 <TEX>${\mu}$</TEX>g/plant로 나타났으며 유기배지로부터의 폐양액 처리구에서도 관행재배와 비슷한 수준이었다. 반면 인 함량이 낮았던 무기배지로부터의 폐양액과 하수처리수 처리구에서 배추가 흡수한 인산 함량이 가장 높은 것으로 나타났다. 배추묘가 흡수한 양이온의 경우 관행재배에 비해 폐양액과 하수처리수 처리구에서 상대적으로 많은 양을 흡수하였다. 이상의 결과로부터 선정된 폐양액 및 하수처리수에 대한 농업용수로써의 재이용 가능성을 확인할 수 있었으며 향후 현장실험을 통해 작물의 생육특성 및 생산량 평가를 실시하고 대체용수 사용에 따른 환경영향을 평가하는 연구가 진행되어야 할 것으로 판단된다. Water shortages are expected to be a major impact of climate change. This study examined the growth of Chinese cabbage seedling using reclaimed wastewater and waste nutrient solution as alternative irrigation resources. Generally, the concentration of nutrients, such as <TEX>$K^+$</TEX>, <TEX>$NH_4^+$</TEX>, <TEX>$Mg^{2+}$</TEX>, <TEX>$Ca^{2+}$</TEX>, <TEX>$Cl^-$</TEX>,<TEX>$NO_3^-$</TEX>, <TEX>$PO_4^-$</TEX> and <TEX>$SO_4^{2-}$</TEX>, in waste nutrient solution was higher than that in wastewater. However, Chinese cabbage seedling irrigated with wastewater was supplied a higher concentration of <TEX>$Na^+$</TEX> and <TEX>$Cl^-$</TEX> than waste nutrient solution. The growth of Chinese cabbage seedling irrigated with waste nutrient solution was similar or higher than those irrigated with groundwater as control, while the growth of those irrigated with wastewater was similar to those irrigated with groundwater. The total nitrogen uptake in Chinese cabbage seedling irrigated with groundwater, waste nutrient solution from organic and inorganic hydroponic cultures, and wastewater was 5.47, 10.02, 5.20, and 4.59 mg/plant, respectively. The nitrogen uptake of Chinese cabbage seedling irrigated with waste nutrient solution from organic hydroponic substrates in a 50% lower dose than recommended was 8.34 mg/plant, which is higher than that of the cabbage irrigated with groundwater. Overall, the results suggest that waste nutrient solution and wastewater can be used as alternate water resources, and can allow a reduction in the amount of fertilizer needed to raise Chinese cabbage seedling.

Several methods to detect the inheritance and resistance to the diamondback moth in transgenic Chinese cabbage.

A positive selection system was developed for Agrobacterium-mediated trasnsformation of using hypocotyl segments of aseptic seedlings of chinese cabbage as explants, regenerated plants with kanamycin resistance were obtained. The transformed plants with CryIA(c) (Bt) gene were confirmed by Southern blotting analysis, indicating the integration of the transgene into the cabbage genome. Majority of the transgenic plants had only a single copy of the inserted CryIA(c) gene. Leaf section bioassays showed that resistance against larvae of diamondback moth in CryIA(c) transgenic cabbage was significantly enhanced. The inheritance patterns of the transgene in T1 offspring of transgenic cabbage were investigated using PCR analysis and kanamycin resistance test on young seedling leaves.

Agrobacterium tumefaciens-mediated hairy root production from seedlings of Chinese cabbage

Cruciferous hairy roots are often used for improving drought adaptability, peroxidase production, andin vitro subculturing ofPlasmodiophora brassicae. For metabolic engineering,Agrobacterium tumefaciens-mediated systems have previously been developed for hairy root production in other plant species. Here, we used therolABC gene binary construct inA. tumefaciens strain GV3101 to establish cultures of Chinese cabbage hairy roots. On both solid and liquid media, therolABC hairy root lines exhibited a wild-type hairy root syndrome in terms of their growth and morphology. This demonstrates that those three genes are sufficient to induce high-quality hairy roots in Chinese cabbage. Such a system could be useful for the stable production of secondary metabolites in that species.