• Journal of Microbiology and Biotechnology
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• 제32권10호
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• pp.1292-1298
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• 2022

Soil autotrophic bacterial communities play a significant role in the soil carbon (C) cycle in paddy fields, but little is known about how rhizosphere soil microorganisms respond to different long-term (35 years) fertilization practices under double rice cropping ecosystems in southern China. Here, we investigated the variation characteristics of rhizosphere soil RubisCO gene cbbL in the double rice ecosystems of in southern China where such fertilization practices are used. For this experiment we set up the following fertilizer regime: without any fertilizer input as a control (CK), inorganic fertilizer (MF), straw returning (RF), and organic and inorganic fertilizer (OM). We found that abundances of cbbL, 16S rRNA genes and RubisCO activity in rhizosphere soil with OM, RF and MF treatments were significantly higher than that of CK treatment. The abundances of cbbL and 16S rRNA genes in rhizosphere soil with OM treatment were 5.46 and 3.64 times higher than that of CK treatment, respectively. Rhizosphere soil RubisCO activity with OM and RF treatments increased by 50.56 and 45.22%, compared to CK treatment. Shannon and Chao1 indices for rhizosphere soil cbbL libraries with RF and OM treatments increased by 44.28, 28.56, 29.60, and 23.13% compared to CK treatment. Rhizosphere soil cbbL sequences with MF, RF and OM treatments mainly belonged to Variovorax paradoxus, uncultured proteobacterium, Ralstonia pickettii, Thermononospora curvata, and Azoarcus sp.KH33C. Meanwhile, cbbL-carrying bacterial composition was obviously influenced by soil bulk density, rhizosphere soil dissolved organic C, soil organic C, and microbial biomass C contents. Fertilizer practices were the principal factor influencing rhizosphere soil cbbL-carrying bacterial communities. These results showed that rhizosphere soil autotrophic bacterial communities were significantly changed under conditions of different long-term fertilization practices Therefore, increasing rhizosphere soil autotrophic bacteria community with crop residue and organic manure practices was found to be beneficial for management of double rice ecosystems in southern China.

• 한국토양비료학회지
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• 제21권4호
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• pp.434-442
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• 1988

논토양(土壤)에 볏짚과 보릿짚을 시용(施用)하여 수도근권토양(水稻根圈土壤)의 화학성분(化學成分), 질소고정미생물(窒素固定微生物), 토양효소활성(土壤酵素活性) 및 질소고정력(窒素固定力)에 미치는 영향(影響)을 조사분석(調査分析)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 토양(土壤) pH는 유수형성기(幼穗形成期) 이후(以後)부터 경시적(經時的)으로 증가(增加)하였다. 2. $Fe^{{+}{+}}$함량(含量)은 근권토양(根圈土壤)에서는 경시적(經時的)으로 감소(減少)하고 비근권토양(非根圈土壤)에서는 증가(增加)하는 경향(傾向)이었다. 3. 토양중(土壤中) $NH_4-N$ 함량(含量)은 생육초기(生育初期)에는 근권토양(根圈土壤)에서 많았으나 후기(後期)에는 비근권토양(非根圈土壤)에서 많게 나타났다. 4. 토양중(土壤中) glucose나 pentose함량(含量)은 근권토양(根圈土壤)이 비근권토양(非根圈土壤)에 비(比)해 많은 경향(傾向)이었다. 5. 토양중(土壤中) 질소고정미생물(窒素固定微生物)의 경시적(經時的) 균수(菌數)의 변화(變化)는 전처리구(全處理區)에 있어서 크지 않았다. 6. Phosphatase, ${\beta}$-glucosidase 및 protease활성(活性)은 근권토양(根圈土壤)이 비근권토양(非根圈土壤)보다 높았다. 7. $C_2H_2$환원력(還元力)은 분얼기(分蘖期)에 가장 높았으며 비근권토양(非根圈土壤)보다 근권토양(根圈土壤)이, 다수계(多收系)인 삼강벼가 일반계(一般系)인 동진벼보다 높은 경향(傾向)이었다. 8. 보릿짚시용구(施用區)가 볏짚시용구(施用區)에 비(比)해 생육초기(生育初期)에 $C_2H_2$ 환원력(還元力)이 약간 높았다.

• 한국미생물·생명공학회지
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• 제49권2호
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• pp.217-224
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• 2021

Rice blast caused by Pyricularia oryzae, which is a major threat to food security worldwide, markedly decreases the yield of rice. Some rhizobacteria called 'plant growth-promoting rhizobacteria' inhibit plant pathogens and improve plant growth by secreting iron-chelating siderophores. The decreased availability of iron adversely affects the survival of pathogens, especially fungal pathogens, in the rhizosphere. This study aimed to determine the morphological diversity of siderophore-producing bacteria, analyze the type of siderophores produced by the bacteria, and examine their growth-inhibitory activity against Pyricularia oryzae. The rhizobacteria were isolated from the rhizosphere of Sembada Hitam variety of black rice plants in Pakem, Sleman, Yogyakarta, Indonesia. In total, 12 distinct isolates were screened for the production of siderophores. It was found that 9 out of 12 bacteria produced siderophore and most of them were Gram positive bacteria. The best siderophore-producing isolates with different type of siderophore were used in further studies. The IS3 and IS14 isolates were found to be the best siderophore producer that produced hydroxamate and mixed type of hydroxamate-carboxylate type of siderophore, respectively. In the dual culture assay, IS14 showed a strong antagonistic effect against Pyricularia oryzae by the 81.17% inhibition.

• Applied Biological Chemistry
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• 제49권3호
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• pp.175-179
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• 2006

동일비료를 장기연용한 토양에서 벼를 단작으로 재배하여 비료의 시용에 따른 벼 품종간 근권 세균 및 방선균의 밀도와 우점균을 조사하였다. 비료는 3요소(NPK)를 기본으로 하여 무질소(PK), 무인산(NK) 무칼리(NP) 및 NPK+퇴비를 처리하였다. 벼의 근권 미생물 밀도는 품종에 따라서는 큰 차이를 보이지 않았고 시용비료에 의해 약간의 차이를 보였는데 세균은 감소하고 방선균은 증가하는 경향을 나타내었다. 근권 미생물의 분포상에는 유기물의 영향이 뚜렷하여 방선균의 경우 NPK+퇴비구 처리구에서 가장 높은 균 밀도를 나타냈다. 배양가능한 호기성 세균에서는 Bacillus속의 B. megaterium, B. mycoides, B. licheniformis, B. subtilis 등이, 방선균에서는 Streptomyces속의 S. spororaveus, S. canus, S. tauricus, S. galbus 등과 Micromonospora속이 우점하여 분포하였다.

• 미생물학회지
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• 제24권3호
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• pp.317-322
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• 1986

It was observed that the strains of Klebsiella pneumoniae isolated from rhizosphere of rice, capable of utilizing chlorivated hervicides, such as 2, 4-dichlorophenoxyacetate, 2-methyl-4-chlorophenoxyacetate and 3-chlorobenzoate, as sole source of carbon and energy and confirmed that their degrading ability of the herbicides was due to plasmid genes. Characteristics of selected strains such as nitrogenase activity, resistances to antibiotics and heavy metal ion were measured.

• 농약과학회지
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• 제17권4호
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• pp.371-378
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• 2013

토양에 서식하는 다양한 미생물 중에서 식물 근권에 서식하는 미생물들은 식물과 상호작용하며 독특한 군집을 형성한다고 알려져 있다. 본 연구에서는 비료 연용 논토양과 무비 논토양에서 재배된 벼(Oryza sativa L.)의 근권으로부터 배양적 접근을 통해 다양한 방선균을 분리하여 항균활성을 조사하였다. 방선균의 선택적 배양을 위해서 4종류의 선택 배지를 이용하였고, 전체 152균주를 분리할 수 있었다. 분리된 균주들의 분류를 위해서 16S rRNA 유전자의 염기서열을 결정하여 표준균주와의 상동성을 비교하였다. 모든 균주들이 기존에 보고된 표준균주들과 99.0~100.0%의 높은 상동성을 나타내었으며, Dactylosporangium, Micromonospora, Kitasatospora, Promicromonospora, Streptomyces, Streptosporangium 등의 6개 속(genus)로 분류되었다. 그 중 Streptomyces 속에 포함되는 균주가 143균주 (94%)로 가장 많았다. 항균활성을 조사한 결과 대다수의 분리 균주들이 식물병원균에 항균성을 나타내는 것을 확인할 수 있었다. 특히 벼 도열병균(Magnaporthe oryzae)에 우수한 항균활성을 보였다. 이와 같은 연구 결과는, 벼의 근권이 다양한 방선균을 분리할 수 있는 우수한 분리원이며, 분리된 방선균에서 다양한 생리활성 물질을 생산할 수 있음을 제시하여 준다. 또한 추후 연구를 통해 친환경 농업을 위한 유용한 미생물 제제로 활용할 수 있을 것으로 기대한다.

• 한국토양비료학회지
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• 제46권6호
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• pp.585-592
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• 2013

To estimate the effect of long-term fertilization on metabolically active bacterial communities in a rice field, RNA was extracted from endosphere (rice root), rhizosphere, and bulk soil that had been subjected to different fertilization regimes for 59 years, and the 16S rRNAs were analyzed using the pyrosequencing method. The richness and diversity of metabolically active bacteria were higher in bulk soil than in the endosphere and rhizosphere, and showed no significant difference between non-fertilized and fertilized plots. Weighted UniFrac analysis showed that each compartment had characteristic bacterial communities and that the effect of long-term fertilization on the structure of bacterial community was more pronounced in bulk soil than in the endosphere and rhizosphere. The 16S rRNAs affiliated with Alphaproteobacteria and Firmicutes were more abundant in the endosphere than in bulk soil while those affiliated with Chloroflexi and Acidobacteria were more abundant in bulk soil than in the endosphere. Several dominant operational taxonomic units (clustered at a 97% similarity cut-off) showed different frequencies between non-fertilized and fertilized plots, suggesting that the fertilization affected their activities in the rice field.

• The Plant Pathology Journal
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• 제34권2호
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• pp.126-138
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• 2018

Rice blast caused by Magnaporthe oryzae is a major disease. In the present study, we aimed to identify and evaluate the novel bacterial isolates from rice rhizosphere for biocontrol of M. oryzae pathogen. Sixty bacterial strains from the rice plant's rhizosphere were tested for their biocontrol activity against M. oryzae under in vitro and in vivo. Among them, B. amyloliquefaciens had significant high activity against the pathogen. The least disease severity and highest germination were recorded in seeds treated with B. amyloliquefaciens UASBR9 (0.96 and 98.00%) compared to untreated control (3.43 and 95.00%, respectively) under in vivo condition. These isolates had high activity of enzymes in relation to growth promoting activity upon challenge inoculation of the pathogen. The potential strains were identified based on 16S rRNA gene sequencing and dominance of these particular genes were associated in Bacillus strains. These strains were also confirmed for the presence of antimicrobial peptide biosynthetic genes viz., srfAA (surfactin), fenD (fengycin), spaS (subtilin), and ituC (iturin) related to secondary metabolite production (e.g., AMPs). Overall, the results suggested that application of potential bacterial strains like B. amyloliquefaciens UASBR9 not only helps in control of the biological suppression of one of the most devastating rice pathogens, M. grisea but also increases plant growth along with a reduction in application of toxic chemical pesticides.

• 한국산학기술학회논문지
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• 제7권4호
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• pp.704-708
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• 2006

경유로 오염된 인공오염토양을 효과적으로 정화하기위하여 물리 화학적 처리방법인 펜톤 산화반응과 생물학적 처리방법인 근권미생물의 활성도를 이용하는 방법을 연속적으로 적용하였다. 펜톤산화반응에서는 과산화수소의 농도가 증가할수록 TPH의 제거율이 증가하였으며 근권미생물 반응실험에서의 TPH 제거 효율은 콩(83.5%)<벼(81.5%)<대조군(76%) 순으로 나타났다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.304-304
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• 2017

In semi-arid countries such as Namibia, the flooding unexpectedly happens in a rainy season, causing losses in the yield of upland-adapted cereal crop. In flooding conditions, rice roots sequentially form aerenchyma and a barrier to radial oxygen loss (ROL), and oxygen is released into the rhizosphere near the root tips. Iijima et al. (2016) and Awala et al. (2016) reported that close mixed-planting with rice can mitigate the flood stress of co-growing upland-adapted cereal crop by modifying their rhizosphere microenvironments via the oxygen released from the rice roots. Moreover, by using the model system of hydroponic culture, it was confirmed that oxygen from rice roots was transferred to co-growing upland-adapted cereal crop in close mixed planting system (Kawato et al., 2016). However, it is not sure whether the ability of oxygen release varies among rice cultivars, because Kawato et al. (2016) used only one japonica cultivar, Nipponbare (Oryza sativa). The objective of this study was to compare the ability of oxygen release in rhizosphere among rice cultivars. The experiment was conducted in a climate chamber in Kindai University. We used 10 rice cultivars from three different rice species (O. sativa (var. japonica (2), var. indica (3)), Oryza glaberrima Steud. (2) and their interspecific progenies (3)) to compare the ability of oxygen release from the roots. According to the method by Kawato et al. (2016), the dissolved oxygen concentration of phase I (with shoot) and phase II (without shoot) were measured by a fiber optic oxygen-sensing probe. The oxygen released from rice roots was calculated from the difference of the measurements between phase I and phase II. The result in this study indicated that all of the rice cultivars released oxygen from their roots, and the amount of released oxygen was significantly correlated with the above-ground biomass (r = 0.710). The ability of oxygen release (the amount of the oxygen release per fresh root weight) of indica cultivars (O. sativa) tended to be higher as compared with the other cultivars. On the other hand, that of African rice (O. glaberrima) and the interspecific progenies tended to be lower. These results suggested that the ability of oxygen release widely varies among rice cultivars, and some of indica cultivars (O. sativa) may be suitable for close mixed-planting to mitigate flood stress of upland-adapted cereal crop.