Plant disease outbreaks are increasing and threaten food security for the vulnerable in many areas of the world. Now a global human pandemic is threatening the health of millions on our planet. A ...stable, nutritious food supply will be needed to lift people out of poverty and improve health outcomes. Plant diseases, both endemic and recently emerging, are spreading and exacerbated by climate change, transmission with global food trade networks, pathogen spillover, and evolution of new pathogen lineages. In order to tackle these grand challenges, a new set of tools that include disease surveillance and improved detection technologies including pathogen sensors and predictive modeling and data analytics are needed to prevent future outbreaks. Herein, we describe an integrated research agenda that could help mitigate future plant disease pandemics.
Abstract
The FAM-1 genotype of
Phytophthora infestans
caused late blight in the 1840s in the US and Europe and was responsible for the Irish famine. We sampled 140 herbarium specimens collected ...between 1845 and 1991 from six continents and used 12-plex microsatellite genotyping (SSR) to identify FAM-1 and the mtDNA lineage (Herb-1/Ia) present in historic samples. FAM-1 was detected in approximately 73% of the historic specimens and was found on six continents. The US-1 genotype was found later than FAM-1 on all continents except Australia/Oceania and in only 27% of the samples. FAM-1 was the first genotype detected in almost all the former British colonies from which samples were available. The data from historic outbreak samples suggest the FAM-1 genotype was widespread, diverse, and spread to Asia and Africa from European sources. The famine lineage spread to six continents over 144 years, remained widespread and likely spread during global colonization from Europe. In contrast, modern lineages of
P. infestans
are rapidly displaced and sexual recombination occurs in some regions.
Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, was responsible for the Irish potato famine of the 1840s. Initial disease outbreaks occurred in the US in 1843, two ...years prior to European outbreaks. We examined the evolutionary relationships and source of the 19th-century outbreaks using herbarium specimens of P. infestans from historic (1846-1970) and more recent isolates (1992-2014) of the pathogen. The same unique SSR multilocus genotype, named here as FAM-1, caused widespread outbreaks in both US and Europe. The FAM-1 lineage shared allelic diversity and grouped with the oldest specimens collected in Colombia and Central America. The FAM-1 lineage of P. infestans formed a genetic group that was distinct from more recent aggressive lineages found in the US. The US-1 lineage formed a second, mid-20th century group. Recent modern US lineages and the oldest Mexican lineages formed a genetic group with recent Mexican lineages, suggesting a Mexican origin of recent US lineages. A survey of mitochondrial haplotypes in a larger set of global herbarium specimens documented the more frequent occurrence of the HERB-1 (type Ia) mitochondrial haplotype in archival collections from 1866-75 and 1906-1915 and the rise of the Ib mitochondrial lineage (US-1) between 1946-1955. The FAM-1 SSR lineage survived for almost 100 years in the US, was geographically widespread, and was displaced first in the mid-20th century by the US-1 lineage and then by distinct new aggressive lineages that migrated from Mexico.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Plant pathogen detection conventionally relies on molecular technology that is complicated, time-consuming and constrained to centralized laboratories. We developed a cost-effective smartphone-based ...volatile organic compound (VOC) fingerprinting platform that allows non-invasive diagnosis of late blight caused by Phytophthora infestans by monitoring characteristic leaf volatile emissions in the field. This handheld device integrates a disposable colourimetric sensor array consisting of plasmonic nanocolorants and chemo-responsive organic dyes to detect key plant volatiles at the ppm level within 1 min of reaction. We demonstrate the multiplexed detection and classification of ten individual plant volatiles with this field-portable VOC-sensing platform, which allows for early detection of tomato late blight 2 d after inoculation, and differentiation from other pathogens of tomato that lead to similar symptoms on tomato foliage. Furthermore, we demonstrate a detection accuracy of ≥95% in diagnosis of P. infestans in both laboratory-inoculated and field-collected tomato leaves in blind pilot tests. Finally, the sensor platform has been beta-tested for detection of P. infestans in symptomless tomato plants in the greenhouse setting.
In-field molecular diagnosis of plant diseases via nucleic acid amplification is currently limited by cumbersome protocols for extracting and isolating pathogenic DNA from plant tissues. To address ...this challenge, a rapid plant DNA extraction method was developed using a disposable polymeric microneedle (MN) patch. By applying MN patches on plant leaves, amplification-assay-ready DNA can be extracted within a minute from different plant species. MN-extracted DNA was used for direct polymerase chain reaction amplification of plant plastid DNA without purification. Furthermore, using this patch device, extraction of plant pathogen DNA (Phytophthora infestans) from both laboratory-inoculated and field-infected leaf samples was performed for detection of late blight disease in tomato. MN extraction achieved 100% detection rate of late blight infections for samples after 3 days of inoculation when compared to the conventional gold standard cetyltrimethylammonium bromide (CTAB)-based DNA extraction method and 100% detection rate for all blind field samples tested. This simple, cell-lysis-free, and purification-free DNA extraction method could be a transformative approach to facilitate rapid sample preparation for molecular diagnosis of various plant diseases directly in the field.
In 1843, a hitherto unknown plant pathogen entered the US and spread to potato fields in the northeast. By 1845, the pathogen had reached Ireland leading to devastating famine. Questions arose ...immediately about the source of the outbreaks and how the disease should be managed. The pathogen, now known as Phytophthora infestans, still continues to threaten food security globally. A wealth of untapped knowledge exists in both archival and modern documents, but is not readily available because the details are hidden in descriptive text. In this work, we (1) used text analytics of unstructured historical reports (1843-1845) to map US late blight outbreaks; (2) characterized theories on the source of the pathogen and remedies for control; and (3) created modern late blight intensity maps using Twitter feeds. The disease spread from 5 to 17 states and provinces in the US and Canada between 1843 and 1845. Crop losses, Andean sources of the pathogen, possible causes and potential treatments were discussed. Modern disease discussion on Twitter included near-global coverage and local disease observations. Topic modeling revealed general disease information, published research, and outbreak locations. The tools described will help researchers explore and map unstructured text to track and visualize pandemics.
We demonstrate an integrated microneedle (MN)-smartphone nucleic acid amplification platform for “sample-to-answer” diagnosis of multiplexed plant pathogens within 30 min. This portable system ...consists of a polymeric MN patch for rapid nucleic acid extraction within a minute and a 3D-printed smartphone imaging device for loop-mediated isothermal amplification (LAMP) reaction and detection. We expanded the extraction of the MN technology for DNA targets as in the previous study (ACS Nano, 2019, 13, 6540–6549) to more fragile RNA biomarkers, evaluated the storability of the extracted nucleic acid samples on MN surfaces, and developed a smartphone-based LAMP amplification and fluorescent reader device that can quantify four LAMP reactions on the same chip. In addition, we have found that the MN patch containing as few as a single needle tip successfully extracted enough RNA for RT-PCR or RT-LAMP analysis. Moreover, MN-extracted RNA samples remained stable on MN surfaces for up to three days. The MN-smartphone platform has been used to detect both Phytophthora infestans DNA and tomato spotted wilt virus (TSWV) RNA down to 1 pg, comparable to the results from a benchtop thermal cycler. Finally, multiplexed detection of P. infestans and TSWV through a single extraction from infected tomato leaves and amplification on the smartphone without benchtop equipment was demonstrated.
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•Rapid extraction of RNA from plant leaves by a simple press and retraction process using a microneedle (MN) patch.•An integrated MN-smartphone platform for on-site “sample-to-answer” detection of plant pathogens within 30 min.•The MN-smartphone platform can simultaneously screen multiple target pathogens from a single MN extraction.•The method enables detecting tomato spotted wilt virus as early as 5 days after inoculation in asymptomatic tomato plants.
is the causal agent of potato late blight, a devastating disease of tomato and potato and a threat to global food security. Early detection and intervention is essential for effective management of ...the pathogen. We developed a loop-mediated isothermal amplification (LAMP) assay for
and compared this assay to conventional PCR, real-time LAMP, and droplet digital PCR for detection of
. The LAMP assay was specific for
on potato and tomato and did not amplify other potato- or tomato-infecting
species or other fungal and bacterial pathogens that infect potato and tomato. The detection threshold for SYBR Green LAMP and real-time LAMP read with hydroxynaphthol blue and EvaGreen was 1 pg/µl. In contrast, detection by conventional PCR was 10 pg/µl. Droplet digital PCR had the lowest detection threshold (100 fg/µl). We adapted the LAMP assay using SYBR Green and a mobile reader (mReader) for use in the field. Detection limits were 584 fg/µl for SYBR Green LAMP read on the mReader, which was more sensitive than visualization with the human eye. The mobile platform records geospatial coordinates and data from positive pathogen detections can be directly uploaded to a cloud database. Data can then be integrated into disease surveillance networks. This system will be useful for real-time detection of
and will improve the timeliness of reports into surveillance systems such as USABlight or EuroBlight.
Bacterial outer membrane vesicles (OMVs) perform a variety of functions in bacterial survival and virulence. In mammalian systems, OMVs activate immune responses and are exploited as vaccines. ...However, little work has focused on the interactions of OMVs with plant hosts. Here, we report that OMVs from Pseudomonas syringae and P. fluorescens activate plant immune responses that protect against bacterial and oomycete pathogens. OMV-mediated immunomodulatory activity from these species displayed different sensitivity to biochemical stressors, reflecting differences in OMV content. Importantly, OMV-mediated plant responses are distinct from those triggered by conserved bacterial epitopes or effector molecules alone. Our study shows that OMV-induced protective immune responses are independent of the T3SS and protein, but that OMV-mediated seedling growth inhibition largely depends on proteinaceous components. OMVs provide a unique opportunity to understand the interplay between virulence and host response strategies and add a new dimension to consider in host-microbe interactions.
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•OMVs from P. syringae and P. fluorescens protect against bacteria and oomycetes•Bacterial OMVs elicit distinct sets of plant immune responses•OMV-mediated effects withstand biochemical disruption•OMVs can serve as new tools to probe the plant immune system
The role that bacterial outer membrane vesicles (OMVs) play in plant-microbe interactions is poorly characterized. McMillan et al. show that OMVs elicit plant immune responses that protect against pathogens. This study also reveals a use for OMVs as tools to probe the plant immune system.
Determination of plant stresses such as infections by plant pathogens is currently dependent on time-consuming and complicated analytical technologies. Here, we report a leaf-attachable ...chemiresistive sensor array for real-time fingerprinting of volatile organic compounds (VOCs) that permits noninvasive and early diagnosis of plant diseases, such as late blight caused by Phytophthora infestans. The imperceptible sensor patch integrates an array of graphene-based sensing materials and flexible silver nanowire electrodes on a kirigami-inspired stretchable substrate, which can minimize strain interference. The sensor patch has been mounted on live tomato plants to profile key plant volatiles at low-ppm concentrations with fast response (<20 s). The multiplexed sensor array allows for accurate detection and classification of 13 individual plant volatiles with >97% classification accuracy. The wearable sensor patch was used to diagnose tomato late blight as early as 4 days post inoculation and abiotic stresses such as mechanical damage within 1 h.
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•We report a leaf-attachable VOC sensor for real-time profiling of plant volatiles•The sensor patch detects plant VOCs at low-ppm concentrations•13 individual plant VOCs were differentiated with >97% accuracy by the sensor•It has been used to detect tomato late blight and mechanical damage noninvasively
Developing a noninvasive sensing technique that enables continuous plant volatile organic compound (VOC) analysis in their natural habitat is essential to capture the VOC flux from plants for accurate monitoring of plant diseases and stresses. Several wearable sensor platforms have recently been developed that can be attached to living plants for continuous monitoring. However, detecting and discrimination of plant chemical cues such as VOCs have rarely been reported by using a wearable sensor platform. Here, a real-time VOC-profiling sensor device on a stretchable substrate has been developed for instant monitoring of plant host responses for early disease diagnosis and rapid stress identification of living plants.
We demonstrate a wearable sensor platform for real-time profiling of plant volatile organic compound markers based on a chemiresistive sensor array made of reduced graphene oxide functionalized with various ligands. This multiplexed sensor array allows for accurate classification of 13 individual plant volatiles with >97% classification accuracy, and detection of late blight infection and mechanical damage noninvasively. This lightweight gas sensor platform could be a powerful alternative to other diagnostics tools available for long-term monitoring of plant health in the field.
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