Differential adaptation strategies to different levels of soil water deficit in two upland and lowland genotypes of rice: a physiological and metabolic approach

Abstract

BACKGROUND: Upland genotypes of rice are less sensitive to soil water deficit (SWD), making them suitable candidates for revealing the strategies underlying plant tolerance. The physiological factors, the biochemical traits needed to withstand oxidative stress, and the metabolite fluctuations of an upland genotype (Azucena) and an intolerant lowland genotype (IR64) genotype were measured under two levels of SWD (withholding water for 7-or 14 days) to identify SWD-responsive strategies associated with tolerance. (up to 1.79-log2FC) in the Azucena leaves may be indicative of their transport to the roots, supplying the carbon source needed for root elongation. Under a 14-day treatment, proline and aspartate family members accumulated to the highest levels in Azucena, whereas an increase in the levels of aromatic amino acids with key roles in the biosynthesis of secondary metabolites was detected in IR64. RESULTS: After withholding water for 7 days, no significant changes in physiological and biochemical traits of Azucena were observed, whereas in IR64, significant decreases in physiological factors were recorded along with increases in oxidative-stress indicators. However, the root length of Azucena increased significantly, showing a clear stress avoidance strategy. Under a prolonged treatment (14 days), IR64 entered an oxidative-damage stage, whereas Azucena exhibited a highly efficient antioxidant system. Our metabolite analysis also revealed two different enriched pathways. After a 7-day SWD, the sugar levels were decreased in the leaves of Azucena but increased in IR64. The reduction in the sugar levelsCONCLUSION: The adaptation strategies identified in two types of rice genotypes in confronting SWD may assist researchers in finding the proper indicators for screening more tolerant genotypes.

Genome-Wide Expression Analysis of Root Tips in Contrasting Rice Genotypes Revealed Novel Candidate Genes for Water Stress Adaptation

“…To cope with environmental stresses, plants have developed different adaptive strategies in a genotype-dependent manner ( Rosa et al, 2009 ). Differential adaptation strategies to water stress in upland and lowland genotypes of rice have been previously reported ( Xia et al, 2019 ; Abdirad et al, 2020 ; Luo et al, 2020 ).…”

“…Rice ( Oryza sativa L.) is a staple food for nearly half of the world’s population ( Bhuiyan, 1992 ). Drought, estimated to affect a large portion of the world’s rice production ( Lesk et al, 2016 ), is defined as a decrease in water input into an ecosystem over time and being sufficient to result in soil water deficit ( Gilbert and Medina, 2016 ; Abdirad et al, 2020 ). Water-deficit stress limits crop growth and development, eventually leading to a sharp decline in productivity ( Michaletti et al, 2018 ).…”

Seasonal Metabolic Investigation in Pomegranate (Punica granatum L.) Highlights the Role of Amino Acids in Genotype- and Organ-Specific Adaptive Responses to Freezing Stress

“…Soluble carbohydrates were extracted and measured according to Abdirad et al (2020). Freeze-dried samples (100 mg) were finely ground using a mixer mill (Retsch, MM200).…”

“…A gradient of 20-70% MeOH in sodium acetate (NaOAc) buffer (50 mM, pH = 7.0) with a flow rate of 1.1 mL/min was used as mobile phases. The amount of each amino acid was calculated by comparing its peak area with that of the corresponding standards (Abdirad et al, 2020). Amino acid concentrations were finally calculated through a calibration curve and expressed as milligrams/gram dry weight.…”

“…The adaptive responses of plants to abiotic stress are diverse and involve highly dynamic metabolic and molecular pathways (Krasensky and Jonak, 2012;Preston and Sandve, 2013;Strimbeck et al, 2015;Abdirad et al, 2020). During the hardening process, plants undergo a wide range of structural, physiological, and metabolic modifications which finally lead to the acquisition of a high degree of tolerance against extreme winter temperatures (Preston and Sandve, 2013;Strimbeck et al, 2015).…”