A Novel Image-Based Screening Method to Study Water-Deficit Response and Recovery of Barley Populations Using Canopy Dynamics Phenotyping and Simple Metabolite Profiling

Abstract

Plant phenotyping platforms offer automated, fast scoring of traits that simplify the selection of varieties that are more competitive under stress conditions. However, indoor phenotyping methods are frequently based on the analysis of plant growth in individual pots. We present a reproducible indoor phenotyping method for screening young barley populations under water stress conditions and after subsequent rewatering. The method is based on a simple read-out of data using RGB imaging, projected canopy height, as a useful feature for indirectly following the kinetics of growth and water loss in a population of barley. A total of 47 variables including 15 traits and 32 biochemical metabolites measured (morphometric parameters, chlorophyll fluorescence imaging, quantification of stress-related metabolites; amino acids and polyamines, and enzymatic activities) were used to validate the method. The study allowed the identification of metabolites related to water stress response and recovery. Specifically, we found that cadaverine (Cad), 1,3-aminopropane (DAP), tryptamine (Tryp), and tyramine (Tyra) were the major contributors to the water stress response, whereas Cad, DAP, and Tyra, but not Tryp, remained at higher levels in the stressed plants even after rewatering. In this work, we designed, optimized and validated a non-invasive image-based method for automated screening of potential water stress tolerance genotypes in barley populations. We demonstrated the applicability of the method using transgenic barley lines with different sensitivity to drought stress showing that combining canopy height and the metabolite profile we can discriminate tolerant from sensitive genotypes. We showed that the projected canopy height a sensitive trait that truly reflects other invasively studied morphological, physiological, and metabolic traits and that our presented methodological setup can be easily applicable for large-scale screenings in low-cost systems equipped with a simple RGB camera. We believe that our approach will contribute to accelerate the study and understanding of the plant water stress response and recovery capacity in crops, such as barley.

Genetic Diversity of Egyptian Barley Cultivars for Water Stress using SSR Markers

“…Water deficit significantly increased the proline content of all Egyptian barley from to a maximum (54.7 mg FWg -1 ) found in Giza 2000 to minimum (23.1 mg FWg -1 ) under well-irrigated treatment. Similar comments have been reported in many studies of the water stress response of proline accumulation in barley (Mamnouie et al, 2006;Mariey et al, 2017;Saade et al, 2018 ;khatab et al, 2019 andMarchetti et al, 2019), which they reported that the plants had a strategy to cope with water-induced stress is to product and accumulate Free Amino Acids in the cell such as proline content which it act as a compatible solute that adjusts the osmotic potential in the plants under stress.…”

“…Regarding total chlorophyll content, in our study we found that water stress had reduced the total Chl content in all cultivars under study. Similar investigations have been studies the response water stress barley such as (Filek et al, 2015;Mariey et al, 2017;Saade et al, 2018;khatab et al, 2019 andMarchetti et al, 2019) which They established that under water stress conditions, barley displays reduced chlorophyll content. However, the mechanisms that confer water stress tolerance and recovery capacity in this crop species are still not fully understood.…”

Leaf Age-Dependent Photosystem II Photochemistry and Oxidative Stress Responses to Drought Stress in Arabidopsis thaliana Are Modulated by Flavonoid Accumulation

“…Chlorophyll fluorescence analysis has been widely used to acquire knowledge about the function of the photosynthetic machinery and for the assessment of photosynthetic tolerance mechanisms to biotic [ 66 , 86 , 101 , 102 ] and abiotic stresses [ 103 , 104 , 105 , 106 , 107 , 108 ], including drought stress [ 21 , 22 , 96 , 108 , 109 , 110 ]. However, DS may not affect a plant leaf uniformly [ 97 ], thus photosynthetic performance may be extremely heterogeneous at the leaf surface, denoting conventional chlorophyll fluorescence measurements non-characteristic of the physiological status of the entire leaf [ 111 , 112 , 113 ].…”

Phloem exudate metabolic content reflects the response to water‐deficit stress in pea plants (Pisum sativum L.)

“…Chlorophyll (Chl) fluorescence parameters were recorded using the top‐view FluorCam. A standard protocol was used for the measurement of Chl fluorescence quenching using the Chl fluorescence imaging (CFIM) protocols of the PlantScreen platform as described by Marchetti et al ( 2019 ). Chl fluorescence parameters were calculated using fluorcam 7 (Photon Systems Instruments, https://psi.cz ).…”