Leaf Cuticular Wax, a Trait for Multiple Stress Resistance in Crop Plants

Cuticular waxes form the primary interface between a plant and its external environment. The most important function of this hydrophobic interface is regulation of non-stomatal water loss, gas exchange and conferring resistance to a wide range of biotic as well as abiotic stresses. The biosynthesis, transport and deposition of the cuticular waxes are tightly coordinated by complex molecular networks, which are also often regulated in response to various developmental, biotic as well as abiotic cues. Evidences from model as well as non-model systems suggest that targeted manipulation of the molecular regulators of wax biosynthetic pathways could enhance plant resistance to multiple stresses as well as enhance the post-harvest quality of produce. Under the current scenario of varying climatic conditions, where plants often encounter multiple stress conditions, cuticular waxes is an appropriate trait to be considered for crop improvement programs, as any attempt to improve cuticular traits would be advantageous to the crop to enhance its adaptability to diverse adverse conditions. This chapter briefs on the significance of cuticular waxes in plants, its biosynthesis, transport and deposition, its implication on plant resistance to adverse conditions, and the current options in targeted manipulation of wax-traits for breeding new crop types

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Stable Epigenetic Variants Selected from an Induced Hypomethylated Fragaria vesca Population

Epigenetic inheritance was transmitted through selection over generations of extreme early, but not late flowering time phenotypic lines in F. vesca. Epigenetic variation was initially induced using the DNA demethylating reagent 5-azacytidine (5-azaC). It is the first report exploring epigenetic variant selection and phenotypic trait inheritance in strawberry, a model plant species for one of the most important temperate fruit crop families, Rosaceae. Transmission frequency of these traits was determined across generations. Early flowering (EF4) and late stolon (LS) phenotypic traits were successfully transmitted through meiosis across at least five and two generations, respectively. Stable mitotic transmission of the early flowering phenotype was also demonstrated using clonal daughters derived from the 4th Generation (S4) mother plant. In order to further explore the DNA methylation patterns underlying the early flowering trait, the standard MSAP method using isoschizomers Hpa II / Msp I, and a newly modified MSAP method using isoschizomers Tfi I / Pfe I which detected DNA methylation at CG, CHG, CHH sites were used in two early flowering lines, EF4 lines 1 (P2) and EF4 lines 2 (P3), and control lines (P1). A significant reduction in the number of fully-methylated bands was detected in P2 and P3 when compared to P1 using the novel MSAP method. In the standard MSAP, the symmetric CG and CHG methylation was maintained over generations in the early flowering lines based on the clustering in P2 and P3, while the novel MSAP approach revealed the asymmetric CHH methylation pattern was not maintained over generations. This study provides evidence of stable selection of phenotypic traits, particularly the early flowering phenotype through both meiosis and mitosis, which is meaningful to both breeding programs and commercial horticulture. The maintenance in CG and CHG methylation over generations suggests the early flowering phenotype might be related to DNA methylation alterations at the CG or CHG sites. Finally, this work provides a new approach for studying the role of epigenetics on complex quantitative trait improvement in strawberry, as well as providing a tool to expand phenotypic diversity and expedite potential new horticulture cultivar releases through either seed or vegetative propagation

The effects of sampling and instrument orientation on LiDAR data from crop plots

Wheat is one of the most widely consumed grains in the world and improving its yield, especially under severe climate conditions, is of great importance to world food security. Phenotyping methods can evaluate plants according to their different traits, such as yield and growth characteristics. Assessing the vertical stand structure of plants can provide valuable information about plant productivity and processes, mainly if this trait can be tracked throughout the plant’s growth. Light Detection And Ranging (LiDAR) is a method capable of gathering three-dimensional data from wheat field trials and is potentially suitable for providing non-destructive, high-throughput estimations of the vertical stand structure of plants. The current study considers LiDAR and focuses on investigating the effects of sub-sampling plot data and data collection parameters on the canopy vertical profile (CVP). The CVP is a normalized, ground-referenced histogram of LiDAR point cloud data representing a plot or other spatial domain. The effects of sub-sampling of plot data, the angular field of view (FOV) of the LiDAR and LiDAR scan line orientation on the CVP were investigated. Analysis of spatial sub-sampling effects on CVP showed that at least 144000 random points (600 scan lines) or an area equivalent to three plants along the row were adequate to characterize the overall CVP of the aggregate plot. A comparison of CVPs obtained from LiDAR data for different FOV showed that CVPs varied with the angular range of the LiDAR data, with narrow ranges having a larger proportion of returns in the upper canopy and a lower proportion of returns in the lower part of the canopy. These findings will be necessary to establish minimum plot and sample sizes and compare data from studies where scan direction or field of view differ. These advancements will aid in making comparisons and inform best practices for using close-range LiDAR in phenotypic studies in crop breeding and physiology research

Evaluation of a cloud cover based model for estimation of hourly global solar radiation in Western Canada

Cloud cover based solar radiation models are relatively simple and convenient as the models require the input of cloud cover data which are mostly available from the meteorological stations. In this study, the performance of a cloud cover based solar radiation model (Kasten–Czeplak model) with original or locally fitted coefficients was evaluated for estimating the hourly global solar radiation for four different locations in Western Canada. The average value of R2, mean bias error, and root mean square error are 0.69, −61.6, and 157.9 W m−2, respectively, for the model with original coefficients, whereas 0.82, 4.4, 107.1 W m−2 with locally fitted coefficients. Results show that the Kasten–Czeplak model with locally fitted coefficients satisfactorily estimated the hourly solar radiation of four different locations in Western Canada. Also, the results indicate that the model with original coefficients has very limited accuracy under intermediate cloud cover conditions

Effect of latitude on narrow-leaved purple coneflower (Echinacea angustifolia DC.) yield and phytochemical quality

The worldwide increase in demand for plant-derived drugs has increased interest in medicinal plants as alternative cash crops across western Canada. The objective of this research was to determine if the Northern Vigor® phenomenon, expressed as a combination of elevated crop yield and phytomedicinal quality in crops grown in northern latitudes, exists in narrow-leaved purple coneflower (Echinacea angustifolia DC.). In a 2-yr study, narrow-leaved purple coneflower was grown in three field sites in Saskatchewan, Canada (SK; Saskatoon, La Ronge, and Outlook) and one field site in Oregon, United States (Madras), to test the effects of latitude on root yield, phenolic, and alkylamide phytochemical markers. Roots harvested in 1999 (all three SK sites) and 2000 (two SK sites) had higher root biomass compared with roots harvested in Oregon. Root echinacoside and cynarin content were significantly higher in both years in the three Saskatchewan sites compared with Madras, whereas root chlorogenic acid content and total alkylamides were significantly higher in all three Saskatchewan sites in 1999. In 2000, root chlorogenic acid content and total alkylamides were higher in two of the three Saskatchewan sites compared with Madras. While Aster Yellows were prevalent in Echinacea in Saskatchewan, this disease did not significantly decrease root yield phenolic or phytochemical content. These data suggest that Saskatchewan has a competitive advantage in producing premium-quality narrow-leaved purple coneflower root in North America.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

A quasi-steady state model for predicting the heating requirements of conventional greenhouses in cold regions

A time-dependent, quasi-steady state thermal model (GREENHEAT) based on the lumped estimation of heat transfer parameters of greenhouses has been developed to predict the hourly heating requirements of conventional greenhouses. The model was designed to predict the hourly heating requirements based on the input of greenhouse indoor environmental control parameters, physical and thermal properties of crops and construction materials, and hourly weather data including temperature, relative humidity, wind speed, and cloud cover. The model includes all of the heat transfer parameters in greenhouses including the heat loss for plant evapotranspiration, and the heat gain from environmental control systems. Results show that the predicted solar radiation data from the solar radiation sub-model are a reasonable fit with the data from the National Solar Radiation Database (NSRDB). Thermal analysis indicates environmental control systems could reduce 13–56% of the total heating requirements over the course of a year in the study greenhouse. During the winter season, the highest amount of greenhouse heat is lost due to conduction and convection, and the heat used for evapotranspiration is dominant in the summer. Finally, the model was validated with actual heating data collected from a commercial greenhouse located in Saskatoon, and the results show that the model satisfactorily predicts the greenhouse heating requirements

Temperature adaptation in a changing climate: Nature at risk

Temperature adaptation is a much neglected field in the minds of climate change researchers and policy makers. However, increasing fluctuations in temperature mean that the risk of cold and heat stress will pose an increasing threat to both wild and cultivated plants and animals, with frost injury expected to cause devastating damage to crops on an increasingly large scale. Thus, improving shared knowledge of the biological mechanisms of temperature adaptation in plants and animals will help prevent major losses of crops and genetic resources in the future. This book is the first to focus on the mechanistic similarities between species in their responses to temperature in a multi-organism approach that addresses the challenges and impacts of climate change on temperature adaptation in micro-organisms (including pathogens), invertebrates, economically and scientifically important plants and vertebrates in both terrestrial and marine environments. The book concludes with a focus on the interactions between organisms, exploring common mechanisms in temperature adaptation