Overexpression of the NMig1 gene encoding a NudC domain protein enhances root growth and abiotic stress tolerance in Arabidopsis thaliana

The family of NudC proteins has representatives in all eukaryotes and plays essential evolutionarily conserved roles in many aspects of organismal development and stress response, including nuclear migration, cell division, folding and stabilization of other proteins. This study investigates an undescribed Arabidopsis homolog of the Aspergillus nidulans NudC gene, named NMig1 (for Nuclear Migration 1), which shares high sequence similarity to other plant and mammalian NudC-like genes. Expression of NMig1 was highly upregulated in response to several abiotic stress factors, such as heat shock, drought and high salinity. Constitutive overexpression of NMig1 led to enhanced root growth and lateral root development under optimal and stress conditions. Exposure to abiotic stress resulted in relatively weaker inhibition of root length and branching in NMig1-overexpressing plants, compared to the wild-type Col-0. The expression level of antioxidant enzyme-encoding genes and other stress-associated genes was considerably induced in the transgenic plants. The increased expression of the major antioxidant enzymes and greater antioxidant potential correlated well with the lower levels of reactive oxygen species (ROS) and lower lipid peroxidation. In addition, the overexpression of NMig1 was associated with strong upregulation of genes encoding heat shock proteins and abiotic stress-associated genes. Therefore, our data demonstrate that the NudC homolog NMig1 could be considered as a potentially important target gene for further use, including breeding more resilient crops with improved root architecture under abiotic stress

Genetic diversity as a paramount factor determining wheat adaptation to drought stress

Wheat (Triticum aestivum L.) is a globally important crop for food and nutritional security that requires sufficient water supply for optimal production. All stages of wheat growth and development are adversely affected by reduced water supply, which limit productivity across large areas of Central and Southern Europe. Since drought episodes are expected to occur more frequently and with a greater intensity, the research efforts are devoted to identification of key traits associated with drought resistance that could be used as direct and indirect selection criteria for wheat drought tolerance. We evaluated and quantified several key genetic and molecular features of wheat genotypes with contrasting drought tolerance under severe dehydration triggered by the treatment of wheat with 250 mM sorbitol in hydroponic systems. Plant status was evaluated non-destructively by measuring leaf chlorophyll index, nitrogen content, and leaf relative water content. The drought-tolerant genotype displayed higher chlorophyll and nitrogen content, when grown under drought and benign conditions. Since root architecture appears to be a key trait for breeding against dehydration, we analysed the members of the DEEPER ROOTING (DRO) gene family that allow the root to penetrate deeper into soil, which could increase the yield even upon water shortage. Expression patterns of the DRO members showed genotype-specific changes under drought stress, which correlated well with plant drought tolerance. Our experiments suggest that genes affecting root system architecture could contribute to development of wheat cultivars with higher drought adaptability

Exploring the Genotype-Dependent Toolbox of Wheat under Drought Stress

Drought stress imposes substantial constraints on the growth and production of wheat (Triticum aestivum L.), a globally important cereal crop essential for food security. To mitigate these adverse effects, researchers are intensifying their efforts to comprehend how different genotypes respond to drought stress, aiding in the development of sustainable breeding and management strategies. This review summarizes past and recent research on genotype-dependent responses of wheat plants to drought stress, encompassing morphological, physiological, biochemical, molecular, genetic, and epigenetic reactions. Screening drought-affected features at early developmental stages can provide valuable insights into the late growth stages that are closely linked to plant productivity. This review underscores the importance of identifying traits associated with drought resistance, and the potential of leveraging wheat diversity to select cultivars with desirable agronomic characteristics. It also highlights recent advancements in investigating Bulgarian wheat genotypes with varying levels of drought tolerance, specifically in detecting essential features contributing to drought tolerance. Cultivating drought-resistant wheat genotypes and understanding stress stability determinants could markedly contribute to enhancing wheat production and ensuring stable yields under changing climate conditions

Genome-wide association study of hemolytic uremic syndrome causing Shiga toxin-producing Escherichia coli from Sweden, 1994-2018

Shiga toxin-producing Escherichia coli (STEC) infection can cause clinical manifestations ranging from diarrhea to potentially fatal hemolytic uremic syndrome (HUS). This study is aimed at identifying STEC genetic factors associated with the development of HUS in Sweden. A total of 238 STEC genomes from STEC-infected patients with and without HUS between 1994 and 2018 in Sweden were included in this study. Serotypes, Shiga toxin gene (stx) subtypes, and virulence genes were characterized in correlation to clinical symptoms (HUS and non-HUS), and pan-genome wide association study was performed. Sixty-five strains belonged to O157:H7, and 173 belonged to non-O157 serotypes. Our study revealed that strains of O157:H7 serotype especially clade 8 were most commonly found in patients with HUS in Sweden. stx2a and stx2a + stx2c subtypes were significantly associated with HUS. Other virulence factors associated with HUS mainly included intimin (eae) and its receptor (tir), adhesion factors, toxins, and secretion system proteins. Pangenome wide-association study identified numbers of accessory genes significantly overrepresented in HUS-STEC strains, including genes encoding outer membrane proteins, transcriptional regulators, phage-related proteins, and numerous genes related to hypothetical proteins. Whole-genome phylogeny and multiple correspondence analysis of pangenomes could not differentiate HUS-STEC from non-HUS-STEC strains. In O157:H7 cluster, strains from HUS patients clustered closely; however, no significant difference in virulence genes was found in O157 strains from patients with and without HUS. These results suggest that STEC strains from different phylogenetic backgrounds may independently acquire genes determining their pathogenicity and confirm that other non-bacterial factors and/or bacteria-host interaction may affect STEC pathogenesis

Whole-genome characterization of hemolytic uremic syndrome-causing Shiga toxin-producing Escherichia coli in Sweden

Shiga toxin-producing Escherichia coli, a foodborne bacterial pathogen, has been linked to a broad spectrum of clinical outcomes ranging from asymptomatic carriage to fatal hemolytic uremic syndrome (HUS). Here, we collected clinical data and STEC strains from HUS patients from 1994 through 2018, whole-genome sequencing was performed to molecularly characterize HUS-associated STEC strains, statistical analysis was conducted to identify bacterial genetic factors associated with severe outcomes in HUS patients. O157:H7 was the most predominant serotype (57%) among 54 HUS-associated STEC strains, followed by O121:H19 (19%) and O26:H11 (7%). Notably, some non-predominant serotypes such as O59:H17 (2%) and O109:H21 (2%) also caused HUS. All O157:H7 strains with one exception belonged to clade 8. During follow-up at a median of 4 years, 41% of the patients had renal sequelae. Fifty-nine virulence genes were found to be statistically associated with severe renal sequelae, these genes encoded type II and type III secretion system effectors, chaperones, and other factors. Notably, virulence genes associated with severe clinical outcomes were significantly more prevalent in O157:H7 strains. In contrast, genes related to mild symptoms were evenly distributed across all serotypes. The whole-genome phylogeny indicated high genomic diversity among HUS-STEC strains. No distinct cluster was found between HUS and non-HUS STEC strains. The current study showed that O157:H7 remains the main cause of STEC-associated HUS, despite the rising importance of other non-O157 serotypes. Besides, O157:H7 is associated with severe renal sequelae in the follow-up, which could be a risk factor for long-term prognosis in HUS patients.Funding Agencies|Scandinavian Society for Antimicrobial Chemotherapy Foundation [SLS884041]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [81701977]; Natural Science Foundations of Guangdong ProvinceNational Natural Science Foundation of Guangdong Province [2019A1515111004, 2021A1515011240]</p