Methylobacterium gossipiicola sp. nov., a pink-pigmented, facultatively methylotrophic bacterium isolated from the cotton phyllosphere

Madhaiyan, Munusamy,Poonguzhali, Selvaraj,Senthilkumar, Murugaiyan,Lee, Jung-Sook,Lee, Keun-Chul Microbiology Society 2012 International journal of systematic and evolutiona Vol.62 No.1

<P>A pink, aerobic, facultatively methylotrophic, motile, Gram-negative rod, designated Gh-105<SUP>T</SUP>, was isolated from the phyllosphere of cotton from Coimbatore (Tamilnadu, India). 16S rRNA gene sequence analysis showed clearly that the isolate belonged to the <I>Methylobacterium</I> cluster. Strain Gh-105<SUP>T</SUP> was most closely related to <I>Methylobacterium adhaesivum</I> AR27<SUP>T</SUP> (99 % 16S rRNA gene sequence similarity) and <I>Methylobacterium iners</I> 5317S-33<SUP>T</SUP> (97.5 %). The isolate grew with C1 compounds such as methanol and dichloromethane, but not with formaldehyde, formate, methylamine, trimethylamine or methane, as sole carbon sources and carried <I>mxaF</I>, which encodes methanol dehydrogenase and supports methylotrophic metabolism. The major fatty acid was C18 : 1ω7<I>c</I> and the G+C content of the genomic DNA was 64.2 mol%. Physiological and biochemical data and DNA-DNA relatedness with <I>M. adhaesivum</I> KACC 12195<SUP>T</SUP> and <I>M. iners</I> KACC 11765<SUP>T</SUP> revealed clear phenotypic and genotypic differences. For this reason, we propose that strain Gh-105<SUP>T</SUP> ( = CCM 7572<SUP>T</SUP> = NRRL B-51692<SUP>T</SUP>) represents the type strain of a novel species, with the name <I>Methylobacterium gossipiicola</I> sp. nov.</P>

<i>Arachidicoccus rhizosphaerae</i> gen. nov., sp. nov., a plant-growth-promoting bacterium in the family <i>Chitinophagaceae</i> isolated from rhizosphere soil

Madhaiyan, Munusamy,Poonguzhali, Selvaraj,Senthilkumar, Murugaiyan,Pragatheswari, Dhandapani,Lee, Jung-Sook,Lee, Keun-Chul International Union of Microbiological Societies 2015 International journal of systematic and evolutiona Vol.65 No.2

<P>Three novel bacterial strains, designated Vu-144<SUP>T</SUP>, Vu-7 and Vu-35, were isolated on minimal medium from rhizosphere soil of field-grown cowpea and subjected to a taxonomic study using a polyphasic approach. Cells of the strains were Gram-stain-negative, non-motile, non-spore-forming, coccoid rods, and formed non-pigmented colonies. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Vu-144<SUP>T</SUP> was affiliated with an uncultivated lineage of the phylum <I>Bacteroidetes</I>. Its closest phylogenetic neighbour was the recently described species <I>Niastella populi</I>, a member of the family <I>Chitinophagaceae</I>, with just 90.7 % sequence similarity to the type strain. The only isoprenoid quinone detected was menaquinone 7 (MK-7). The fatty acid profiles showed large amounts of iso-C<SUB>15 : 0</SUB>, iso-C<SUB>17 : 0</SUB> 3-OH and iso-C<SUB>15 : 1</SUB> G and minor amounts of summed feature 3 (C<SUB>16 : 1</SUB>ω7<I>c</I> and/or iso-C<SUB>15 : 0</SUB> 2-OH), C<SUB>16 : 0</SUB> and other fatty acids, allowing the differentiation of the strains from other genera. The G+C content of the genomic DNA of the three strains ranged from 43.1 to 44.3 mol%. In addition to phosphatidylethanolamine, the major polar lipids were three unidentified aminophospholipids (APL1–APL3), two unidentified phospholipids (PL1, PL2) and three unidentified lipids (UL1–UL3). Biochemical test patterns also differed from those of <I>Niastella populi</I> and members of other genera. All three isolates showed plant-growth-promoting properties, e.g. the ability to produce indole-3-acetic acid and NH<SUB>3</SUB> and to solubilize phosphate, utilized 1-aminocyclopropane 1-carboxylate (ACC) as a sole source of nitrogen and possessed the ACC deaminase enzyme. The novel isolates readily colonized roots and stimulated growth of tomato and cowpea under glasshouse conditions. Inoculated plants showed a 45–60 % increase in dry matter weight with respect to uninoculated controls. On the basis of the evidence from our polyphasic study, isolate Vu-144<SUP>T</SUP> represents a novel genus and species in the family <I>Chitinophagaceae</I>, for which the name <I>Arachidicoccus rhizosphaerae</I> gen. nov., sp. nov. is proposed. The type strain of <I>Arachidicoccus rhizosphaerae</I> is Vu-144<SUP>T</SUP> ( = KCTC 22378<SUP>T</SUP> = NCIMB 14473<SUP>T</SUP>).</P>

Leifsonia soli sp. nov., a yellow-pigmented actinobacterium isolated from teak rhizosphere soil

Madhaiyan, Munusamy,Poonguzhali, Selvaraj,Lee, Jung-Sook,Senthilkumar, Murugaiyan,Lee, Keun Chul,Sundaram, Subbiah Microbiology Society 2010 International journal of systematic and evolutiona Vol.60 No.6

<P>Two yellow-pigmented, Gram-stain-positive, aerobic, motile, short rod-shaped bacteria were isolated from natural teak tree rhizosphere soil and their taxonomic positions were determined by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strains TG-S248<SUP>T</SUP> and TG-S240 formed a distinct phyletic line within the genus <I>Leifsonia</I>. 16S rRNA gene sequence analysis of strain TG-S248<SUP>T</SUP> with sequences from <I>Leifsonia shinshuensis</I> DB 102<SUP>T</SUP>, <I>L. poae</I> VKM Ac-1401<SUP>T</SUP>, <I>L. naganoensis</I> DB 103<SUP>T</SUP>, <I>L. aquatica</I> DSM 20146<SUP>T</SUP> and <I>L. xyli</I> subsp. <I>cynodontis</I> JCM 9733<SUP>T</SUP> revealed pairwise similarities ranging from 98.7 to 99.1 %. The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The G+C content of the DNA of the type strain was 69.4 mol%. DNA-DNA hybridization experiments revealed low levels of DNA-DNA relatedness (32 % or less) between strain TG-S248<SUP>T</SUP> and its closest relatives. Based on differences in phenotypic and genotypic characteristics, strain TG-S248<SUP>T</SUP> (=LMG 24767<SUP>T</SUP> =JCM 15679<SUP>T</SUP>) is designated the type strain of a novel species of the genus <I>Leifsonia</I>, for which the name <I>Leifsonia soli</I> sp. nov. is proposed.</P>

MicroTom ? A Model Plant System to Study Bacterial Wilt by Ralstoniasolanacearum

박은진,이승돈,정유진,이명환,엄해용,Senthilkumar Murugaiyan,문병주,이선우 한국식물병리학회 2007 Plant Pathology Journal Vol.23 No.4

MicroTom is a miniature tomato plants with various properties that make it as a model system for experiments in plant molecular biology. To extend its utility as a model plant to study a plant - bacterial wilt system, we investigated the potential of the MicroTom as a host plant of bacterial wilt caused by Ralstonia solanacearum. We compared the disease progress on standard tomato and MicroTom by two inoculation methods, root dipping and soil drenching, using a race 1 strain GMI1000. Both methods caused the severe wilting on MicroTom comparable to commercial tomato plant, although initial disease development was faster in root dipping. From the diseased MicroTom plants, the same bacteria were successfully reisolated using semiselective media to fulfill Koch’s postulates. Race specific and isolate specific virulence were investigated by root dipping with 10 isolates of R. solanacearum isolated from tomato and potato plants. All of the tested isolates caused the typical wilt symptom on MicroTom. Disease severities by isolates of race 3 was below 50% until 15 days after inoculation, while those by isolates of race 1 reached over 50% to death until 15 days. This result suggested that MicroTom can be a model host plant to study R. solanacearum - plant interaction.

Biocontrol Potential of a Lytic Bacteriophage PE204 against Bacterial Wilt of Tomato

( Bae Ju Young ),( Jing Wu ),( Hyoung Ju Lee ),( Eun Jeong Jo ),( Senthilkumar Murugaiyan ),( Eun Sook Chung ),( Seon Woo Lee ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.12

Bacterial wilt caused by Ralstonia solanacearum is a devastating disease of many economically important crops. Since there is no promising control strategy for bacterial wilt, phage therapy could be adopted using virulent phages. We used phage PE204 as a model lytic bacteriophage to investigate its biocontrol potential for bacterial wilt on tomato plants. The phage PE204 has a short-tailed icosahedral structure and double-stranded DNA genome similar to that of the members of Podoviridae. PE204 is stable under a wide range of temperature and pH, and is also stable in the presence of the surfactant Silwet L-77. An artificial soil microcosm (ASM) to study phage stability in soil was adopted to investigate phage viability under a controlled system. Whereas phage showed less stability under elevated temperature in the ASM, the presence of host bacteria helped to maintain a stable phage population. Simultaneous treatment of phage PE204 at 108 PFU/ml with R. solanacearum on tomato rhizosphere completely inhibited bacterial wilt occurrence, and amendment of Silwet L-77 at 0.1% to the phage suspension did not impair the disease control activity of PE204. The biocontrol activities of phage PE204 application onto tomato rhizosphere before or after R. solanacearum inoculation were also investigated. Whereas pretreatment with the phage was not effective in the control of bacterial wilt, post-treatment of PE204 delayed bacterial wilt development. Our results suggested that appropriate application of lytic phages to the plant root system with a surfactant such as Silwet L-77 could be used to control the bacterial wilt of crops.

Endomicrobial Community Profiles of Two Different Mealybugs: Paracoccus marginatus and Ferrisia virgata

( Polpass Arul Jose ),( Ramasamy Krishnamoorthy ),( Pandiyan Indira Gandhi ),( Murugaiyan Senthilkumar ),( Veeranan Janahiraman ),( Karunandham Kumutha ),( Aritra Roy Choudhury ),( Sandipan Samaddar ) 한국미생물 · 생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.7

Mealybugs (Hemiptera: Coccomorpha: Pseudococcidae) harbor diverse microbial symbionts that play essential roles in host physiology, ecology, and evolution. In this study we aimed to reveal microbial communities associated with two different mealybugs, papaya mealybug (Paracoccus marginatus) and two-tailed mealybug (Ferrisia virgata) collected from the same host plant. Comparative analysis of microbial communities associated with these mealybugs revealed differences that appear to stem from phylogenetic associations and different nutritional requirements. This first report on both bacterial and fungal communities associated with these mealybugs provides a preliminary insight on factors affecting the endomicrobial communities.

MicroTom - A Model Plant System to Study Bacterial Wilt by Ralstonia solanacearum

Park, Eun-Jin,Lee, Seung-Don,Chung, Eu-Jin,Lee, Myung-Hwan,Um, Hae-Young,Murugaiyan, Senthilkumar,Moon, Byung-Ju,Lee, Seon-Woo The Korean Society of Plant Pathology 2007 Plant Pathology Journal Vol.23 No.4

MicroTom is a miniature tomato plants with various properties that make it as a model system for experiments in plant molecular biology. To extend its utility as a model plant to study a plant - bacterial wilt system, we investigated the potential of the MicroTom as a host plant of bacterial wilt caused by Ralstonia solanacearum. We compared the disease progress on standard tomato and MicroTom by two inoculation methods, root dipping and soil drenching, using a race 1 strain GMI1000. Both methods caused the severe wilting on MicroTom comparable to commercial tomato plant, although initial disease development was faster in root dipping. From the diseased MicroTom plants, the same bacteria were successfully reisolated using semiselective media to fulfill Koch's postulates. Race specific and isolate specific virulence were investigated by root dipping with 10 isolates of R. solanacearum isolated from tomato and potato plants. All of the tested isolates caused the typical wilt symptom on MicroTom. Disease severities by isolates of race 3 was below 50 % until 15 days after inoculation, while those by isolates of race 1 reached over 50% to death until 15 days. This result suggested that MicroTom can be a model host plant to study R. solanacearum - plant interaction.