Biological control of hairy root (Rhizobium rhizogenes) in apple nurseries through Rhizobium radiobacter antagonists (strain K-84 and native strain UHFBA-218)

ABSTRACT A large number of strains in the Rhizobium radiobacter species complex (biovar 1 Agrobacterium) have been known as causative pathogens for crown gall and hairy root diseases. Strains within this complex were also found as endophytes in many plant species with no symptoms. The aim of this study was to reveal the endophyte variation of this complex and how these endophytic strains differ from pathogenic strains. In this study, we devised a simple but effective screening method by exploiting the high resolution power of mass spectrometry. We screened endophyte isolates from young wheat and barley plants, which are resistant to the diseases, and identified seven isolates from wheat as members of the R. radiobacter species complex. Through further analyses, we assigned five strains to the genomovar (genomic group) G1 and two strains to G7 in R. radiobacter. Notably, these two genomovar groups harbor many known pathogenic strains. In fact, the two G7 endophyte strains showed pathogenicity on tobacco, as well as the virulence prerequisites, including a 200-kbp Ri plasmid. All five G1 strains possessed a 500-kbp plasmid, which is present in well-known crown gall pathogens. These data strongly suggest that healthy wheat plants are reservoirs for pathogenic strains of R. radiobacter. IMPORTANCE Crown gall and hairy root diseases exhibit very wide host-plant ranges that cover gymnosperm and dicot plants. The Rhizobium radiobacter species complex harbors causative agents of the two diseases. Recently, endophyte isolates from many plant species have been assigned to this species complex. We isolated seven endophyte strains belonging to the species complex from wheat plants and revealed their genomovar affiliations and plasmid profile. The significance of this study is the finding of the genomovar correlation between the endophytes and the known pathogens, the presence of a virulence ability in two of the seven endophyte strains, and the high ratio of the pathogenic strains in the endophyte strains. This study therefore provides convincing evidence that could unravel the mechanism that maintains pathogenic agents of this species and sporadically delivers them to susceptible plants.

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The genome sequence of hairy root Rhizobium rhizogenes strain LBA9402. Bioinformatics analysis suggests the presence of a new opine system in the agropine Ri plasmid

10.22541/au.161339244.46256081/v1 ◽

2021 ◽

Author(s):

Marjolein Hooykaas ◽

Paul Hooykaas

Keyword(s):

Genome Sequence ◽

Hairy Root ◽

Complete Genome ◽

Dynamic Nature ◽

Ri Plasmid ◽

Ti Plasmids ◽

Long Reads ◽

Oxford Nanopore ◽

Rhizobium Rhizogenes ◽

Biocontrol Strain

We report here the complete genome sequence of the Rhizobium rhizogenes (formerly Agrobacterium rhizogenes) strain LBA9402 (NCPPB1855rifR), a pathogenic strain causing hairy root disease. In order to assemble a complete genome we obtained short-reads from Illumina sequencing as well as long-reads from Oxford Nanopore Technology sequencing. The genome consists of a 3,958,212 bp chromosome, a 2,005,144 bp chromid (secondary chromosome) and a 252,168 bp Ri plasmid (pRi1855), respectively. The primary chromosome was very similar to that of the avirulent biocontrol strain K84, but the chromid showed a 724 kbp deletion accompanied by a large 1.8 Mbp inversion revealing the dynamic nature of these secondary chromosomes. The sequence of the agropine Ri plasmid was compared to other types of Ri and Ti plasmids. Thus we identified the genes responsible for agropine catabolism, but also a unique segment adjacent to the TL-region that has the signature of a new opine catabolic gene cluster including the three genes that together encode an opine dehydrogenase. Our sequence analysis also revealed a novel gene at the very right end of the TL-DNA, which is unique for the agropine Ri plasmid. The protein encoded by this gene was most related to the succinamopine synthases of chrysopine and agropine Ti plasmids and thus may be involved in synthesis of the unknown opine that can be degraded by the adjacent catabolic cluster. The available sequence will facilitate the use of R. rhizogenes and especially LBA9402 in both the laboratory and for biotechnological purposes.

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Detection of endogenous phthalates in bacterial pathogens of plants and animals

Доклады Академии наук ◽

10.31857/s0869-56524841121-124 ◽

2019 ◽

Vol 484 (1) ◽

pp. 121-124

Author(s):

T. N. Shafikova ◽

U. V. Оmelichkina ◽

S. V. Boyarkina ◽

А. G. Еnikeev ◽

L. А. Мaksimova ◽

...

Keyword(s):

Escherichia Coli ◽

Phthalic Acid ◽

Bacterial Pathogens ◽

Pectobacterium Carotovorum ◽

Clavibacter Michiganensis ◽

Rhizobium Radiobacter ◽

Rhizobium Rhizogenes

The endogenous esters of ortho-phthalic acid, dibutil phthalate (DBP) and di-(2-ethylhexil)-o-phthalate (DEHP), have been first detected in bacterial pathogens of plants (Clavibacter michiganensis ssp. sepedonicus, Pectobacterium carotovorum ssp. carotovorum, Rhizobium rhizogenes, Rhizobium radiobacter) and animals (Escherichia coli).

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First report of root mat (hairy root) of tomato (Lycopersicon esculentum) caused by Rhizobium radiobacter harboring cucumopine Ri plasmid in Japan.

Japanese Journal of Phytopathology ◽

10.3186/jjphytopath.80.98 ◽

2014 ◽

Vol 80 (2) ◽

pp. 98-114 ◽

Cited By ~ 4

Author(s):

H. SAWADA ◽

K. AZEGAMI

Keyword(s):

Lycopersicon Esculentum ◽

Hairy Root ◽

Rhizobium Radiobacter ◽

First Report ◽

Ri Plasmid

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Electron investigations of rhabdovirus-like particles in mexican bean beetles and crickets

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082753 ◽

1978 ◽

Vol 36 (2) ◽

pp. 378-379

Author(s):

J. R. Adams ◽

G. J Tompkins ◽

A. M. Heimpel ◽

E. Dougherty

Keyword(s):

Biological Control ◽

Integrated Pest Management ◽

Pest Management ◽

Developmental Stages ◽

Management Program ◽

Acheta Domesticus ◽

Epilachna Varivestis ◽

House Cricket ◽

Similar Morphology ◽

Bean Beetle

As part of a continual search for potential pathogens of insects for use in biological control or on an integrated pest management program, two bacilliform virus-like particles (VLP) of similar morphology have been found in the Mexican bean beetle Epilachna varivestis Mulsant and the house cricket, Acheta domesticus (L. ).Tissues of diseased larvae and adults of E. varivestis and all developmental stages of A. domesticus were fixed according to procedures previously described. While the bean beetles displayed no external symptoms, the diseased crickets displayed a twitching and shaking of the metathoracic legs and a lowered rate of activity.Examinations of larvae and adult Mexican bean beetles collected in the field in 1976 and 1977 in Maryland and field collected specimens brought into the lab in the fall and reared through several generations revealed that specimens from each collection contained vesicles in the cytoplasm of the midgut filled with hundreds of these VLP's which were enveloped and measured approximately 16-25 nm x 55-110 nm, the shorter VLP's generally having the greater width (Fig. 1).

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