Leon Kochian

Leon Kochian
University of Saskatchewan | U of S · Global Institutue for Food Security (GIFS)

PhD

About

415
Publications
101,572
Reads
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36,075
Citations
Citations since 2016
78 Research Items
13955 Citations
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201620172018201920202021202205001,0001,5002,000
201620172018201920202021202205001,0001,5002,000
Additional affiliations
September 1985 - present
Cornell University
September 1985 - present
United States Department of Agriculture

Publications

Publications (415)
Article
Full-text available
Accurate segmentation of root system architecture (RSA) from 2D images is an important step in studying phenotypic traits of root systems. Various approaches to image segmentation exist but many of them are not well suited to the thin and reticulated structures characteristic of root systems. The findings presented here describe an approach to RSA...
Article
Full-text available
In plants, the actin cytoskeleton plays a critical role in defense against diverse pathogens. The formation of actin patches is essential for the intracellular transport of organelles and molecules toward pathogen penetration sites and the formation of papillae for an early cellular response to powdery mildew attack in Arabidopsis thaliana. This re...
Article
Full-text available
Efficient acquisition and use of available phosphorus from the soil is crucial for plant growth, development, and yield. With an ever‐increasing acreage of croplands with suboptimal available soil phosphorus, genetic improvement of sorghum germplasm for enhanced phosphorus acquisition from soil is crucial to increasing agricultural output and reduc...
Article
Full-text available
The economically valuable Brassica species include the six related members of U’s Triangle. Despite the agronomic and economic importance of these Brassicas, the impacts of evolution and relatively recent domestication events on the genetic landscape of seed development have not been comprehensively examined in these species. Here we present a 3D t...
Article
Full-text available
Key message Association analysis for ionomic concentrations of 20 elements identified independent genetic factors underlying the root and shoot ionomes of rice, providing a platform for selecting and dissecting causal genetic variants. Abstract Understanding the genetic basis of mineral nutrient acquisition is key to fully describing how terrestri...
Preprint
Full-text available
Copper and iron are essential micronutrients but are toxic when accumulating in cells in excess. Thus, their uptake by roots is tightly regulated. While plants sense and respond to local copper availability, the systemic regulation of copper uptake has not been documented. By contrast, both local and systemic control for iron uptake has been report...
Preprint
Full-text available
Efficient acquisition and use of available phosphorus from the soil is crucial for plant growth, development, and yield. With an ever-increasing acreage of croplands with suboptimal available soil phosphorus, genetic improvement of sorghum germplasm for enhanced phosphorus acquisition from soil is crucial to increasing agricultural output and reduc...
Article
Full-text available
Fatty acids in crop seeds are a major source for both vegetable oils and industrial applications. Genetic improvement of fatty acid composition and oil content is critical to meet the current and future demands of plant-based renewable seed oils. Addressing this challenge can be approached by network modeling to capture key contributors of seed met...
Article
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Among polyploid species with complex genomic architecture, variations in the regulation of alternative splicing (AS) provide opportunities for transcriptional and proteomic plasticity and the potential for generating trait diversities. However, the evolution of AS and its influence on grain development in diploid grass and valuable polyploid wheat...
Article
Malate-efflux from roots, which is regulated by the transcription factor STOP1 (SENSITIVE-TO-PROTON-RHIZOTOXICITY1), which mediates aluminum-induced expression of ALUMINUM-ACTIVATED-MALATE-TRANSPORTER1 (AtALMT1), is critical for aluminum-resistance in Arabidopsis thaliana. Several studies showed that root AtALMT1 expression is rapidly observed in r...
Article
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Key message A multiparental random mating population used in sorghum breeding is amenable for the detection of QTLs related to tropical soil adaptation, fine mapping of underlying genes and genomic selection approaches. Abstract Tropical soils where low phosphorus (P) and aluminum (Al) toxicity limit sorghum [Sorghum bicolor (L.) Moench] productio...
Article
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Embryonic development represents an important reproductive phase of sexually reproducing plant species. The fusion of egg and sperm produces the plant zygote, a totipotent cell that through cell division and cell identity specification in early embryogenesis establishes the major cell lineages and tissues of the adult plant. The subsequent morphoge...
Article
Full-text available
Crop tolerance to multiple abiotic stresses has long been pursued as a Holy Grail in plant breeding efforts that target crop adaptation to tropical soils. On tropical, acidic soils, aluminum (Al) toxicity, low phosphorus (P) availability and drought stress are the major limitations to yield stability. Molecular breeding based on a small suite of pl...
Article
Full-text available
Organic acids (OA) are released from roots in response to aluminum (Al), conferring an Al tolerance to plants that is regulated by OA transporters such as ALMT (Al‐activated malate transporter) and multi‐drug and toxic compound extrusion (MATE). We have previously reported that the expression level polymorphism (ELP) of AtALMT1 is strongly associat...
Article
Full-text available
On acid soils, the trivalent aluminum ion (Al³⁺) predominates and is very rhizotoxic to most plant species. For some native plant species adapted to acid soils including tea (Camellia sinensis), Al³⁺ has been regarded as a beneficial mineral element. In this study, we discovered that Al³⁺ is actually essential for tea root growth and development in...
Preprint
Previous studies have alternately supported and discounted the hypothesis that the maternal genome plays a predominant role in early embryogenesis in plants. We used 24 embryo defective (emb) mutants of Arabidopsis thaliana to test for maternal and paternal effects in early embryogenesis. 5 emb mutants had equal maternal and paternal effects, 5 sho...
Article
Modern wheat production comes from two polyploid species Triticum (T.) aestivum and T. turgidum (var. durum), which putatively arose from diploid ancestors, T. urartu, Aegilops (Ae.) speltoides and Ae. tauschii. How gene expression during embryogenesis and grain development in wheats has been shaped by differing contributions of diploid genomes thr...
Article
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Whilst the mechanisms involved in the regulation of gene expression in response to phosphate (Pi) deficiency have been extensively studied, their chromatin‐level regulation remains poorly understood. We examined the role of histone acetylation in response to Pi deficiency by using histone deacetylase complex1 (hdc1) mutant. Genes involved in root s...
Article
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Although citrate transporters are involved in iron (Fe) translocation or aluminum (Al) tolerance in plants, none of them have been shown to confer both biological functions in Fe absorption strategy I plant species so far. We demonstrate that AhFRDL1, a citrate transporter gene from peanut (Arachis hypogaea L.) induced by both Fe-deficiency and Al-...
Article
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Background Phosphorus (P) fixation on aluminum (Al) and iron (Fe) oxides in soil clays restricts P availability for crops cultivated on highly weathered tropical soils, which are common in developing countries. Hence, P deficiency becomes a major obstacle for global food security. We used multi-trait quantitative trait loci (QTL) mapping to study t...
Article
Full-text available
Acidic soils, where aluminum (Al) toxicity is a major agricultural constraint, are globally widespread and are prevalent in developing countries. In sorghum, the root citrate transporter SbMATE confers Al tolerance by protecting root apices from toxic Al ³⁺ , but can exhibit reduced expression when introgressed into different lines. We show that al...
Article
Full-text available
Rapeseed (Brassica napus) is an important oil crop worldwide. However, severe inhibition of rapeseed production often occurs in the field due to nitrogen (N) deficiency. The root system is the main organ to acquire N for plant growth, but little is known about the mechanisms underlying rapeseed root adaptions to N deficiency. Here, dynamic changes...
Article
Full-text available
Main conclusion: An SPL-type transcription factor, LeSPL-CNR, is negatively involved in NO production by modulating SlNR expression and nitrate reductase activity, which contributes to Cd tolerance. Cadmium (Cd) is a highly toxic pollutant. Identifying factors affecting Cd accumulation in plants is a prerequisite for minimizing dietary uptake of C...
Article
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Aluminum (Al) toxicity on acidic soils significantly damages plant roots and inhibits root growth. Hence, crops intoxicated by Al become more sensitive to drought stress and mineral nutrient deficiencies, particularly phosphorus (P) deficiency, which is highly unavailable on tropical soils. Advances in our understanding of the physiological and gen...
Article
Full-text available
Root damage due to aluminum (Al) toxicity restricts crop production on acidic soils, which are extensive in the tropics. The sorghum root Al-activated citrate transporter, SbMATE, underlies the Al tolerance locus, AltSB, and increases grain yield under Al toxicity. Here, AltSB loci associated with Al tolerance were converted into Amplification Refr...
Article
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Background: Genetic improvement of root system architecture is a promising approach for improved uptake of water and mineral nutrients distributed unevenly in the soil. To identify genomic regions associated with the length of different root types in rice, we quantified root system architecture in a set of 26 chromosome segment substitution lines...
Article
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Al-induced organic acid secretion from the root apex is an important Al resistance mechanism. However, it remains unclear how plants fine-tune root organic acid secretion which can contribute significantly to the loss of fixed carbon from the plant. Here, we demonstrate that Al-induced citrate secretion from the rice bean root apex is biphasic, con...
Chapter
Full-text available
Low-phosphorus (P) availability caused by P fixation on soil clay minerals is a serious constraint for agricultural production and food security, particularly in the humid tropics and subtropics. Here we look at the underlying basis of root phenotypes that can potentially enhance a crop’s ability to acquire P under low availability in the soil. In...
Article
Full-text available
About 50% of the world's arable land is strongly acidic (pH ≤ 5). The low pH solubilizes root-toxic ionic aluminium (Al3+) species from clay minerals, driving the evolution of counteractive adaptations in cultivated crops. The food crop Sorghum bicolor upregulates the membrane-embedded transporter protein SbMATE in its roots. SbMATE mediates efflux...
Presentation
Full-text available
This work presents a new pipeline for digital optical phenotyping the root system architecture of agricultural crops. The pipeline begins with a 3D root-system imaging apparatus for hydroponically grown crop lines of interest. The apparatus acts as a self-containing dark room, which includes an imaging tank, motorized rotating bearing and digital c...
Article
Full-text available
A deficiency of the micronutrient copper (Cu) leads to infertility and grain/seed yield reduction in plants. How Cu affects fertility, which reproductive structures require Cu, and which transcriptional networks coordinate Cu delivery to reproductive organs is poorly understood. Using RNA-seq analysis, we showed that the expression of a gene encodi...
Article
Transcription factors (TFs) regulate the expression of other genes to indirectly mediate stress resistance mechanisms. Therefore, when studying TF-mediated stress resistance, it is important to understand how TFs interact with genes in the genetic background. Here, we fine-mapped the aluminum (Al) resistance QTL Alt12.1 to a 44-kb region containing...
Preprint
Full-text available
Transcription factors (TFs) mediate stress resistance indirectly via physiological mechanisms driven by the genes they regulate. When studying TF-mediated stress resistance, it is important to understand how TFs interact with different genetic backgrounds. Here, we fine-mapped the aluminum (Al) resistance QTL Alt12.1 to a 44 Kb region containing si...
Preprint
Full-text available
About 50% of the world’s arable land is strongly acidic (soil pH < 5). The low pH of these soils solubilizes root-toxic ionic aluminium (Al ³⁺ ) species from clay minerals, driving the evolution of various counteractive adaptations in cultivated crops. The food crop Sorghum bicolor , for example, upregulates the membrane-embedded transporter protei...
Article
Full-text available
Background Proton stress and aluminum (Al) toxicity are major constraints limiting crop growth and yields on acid soils (pH < 5). In Arabidopsis, STOP1 is a master transcription factor that controls the expression of a set of well-characterized Al tolerance genes and unknown processes involved in low pH resistance. As a result, loss-of-function sto...
Article
Full-text available
Significance Aluminum (Al) toxicity is a major constraint for crops grown on acid soils. Various plant species have adopted an Al exclusion/avoidance mechanism and/or internal tolerance mechanisms to ameliorate Al toxicity. In Arabidopsis , the root organic acid exudation-based Al exclusion mechanism has been well characterized; however, no evidenc...
Article
Full-text available
Despite the physiological importance of aluminum (Al) phytotoxicity for plants, it remained unknown if, and how, calcineurin B-like calcium sensors (CBLs) and CBL-interacting protein kinases (CIPKs) are involved in Al resistance. We performed a comparative physiological and whole transcriptome investigation of an Arabidopsis CBL1 mutant (cbl1) and...
Article
Full-text available
Aluminum (Al) toxicity inhibits root growth and limits crop yields on acid soils worldwide. However, quantitative information is scarce on protein expression profiles under Al stress in crops. In this study, we report on the identification of potential Al responsive proteins from root tips of Al sensitive BR007 and Al tolerant SC566 sorghum lines u...