Bacterial Community Structure and the Dominant Species in Imported Pollens for Artificial Pollination

Kim, Su-Hyeon; Do, Heeil; Cho, Gyeongjun; Kim, Da-Ran; Kwak, Youn‐Sig

doi:10.5423/ppj.nt.02.2021.0029

Cited by 7 publications

(5 citation statements)

References 20 publications

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“…These results indicate that traversianal can inhibit the infection behavior of C. orbiculare on cucumber leaves. The same tricyclic carbon framework is present in fusicoccins, cotylenins, and ophiobolins, some of which are phytotoxic (Camusso et al 2007;Kim et al 1999). The phytotoxicity of fusicoccins, cotylenins, and ophiobolins strongly depends on both the substituents and the tricyclic stereochemistry (Stoessl et al 1989).…”

Section: Discussionmentioning

confidence: 99%

Identification of antifungal compound isolated from Cercospora sp. ME202 and evaluation of its inhibitory activity against Colletotrichum orbiculare

Ino,

Kihara,

Ishihara

et al. 2023

J Gen Plant Pathol

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Cucumber anthracnose, an important disease caused by Colletotrichum orbiculare, is controlled using fungicides. However, this can lead to the development of fungicide resistance. We have previously shown that an ethyl acetate extract of the culture ltrate of Cercospora sp. ME202 (ME202-ECF) exhibits fungicidal activity and inhibits the formation of anthracnose lesions caused by C. orbiculare. However, studies on the control of plant diseases using the antimicrobial compounds produced by Cercospora have not been conducted. Here, we aimed to isolate and identify antifungal compounds produced by Cercospora sp. ME202 and evaluate their antifungal activity against C. orbiculare. We identi ed traversianal, a tricyclic diterpenoid aldehyde with a molecular weight of 316.4 from ME202-ECF. The traversianal structure was determined by liquid chromatography-mass spectrometry using electrospray ionization and nuclear magnetic resonance spectroscopy after puri cation by column chromatography and high-performance liquid chromatography. The inhibitory activity of isolated traversianal was detected as a mycelial growth inhibition zone at Rf 0.92 by thin layer chromatography bio-assay. Traversianal also inhibited the conidial germination of C. orbiculare at 2-10 ppm and exhibited fungicidal activity at 5-10 ppm. Furthermore, pretreatment of cucumber leaves with 10, 20, and 30 ppm traversianal signi cantly suppressed lesion formation in C. orbiculare without phytotoxicity. These results indicate that the traversianal produced from Cercospora sp. ME202 is a potential candidate as a new fungicide against C. orbiculare.

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Section: Discussionmentioning

confidence: 99%

Identification of antifungal compound isolated from Cercospora sp. ME202 and evaluation of its inhibitory activity against Colletotrichum orbiculare

Ino,

Kihara,

Ishihara

et al. 2023

J Gen Plant Pathol

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“…During the process of fertilization, pollen reduces the survival of its future progeny by inadvertently carrying pathogens ( Card et al., 2007 ; Donati et al., 2018 ; Kim et al., 2018 ; Kim et al., 2021 ; Fetters et al., 2022 ). Furthermore, the ovary becomes exposed to airborne pathogens including, in maize, Gibberella ear rot (GER) associated Fusarium species, because the ovary is connected to the style passage which, by necessity, is exposed to the environment to capture pollen; the style then transmits the male gametes to awaiting eggs ( Kapu and Cosgrove, 2010 ; Thompson and Raizada, 2018 ; Khalaf et al., 2021 ).…”

Section: Discussionmentioning

confidence: 99%

“…Style-entering fungal pathogens cause billions of dollars of losses to farmers globally and endanger human and livestock health by depositing mycotoxins in the grain ( Miller et al., 2007 ; Maiorano et al., 2009 ; Thompson and Raizada, 2018 ). Though many of these pathogens are airborne, they can also be hitchhikers on pollen, including viruses, bacteria, and some fungi ( Card et al., 2007 ; Donati et al., 2018 ; Kim et al., 2018 ; Kim et al., 2021 ; Fetters et al., 2022 ). Ultimately, these pathogens reduce progeny seed fitness and endanger the genetic contribution of the male gametes.…”

Section: Introductionmentioning

confidence: 99%

Maize pollen carry bacteria that suppress a fungal pathogen that enters through the male gamete fertilization route

Shrestha,

Limay-Rios,

Brettingham

et al. 2024

Front. Plant Sci.

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In flowering plants, after being released from pollen grains, the male gametes use the style channel to migrate towards the ovary where they fertilize awaiting eggs. Environmental pathogens exploit the style passage, resulting in diseased progeny seed. The belief is that pollen also transmits pathogens into the style. By contrast, we hypothesized that pollen carries beneficial microbes that suppress environmental pathogens on the style passage. No prior studies have reported pollen-associated bacterial functions in any plant species. Here, bacteria were cultured from maize (corn) pollen encompassing wild ancestors and farmer-selected landraces from across the Americas, grown in a common field in Canada for one season. In total, 298 bacterial isolates were cultured, spanning 45 genera, 103 species, and 88 OTUs, dominated by Pantoea, Bacillus, Pseudomonas, Erwinia, and Microbacterium. Full-length 16S DNA-based taxonomic profiling showed that 78% of bacterial taxa from the major wild ancestor of maize (Parviglumis teosinte) were present in at least one cultivated landrace. The species names of the bacterial isolates were used to search the pathogen literature systematically; this preliminary evidence predicted that the vast majority of the pollen-associated bacteria analyzed are not maize pathogens. The pollen-associated bacteria were tested in vitro against a style-invading Fusarium pathogen shown to cause Gibberella ear rot (GER): 14 isolates inhibited this pathogen. Genome mining showed that all the anti-Fusarium bacterial species encode phzF, associated with biosynthesis of the natural fungicide, phenazine. To mimic the male gamete migration route, three pollen-associated bacterial strains were sprayed onto styles (silks), followed by Fusarium inoculation; these bacteria reduced GER symptoms and mycotoxin accumulation in progeny seed. Confocal microscopy was used to search for direct evidence that pollen-associated bacteria can defend living silks against Fusarium graminearum (Fg); bacterial strain AS541 (Kluyvera intermedia), isolated from pollen of ancestral Parviglumis, was observed to colonize the susceptible style/silk entry points of Fg (silk epidermis, trichomes, wounds). Furthermore, on style/silk tissue, AS541 colonized/aggregated on Fg hyphae, and was associated with Fg hyphal breaks. These results suggest that pollen has the potential to carry bacteria that can defend the style/silk passage against an environmental pathogen – a novel observation.

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“…However, we do not know the relative influence of insect vectors on phyllosphere colonisation in our orchards, so we cannot draw strong conclusions. Additionally, management practices such as artificial pollination can alter the microbial communities in orchards [ 39 ].…”

Section: Dominant Community Assembly Processes Contrast Between the S...mentioning

confidence: 99%

Soil bacterial community composition is more stable in kiwifruit orchards relative to phyllosphere communities over time

Louisson,

Ranjard,

Buckley

et al. 2023

Environmental Microbiome

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Background Soil and phyllosphere (leaves and fruit) microbes play critical roles in the productivity and health of crops. However, microbial community dynamics are currently understudied in orchards, with a limited number incorporating temporal monitoring. We used 16S rRNA gene amplicon sequencing to investigate bacterial community temporal dynamics and community assembly processes on the leaves and fruit, and in the soil of 12 kiwifruit orchards across a cropping season in New Zealand. Results Community composition significantly differed (P < 0.001) among the three sample types. However, the communities in the phyllosphere substrates more closely resembled each other, relative to the communities in the soil. There was more temporal stability in the soil bacterial community composition, relative to the communities residing on the leaves and fruit, and low similarity between the belowground and aboveground communities. Bacteria in the soil were more influenced by deterministic processes, while stochastic processes were more important for community assembly in the phyllosphere. Conclusions The higher temporal variability and the stochastic nature of the community assembly processes observed in the phyllosphere communities highlights why predicting the responsiveness of phyllosphere communities to environmental change, or the likelihood of pathogen invasion, can be challenging. The relative temporal stability and the influence of deterministic selection on soil microbial communities suggests a greater potential for their prediction and reliable manipulation.

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Bacterial Community Structure and the Dominant Species in Imported Pollens for Artificial Pollination

Cited by 7 publications

References 20 publications

Identification of antifungal compound isolated from Cercospora sp. ME202 and evaluation of its inhibitory activity against Colletotrichum orbiculare

Identification of antifungal compound isolated from Cercospora sp. ME202 and evaluation of its inhibitory activity against Colletotrichum orbiculare

Maize pollen carry bacteria that suppress a fungal pathogen that enters through the male gamete fertilization route

Soil bacterial community composition is more stable in kiwifruit orchards relative to phyllosphere communities over time

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