Detection of Diseases and Volatile Discrimination of Plants

Author(s):  
Reza Ghaffari ◽  
Fu Zhang ◽  
D. D. Iliescu ◽  
Evor L. Hines ◽  
Mark S. Leeson ◽  
...  

The diagnosis of plant diseases is an important part of commercial greenhouse crop production and can enable continued disease and pest control. A plant subject to infection typically releases exclusive volatile organic compounds (VOCs) which may be detected by appropriate sensors. In this work, an Electronic Nose (EN) is employed as an alternative to Gas Chromatography - Mass Spectrometry (GC-MS) to sample the VOCs emitted by control and artificially infected tomato plants. A case study in which powdery mildew and spider mites may be present on tomato plants is considered. The data from the EN was analyzed and visualized using Fuzzy C-Mean Clustering (FCM) and Self-Organizing Maps (SOM). The VOC samples from healthy plants were successfully distinguished from the infected ones using the clustering techniques. This study suggests that the proposed methodology is promising for enhancing the automated detection of crop pests and diseases and may be an attractive tool to be deployed in horticultural settings.

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3480 ◽  
Author(s):  
Shaoqing Cui ◽  
Elvia Adriana Alfaro Inocente ◽  
Nuris Acosta ◽  
Harold. M. Keener ◽  
Heping Zhu ◽  
...  

An electronic nose (E-nose) system equipped with a sensitive sensor array was developed for fast diagnosis of aphid infestation on greenhouse tomato plants at early stages. Volatile organic compounds (VOCs) emitted by tomato plants with and without aphid attacks were detected using both the developed E-nose system and gas chromatography mass spectrometry (GC-MS), respectively. Sensor performance, with fast sensor responses and high sensitivity, were observed using the E-nose system. A principle component analysis (PCA) indicated accurate diagnosis of aphid-stressed plants compared to healthy ones, with the first two PCs accounting for 86.7% of the classification. The changes in VOCs profiles of the healthy and infested tomato plants were quantitatively determined by GC-MS. Results indicated that a group of new VOCs biomarkers (linalool, carveol, and nonane (2,2,4,4,6,8,8-heptamethyl-)) played a role in providing information on the infestation on the tomato plants. More importantly, the variation in the concentration of sesquiterpene VOCs (e.g., caryophyllene) and new terpene alcohol compounds was closely associated with the sensor responses during E-nose testing, which verified the reliability and accuracy of the developed E-nose system. Tomato plants growing in spring had similar VOCs profiles as those of winter plants, except several terpenes released from spring plants that had a slightly higher intensity.


2008 ◽  
Vol 63 (1-2) ◽  
pp. 113-123
Author(s):  
Kiriakos Kotzabasis ◽  
Eleni Navakoudis ◽  
Demetrios J. Vakalounakis

Plants, as well as fungi, use ambient sunlight as information to regulate photomorphogenetic processes. The photobiological control of this information showed that the development of photobiological greenhouse plastic covers simulates a photonic information that leads to a physiological enhancement of plant productivity and fungal disease control, thus minimizing the need for the use of agrochemicals. The main characteristics of these photobiological greenhouse plastic covers are the high transmission of photosynthetically active radiation (PAR, 400 − 700 nm) combined with an increase of the factor ζ =RL(655 −665 nm)/FRL(725 −735 nm), which affects the cellular phytochromic equilibrium Φ = Pfr/(Pfr + Pr) and regulates the photosynthetic activity and therefore the plant productivity. Additionally, increase of the spectral ratios from the transmitted light: BL(420-500 nm)/nearUV(290-370 nm) and BL(420 −500 nm)/ FRL(725 −735 nm), cause mainly the induction of biochemical, physiological and morphological responses, regulated by cryptochromes in plants (e. g. inflorescence and infructescence) and mycochrome in fungi (e. g. inhibition of sporulation). In the present work, comparative studies with randomly selected greenhouse plastics showed that small changes in the abovementioned “photobiological” parameters raise the productivity of tomato plants and inhibit the sporulation of several isolates of the fungal pathogen Botrytis cinerea. Thus, a model for the photoregulation of these two phenomena in greenhouses is proposed.


2021 ◽  
Vol 7 (3) ◽  
pp. 187
Author(s):  
On-Uma Ruangwong ◽  
Prisana Wonglom ◽  
Nakarin Suwannarach ◽  
Jaturong Kumla ◽  
Narit Thaochan ◽  
...  

Soil microorganisms are well studied for their beneficial effects on plant growth and their impact on biocontrol agents. The production of volatile antifungal compounds emitted from soil fungi is considered to be an effective ability that can be applied in biofumigants in the control of plant diseases. A soil fungus, Trichoderma asperelloides TSU1, was isolated from flamingo flower cultivated soil and identified on the basis of the morphology and molecular analysis of the internal transcribed spacer (ITS), rpb2, and tef1-α genes. To test T. asperelloides TSU1-produced volatile organic compounds (VOCs) with antifungal activity, the sealed plate method was used. The VOCs of T. asperelloides TSU1 inhibited the mycelial growth of fungal pathogens that were recently reported as emerging diseases in Thailand, namely, Corynespora cassiicola, Fusarium incarnatum, Neopestalotiopsis clavispora, N. cubana, and Sclerotium rolfsii, with a percentage inhibition range of 38.88–68.33%. Solid-phase microextraction (SPME) was applied to trap VOCs from T. asperelloides TSU1 and tentatively identify them through gas chromatography–mass spectrometry (GC/MS). A total of 17 compounds were detected in the VOCs of T. asperelloides TSU1, and the dominant compounds were identified as fluoro(trinitro)methane (18.192% peak area) and 2-phenylethanol (9.803% peak area). Interestingly, the commercial 2-phenyethanol showed antifungal activity against fungal pathogens that were similar to the VOCs of T. asperelloides TSU1 by bioassay. On the basis of our study’s results, T. asperelloides TSU1 isolated from soil displayed antifungal abilities via the production of VOCs responsible for restricting pathogen growth.


Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 509
Author(s):  
Juan Mayo-Hernández ◽  
Enrique Ramírez-Chávez ◽  
Jorge Molina-Torres ◽  
María de Lourdes Guillén-Cisneros ◽  
Raúl Rodríguez-Herrera ◽  
...  

Domesticated tomato (Solanum lycopersicum L.) crops have presented an increased susceptibility to pests under field and greenhouse conditions. Among these pests is tomato/potato psyllid, Bactericera cockerelli Sulc (Hemiptera: Triozidae), a major pest in solanaceous crops. In this study, we evaluated volatile organic compound (VOC) emissions from the headspace in three healthy varieties of tomato plants (Floradade, Micro-Tom and wild) under greenhouse conditions using solid-phase microextraction and gas chromatography–mass spectrometry (SPME/GC-MS). Later, independent bioassays were performed to evaluate VOC emissions with three varieties infested with nymphs of B. cockerelli. The results in healthy plants showed markedly different VOC profiles in each variety (14 compounds for wild, 17 for Floradade and 4 for Micro-Tom). Plants infested with nymphs showed changes in VOC emissions distinctly in Floradade and wild varieties. We suggest that these qualitative differences in VOC profiles by the degree of domestication could explain the preferences of B. cockerelli.


2020 ◽  
Vol 10 (3) ◽  
pp. 316-329
Author(s):  
Fateme Mirzajani ◽  
Amin Hamidi

Introduction: In this project, the growth and volatile metabolites profiles of Escherichia coli (E. coli ) and Staphylococcus aureus were monitored under the influence of silver base chemical, nanoparticle and ultra-highly diluted compounds. Materials & Methods: The treatments were done for 12000 life cycles using silver nanoparticles (AgNPs) as well as ultra-highly diluted Argentum nitricum (Arg-n). Volatile organic metabolites analysis was performed using gas chromatography mass spectrometry (GC-MS). The results indicated that AgNPs treatment made the bacteria resistant and adapted to growth in the nanoparticle condition. The use of ultra-highly diluted Arg-n initially increased growth but it decreased later. Also, with the continuous usage of these materials, no more bacterial growth was observed. Results: The most important compounds produced by E. coli are Acetophenone, Octyl acetate, Styrene, 1,8-cineole, 4-t-butyl-2-(1-methyl-2-nitroethyl)cyclohexane, hexadecane and 2-Undecanol. The main compounds derived from S. aureus are Acetophenone,1,8-cineole, Benzaldehyde, 2-Hexan-1-ol, Tridecanol, Dimethyl Octenal and tetradecane. Acetophenone and 1,8-cineole were common and produced by both organisms. Conclusion: Based on the origin of the produced volatiles, main volatiles percentage of untreated sample is hydrocarbon (>50%), while bacteria treatments convert the ratio in to aldehydes, ketones and alcohols in the case of AgNPs, (>80%) and aldehydes, ketones and terpenes in the case of Arg-n (>70%).


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3341
Author(s):  
Alessandra Frau ◽  
Lauren Lett ◽  
Rachael Slater ◽  
Gregory R. Young ◽  
Christopher J. Stewart ◽  
...  

The fecal metabolome in early life has seldom been studied. We investigated its evolution in pre-term babies during their first weeks of life. Multiple (n = 152) stool samples were studied from 51 babies, all <32 weeks gestation. Volatile organic compounds (VOCs) were analyzed by headspace solid phase microextraction gas chromatography mass spectrometry. Data were interpreted using Automated Mass Spectral Deconvolution System (AMDIS) with the National Institute of Standards and Technology (NIST) reference library. Statistical analysis was based on linear mixed modelling, the number of VOCs increased over time; a rise was mainly observed between day 5 and day 10. The shift at day 5 was associated with products of branched-chain fatty acids. Prior to this, the metabolome was dominated by aldehydes and acetic acid. Caesarean delivery showed a modest association with molecules of fungal origin. This study shows how the metabolome changes in early life in pre-term babies. The shift in the metabolome 5 days after delivery coincides with the establishment of enteral feeding and the transition from meconium to feces. Great diversity of metabolites was associated with being fed greater volumes of milk.


Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 60
Author(s):  
Vincenzo Michele Sellitto ◽  
Severino Zara ◽  
Fabio Fracchetti ◽  
Vittorio Capozzi ◽  
Tiziana Nardi

From a ‘farm to fork’ perspective, there are several phases in the production chain of fruits and vegetables in which undesired microbial contaminations can attack foodstuff. In managing these diseases, harvest is a crucial point for shifting the intervention criteria. While in preharvest, pest management consists of tailored agricultural practices, in postharvest, the contaminations are treated using specific (bio)technological approaches (physical, chemical, biological). Some issues connect the ‘pre’ and ‘post’, aligning some problems and possible solution. The colonisation of undesired microorganisms in preharvest can affect the postharvest quality, influencing crop production, yield and storage. Postharvest practices can ‘amplify’ the contamination, favouring microbial spread and provoking injures of the product, which can sustain microbial growth. In this context, microbial biocontrol is a biological strategy receiving increasing interest as sustainable innovation. Microbial-based biotools can find application both to control plant diseases and to reduce contaminations on the product, and therefore, can be considered biocontrol solutions in preharvest or in postharvest. Numerous microbial antagonists (fungi, yeasts and bacteria) can be used in the field and during storage, as reported by laboratory and industrial-scale studies. This review aims to examine the main microbial-based tools potentially representing sustainable bioprotective biotechnologies, focusing on the biotools that overtake the boundaries between pre- and postharvest applications protecting quality against microbial decay.


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