scholarly journals Ethylene Is Not Essential for R-Gene Mediated Resistance but Negatively Regulates Moderate Resistance to Some Aphids in Medicago truncatula

2020 ◽  
Vol 21 (13) ◽  
pp. 4657
Author(s):  
Lijun Zhang ◽  
Lars G. Kamphuis ◽  
Yanqiong Guo ◽  
Silke Jacques ◽  
Karam B. Singh ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Plant Biomass ◽  
Genetic Resistance ◽  
Aphid Species ◽  
Aphid Resistance ◽  
Plant Responses ◽  
Ethylene Signaling ◽  
Plant Tolerance ◽  
Aphid Infestation ◽  
Moderate Resistance

Ethylene is important for plant responses to environmental factors. However, little is known about its role in aphid resistance. Several types of genetic resistance against multiple aphid species, including both moderate and strong resistance mediated by R genes, have been identified in Medicago truncatula. To investigate the potential role of ethylene, a M. truncatula ethylene- insensitive mutant, sickle, was analysed. The sickle mutant occurs in the accession A17 that has moderate resistance to Acyrthosiphon kondoi, A. pisum and Therioaphis trifolii. The sickle mutant resulted in increased antibiosis-mediated resistance against A. kondoi and T. trifolii but had no effect on A. pisum. When sickle was introduced into a genetic background carrying resistance genes, AKR (A. kondoi resistance), APR (A. pisum resistance) and TTR (T. trifolii resistance), it had no effect on the strong aphid resistance mediated by these genes, suggesting that ethylene signaling is not essential for their function. Interestingly, for the moderate aphid resistant accession, the sickle mutant delayed leaf senescence following aphid infestation and reduced the plant biomass losses caused by both A. kondoi and T. trifolii. These results suggest manipulation of the ethylene signaling pathway could provide aphid resistance and enhance plant tolerance against aphid feeding.

Patterns of resistance to three cereal aphids among wheats in the genus Triticum (Poaceae)

2003 ◽  
Vol 93 (4) ◽  
pp. 323-333 ◽  
Author(s):  
S.M. Migui ◽  
R.J. Lamb
Keyword(s):  
Plant Biomass ◽  
Rhopalosiphum Padi ◽  
Diploid Species ◽  
Aphid Species ◽  
Cereal Aphids ◽  
Wheat Species ◽  
Aphid Infestation ◽  
Triticum Boeoticum ◽  
Overall Resistance ◽  
Triticum Araraticum

AbstractForty-one accessions of wild and cultivated wheats belonging to 19 Triticum species were tested in the field for resistance to three species of aphids, Rhopalosiphum padi Linnaeus, Sitobion avenae Fabricius and Schizaphis graminum Rondani. Antibiotic resistance was estimated by the increase in biomass of aphids over 21 days on adult plants. Overall resistance was estimated by the plant biomass lost due to aphid infestation. All three species of aphids survived and reproduced on all wheats, and reduced spike biomass compared to uninfested controls. The level of antibiosis varied among wheat species and among accessions, with accessions from three, five and one species showing antibiosis to R. padi, S. avenae and S. graminum, respectively. Overall resistance to the three aphid species was observed in five to seven accessions per aphid species. Resistance was usually specific to one aphid species. The frequency of accessions with antibiosis or overall resistance was associated with the ploidy level of the plant species. Except for overall resistance to R. padi, resistance was highest for diploid species and lowest for hexaploid species. No consistent relationship between resistance and level of domestication was detected. Accessions of the wild wheats, Triticum boeoticum Bois, Triticum tauschii (Coss.) Schmal. and Triticum araraticum Jakubz. exhibited high levels of resistance to aphids, as did Triticum monococcum L. which is derived from T. boeoticum. Nevertheless, individual susceptible or resistant accessions occurred at all levels within the evolutionary tree of wheat.

scholarly journals Involvement of the Octadecanoid Pathway in Bluegreen Aphid Resistance in Medicago truncatula

2007 ◽  
Vol 20 (1) ◽  
pp. 82-93 ◽  
Author(s):  
Ling-Ling Gao ◽  
Jonathan P. Anderson ◽  
John P. Klingler ◽  
Ramakrishnan M. Nair ◽  
Owain R. Edwards ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Insect Pests ◽  
Dominant Gene ◽  
Aphid Resistance ◽  
Octadecanoid Pathway ◽  
Model Legume ◽  
Aphid Infestation ◽  
Resistance Trait ◽  
Plant Pathogen Interactions ◽  
Kinetics Of

Aphids are major insect pests of plants that feed directly from the phloem. We used the model legume Medicago truncatula Gaert. (barrel medic) to elucidate host resistance to aphids and identified a single dominant gene which confers resistance to Acyrthosiphon kondoi Shinji (bluegreen aphid). To understand how this gene conditions resistance to bluegreen aphid, transcription profiling of 23 defense-related genes representing various signaling pathways was undertaken using a pair of near-isogenic lines that are susceptible or resistant to bluegreen aphid. All salicylic acid- and ethylene-responsive genes tested were induced by blue-green aphid in resistant and susceptible plants, although there were some differences in the magnitude and kinetics of the induction. In contrast, 10 of 13 genes associated with the octadecanoid pathway were induced exclusively in the resistant plants following bluegreen aphid infestation. These results are in contrast to plant-pathogen interactions where similar sets of defense genes typically are induced in compatible interactions, but to a lesser degree and later than in incompatible interactions. Treatment of susceptible plants with methyl jasmonate reduced bluegreen aphid infestation but not to the same levels as the resistant line. Together, these results strongly suggest that the octa-decanoid pathway is important for this naturally derived aphid resistance trait.

Interspecific competition and tolerance to defoliation in four grassland species

2004 ◽  
Vol 82 (7) ◽  
pp. 871-877 ◽  
Author(s):  
Ek del-Val ◽  
Michael J Crawley
Keyword(s):  
Plant Biomass ◽  
Plant Competition ◽  
Plant Performance ◽  
Plant Responses ◽  
Plant Tolerance ◽  
Grassland Species ◽  
Rumex Acetosella ◽  
Below Ground ◽  
Trifolium Repens L ◽  
Biomass Compensation

Herbivory and competition are known to influence plant performance. Recent investigations showed that tolerance is an important strategy for plant survival under herbivory, but few have examined its interaction with plant competition. We evaluated in a greenhouse experiment if plant tolerance to defoliation is related to species presence in a grazed habitat and how plant tolerance to herbivory changes in a competitive environment. Regrowth capacity of four grassland species, Trifolium repens L., Rumex acetosella L., Vicia sativa L. subsp. nigra (L.) Ehrh., and Senecio jacobaea L., was evaluated as the capacity to compensate for 75% of aboveground biomass removed. Target plants were also grown in competition with Festuca rubra L. subsp. rubra, and different clipping treatments were applied. Plant biomass (above- and below-ground) was measured after 5 months. Rumex acetosella, T. repens, and S. jacobaea were able to compensate fully when grown alone. In competition, only R. acetosella was still able to regrow. In no case did clipping the competitor improve target plant performance (i.e., no beneficial effect from competitor release). These results highlight the importance of considering plant competition when studying plant responses to herbivory.Key words: herbivory, regrowth, competitor release, biomass compensation.

Drought stress increases the expression of barley defence genes with negative consequences for infesting cereal aphids

2021 ◽  
Author(s):  
Daniel Leybourne ◽  
Tracy Valentine ◽  
Kirsty Binnie ◽  
Anna Taylor ◽  
Alison Jane Karley ◽  
...  
Keyword(s):  
Drought Stress ◽  
Aphid Species ◽  
Susceptible Variety ◽  
Aphid Resistance ◽  
Herbivorous Insects ◽  
Cereal Aphids ◽  
Negative Consequences ◽  
Resistant Plant ◽  
Negative Effect ◽  
The Impact

Crops are exposed to myriad abiotic and biotic stressors with negative consequences. Two stressors that are expected to increase under climate change are drought and infestation with herbivorous insects, including important aphid species. Expanding our understanding of the impact drought has on the plant-aphid relationship will become increasingly important under future climate scenarios. Here we use a previously characterised plant-aphid system comprising a susceptible variety of barley, a wild relative of barley with partial-aphid resistance, and the bird cherry-oat aphid to examine the drought-plant-aphid relationship. We show that drought has a negative effect on plant physiology and aphid fitness and provide evidence to suggest that plant resistance influences aphid responses to drought stress, with the expression of aphid detoxification genes increasing under drought when feeding on the susceptible plant but decreasing on the partially-resistant plant. Furthermore, we show that the expression of thionin genes, plant defensive compounds that contribute aphid resistance, increase ten-fold in susceptible plants exposed to drought stress but remain at constant levels in the partially-resistant plant, suggesting they play an important role in modulating aphid populations. This study highlights the role of plant defensive processes in mediating the interactions between the environment, plants, and herbivorous insects.

scholarly journals Inoculation with Efficient Nitrogen Fixing and Indoleacetic Acid Producing Bacterial Microsymbiont Enhance Tolerance of the Model LegumeMedicago truncatulato Iron Deficiency

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Nadia Kallala ◽  
Wissal M’sehli ◽  
Karima Jelali ◽  
Zribi Kais ◽  
Haythem Mhadhbi
Keyword(s):  
Oxidative Stress ◽  
Iron Deficiency ◽  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Plant Biomass ◽  
High Growth ◽  
Fe Deficiency ◽  
Nitrogen Fixing ◽  
Bacterial Strains ◽  
Negative Effect

The aim of this study was to assess the effect of symbiotic bacteria inoculation on the response ofMedicago truncatulagenotypes to iron deficiency. The present work was conducted on threeMedicago truncatulagenotypes: A17, TN8.20, and TN1.11. Three treatments were performed: control (C), direct Fe deficiency (DD), and induced Fe deficiency by bicarbonate (ID). Plants were nitrogen-fertilized (T) or inoculated with two bacterial strains:Sinorhizobium melilotiTII7 andSinorhizobium medicaeSII4. Biometric, physiological, and biochemical parameters were analyzed. Iron deficiency had a significant lowering effect on plant biomass and chlorophyll content in allMedicago truncatulagenotypes. TN1.11 showed the highest lipid peroxidation and leakage of electrolyte under iron deficiency conditions, which suggest that TN1.11 was more affected than A17 and TN8.20 by Fe starvation. Iron deficiency affected symbiotic performance indices of allMedicago truncatulagenotypes inoculated with bothSinorhizobiumstrains, mainly nodules number and biomass as well as nitrogen-fixing capacity. Nevertheless, inoculation withSinorhizobiumstrains mitigates the negative effect of Fe deficiency on plant growth and oxidative stress compared to nitrogen-fertilized plants. The highest auxin producing strain, TII7, preserves relatively high growth and root biomass and length when inoculated to TN8.20 and A17. On the other hand, both TII7 and SII4 strains improve the performance of sensitive genotype TN1.11 through reduction of the negative effect of iron deficiency on chlorophyll and plant Fe content. The bacterial inoculation improved Fe-deficient plant response to oxidative stress via the induction of the activities of antioxidant enzymes.

scholarly journals Cultivar-Dependent Responses in Plant Growth, Leaf Physiology, Phosphorus Use Efficiency, and Tuber Quality of Potatoes Under Limited Phosphorus Availability Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Leangsrun Chea ◽  
Ana Meijide ◽  
Catharina Meinen ◽  
Elke Pawelzik ◽  
Marcel Naumann
Keyword(s):  
Tuber Yield ◽  
Plant Biomass ◽  
P Uptake ◽  
Tuber Quality ◽  
P Availability ◽  
Plant Tolerance ◽  
P Deficiency ◽  
Leaf Physiology ◽  
Use Efficiency

The limited availability of phosphorus (P) in soils causes a major constraint in the productivity of potatoes, which requires increased knowledge of plant adaptation responses in this condition. In this study, six potato cultivars, namely, Agria, Lady Claire, Milva, Lilly, Sieglinde, and Verdi, were assessed for their responses on plant growth, leaf physiology, P use efficiency (PUE), and tuber quality with three P levels (Plow, Pmed, and Phigh). The results reveal a significant variation in the cultivars in response to different P availabilities. P-efficient cultivars, Agria, Milva, and Lilly, possessed substantial plant biomass, tuber yield, and high P uptake efficiency (PUpE) under low P supply conditions. The P-inefficient cultivars, Lady Claire, Sieglinde, and Verdi, could not produce tubers under P deprivation conditions, as well as the ability to efficiently uptake P under low-level conditions, but they were efficient in P uptake under high soil P conditions. Improved PUpE is important for plant tolerance with limited P availability, which results in the efficient use of the applied P. At the leaf level, increased accumulations of nitrate, sulfate, sucrose, and proline are necessary for a plant to acclimate to P deficiency-induced stress and to mobilize leaf inorganic phosphate to increase internal PUE and photosynthesis. The reduction in plant biomass and tuber yield under P-deficient conditions could be caused by reduced CO2 assimilation. Furthermore, P deficiency significantly reduced tuber yield, dry matter, and starch concentration in Agria, Milva, and Lilly. However, contents of tuber protein, sugars, and minerals, as well as antioxidant capacity, were enhanced under these conditions in these cultivars. These results highlight the important traits contributing to potato plant tolerance under P-deficient conditions and indicate an opportunity to improve the P efficiency and tuber quality of potatoes under deficient conditions using more efficient cultivars. Future research to evaluate molecular mechanisms related to P and sucrose translocation, and minimize tuber yield reduction under limited P availability conditions is necessary.

scholarly journals Down-Regulation of Cytokinin Receptor Gene SlHK2 Improves Plant Tolerance to Drought, Heat, and Combined Stresses in Tomato

Plants ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 154
Author(s):  
Naveed Mushtaq ◽  
Yong Wang ◽  
Junmiao Fan ◽  
Yi Li ◽  
Jing Ding
Keyword(s):  
Abiotic Stress Tolerance ◽  
Receptor Gene ◽  
Antioxidant Enzyme Activities ◽  
Plant Responses ◽  
Plant Tolerance ◽  
Combined Stress ◽  
Cytokinin Signaling ◽  
Down Regulation ◽  
Cytokinin Receptor ◽  
Combined Stresses

Environmental stresses negatively affect the growth and development of plants. Several previous studies have elucidated the response mechanisms of plants to drought and heat applied separately; however, these two abiotic stresses often coincide in environmental conditions. The global climate change pattern has projected that combined drought and heat stresses will tend to increase in the near future. In this study, we down-regulated the expression of a cytokinin receptor gene SlHK2 using RNAi and investigated the role of this gene in regulating plant responses to individual drought, heat, and combined stresses (drought + heat) in tomato. Compared to the wild-type (WT), SlHK2 RNAi plants exhibited fewer stress symptoms in response to individual and combined stress treatments. The enhanced abiotic stress tolerance of SlHK2 RNAi plants can be associated with increased membrane stability, osmoprotectant accumulation, and antioxidant enzyme activities. Furthermore, photosynthesis machinery was also protected in SlHK2 RNAi plants. Collectively, our results show that down-regulation of the cytokinin receptor gene SlHK2, and consequently cytokinin signaling, can improve plant tolerance to drought, heat, and combined stress.

scholarly journals Arbuscular Mycorrhizal Fungal Diversity In Medicinal Plants Of Sirumalai Hills, Eastern Ghats And Their Role In Melia Dubia Cav

2021 ◽  
Author(s):  
Santhoshkumar S ◽  
Nagarajan N
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Eastern Ghats ◽  
Nutrient Cycle ◽  
Plant Responses ◽  
Plant Interactions ◽  
Plant Tolerance ◽  
Agricultural Ecosystem ◽  
Microbial World ◽  
Melia Dubia ◽  
Arbuscular Mycorrhizal Fungal

The microbial World is the largest unexplored reservoir of biodiversity on earth. Interest in the exploration of microbial diversity has been promoted by the fact that a microbe performs numerous functions essential for the biosphere that include nutrient cycle and environmental detoxification. Notably, under natural circumstances, plants frequently interact with microbes,which directly arbitrate plant responses to environmental adversities. Some microbe-plant interactions lead to a mitigation of stress-related damages and improvement of plant tolerance to stressful conditions. As a crucial element of soils, microbes are an integral part of the agricultural ecosystem.

scholarly journals Aphid Resistance in Medicago truncatula Involves Antixenosis and Phloem-Specific, Inducible Antibiosis, and Maps to a Single Locus Flanked by NBS-LRR Resistance Gene Analogs

2005 ◽  
Vol 137 (4) ◽  
pp. 1445-1455 ◽  
Author(s):  
John Klingler ◽  
Robert Creasy ◽  
Lingling Gao ◽  
Ramakrishnan M. Nair ◽  
Alonso Suazo Calix ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Medicago Truncatula ◽  
Aphid Resistance ◽  
Single Locus ◽  
Resistance Gene Analogs

Trophic interactions between three species of cereal aphid (Hemiptera: Aphididae) and spring wheat (Poaceae): implications for pest management

2007 ◽  
Vol 139 (6) ◽  
pp. 850-863 ◽  
Author(s):  
Samuel M. Migui ◽  
Robert J. Lamb
Keyword(s):  
Spring Wheat ◽  
Trophic Interactions ◽  
Plant Biomass ◽  
Rhopalosiphum Padi ◽  
Aphid Species ◽  
Economic Damage ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Economic Thresholds ◽  
Specific Impact

AbstractThe susceptibilities of genetically diverse Canadian spring wheats, Triticum aestivum L. and Triticum durum Desf., to three aphid species, Rhopalosiphum padi (L.), Sitobion avenae (Fabricius), and Schizaphis graminum (Rondani), were investigated. Trophic interactions measured as changes in biomass of aphids and wheat plants were used to quantify levels of resistance, components of resistance, and impact of aphids on yield. Plants in field cages were infested with small numbers of aphids for 21 days at heading. These plants were usually more suitable for the development of S. avenae and S. graminum than of R. padi. Partial resistance, measured as seed production by infested plants as a proportion of that by a control, varied from 11% to 59% for different aphid species and wheat classes when all wheat plants were infested at the same stage. Cultivars within wheat classes responded similarly to each of the aphid species. None of the wheat cultivars showed agriculturally effective levels of antibiosis. The specific impact of each aphid species and wheat class varied from 5 to 15 mg of plant biomass lost for each milligram of biomass gained by the aphids. Canadian Western Red Spring wheat had a lower specific impact and therefore was more tolerant to aphids than the other two classes, but not tolerant enough to avoid economic damage at the aphid densities observed. Plants did not compensate for feeding damage after aphid feeding ceased, based on the higher specific impacts observed for mature plants than for plants that were heading. The interactions between aphids and plants show that current economic thresholds probably underestimate the damage caused by cereal aphids to Canadian spring wheat.

Sign in / Sign up

Export Citation Format

Share Document