Research Associate at the Dept. of Genetics and Plant Breeding of AUTh (1999-2000)
Senior Researcher at the Institute of Agrobiotechnology (currently Institute of Applied Biosciences) of the Centre for Research and Technology Hellas (CERTH) (2001-2008).
Assistant Professor (2009-2014) Associate Professor (2014-2019) and is currently (2019-now) Professor of Molecular Breeding and Director of the Genetics and Plant Breeding laboratory of Aristotle University of Thessaloniki, Greece.
EDUCATION
Dr. Alexios N. Polidoros received his PhD in 1993, from the Dept. of Genetics and Plant Breeding of Aristotle University of Thessaloniki (AUTh), studying molecular aspects of heterosis in maize. Then he moved to the Department of Genetics, North Carolina State University where he was appointed Research Assistant in John Scandalios’ lab, studying antioxidant gene responses to abiotic stress for more than 4 years (1994-1998).
RESEARCH, TEACHING, or OTHER INTERESTS
Agricultural and Biological Sciences, Plant Science, Molecular Biology, Genetics
GGE Biplot Analysis for the Assessment and Selection of Bread Wheat Genotypes Under Organic and Low-Input Stress Environments Evangelos Korpetis, Elissavet Ninou, Ioannis Mylonas, Dimitrios Katsantonis, Nektaria Tsivelika, et al. Agriculture Switzerland, 2026 Bread wheat variety development suited to organic farming conditions remains a major challenge mainly because of the high breeding costs involved and the few cultivars adapted to low-input systems. The present work explores whether early generation selection needs to take place under organic conditions for subsequent adaptation or whether conventional testing at an early stage could be adequate. A diverse set of crosses involving Greek landraces and commercial cultivars were developed and advanced by honeycomb pedigree selection under both organic and conventional environments. Subsequently, F4 progenies and an upgraded landrace were evaluated over two years in neighboring organic and conventional trials. Both statistical and GGE biplot analyses revealed significant genotype × environment interactions. The results clearly indicate that early selection under organic conditions did not provide a consistent advantage for subsequent performance under organic management compared with conventional early selection. Genotypes derived from the Africa × Atheras cross consistently showed the highest and most stable yields across the two environments, irrespective of the early selection environment. These results indicate that genetic background and landrace-derived diversity are more important than the early selection environment for the expression of performance. A staged breeding strategy involving initial selection in conventional management followed by multi-environment testing in organic conditions can provide a cost-effective approach to developing resilient, high-yielding wheat cultivars suitable for organic farming systems, which are typically characterized by low-input management practices, and in tune with the EU targets for expanded organic farming.
Primed acclimation of two Greek olive cultivars to water deficit Georgia-Maria Nteve, Evangelia Stavridou, Emmanouil D. Pratsinakis, Christina Skodra, Michail Michailidis, et al. Physiology and Molecular Biology of Plants, 2026 Water scarcity, intensified by climate change, threatens olive cultivation in the Mediterranean region. Understanding cultivar responses to drought is key to developing strategies to sustain this vital crop. Ιn the present work, we studied the responses of two Greek olive cultivars, "Lefkolia Serron" and "Chondrolia Chalkidikis", to water limitation and we evaluated their ability to acclimatize through cis long term-priming, using a combination of morpho-physiological parameters, primary metabolite profiling and gene expression analysis of drought-related genes. Our findings indicated that the two cultivars follow different strategies to cope with water shortage and priming. Particularly, "Lefkolia Serron" showed a more conservative response, maintaining greater photosynthetic functionality, intrinsic Water Use Efficiency (iWUE) and antioxidant activity upon stress re-exposure. "Chondrolia Chalkidikis" showed greater susceptibility to stress with more pronounced changes at the morpho-physiological, metabolic and gene expression levels. Metabolomic data demonstrated shifts in energy metabolism in response to the drought cycles, while principal component analysis of gene expression patterns showed that drought priming can regulate transcriptional processes, such that drought priming aligned primed plants with controls. Pre-exposure to drought induces a form of transcriptional memory, making the plant more efficient in responding to repeated stress. These findings suggest that long-term drought priming may function as a coping strategy for stressful environmental conditions, however, it is genotype-dependent, as the outcomes vary with genetic background. Understanding olive stress responses and applying eco-friendly strategies like drought priming is a sustainable way to protect this crop from environmental threats.
Genome-Editing Products Line up for the Market: Will Europe Harvest the Benefits from Science and Innovation? Alexios Polidoros, Irini Nianiou-Obeidat, Nikolaos Tsakirpaloglou, Nestor Petrou, Eleftheria Deligiannidou, et al. Genes, 2024 Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technologies have revolutionized genome editing, significantly advancing the improvement of cultivated crop species. This review provides an overview of genome-edited crops that have either reached the market or received the necessary approvals but are not yet available to consumers. We analyze various genome-editing studies to understand the distribution of different genome-editing systems, the types of site-directed nucleases employed, and the geographical spread of these studies, with a specific focus on global and European contexts. Additionally, we examine the target crops involved. The review also outlines the multiple steps required for the legal acceptance of genome-edited crops within European jurisdictions. We conclude with suggestions for the future prospects of genome-editing research in Europe, aiming to streamline the approval process and enhance the development and adoption of genome-edited crops.
Impact of nitrapyrin on urea-based fertilizers in a Mediterranean calcareous soil: Nitrogen and microbial dynamics Georgios Giannopoulos, Lars Elsgaard, Vasileios A. Tzanakakis, Rima B. Franklin, Bonnie L. Brown, et al. European Journal of Soil Science, 2024 Nitrification inhibitors, such as nitrapyrin (NI), are increasingly co‐applied with nitrogen (N) fertilizers as part of sustainable agricultural practice. Several studies in temperate regions have documented the effectiveness of NI in retaining soil ammonium (NH4+), minimizing N loss and increasing crop yields. However, less is known about the effects of NI in Mediterranean regions, where agricultural production is challenging and requires intensive irrigation and fertilization. We investigated the short‐term impact of the nitrification inhibitor nitrapyrin (2‐chloro‐6‐(trichloromethyl)pyridine) in a two‐factor mesocosm experiment, using a typical Mediterranean soil, where NI was co‐applied with a selection of urea‐based fertilizers: urea (U), U with urease inhibitors (U + UI), methylene urea (MU) and zeolite‐coated urea (ZU). NI co‐applied with urea fertilizers resulted in higher availability of soil NH4+ and a concurrent increase in NH3 volatilization. Net cumulative soil NH4+ availability was 1.5–3.3 fold greater when NI was applied. Concurrently, net cumulative nitrate (NO3−) and nitrite (NO2−) availability was reduced by 10%–60%; this was found for all the tested fertilizer types except MU fertilizer, where the net cumulative soil NO3− and NO2− doubled. Nitrous oxide (N2O) emissions from urea fertilization were reduced by 40% with UI, 50% with NI and 66% with NI + UI. Interestingly, after 28 d, the composition of soil microbial communities was distinctly different, due to NI application. Specifically, NI application dramatically reduced the abundance of ammonia‐oxidizing and denitrifying bacterial functional groups. NI was effective in reducing N2O emissions in this calcareous soil; however, NH3 emissions were remarkably enhanced. These findings have important implications for the large‐scale adoption of inhibitor technologies in Mediterranean agroecosystems and for the reduction of greenhouse gas emissions.
Adaptation Mechanisms of Olive Tree under Drought Stress: The Potential of Modern Omics Approaches Georgia-Maria Nteve, Stefanos Kostas, Alexios N. Polidoros, Panagiotis Madesis, Irini Nianiou-Obeidat Agriculture Switzerland, 2024 Olive (Olea europaea L.) is a crop of enormous economic and cultural importance. Over the years, the worldwide production of olive oil has been decreasing due to various biotic and abiotic factors. The current drop in olive oil production resulting from climate change raises concerns regarding the fulfillment of our daily demand for olive oil and has led to a significant increase in market prices. In the future, there will be a higher chance that we will face a severe shortage of olive oil, which could harm both the economic sector and the food supply. As olive groves cover more than 5 million hectares in the European Union alone, the need to preserve the crop in the context of extreme climatic events is imperative. As drought is considered one of the most limiting factors in agriculture, drought-resistant varieties and sustainable irrigation strategies are being developed to mitigate the impact of drought on crop productivity and secure the future supply of olive oil. This review focuses on recently gained insights into drought stress in olive trees through omics and phenomics approaches to unravelling mechanisms that may lead to developing new varieties that are tolerant against drought elicited by changes in growing systems.
Lentil Landrace Seed Origin and Genotype Affects Rhizosphere Microbiome Anthoula Gleridou, Georgios Giannopoulos, Alexios N. Polidoros, Photini V. Mylona Agronomy, 2023 Lentil (Lens culinaris Medik.) is an essential legume crop providing healthy and nutritious food for people in low- to middle-income countries, worldwide. Lentil roots support symbiotic interactions with soil rhizobia species fostering nitrogen fixation; however, assemblage and diversity of the complete microbial rhizosphere community and the effect of seed genotype and origin remain largely unexplored. In this study we examined, via metagenomic analysis, the effects of seed origin on the rhizosphere’s communities in samples of the famous Greek lentil landrace, Eglouvis, derived from different local farmers and farming systems (including a Gene Bank sample), in comparison to a commercial variety. The landrace exhibited higher rhizosphere microbiome diversity compared to the commercial variety for all indexes. A core microbiome comprised of 158 taxa was present in all samples, while a greater number of unique bacterial taxa was recorded in the landrace samples compared to the commercial cultivar. Notably, landrace samples originated from organic farming had more than double the number of unique taxa compared to conventional counterparts. The study revealed a higher diversity of N2 fixers and archaea, Crenarchaeota and Thaumarchaeota, in landrace samples and particularly in those derived from organic farming, underpinning the distinct recruiting efficiency of beneficial soil microbes by the landrace.
The Effect of Phosphorus Fertilization on Transcriptome Expression Profile during Lentil Pod and Seed Development Ekaterini Koura, Adamantia Pistikoudi, Margaritis Tsifintaris, George Tsiolas, Evangelia Mouchtaropoulou, et al. Applied Sciences Switzerland, 2023 Seed coat hardness and water permeability, which are determined by the accumulation of tannins through the phenylpropanoid pathway in the seed, are important lentil quality characteristics. The impact of seeds’ developmental stage and phosphorus (P) fertilization levels on tannin accumulation is still under research. Through RNA sequencing, this study explored the effect of three P treatments (P0, 6 mg kg−1; P1, 15 mg kg−1; and P2, 21 mg kg−1) and three seed maturity stages (S1, immature 2 mm seed in a flat pod; S2, fully developed seed within the pod; and S3, mature seed at the beginning of the pod’s discoloration) on lentil gene expression. The key findings highlighted a significant influence of the seed maturity stage on phenylpropanoid genes, with S1 displaying the highest expression levels, and on phosphorus-related Gene Ontology (GO) terms that presented the highest number of downregulated genes in the S3 to S1 comparison. P exhibited a targeted effect on the flavanone 3-hydroxylase (F3H) and flavonol synthase (FLS) genes and specific gene clusters, as shown by the differential gene expression analysis. This study investigates the molecular mechanisms related to phosphorus fertilization and seed maturity stages that influence tannin accumulation, offering valuable information for the enhancement of lentil product quality through breeding programs.
Whole genome scanning of a Mediterranean basin hotspot collection provides new insights into olive tree biodiversity and biology Christos Bazakos, Konstantinos G. Alexiou, Sebastián Ramos‐Onsins, Georgios Koubouris, Nikolaos Tourvas, et al. Plant Journal, 2023 Olive tree (Olea europaea L. subsp. europaea var. europaea) is one of the most important species of the Mediterranean region and one of the most ancient species domesticated. Τhe availability of whole genome assemblies and annotations of olive tree cultivars and oleasters have contributed to a better understanding of genetic and genomic differences between olive tree cultivars. However, compared to other plant species there is still a lack of genomic resources with olive tree populations that span across the entire Mediterranean region. This study has developed the most complete genomic variation map and comprehensive catalogue/resource of molecular variation to date for 89 olive tree genotypes originating from the entire Mediterranean basin, revealing the genetic diversity of this commercially significant crop tree and explaining the divergence/similarity among different variants. Additionally, the monumental ancient tree "Throuba Naxos" was studied to characterize the potential origin or routes of olive tree domestication. Several candidate genes, known to be associated with key agronomic traits, including olive oil quality and fruit yield, were uncovered by selective sweep scan to be under selection pressure on all olive tree chromosomes. To exploit further the genomic and phenotypic resources obtained from the current work, Genome Wide Association Analyses were performed for twenty-three morphological and two agronomic traits. Significant associations were detected for eight traits that provide valuable candidates for fruit tree breeding and for deeper understanding of the olive tree biology.
Lentil Gene Pool for Breeding Alexios N. Polidoros, Ilias D. Avdikos, Anthoula Gleridou, Stauroula D. Kostoula, Ekaterini Koura, et al. Cash Crops Genetic Diversity Erosion Conservation and Utilization, 2021
Circadian expression of the maize catalase Cat3 gene is highly conserved among diverse maize genotypes with structurally different promoters Genetics, 1998