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32
result(s) for
"Ligaba‐Osena, Ayalew"
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Loss-of-function mutation of the calcium sensor CBL1 increases aluminum sensitivity in Arabidopsis
2017
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 the wild-type (WT).
cbl1 plants exudated less Al-chelating malate, accumulated more Al, and displayed a severe root growth reduction in response to Al. Genes involved in metabolism, transport, cell wall modification, transcription and oxidative stress were differentially regulated between the two lines, under both control and Al stress treatments. Exposure to Al resulted in upregulation of a large set of genes only in WT and not cbl1 shoots, while a different set of genes were down-regulated in cbl1 but not in WT roots. These differences allowed us, for the first time, to define a calcium-regulated/dependent transcriptomic network for Al stress responses.
Our analyses reveal not only the fundamental role of CBL1 in the adjustment of central transcriptomic networks involved in maintaining adequate physiological homeostasis processes, but also that a high shoot–root dynamics is required for the proper deployment of Al resistance responses in the root.
Journal Article
Heatwaves leave a legacy on a dominant understory grass in longleaf pine savanna
by
Green, Curtis E.
,
Sabiston, Natalie C.
,
Mann, William T.
in
antioxidant enzyme activity
,
Biodiversity
,
Biomass
2025
The frequency and intensity of extreme climatic events such as heatwaves are predicted to increase under continued climate change and rising atmospheric CO2. Degraded and fragmented ecosystems are at particular risk of being greatly impacted by such extreme events. The longleaf pine (LLP) savanna ecosystem, once the dominant ecosystem throughout the Southeast Coastal Plains of the United States, has been reduced to a small percentage of its pre‐colonization range. While the effect of heatwaves on grassland systems has been well explored, less focus has been given to the legacy effects of previous climatic events. Through a greenhouse experiment using Schizachyrium scoparium (little bluestem), a dominant understory grass species in LLP savanna ecosystems, we aimed to study the legacy effects of heatwaves (i.e., higher temperatures and lower precipitation and humidity) across multiple plant performance metrics and stress responses. S. scoparium had a negative response to an early heatwave, showing increased mortality, smaller maximum leaf length, fewer leaves, decreased specific leaf area (SLA), decreased leaf thickness, and reduced belowground net primary productivity (NPP) when compared to plants that did not experience a heatwave. S. scoparium individuals exposed to a late heatwave had fewer leaves, reduced SLA, and thinner leaves when compared to plants that did not experience a heatwave. While plants exposed to both an early and late heatwave experienced an increase in some stress responses as observed by increased catalase activity and plant mortality, they exhibited no change in other stress responses studied (e.g., maximum leaf length, relative growth rate, productivity, leaf thickness, peroxidase levels, or fuel load). Overall, our study revealed that S. scoparium may show neutral‐to‐positive legacy effects in response to multiple heatwaves. This indicates that LLP savanna ecosystems dominated by S. scoparium may display resistance to the predicted increased frequency of heatwaves in the southeastern United States, an important outcome for the heavily degraded and endangered ecosystem.
Journal Article
Comprehensive in silico analysis of the underutilized crop tef (Eragrostis tef (Zucc.) Trotter) genome reveals drought tolerance signatures
by
Ligaba-Osena, Ayalew
,
Bekele-Alemu, Abreham
in
Abiotic stress
,
Abscisic acid
,
Agricultural production
2023
Background
Tef (
Eragrostis tef
) is a C
4
plant known for its tiny, nutritious, and gluten-free grains. It contains higher levels of protein, vitamins, and essential minerals like calcium (Ca), iron (Fe), copper (Cu), and zinc (Zn) than common cereals. Tef is cultivated in diverse ecological zones under diverse climatic conditions. Studies have shown that tef has great diversity in withstanding environmental challenges such as drought. Drought is a major abiotic stress severely affecting crop productivity and becoming a bottleneck to global food security. Here, we used
in silico
-based functional genomic analysis to identify drought-responsive genes in tef and validated their expression using quantitative RT-PCR.
Results
We identified about 729 drought-responsive genes so far reported in six crop plants, including rice, wheat, maize, barley, sorghum, pearl millet, and the model plant Arabidopsis, and reported 20 genes having high-level of GO terms related to drought, and significantly enriched in several biological and molecular function categories. These genes were found to play diverse roles, including water and fluid transport, resistance to high salt, cold, and drought stress, abscisic acid (ABA) signaling, de novo DNA methylation, and transcriptional regulation in tef and other crops. Our analysis revealed substantial differences in the conserved domains of some tef genes from well-studied rice orthologs. We further analyzed the expression of sixteen tef orthologs using quantitative RT-PCR in response to PEG-induced osmotic stress.
Conclusions
The findings showed differential regulation of some drought-responsive genes in shoots, roots, or both tissues. Hence, the genes identified in this study may be promising candidates for trait improvement in crops via transgenic or gene-editing technologies.
Journal Article
Rethinking progress: harmonizing the discourse on genetically modified crops
by
Bekele-Alemu, Abreham
,
Ligaba-Osena, Ayalew
,
Dessalegn-Hora, Obssi
in
biotech crops
,
Biotechnology
,
Cognition & reasoning
2025
Genetically modified crops (GM crops) also known as biotech crops are crops that have been altered through genetic engineering techniques and under cultivation for approximately 28 years. By October 2024, over 30 nations have approved the cultivation of GM crops. The global area utilized for biotech crop production has reached 206.3 million hectares. Despite the substantial growth in the cultivation of these crops, debate continues between proponents and opponents of GM crops. In this article, critical concerns and common ground between the arguments of both sides were described. The main issues addressed include the naturalness of GM crops, religious perspectives, beneficial aspects, safety issues, socio-economic impacts and intellectual property rights. We argue that the classification GM crops as unnatural is a claim that lacks scientific reality. In a similar vein, comparing GM technology to the act of playing God is inappropriate. Moreover, the belief that GM crops do not contribute to yield improvements is inconsistent with empirical evidence. Additionally, the claim that foods produced from GM crops are unsafe for human consumption holds unseen concerns that is not on the ground. We have also highlighted the necessity of implementing intellectual property rights that support seed developers for a limited duration without violating farmers’ rights. In conclusion, as a consumer has the right to know what they eat, labeling of GM food products fosters transparency and enhance consumer autonomy.
Journal Article
Analysis of miRNAs responsive to long‐term calcium deficiency in tef (Eragrostis tef (Zucc.) Trotter)
2022
MicroRNAs (miRNAs) play an important role in growth, development, stress resilience, and epigenetic modifications of plants. However, the effect of calcium (Ca2+) deficiency on miRNA expression in the orphan crop tef (Eragrostis tef) remains unknown. In this study, we analyzed expression of miRNAs in roots and shoots of tef in response to Ca2+ treatment. miRNA‐seq followed by bioinformatic analysis allowed us to identify a large number of small RNAs (sRNAs) ranging from 17 to 35 nt in length. A total of 1380 miRNAs were identified in tef experiencing long‐term Ca2+ deficiency while 1495 miRNAs were detected in control plants. Among the miRNAs identified in this study, 161 miRNAs were similar with those previously characterized in other plant species and 348 miRNAs were novel, while the remaining miRNAs were uncharacterized. Putative target genes and their functions were predicted for all the known and novel miRNAs that we identified. Based on gene ontology (GO) analysis, the predicted target genes are known to have various biological and molecular functions including calcium uptake and transport. Pairwise comparison of differentially expressed miRNAs revealed that some miRNAs were specifically enriched in roots or shoots of low Ca2+‐treated plants. Further characterization of the miRNAs and their targets identified in this study may help in understanding Ca2+ deficiency responses in tef and related orphan crops.
Journal Article
Seasonal Variation in Transcriptomic Profiling of Tetrastigma hemsleyanum Fully Developed Tuberous Roots Enriches Candidate Genes in Essential Metabolic Pathways and Phytohormone Signaling
2021
Tetrastigma hemsleyanum Diels et Gilg (Sanyeqing, SYQ) is a perennial climbing liana and an endemic plant to southern China. Its tuberous roots (TRs) are used in traditional Chinese medicine for treating some diseases such as high fever, pneumonia, asthma, hepatitis, and cancers. However, the mechanisms underlying the development of TR and the content of flavonoids and phenylpropanoids (FPs) are not well-understood. In this study, we performed a transcriptomic analysis of 12 fully developed TR (FD-TR) samples harvested in four seasons [spring (Sp), summer (Su), autumn (Au), and winter (Wi)] using the RNA-Sequencing (RNA-Seq). We obtained a total of 78.54 Gb raw data and 65,578 unigenes. Then, the unigenes were annotated by using six databases such as non-redundant protein database (NR), Pfam, eggNOG, SWISSProt, Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene ontology (GO). The transcriptomic profiling showed closer relationships between the samples obtained in Su and Au than those obtained in Sp and Wi based on the results of both total unigenes and differentially expressed genes (DEGs). Three pathways, including the biosynthesis of FPs, metabolism of starch and sucrose, and signaling of phytohormones, were highly enriched, suggesting a gene-level seasonal variation. Based on the numbers of DEGs, brassinosteroid (BR) signal transduction factors appeared to play a key role in modulating the development of TRs while most of the auxin signaling genes were mainly activated in Wi and Sp FD-TRs. Most genes in the biosynthesis and biodegradation of starch and biodegradation of cellulose were activated in Wi FD-TRs. As determined by the high performance liquid chromatography (HPLC) and aluminum nitrate colorimetric method, the contents of total flavonoids and most detected FP components increased from Sp to Au but decreased in Wi. Enhanced expression levels of some genes in the biosynthetic pathways of FPs were detected in Su and Au samples, which corroborated well with metabolite content. Our findings provide the first transcriptomic and biochemical data on a seasonal variation in the composition of medically important metabolites in SYQ FD-TRs.
Journal Article
Constitutive overexpression of Qui-Quine Starch gene simultaneously improves starch and protein content in bioengineered cassava (Manihot esculenta Crantz)
by
Ahlawat, Yogesh K.
,
Hankoua, Bertrand Bachaumond
,
Garcia, Rafael A.
in
Agricultural production
,
Amino acids
,
Arabidopsis thaliana
2025
Cassava is a crucial source of daily calorie intake for millions of people in sub-Saharan Africa (SSA) but has an inferior protein content. Despite numerous attempts utilizing both traditional and biotechnological methods, efforts to address protein deficiency in cassava have yet to meet with much success. We aim to leverage modern biotechnologies to enhance cassava's nutritional value by creating bioengineered cassava cultivars with increased protein and starch content. In this study, we utilized Qui-Quine Starch ( QQS ), a novel orphan gene unique to Arabidopsis thaliana , to develop transgenic cassava plants with increased protein and starch accumulation in their tissues. A total of 10 independent transgenic cassava lines expressing QQS were successfully regenerated in this study, among which line R7 (F) demonstrated superior growth vigor. Quantitative RT-PCR verified the expression of the QQS gene in the transgenic lines. Data showed that QQS expression in cassava plants increased leaf protein content by 36% in line R’’’ (LA) L2 and root protein by 17% for the same line compared to their wild-type and empty vector (NPTII) control plants. Moreover, leaf-soluble total carbohydrates increased by 51.76% in line R (G) L2, and root-soluble total carbohydrates increased by 46.75% in line R7 (F). The novel function of QQS in increasing the starch content in the transgenic biomass is demonstrated. No significant change in the content of specific amino acids was observed among the lines and various plant parts. In addition, QQS expression revealed increased biomass, plant vigor, and early In vitro mini-tubers production for line R7 (F). Gene interaction study between AtQQS and 59 interacting partners generated 184 interactions or edges. These gene networks comprised several functional categories regulating the starch metabolic and auxin biosynthetic processes. The role of QQS in imparting starch and protein content of transgenic cassava plants is validated. The next logical step is the evaluation of biochemical profiles of cassava lines expressing QQS that reach maturity and the transferability of these findings to consumer-preferred cassava cultivars and local landraces grown in SSA. This study represents the first biotechnological report demonstrating a simultaneous increase of protein and starch content in bioengineered cassava.
Journal Article
Silicon Enhances Biomass and Grain Yield in an Ancient Crop Tef Eragrostis tef (Zucc.) Trotter
by
Guo, Wanli
,
Limmer, Matthew Alan
,
Seyfferth, Angelia L.
in
Abiotic stress
,
Agricultural production
,
Barley
2020
Silicon (Si) is one of the beneficial plant mineral nutrients which is known to improve biotic and abiotic stress resilience and productivity in several crops. However, its beneficial role in underutilized or “orphan” crop such as tef [ Eragrostis tef (Zucc.) Trotter ] has never been studied before. In this study, we investigated the effect of Si application on tef plant performance. Plants were grown in soil with or without exogenous application of Na 2 SiO 3 (0, 1.0, 2.0, 3.0, 4.0, and 5.0 mM), and biomass and grain yield, mineral content, chlorophyll content, plant height, and expression patterns of putative Si transporter genes were studied. Silicon application significantly increased grain yield (100%) at 3.0 mM Si, and aboveground biomass yield by 45% at 5.0 mM Si, while it had no effect on plant height. The observed increase in grain yield appears to be due to enhanced stress resilience and increased total chlorophyll content. Increasing the level of Si increased shoot Si and Na content while it significantly decreased the content of other minerals including K, Ca, Mg, P, S, Fe, and Mn in the shoot, which is likely due to the use of Na containing Si amendment. A slight decrease in grain Ca, P, S, and Mn was also observed with increasing Si treatment. The increase in Si content with increasing Si levels prompted us to analyze the expression of Si transporter genes. The tef genome contains seven putative Si transporters which showed high homology with influx and efflux Lsi transporters reported in various plant species including rice. The tef Lsi homologs were deferentially expressed between tissues (roots, leaves, nodes, and inflorescences) and in response to Si, suggesting that they may play a role in Si uptake and/or translocation. Taken together, these results show that Si application improves stress resilience and yield and regulates the expression of putative Si transporter genes. However, further study is needed to determine the physiological function of the putative Si transporters, and to study the effect of field application of Si on tef productivity.
Journal Article