preparing the stress-induced potato plant for phenotyping procedure

Potato Resilience Analysis Under Climate-Related Stresses

The potential effects of climate change, including the increase in the intensity and frequency of heat waves, flooding, and drought events, have negative impacts on growing crops1. It is important to understand the influence of climate change on crop variability and the consequent fluctuations in annual crop production2. With increasing population and food demand, maintaining the yield of crop plants is a challenge, thereby, finding climate-resilient crops for breeding is urgently required3,4. Potato (Solanum tuberosum L.) is one of the essential food crops that contributes to global food security because of its high nutritional value and increased water use efficiency. However, reduction in growth and yield under unfavorable conditions is a main problem, particularly in the susceptible varieties5,6. Many studies highlighted the importance of investigating alternative approaches to maintain potato crop productivity, including agricultural practices, finding tolerant genotypes, and understanding the impact of stress on the development and yield7,8,9, which is also highly demanded by European potato growers (or farmers)10.
Automated phenotyping platforms, including image-based phenotyping, enable the quantitative analyses of plant structure and function that are essential for selecting relevant traits of interest11,12. High throughput phenotyping is an advanced non-invasive technique to determine various morphological and physiological traits of interest in a reproducible and rapid manner 13. Although phenotype reflects genotypic differences in connection to environmental effects, comparing plants under controlled conditions with stress enables linking the&#160;extensive phenotyping information to a specific (stress) condition14. Image-based phenotyping is essential in describing phenotypic variability, and it is also capable of screening a set of traits across plant development regardless of the population size15. For instance, the measurement of morphological traits, including the shape, size, and color index of leaves using Red-Green-Blue (RGB) imaging sensors, is used to determine plant growth and development. Moreover, measurements of physiological traits, including photosynthetic performance, canopy temperature, and leaf reflectance, are quantified using multiple types of sensors, such as chlorophyll fluorescence, thermal infrared (IR), and hyperspectral imaging16. Recent studies in controlled environments showed the potential of using image-based phenotyping in assessing different mechanisms and physiological responses of plants under abiotic stresses such as heat in potato17, drought in barley18, rice19, and combined drought and heat treatments in wheat20. Even though studying the responses of plants to multiple stress interactions is complex, the findings reveal new insights in understanding plant mechanisms in coping with rapid change in climate conditions21.
Plant physiological and morphological responses are directly influenced by abiotic stress conditions (high temperature, water deficit, and flooding), resulting in yield reduction22. Even though potatoes have a high water use efficiency compared to other crops, water deficit negatively affects the yield quantity and quality due to the shallow root architecture5. Depending on the intensity and duration of drought level, the leaf area index is reduced, and retardation in canopy growth with inhibition of new leaf formation is pronounced during later stages of stress leading to a reduction in the photosynthetic rate23. The threshold level of water is critical with excess water or prolonged drought periods, resulting in a negative effect on plant growth and tuber development due to oxygen limitation, decreased root hydraulic conductivity, and restriction of gas exchange24,25. Moreover, potatoes are sensitive to high temperatures where temperatures above optimum levels result in delayed tuber initiation, growth, and assimilation rates26. When stresses appear in combination, the biochemical regulations and physiological responses differ from individual stress responses, highlighting the necessity of investigating the plant responses to stress combinations27. Combined stresses can result in (even more) severe reductions in plant growth and determinantal effects on reproductive-related traits28. The impact of stress combination depends on the dominancy of each stress over the others, leading to enhanced or suppressed plant response (e.g., drought usually leads to stomata closure while stomata are open to allow cooling of leaf surface under heat stress). However, combined stress research is still emerging, and further investigations are required to understand better the complex regulation mediating plant responses under these conditions29. Thus, this study aims to highlight and recommend a phenotyping protocol using multiple imaging sensors that can be suitable to assess morpho-physiological responses and understand the underlying mechanisms of potato overall performance under single and combined stress treatments. As hypothesized, combining multiple imaging sensors proved to be a valuable tool to characterize the early and later strategies during plant stress response. Optimizing image-based phenotyping protocol will be an interactive tool for plant researchers and breeders to find traits of interest for abiotic stress tolerance.

Author Spotlight: Unraveling Plant Responses to Abiotic Stresses Using the PlantScreen Robotic Platform

High Throughput Image-Based Phenotyping for Determining Morphological and Physiological Responses to Single and Combined Stresses in Potato

So here in PSI, we use PlantScreen phenotyping systems, which are robotic type of solutions for high-throughput plant phenotyping, and these systems are based on using a range of modules, modules both for plant cultivation and handling, like automated watering and weighing units, as well as modules for automated digital-based imaging of the plants, and this both for structural morphological features of the plants as well as physiological traits of the plants. The advantage of the applied protocol in this study is that we are using the multiple imaging sensor, including the plant growth dynamics that we measure by using the RGP imaging and connect this with the other physiological responses, including the photosynthetic efficiency from chlorophyll fluorescence imaging, assessing the stomatal regulation from the canopy temperature by the measuring of the thermal imaging, and also the leaf reflectance indices that we measure by using the hyperspectral imaging. Our findings focuses on highlighting how to elucidate the response of plants when they are induced to combined stress versus their individual stress, and be able to assess the early and late response to stresses and recovery phase afterwards, and highlighting the necessity of using multiple imaging sensor for integrative and better understanding of plant underlying mechanism to future climate change conditions.

Preparing the Stress-Induced Potato Plant for Phenotyping Procedure

preparing-the-stress-induced-potato-plant-for-phenotyping-procedure

Research

JoVE Journal

Biology

High throughput image-based phenotyping is a powerful tool to non-invasively determine the development and performance of plants under specific conditions over time. By using multiple imaging sensors, many traits of interest can be assessed, including plant biomass, photosynthetic efficiency, canopy temperature, and leaf reflectance indices. Plants are frequently exposed to multiple stresses under field conditions where severe heat waves, flooding, and drought events seriously threaten crop productivity. When stresses coincide, resulting effects on plants can be distinct due to synergistic or antagonistic interactions. To elucidate how potato plants respond to single and combined stresses that resemble naturally occurring stress scenarios, five different treatments were imposed on a selected potato cultivar (Solanum tuberosum L., cv. Lady Rosetta) at the onset of tuberization, i.e. control, drought, heat, waterlogging, and combinations of heat, drought, and waterlogging stresses. Our analysis shows that waterlogging stress had the most detrimental effect on plant performance, leading to fast and drastic physiological responses related to stomatal closure, including a reduction in the quantum yield and efficiency of photosystem II and an increase in canopy temperature and water index. Under heat and combined stress treatments, the relative growth rate was reduced in the early phase of stress. Under drought and combined stresses, plant volume and photosynthetic performance dropped with an increased temperature and stomata closure in the late phase of stress. The combination of optimized stress treatment under defined environmental conditions together with selected phenotyping protocols allowed to reveal&#160;the dynamics of morphological and physiological responses to single and combined stresses. Here, a useful tool is presented for plant researchers looking to identify plant traits indicative of resilience to several climate change-related stresses.

We designed an image-based phenotyping protocol to determine the morphological and physiological responses to single and combined heat, drought, and waterlogging treatments. This approach enabled the identification of early, late, and recovery responses at a whole plant level, particularly above-ground parts, and highlighted the necessity of using multiple imaging sensors.

High throughput image-based phenotyping is a powerful tool to non-invasively determine the development and performance of plants under specific conditions ...