Leaf Responses to Mild Drought Stress in Natural Variants of Arabidopsis  

Abstract

Although the response of plants exposed to severe drought stress has been studied extensively, little is known about how plants adapt their growth under mild drought stress conditions. Here, we analyzed the leaf and rosette growth response of six Arabidopsis (Arabidopsis thaliana) accessions originating from different geographic regions when exposed to mild drought stress. The automated phenotyping platform WIWAM was used to impose stress early during leaf development, when the third leaf emerges from the shoot apical meristem. Analysis of growth-related phenotypes showed differences in leaf development between the accessions. In all six accessions, mild drought stress reduced both leaf pavement cell area and number without affecting the stomatal index. Genome-wide transcriptome analysis (using RNA sequencing) of early developing leaf tissue identified 354 genes differentially expressed under mild drought stress in the six accessions. Our results indicate the existence of a robust response over different genetic backgrounds to mild drought stress in developing leaves. The processes involved in the overall mild drought stress response comprised abscisic acid signaling, proline metabolism, and cell wall adjustments. In addition to these known severe drought-related responses, 87 genes were found to be specific for the response of young developing leaves to mild drought stress.

Leaf Growth Response to Mild Drought: Natural Variation in Arabidopsis Sheds Light on Trait Architecture

“…One of the main environmental factors impacting plants is the availability of water. Until now, the focus of many studies has primarily been on the mechanisms regulating plant survival during severe drought stress, but also mild, nonlethal drought conditions significantly alter growth as a result of reduced cell proliferation and/or expansion (Aguirrezabal et al, 2006;Pereyra-Irujo et al, 2008;Clauw et al, 2015). The regulatory mechanisms behind this growth reduction are distinct from those during severe drought and are poorly understood .…”

“…Different accessions (naturally occurring inbred lines) have been found to be genetically adapted to their specific environments (Fournier-Level et al, 2011). Extensive phenotypic variation is observed for traits such as flowering time, water use efficiency, nitrate uptake and nitrate use efficiency, heat and drought stress responses, salt tolerance, and growth responses upon moderate drought stress (Kenney et al, 2014;Bouchabke et al, 2008;Chardon et al, 2010;Vile et al, 2012;Katori et al, 2010;Clauw et al, 2015).…”

Accelerating genetic gains in legumes for the development of prosperous smallholder agriculture: integrating genomics, phenotyping, systems modelling and agronomy

“…which genotype performs best under drought stress) • Automated phenotyping platform for automated weighing, watering, and imaging of plants and, therefore, strictly controlling the applied watering regime Skirycz et al (2011), Clauw et al (2015 and Geosciences suitable for investigating root systems and root plasticity of large sets of both dicots and monocots (Gioia et al, 2016). The LeasyScan platform developed at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) offers a novel 3D scanning technique that capture leaf area development continuously and phenotype traits controlling plant water budget (Vadez et al, 2015).…”

Leaf Development Monitoring and Early Detection of Water Deficiency by Low Field Nuclear Magnetic Resonance Relaxation in Nicotiana tabacum Plants

“…Water stress thus negatively affects the quantity and quality of the yield of most crops. Plant responses to water deficiency depend on the species [4], the age of the plant [5], the genotype [6], and the intensity of the stress [7]. Severe drought has been extensively studied [8][9][10], whereas mild drought stress has not, even though mild stress occurs more frequently in cultivated areas [6].…”