Research Paper
Plant breeding for abiotic & biotic stresses
Masoud Fakhrfeshani; Farajollah Shahriari-Ahmadi; Ali Niazi; Nasrin Moshtaghi; Mohammad Zare-Mehrjerdi
Abstract
Among abiotic stresses, salinity has been increasing over the time for many reasons like using chemical fertilizers, global warming and rising sea levels. Under salinity stress, the loss of water availability, toxicity of Na+ and ion imbalance directly reduces carbon fixation and biomass production in ...
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Among abiotic stresses, salinity has been increasing over the time for many reasons like using chemical fertilizers, global warming and rising sea levels. Under salinity stress, the loss of water availability, toxicity of Na+ and ion imbalance directly reduces carbon fixation and biomass production in plants. K+ is a major agent that can counteract Na+ stresses, thus the potential of plants to tolerate salinity is strongly dependent on their potassium nutrition. HKTs (High-affinity K+ Transporters) are a family of transporters that mediate Na+-specific or Na+-K+ transport and play a key role in the regulation of ion homeostasis. In this study, we intended to focus on Electrolyte Leakage, ratio of K+/Na+, transcriptomic responses of a subclass two HKT in the roots of Aeluropus littoralis under salt stress. We investigated a noticeably different expression pattern over studied time points and found a snappy increase of AlHKT and rebalance of K+ concentration. It can be suggested that the early and high response of a Na+-K+ coupled transporter acted as a part of A. littoralis salt tolerance.
Research Paper
Plant breeding for abiotic & biotic stresses
Abbas Hajipour; Mohammad-Mehdi Sohani; Valiollah Babaeizad; Hasan Hasani-Kumleh
Abstract
The root endophytic fungus, Piriformospora indica, colonizes roots of a large number of plant species including Cereals and Brasicaceae. There are several reports indicating that P. indica protects roots from different path- ogens. In the present study, rice plants were pre-inoculated with P. indica ...
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The root endophytic fungus, Piriformospora indica, colonizes roots of a large number of plant species including Cereals and Brasicaceae. There are several reports indicating that P. indica protects roots from different path- ogens. In the present study, rice plants were pre-inoculated with P. indica and were subsequently infected with Fusarium proliferatum, as the causal agent of root rot and crown rot (Bakanae) disease. The effects of P. indica on the protection of rice plants against F. proliferatum were evaluated. Transcription levels of some pathogenesis-related genes such as NPR1, PR1, PR4 and PR5, as well as two transcriptional factor genes namely WRKY62 and WRKY85 were quantified via quantitative real time PCR in rice roots. Pre-inoculated and challenged rice plants showed mild disease symptoms with two weeks delay compared to non P. indica colonized plants. Quantification of Fusarium in roots via q-PCR con- firmed the higher quantity of the fungi in non pre-inoculated plants. Expression analysis revealed a faster induction of pathogenesis related genes following F. proliferatum inoculation of pre-inoculated plants i.e. priming of these genes is a part of mechanism of P. indica induced systemic resistance.
Research Paper
Micropropagation & plant breeding
Mehdi Movahedi; Valiollah Ghasemi-Omran; Sepide Torabi
Abstract
The present study was carried out to investigate micropropagation possibility and determine the optimal medium composition and plant growth regulators (PGRs) combinations under in vitro conditions. The cotyledon and epicotyl explants obtained from 1 month old in vitro grown seedlings were used in MS ...
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The present study was carried out to investigate micropropagation possibility and determine the optimal medium composition and plant growth regulators (PGRs) combinations under in vitro conditions. The cotyledon and epicotyl explants obtained from 1 month old in vitro grown seedlings were used in MS medium containing BA (0.1, 0.2, 0.5, 1, 2 and 3 mg-1) and TDZ (0.1, 0.2, 0.5, 1, 2 and 3 mg-1) either alone or in combination with 0.5 mg-1 IBA. The response of cannabis explants to PGRs treatments was much different from those observed in most of plant species. That is, callus formation had priority over direct regeneration in most of the PGRs treatments. Comparing the two explants, cotyledon had higher callus formation frequency and the largest callus volume was obtained for this explant in MS medium supplemented with 3 mg-1 TDZ + 0.5 mg-1 IBA. The highest callus fresh weight (3.15 gr) was obtained for cotyledon explant treated with 2 mg-1 TDZ+ 0.5 mg-1 IBA. In shoot formation step, the highest rate of shoot regeneration was achieved in the calli produced from epicotyl explant treated with 2 mg-1 BA + 0.5 mg-1 IBA; and the highest length of regenerated shoots (1.23 cm) was observed in 2 mg-1 BA + 0.5 mg-1 IBA treatment. In general, cotyledon was the best explant and TDZ in combination with IBA was the best treatment for callus formation. Epicotyl explant also showed better regeneration compared to cotyledon.
Research Paper
Plant breeding for abiotic & biotic stresses
Khalil Malekzadeh; Ali Niazi; Farajollah Shahriari-Ahmadi; Amin Mirshamsi-Kakhaki; Mohammad Zare-Mehrjerdi
Abstract
Salinity is one of the most important abiotic stresses that limit crop growth and production. Salt stress influences plants in two ways: by affecting ion toxicity and increasing osmotic stress. Ion homeostasis, the excretion of Na+ and using antioxidant systems are the major strategies of salt tolerance ...
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Salinity is one of the most important abiotic stresses that limit crop growth and production. Salt stress influences plants in two ways: by affecting ion toxicity and increasing osmotic stress. Ion homeostasis, the excretion of Na+ and using antioxidant systems are the major strategies of salt tolerance in plants. Na+ and K+ transporters with enzymes that are involved in detoxification of reactive oxygen species play key roles in salt tolerance in plants. The aim of this study was to investigate the responses of high affinity K+ transporter2;1 gene (HKT2;1) which is involved in regulation of ion homeostasis and L-gulonolactone oxidase (GLOase) which is involved in the ascorbic acid biosynthesis pathway, under different concentrations of NaCl over different time points in Aeluropus littoralis shoots. Results from Real Time PCR data showed that expressions of both genes were influenced by external and internal concentrations of Na+ and the internal K+ content. AlHKT2;1 was significantly upregulated by increasing Na+ concentration at all time points. Furthermore, its highest expression level in shoots occurred after 6 days in 300mM NaCl in shoots which was 25folds more than untreated shoots. AlGLOase expression levels increased 54 h after initiation of salt stress. These results indicate that AlHKT2;1 and AlGLOase respond to different salinity conditions and probably are part of the mechanisms involved in tolerance to high salt concentrations in A. littoralis.
Research Paper
Molecular markers & plant breeding
Mohammad-Ali Ebrahimi; Masoud Tohidfar; Mahsa Karimi; Fatehmeh Zawarei
Abstract
One concern about using transgenic plants is the genetic variation that occurred from theirs tissue culture and regeneration. Molecular markers are an important element for efficient and effective determination of genetic variation. The present work was carried out to assess the genetic uniformity of ...
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One concern about using transgenic plants is the genetic variation that occurred from theirs tissue culture and regeneration. Molecular markers are an important element for efficient and effective determination of genetic variation. The present work was carried out to assess the genetic uniformity of transgenic cottons (Bt and chitinase lines), using RAPD, ISSR molecular markers and SDS-PAGE analysis. Similarity matrix for RAPD marker based on Nei and Li’s coefficient revealed that pairwise value between Bt and chitinase cottons and their conventional counterpart plant was 93% and 95% respectively. Also, similarity matrix for ISSR marker revealed that pair wise value between Bt and chitinase lines and their conventional counterpart was 94% and 96% respectively. Pairwise similarity coefficient among two transgenic plants and their conventional counterpart ranged from 0.94 to 0.99 SDS-protein patterns exhibited four major bands, molecular weight ranged from 10 KD to 35 KD. Similarity matrix for protein patterns revealed that pairwise value between Bt and chitinase lines and their conventional counterpart was 100%.All protein bands of three cultivars are the same and no polymorphic bands was detected. Pairwise similarity coefficient among two transgenic plants and their conventional counterpart ranged from 0.94 to 0.99. These lines could be used for more in-dept.evaluation and biosafety studies on their way to commercialization
Research Paper
Molecular biology and (trans) gene expression technology in plant breeding
Sahand Amini; Cyrus Ghobadi; Ahad Yamchi
Abstract
Under osmotic stresses, proline accumulation is an important response of plants to these conditions. Proline is a compatible osmolyte which affects many cellular and molecular aspects of plant in both normal and stressful situations. Proline is shown to be involved in plant development in normal condition ...
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Under osmotic stresses, proline accumulation is an important response of plants to these conditions. Proline is a compatible osmolyte which affects many cellular and molecular aspects of plant in both normal and stressful situations. Proline is shown to be involved in plant development in normal condition and in conferring resistance to plant under biotic and abiotic stresses. Therefore, many surveys have already been designed to unveil its mechanisms and signaling pathway, so that it might be an insight into resolving growing challenge of agriculture, drought and soil salinity. Δ1-pyrroline-5-carboxylate synthetase (P5CS), one of two main enzymes in proline biosynthesis pathway from glutamate precursor, has been demonstrated to play significant role in proline accumulation in plants under water stresses. Regarding the role of P5CS under osmotic stress, there are controversial observations in various plants, hence making it still unknown, whether P5CS is rate-limiting enzyme in the pathway or not. Obviously, transgene P5CS is proved to give higher resistance to transgenic plants under drought and salinity, by elevating proline content. In this literature, proline and its identified various functions in plants, characteristics of P5CS enzyme, signals, inducers and inhibitors of P5CS gene, expression pattern of P5CS under differential conditions in studied plant species are discussed. Finally, we have reviewed generated transgenic plants overexpressing P5CS and consequences of these transformations.