Bacterial Volatiles in Promotion of Plant Under Biotic Stress

Genome-wide transcriptome analysis using RNA-Seq of Lilium longiflorum revealed valuable genes responding to biotic stresses. WRKY transcription factors are regulatory proteins playing essential roles in defense processes under environmental stresses, causing considerable losses in flower quality and production. Thirty-eight WRKY genes were identified from the transcriptomic profile from lily genotypes, exhibiting leaf blight caused by Botrytis elliptica. Lily WRKYs have a highly conserved motif, WRKYGQK, with a common variant, WRKYGKK. Phylogeny of LlWRKYs with homologous genes from other representative plant species classified them into three groups- I, II, and III consisting of seven, 22, and nine genes, respectively. Base on functional annotation, 22 LlWRKY genes were associated with biotic stress, nine with abiotic stress, and seven with others. Sixteen unique LlWRKY were studied to investigate responses to stress conditions using gene expression under biotic and abiotic stress treatments. Five genes—LlWRKY3, LlWRKY4, LlWRKY5, LlWRKY10, and LlWRKY12—were substantially upregulated, proving to be biotic stress-responsive genes in vivo and in vitro conditions. Moreover, the expression patterns of LlWRKY genes varied in response to drought, heat, cold, and different developmental stages or tissues. Overall, our study provides structural and molecular insights into LlWRKY genes for use in the genetic engineering in Lilium against Botrytis disease.

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Proteomics and Metabolomics Studies on the Biotic Stress Responses of Rice: an Update

Rice ◽

10.1186/s12284-021-00461-4 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Kieu Thi Xuan Vo ◽

Md Mizanor Rahman ◽

Md Mustafizur Rahman ◽

Kieu Thi Thuy Trinh ◽

Sun Tae Kim ◽

...

Keyword(s):

Stress Responses ◽

Biotic Stress ◽

Defense Mechanisms ◽

Defense Responses ◽

Global Changes ◽

Biotic Stresses ◽

Novel Proteins ◽

Stress Agent ◽

Global Food ◽

Shed Light

AbstractBiotic stresses represent a serious threat to rice production to meet global food demand and thus pose a major challenge for scientists, who need to understand the intricate defense mechanisms. Proteomics and metabolomics studies have found global changes in proteins and metabolites during defense responses of rice exposed to biotic stressors, and also reported the production of specific secondary metabolites (SMs) in some cultivars that may vary depending on the type of biotic stress and the time at which the stress is imposed. The most common changes were seen in photosynthesis which is modified differently by rice plants to conserve energy, disrupt food supply for biotic stress agent, and initiate defense mechanisms or by biotic stressors to facilitate invasion and acquire nutrients, depending on their feeding style. Studies also provide evidence for the correlation between reactive oxygen species (ROS) and photorespiration and photosynthesis which can broaden our understanding on the balance of ROS production and scavenging in rice-pathogen interaction. Variation in the generation of phytohormones is also a key response exploited by rice and pathogens for their own benefit. Proteomics and metabolomics studies in resistant and susceptible rice cultivars upon pathogen attack have helped to identify the proteins and metabolites related to specific defense mechanisms, where choosing of an appropriate method to identify characterized or novel proteins and metabolites is essential, considering the outcomes of host-pathogen interactions. Despites the limitation in identifying the whole repertoire of responsive metabolites, some studies have shed light on functions of resistant-specific SMs. Lastly, we illustrate the potent metabolites responsible for resistance to different biotic stressors to provide valuable targets for further investigation and application.

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Identifying volatile in vitro biomarkers for oral bacteria with proton-transfer-reaction mass spectrometry and gas chromatography–mass spectrometry

Scientific Reports ◽

10.1038/s41598-021-96287-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kajsa Roslund ◽

Markku Lehto ◽

Pirkko Pussinen ◽

Kari Hartonen ◽

Per-Henrik Groop ◽

...

Keyword(s):

Mass Spectrometry ◽

Gas Chromatography ◽

Proton Transfer ◽

Transfer Reaction ◽

Proton Transfer Reaction ◽

Oral Bacteria ◽

Gas Chromatography Mass Spectrometry ◽

Volatile Analysis ◽

Bacterial Volatiles

AbstractWe have measured the volatile fingerprints of four pathogenic oral bacteria connected to periodontal disease and dental abscess: Porphyromonas gingivalis (three separate strains), Prevotella intermedia, Prevotella nigrescens and Tannerella forsythia. Volatile fingerprints were measured in vitro from the headspace gas of the bacteria cultured on agar. Concrete identification of new and previously reported bacterial volatiles were performed by a combination of solid phase microextraction (SPME) and offline gas chromatography–mass spectrometry (GC–MS). We also studied the effect of the reduced electric field strength (E/N) on the fragmentation patterns of bacterial volatiles in online proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS). We aimed to discover possible new biomarkers for the studied oral bacteria, as well as to validate the combination of GC–MS and PTR-MS for volatile analysis. Some of the most promising compounds produced include: 1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ), indole, and a cascade of sulphur compounds, such as methanethiol, dimethyl disulphide (DMDS) and dimethyl trisulphide (DMTS). We also found that several compounds, especially alcohols, aldehydes and esters, fragment significantly with the PTR-MS method, when high E/N values are used. We conclude that the studied oral bacteria can be separated by their volatile fingerprints in vitro, which could have importance in clinical and laboratory environments. In addition, using softer ionization conditions can improve the performance of the PTR-MS method in the volatile analysis of certain compounds.

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C4 Bacterial Volatiles Improve Plant Health

Pathogens ◽

10.3390/pathogens10060682 ◽

2021 ◽

Vol 10 (6) ◽

pp. 682

Author(s):

Bruno Henrique Silva Dias ◽

Sung-Hee Jung ◽

Juliana Velasco de Castro Oliveira ◽

Choong-Min Ryu

Keyword(s):

Plant Growth ◽

Volatile Compounds ◽

Large Scale ◽

Growth Promotion ◽

Plant Growth Promoting Rhizobacteria ◽

Plant Health ◽

Systemic Resistance ◽

Potential Applications ◽

Plant Growth Promoting ◽

Bacterial Volatiles

Plant growth-promoting rhizobacteria (PGPR) associated with plant roots can trigger plant growth promotion and induced systemic resistance. Several bacterial determinants including cell-wall components and secreted compounds have been identified to date. Here, we review a group of low-molecular-weight volatile compounds released by PGPR, which improve plant health, mostly by protecting plants against pathogen attack under greenhouse and field conditions. We particularly focus on C4 bacterial volatile compounds (BVCs), such as 2,3-butanediol and acetoin, which have been shown to activate the plant immune response and to promote plant growth at the molecular level as well as in large-scale field applications. We also disc/ uss the potential applications, metabolic engineering, and large-scale fermentation of C4 BVCs. The C4 bacterial volatiles act as airborne signals and therefore represent a new type of biocontrol agent. Further advances in the encapsulation procedure, together with the development of standards and guidelines, will promote the application of C4 volatiles in the field.

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Gene Pool of Winter Wheat from the World Collection of N.I. Vavilov Institute of Plant Industry (VIR) for Biotic Stress Resistance

Pathogens ◽

10.3390/pathogens10050514 ◽

2021 ◽

Vol 10 (5) ◽

pp. 514

Author(s):

Sulukhan Temirbekova ◽

Ibrahim Jafarov ◽

Ivan Kulikov ◽

Yuliya Afanaseva ◽

Elena Kalashnikova

Keyword(s):

Winter Wheat ◽

Stress Resistance ◽

Biotic Stress ◽

Gene Pool ◽

Barley Yellow Dwarf Virus ◽

Economic Damage ◽

Head Blight ◽

World Collection ◽

Methodological Guidelines ◽

The Ideal

This paper presents the results of the 50 year-long research into the winter wheat gene pool from the VIR world collection in the Moscow region to assess biotic stress resistance following N.I. Vavilov’s concept of the ‘ideal variety’, proposed in 1935. The Federal Scientific Selection and Technology Center for Horticulture and Nursery was responsible for the field studies of winter wheat, and the All-Russian Research Institute of Phytopathology and Russian State Agrarian University—Moscow Timiryazev Agricultural Academy—for phytopathological studies. The wheat collection was studied in compliance with the VIR Methodological Guidelines using the International COMECON list of descriptors for the genus Triticum L. Resistance against the enzyme–mycotic depletion of seeds (EMDS) was tested using original techniques. It was found that annual brown rust and powdery mildew attacks in the collection’s winter wheat samples caused no significant economic damage. One case of Septoria head and leaf blotch, two cases of Fusarium head blight, one case of root rot, one case of barley yellow dwarf virus, 20 cases of EMDS, and three cases of 3rd-degree EMDS, i.e., seed germination in an ear, were recorded. The parent material resistant to the biotic stresses of the region was selected for breeding. Domestic breeders have created outstanding wheat varieties close to the ‘ideal’ as noted by N.I. Vavilov.

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