Peer Review #1 of "Phytotoxin synthesis genes and type III effector genes of Pseudomonas syringae pv. actinidiae biovar 6 are regulated by culture conditions (v0.2)"

The kiwifruit bacterial canker (Pseudomonas syringae pv. actinidiae; Psa) causes severe damage to kiwifruit production worldwide. Psa biovar 6 (Psa6), which was isolated in Japan in 2015, produces two types of phytotoxins: coronatine and phaseolotoxin. To elucidate the unique virulence of Psa6, we performed transcriptomic analysis of phytotoxin synthesis genes and type III effector genes in in vitro cultivation using various media. The genes related to phytotoxin synthesis and effectors of Psa6 were strictly regulated in the coronatine-inducing mediums (HS and HSC); 14 of 23 effector genes and a hrpL sigma factor gene were induced at 3 h after transferring to the media (early-inducible genes), and phytotoxin synthesis genes such as argD of phaseolotoxin and cfl of coronatine were induced at 6 and 12 h after transferring to the media (late-inducible genes). In contrast, induction of these genes was not observed in the hrp-inducing medium. Next, to examine whether the changes in gene expression in different media is specific to Psa6, we investigated gene expression in other related bacteria. For Psa biovar 1 (Psa1), biovar 3 (Psa3), and P. s. pv. glycinea (Psg), no clear trends were observed in expression behavior across various culture media and incubation times. Therefore, Psa6 seems to exert its virulence efficiently by using two phytotoxins and effectors according to environmental changes. This is not seen in other biovars and pathovars, so it is thought that Psa6 has acquired its own balance of virulence.

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Phytotoxin synthesis genes and type III effector genes of Pseudomonas syringae pv. actinidiae biovar 6 are regulated by culture conditions

10.1101/2020.04.25.060921 ◽

2020 ◽

Author(s):

Karin Hirose ◽

Yasuhiro Ishiga ◽

Takashi Fujikawa

Keyword(s):

Gene Expression ◽

Pseudomonas Syringae ◽

Environmental Changes ◽

Culture Media ◽

Type Iii Effector ◽

Type Iii ◽

Effector Genes ◽

The Media ◽

Inducible Genes

AbstractThe kiwifruit bacterial canker (Pseudomonas syringae pv. actinidiae; Psa) causes severe damage to kiwifruit production worldwide. Psa biovar 6 (Psa6), which was isolated in Japan in 2015, produces two types of phytotoxins: coronatine and phaseolotoxin. To date, no other phytopathogenic bacteria are known to produce two phytotoxins. To elucidate the unique virulence of Psa6, we performed transcriptomic analysis of phytotoxin synthesis genes and type III effector genes in in vitro cultivation using various media. The genes related to phytotoxin synthesis and effectors of Psa6 were strictly regulated in the coronatine-inducing mediums (HS and HSC); 14 of 23 effector genes and a hrpL sigma factor gene were induced at 3 h after transferring to the media (early-inducible genes), and phytotoxin synthesis genes such as argD of phaseolotoxin and cfl of coronatine were induced at 6 and 12 h after transferring to the media (late-inducible genes). In contrast, induction of these genes was not observed in the hrp-inducing medium. Next, to examine whether the changes in gene expression in different media is specific to Psa6, we investigated gene expression in other related bacteria. For Psa biovar 1 (Psa1), biovar 3 (Psa3), and P. s. pv. glycinea (Psg), no clear trends were observed in expression behavior across various culture media and incubation times. Therefore, Psa6 seems to exert its virulence efficiently by using two phytotoxins and effectors according to environmental changes. This is not seen in other biovars and pathovars, so it is thought that Psa6 has acquired its own balance of virulence.

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A high-throughput, near-saturating screen for type III effector genes from Pseudomonas syringae

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0409660102 ◽

2005 ◽

Vol 102 (7) ◽

pp. 2549-2554 ◽

Cited By ~ 172

Author(s):

J. H. Chang ◽

J. M. Urbach ◽

T. F. Law ◽

L. W. Arnold ◽

A. Hu ◽

...

Keyword(s):

Pseudomonas Syringae ◽

High Throughput ◽

Type Iii Effector ◽

Type Iii ◽

Effector Genes

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Pseudomonas syringae Strains Naturally Lacking the Classical P. syringae hrp/hrc Locus Are Common Leaf Colonizers Equipped with an Atypical Type III Secretion System

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-23-2-0198 ◽

2010 ◽

Vol 23 (2) ◽

pp. 198-210 ◽

Cited By ~ 69

Author(s):

Christopher R. Clarke ◽

Rongman Cai ◽

David J. Studholme ◽

David S. Guttman ◽

Boris A. Vinatzer

Keyword(s):

Pseudomonas Syringae ◽

Type Iii Secretion ◽

Plant Cells ◽

Type Iii Secretion System ◽

Ice Nucleation ◽

Secretion System ◽

Effector Proteins ◽

Population Densities ◽

Type Iii ◽

Effector Genes

Pseudomonas syringae is best known as a plant pathogen that causes disease by translocating immune-suppressing effector proteins into plant cells through a type III secretion system (T3SS). However, P. syringae strains belonging to a newly described phylogenetic subgroup (group 2c) are missing the canonical P. syringae hrp/hrc cluster coding for a T3SS, flanking effector loci, and any close orthologue of known P. syringae effectors. Nonetheless, P. syringae group 2c strains are common leaf colonizers and grow on some tested plant species to population densities higher than those obtained by other P. syringae strains on nonhost species. Moreover, group 2c strains have genes necessary for the production of phytotoxins, have an ice nucleation gene, and, most interestingly, contain a novel hrp/hrc cluster, which is only distantly related to the canonical P. syringae hrp/hrc cluster. This hrp/hrc cluster appears to encode a functional T3SS although the genes hrpK and hrpS, present in the classical P. syringae hrp/hrc cluster, are missing. The genome sequence of a representative group 2c strain also revealed distant orthologues of the P. syringae effector genes avrE1 and hopM1 and the P. aeruginosa effector genes exoU and exoY. A putative life cycle for group 2c P. syringae is discussed.

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Genetic and molecular evidence that the Pseudomonas syringae type III effector protein AvrRpt2 is a cysteine protease

Molecular Microbiology ◽

10.1046/j.1365-2958.2003.03666.x ◽

2003 ◽

Vol 49 (6) ◽

pp. 1537-1546 ◽

Cited By ~ 144

Author(s):

Michael J. Axtell ◽

Stephen T. Chisholm ◽

Douglas Dahlbeck ◽

Brian J. Staskawicz

Keyword(s):

Pseudomonas Syringae ◽

Cysteine Protease ◽

Molecular Evidence ◽

Effector Protein ◽

Type Iii Effector ◽

Type Iii

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The type III effector repertoire of Pseudomonas syringae pv. syringae B728a and its role in survival and disease on host and non-host plants

Molecular Microbiology ◽

10.1111/j.1365-2958.2006.05350.x ◽

2006 ◽

Vol 62 (1) ◽

pp. 26-44 ◽

Cited By ~ 128

Author(s):

Boris A. Vinatzer ◽

Gail M. Teitzel ◽

Min-Woo Lee ◽

Joanna Jelenska ◽

Sara Hotton ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Host Plants ◽

Type Iii Effector ◽

Type Iii

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Characterization, Phylogeny, and Genome Analyses of Nonpathogenic Xanthomonas campestris Strains Isolated from Brassica Seeds

Phytopathology ◽

10.1094/phyto-08-19-0319-r ◽

2020 ◽

Vol 110 (5) ◽

pp. 981-988 ◽

Cited By ~ 2

Author(s):

Yung-An Lee ◽

Pei-Yu Yang ◽

Shau-Chang Huang

Keyword(s):

Type Iii Secretion ◽

Xanthomonas Campestris ◽

Pathogenicity Island ◽

Whole Genome Sequence ◽

Effector Protein ◽

Type Iii Effector ◽

Type Iii ◽

Effector Genes ◽

Genome Analyses ◽

Xanthomonas Campestris Pv Campestris

Xanthomonads were detected by using the Xan-D(CCF) medium from the brassica seeds, and their pathogenicity was determined by plant inoculation tests. It was found that some seed lots were infested with Xanthomonas campestris pv. campestris, some with X. campestris pv. raphani, and some with nonpathogenic xanthomonads. The nonpathogenic xanthomonad strains were identified as X. campestris, and the multilocus sequence analysis showed that the nonpathogenic X. campestris strains were grouped together with pathogenic X. campestris, but not with nonpathogenic strains of X. arboricola. In addition, all isolated X. campestris pv. campestris and X. campestris pv. raphani strains were positive in the hrpF-PCR, but the nonpathogenic strains were negative. It was further found that nonpathogenic X. campestris strain nE1 does not contain the entire pathogenicity island (hrp gene cluster; type III secretion system) and all type III effector protein genes based on the whole genome sequence analyses. The nonpathogenic X. campestris strain nE1 could acquire the entire pathogenicity island from the endemic X. campestris pv. campestris and X. campestris pv. raphani strains by conjugation, but type III effector genes were not cotransferred. The studies showed that the nonpathogenic X. campestris strains indeed exist on the brassica seeds, but it could be differentiated by the PCR assays on the hrp and type III effector genes. Nevertheless, the nonpathogenic X. campestris strains cannot be ignored because they may be potential gene resources to increase genetic diversity in the endemic pathogenic X. campestris pv. campestris and X. campestris pv. raphani strains.

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