Transposon mutagenesis reveals Pseudomonas cannabina pv. alisalensis optimizes its virulence factors for pathogenicity on different hosts

Pseudomonas cannabina pv. alisalensis (Pcal), which causes bacterial blight disease of Brassicaceae, is an economically important pathogen worldwide. To identify Pcal genes involved in pathogenesis, we conducted a screen for 1,040 individual Pcal KB211 Tn5 mutants with reduced virulence on cabbage plants using a dip-inoculation method. We isolated 53 reduced virulence mutants and identified several potential virulence factors involved in Pcal virulence mechanisms such as the type III secretion system, membrane transporters, transcription factors, and amino acid metabolism. Importantly, Pcal is pathogenic on a range of monocotyledonous and dicotyledonous plants. Therefore, we also carried out the inoculation test on oat plants, which are cultivated after cabbage cultivation as green manure crops. Interestingly among the 53 mutants, 31 mutants also exhibited reduced virulence on oat seedlings, indicating that Pcal optimizes its virulence factors for pathogenicity on different host plants. Our results highlight the importance of revealing the virulence factors for each plant host-bacterial interaction, and will provide new insights into Pcal virulence mechanisms.

Download Full-text

Coronatine contributes Pseudomonas cannabina pv. alisalensis virulence by overcoming both stomatal and apoplastic defenses in dicot and monocot plants

10.1101/2020.08.19.256685 ◽

2020 ◽

Author(s):

Nanami Sakata ◽

Takako Ishiga ◽

Shunsuke Masuo ◽

Yoshiteru Hashimoto ◽

Yasuhiro Ishiga

Keyword(s):

Pseudomonas Syringae ◽

Virulence Factors ◽

Bacterial Blight ◽

Host Plants ◽

Disease Outbreaks ◽

Brown Spot ◽

Wide Range ◽

Infection Processes ◽

Cruciferous Plants ◽

Green Manure Crops

AbstractP. cannabina pv. alisalensis (Pcal) is a causative agent of bacterial blight of crucifer including cabbage, radish, and broccoli. Importantly, Pcal can infect not only a wide range of Brassicaceae, but also green manure crops such as oat. However, Pcal virulence mechanisms have not been investigated and are not fully understood. We focused on coronatine (COR) function, which is one of the well-known P. syringae pv. tomato DC3000 virulence factors, in Pcal infection processes on both dicot and monocot plants. Cabbage and oat plants dip-inoculated with a Pcal KB211 COR mutant (ΔcmaA) exhibited reduced virulence compared to Pcal WT. Moreover, ΔcmaA failed to reopen stomata on both cabbage and oat, suggesting that COR facilitates Pcal entry through stomata into both plants. Furthermore, cabbage and oat plants syringe-infiltrated with ΔcmaA also showed reduced virulence, suggesting that COR is involved in overcoming not only stomatal-based defense, but also apoplastic defense. Indeed, defense related genes, including PR1 and PR2, were highly expressed in plants inoculated with ΔcmaA compared to Pcal WT, indicating that COR suppresses defense-related genes of both cabbage and oat. Additionally, SA accumulation increases after ΔcmaA inoculation compared to Pcal WT. Taken together, COR contributes to cause disease by suppressing stomatal-based defense and apoplastic defense in both dicot and monocot plants. This is the first study to investigate COR functions in the interaction of Pcal and different host plants (dicot and monocot plants) using genetically and biochemically defined COR deletion mutants.Author summaryDisease outbreaks caused by new Pseudomonas syringae isolates are problems worldwide. P. cannabina pv. alisalensis (Pcal) causes bacterial blight on a wide range of cruciferous plants and bacterial brown spot on oat plants. Although P. syringae deploys a variety of virulence factors, Pcal virulence factors have not been investigated. We focused on coronatine (COR) function, which is one of the well-known P. syringae virulence factors. COR is a non-host-specific phytotoxin and contributes to P. syringae growth and lesion formation or expansion in several host plants. COR function has been mainly studied in the model pathogen P. syringae pv. tomato DC3000 and model the plant Arabidopsis thaliana. Thus, COR roles in Pcal infection especially on monocot plants have not been well studied. Therefore, we investigated COR role in Pcal interaction with both dicot and monocot plants. Here, we revealed that COR functions as a multifunctional suppressor to manage Pcal virulence on both plants.

Download Full-text

Coronatine contributes to Pseudomonas cannabina pv. alisalensis virulence by overcoming both stomatal and apoplastic defenses in dicot and monocot plants

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-09-20-0261-r ◽

2021 ◽

Author(s):

Nanami Sakata ◽

Takako Ishiga ◽

Shunsuke Masuo ◽

Yoshiteru Hashimoto ◽

Yasuhiro Ishiga

Keyword(s):

Virulence Factors ◽

Causative Agent ◽

Green Manure ◽

Bacterial Blight ◽

Host Plants ◽

Deletion Mutants ◽

Tomato Dc3000 ◽

Wide Range ◽

Infection Processes ◽

Green Manure Crops

Pseudomonas cannabina pv. alisalensis (Pcal) is a causative agent of bacterial blight of crucifer including cabbage, radish, and broccoli. Importantly, Pcal can infect not only a wide range of Brassicaceae, but also green manure crops such as oat. However, Pcal virulence mechanisms have not been investigated and are not fully understood. We focused on coronatine (COR) function, which is one of the well-known P. syringae pv. tomato DC3000 virulence factors, in Pcal infection processes on both dicot and monocot plants. Cabbage and oat plants dip-inoculated with a Pcal KB211 COR mutant (ΔcmaA) exhibited reduced virulence compared to Pcal WT. Moreover, ΔcmaA failed to reopen stomata on both cabbage and oat, suggesting that COR facilitates Pcal entry through stomata into both plants. Furthermore, cabbage and oat plants syringe-infiltrated with ΔcmaA also showed reduced virulence, suggesting that COR is involved in overcoming not only stomatal-based defense, but also apoplastic defense. Indeed, defense related genes, including PR1 and PR2, were highly expressed in plants inoculated with ΔcmaA compared to Pcal WT, indicating that COR suppresses defense-related genes of both cabbage and oat. Additionally, SA accumulation increases after ΔcmaA inoculation compared to Pcal WT. Taken together, COR contributes to cause disease by suppressing stomatal-based defense and apoplastic defense in both dicot and monocot plants. Here, we investigated COR functions in the interaction of Pcal and different host plants (dicot and monocot plants) using genetically and biochemically defined COR deletion mutants.

Download Full-text

Xa7, a new executor R gene that confers durable and broad-spectrum resistance to bacterial blight disease in rice

Plant Communications ◽

10.1016/j.xplc.2021.100143 ◽

2021 ◽

pp. 100143

Author(s):

Xifeng Chen ◽

Pengcheng Liu ◽

Le Mei ◽

Xiaoling He ◽

Long Chen ◽

...

Keyword(s):

Broad Spectrum ◽

Bacterial Blight ◽

R Gene ◽

Broad Spectrum Resistance ◽

Bacterial Blight Disease ◽

Blight Disease

Download Full-text

Identification of ferrichrome- and ferrioxamine B-mediated iron uptake by Aspergillus fumigatus

Biochemical Journal ◽

10.1042/bcj20160066 ◽

2016 ◽

Vol 473 (9) ◽

pp. 1203-1213 ◽

Cited By ~ 11

Author(s):

Yong-Sung Park ◽

Ju-Yeon Kim ◽

Cheol-Won Yun

Keyword(s):

Gene Expression ◽

Plasma Membrane ◽

Aspergillus Fumigatus ◽

Virulence Factors ◽

Membrane Transporters ◽

Yeast Cells ◽

Double Deletion ◽

Ferrioxamine B ◽

Uptake Activity ◽

Opportunistic Fungal Pathogen

Aspergillus fumigatus is an opportunistic fungal pathogen for immunocompromised patients, and genes involved in siderophore metabolism have been identified as virulence factors. Recently, we identified the membrane transporters sit1 and sit2, which are putative virulence factors of A. fumigatus; sit1 and sit2 are homologous to yeast Sit1, and sit1 and sit2 gene expression was up-regulated after iron depletion. When expressed heterologously in Saccharomyces cerevisiae, sit1 and sit2 were localized to the plasma membrane; sit1 efficiently complemented ferrichrome (FC) and ferrioxamine B (FOB) uptake in yeast cells, whereas sit2 complemented only FC uptake. Deletion of sit1 resulted in a decrease in FOB and FC uptake, and deletion of sit2 resulted in a decrease in FC uptake in A. fumigatus. It is of interest that a sit1 and sit2 double-deletion mutant resulted in a synergistic decrease in FC uptake activity. Both sit1 and sit2 were localized to the plasma membrane in A. fumigatus. The expression levels of the sit1 and sit2 genes were dependent on hapX under low-but not high-iron conditions. Furthermore, mirB, and sidA gene expression was up-regulated and sreA expression down-regulated when sit1 and sit2 were deleted. Although sit1 and sit2 failed to affect mouse survival rate, these genes affected conidial killing activity. Taken together, our results suggest that sit1 and sit2 are siderophore transporters and putative virulence factors localized to the plasma membrane.

Download Full-text