scholarly journals Comparative transcriptomic and metabolic analysis of wild and domesticated wheat genotypes reveals differences in chemical and physical defense responses against aphids

2019 ◽  
Author(s):  
Zhaniya S Batyrshina ◽  
Beery Yaakov ◽  
Reut Shavit ◽  
Anuradha Singh ◽  
Vered Tzin
Keyword(s):  
Chinese Spring ◽  
Defense Mechanisms ◽  
Chemical Defenses ◽  
Wild Emmer ◽  
Primary Metabolism ◽  
Trichome Density ◽  
Wheat Seedlings ◽  
Wheat Genotypes ◽  
Physical Defenses ◽  
In The Wild

Abstract Background Young wheat plants are continuously exposed to herbivorous insect attack. To reduce insect damage and maintain their growth, plants evolved different defense mechanisms, including the biosynthesis of deterrent compounds named benzoxazinoids, and/or trichome formation that provides physical barriers. It is unclear whether both of these mechanisms are equally critical in providing an efficient defense for wheat seedlings against aphids—an economically costly pest in cereal production. Results: In this study, we compared the transcriptome, metabolome, benzoxazinoids, and trichome density of three selected wheat genotypes, with a focus on differences related to defense mechanisms. We chose diverse wheat genotypes: two tetraploid wheat genotypes, domesticated durum ‘Svevo’ and wild emmer ‘Zavitan,’ and one hexaploid bread wheat, ‘Chinese Spring.’ The full transcriptomic analysis revealed a major difference between the three genotypes, while the clustering of significantly different genes suggested a higher similarity between the two domesticated wheats than between either and the wild wheat. A pathway enrichment analysis indicated that the genes associated with primary metabolism, as well as the pathways associated with defense such as phytohormones and specialized metabolites, were different between the three genotypes. Measurement of benzoxazinoid levels at the three time points (11, 15, and 18 days after germination) revealed high levels in the two domesticated genotypes, while in wild emmer wheat, they were below detection level. In contrast to the benzoxazinoid levels, the trichome density was dramatically higher in the wild emmer than in the domesticated wheat. Lastly, we tested the bird cherry-oat aphid’s ( Rhopalosiphum padi ) performance and found that Chinese Spring is more resistant than the tetraploid genotypes. Conclusions: Our results show that benzoxazinoids play a more significant defensive role than trichomes. Differences between the abundance of defense mechanisms in the wild and domesticated plants were observed in which wild emmer possesses high physical defenses while the domesticated wheat genotypes have high chemical defenses. These findings provide new insights into the defense adaptations of wheat plants against aphids.

scholarly journals Comparative transcriptomic and metabolic analysis of wild and domesticated wheat genotypes reveals differences in chemical and physical defense responses against aphids

2019 ◽  
Author(s):  
Zhaniya S Batyrshina ◽  
Beery Yaakov ◽  
Reut Shavit ◽  
Anuradha Singh ◽  
Vered Tzin
Keyword(s):  
Chinese Spring ◽  
Defense Mechanisms ◽  
Chemical Defenses ◽  
Wild Emmer ◽  
Primary Metabolism ◽  
Trichome Density ◽  
Wheat Seedlings ◽  
Wheat Genotypes ◽  
Physical Defenses ◽  
In The Wild

Abstract Background: Young wheat plants are continuously exposed to herbivorous insect attack. To reduce insect damage and maintain their growth, plants evolved different defense mechanisms, including the biosynthesis of deterrent compounds named benzoxazinoids, and/or trichome formation that provides physical barriers. It is unclear whether both of these mechanisms are equally critical in providing an efficient defense for wheat seedlings against aphids—an economically costly pest in cereal production. Results: In this study, we compared the transcriptome, metabolome, benzoxazinoids, and trichome density of three selected wheat genotypes, with a focus on differences related to defense mechanisms. We chose diverse wheat genotypes: two tetraploid wheat genotypes, domesticated durum ‘Svevo’ and wild emmer ‘Zavitan,’ and one hexaploid bread wheat, ‘Chinese Spring.’ The full transcriptomic analysis revealed a major difference between the three genotypes, while the clustering of significantly different genes suggested a higher similarity between the two domesticated wheats than between either and the wild wheat. A pathway enrichment analysis indicated that the genes associated with primary metabolism, as well as the pathways associated with defense such as phytohormones and specialized metabolites, were different between the three genotypes. Measurement of benzoxazinoid levels at the three time points (11, 15, and 18 days after germination) revealed high levels in the two domesticated genotypes, while in wild emmer wheat, they were below detection level. In contrast to the benzoxazinoid levels, the trichome density was dramatically higher in the wild emmer than in the domesticated wheat. Lastly, we tested the bird cherry-oat aphid’s ( Rhopalosiphum padi ) performance and found that Chinese Spring is more resistant than the tetraploid genotypes. Conclusions: Our results show that benzoxazinoids play a more significant defensive role than trichomes. Differences between the abundance of defense mechanisms in the wild and domesticated plants were observed in which wild emmer possesses high physical defenses while the domesticated wheat genotypes have high chemical defenses. These findings provide new insights into the defense adaptations of wheat plants against aphids.

scholarly journals Comparative transcriptome and metabolic analysis of wild and domesticated wheat genotypes reveals differences in chemical and physical defense responses against aphids

2019 ◽  
Author(s):  
Zhaniya S Batyrshina ◽  
Beery Yaakov ◽  
Reut Shavit ◽  
Anuradha Singh ◽  
Vered Tzin
Keyword(s):  
Bread Wheat ◽  
Chinese Spring ◽  
Wild Emmer ◽  
Primary Metabolism ◽  
Wheat Seedlings ◽  
Wheat Genotypes ◽  
Time Points ◽  
Physical Defenses ◽  
In The Wild ◽  
Physical Barriers

Abstract Background: Young wheat plants are continuously exposed to insect herbivorous attack. To maintain their fitness, plants have evolved different defense mechanisms, including the biosynthesis of deterrent compounds named benzoxazinoids, and/or trichome formation that provides physical barriers. It is unclear whether both of these mechanisms are equally critical in providing an efficient defense for wheat seedlings against the bird cherry-oat ( Rhopalosiphum padi ) aphid—an economically costly pest in cereal production. Results: In this study, we compared the transcriptomic, metabolomic, chemical, and physical defenses of three selected wheat genotypes to aphid performance. We chose diverse wheat genotypes, two tetraploid wheat genotypes, domesticated durum ‘Svevo’ and wild emmer ‘Zavitan,’ and one hexaploid bread wheat, ‘Chinese Spring.’ The full transcriptomic analysis revealed a major difference between the three genotypes, while the clustering of significantly different genes suggested a higher similarity between the two domesticated than the wild wheat. A pathway enrichment analysis indicated that genes associated with primary metabolism, as well as the pathways associated with defense such as phytohormones and specialized metabolites, were altered between the three genotypes. Measurement of benzoxazinoid levels at the three time-points (11, 15 and 18 days-after-germination) revealed high abundance levels in the two domesticated genotypes, while the levels were very low in the wild emmer wheat. The Chinese Spring showed a more diverse benzoxazinoid (known and putative) composition than the other two genotypes. In contrast to the benzoxazinoid levels, the trichome density was dramatically higher in the wild emmer than in the domesticated wheat. Evaluation of aphid reproduction indicated that the domesticated bread wheat is more resistant than the tetraploid genotypes. Conclusions: We compared the amount of benzoxazinoids, the trichome number, and aphid reproduction at three time-points, as well as performing a transcriptome analysis. Overall, the results suggested that although wheat seedlings possess both chemical and physical defenses, the chemical defense plays a more significant defensive role than the physical barriers.

scholarly journals The Effects of Silica Fertilizer as an Anti-Herbivore Defense in Cucumber

2017 ◽  
Vol 25 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Kristine L. Callis-Duehl ◽  
Heather J. McAuslane ◽  
Adrian J. Duehl ◽  
Douglas J. Levey
Keyword(s):  
Plant Defense ◽  
Water Content ◽  
Lignin Content ◽  
Chemical Defenses ◽  
Fertilizer Treatment ◽  
Trichome Density ◽  
Carbon And Nitrogen ◽  
Physical Defenses ◽  
Significant Difference ◽  
And Control

AbstractThis study aims to improve our understanding of silicon’s role in deterring herbivores from Cucumis sativa. We hypothesized that silicon’s role in plant defense is due to the presence of silica augmenting other physical and/or chemical defenses used by the plant. Using C. sativa plants treated with either a silica fertilizer treatment (Si+) or a control solution (Si-), we monitored feeding preferences of two types of herbivores, a chewing herbivore (Diabrotica balteata) and a piercing/sucking herbivore (Bemisia tabaci). Leaves from treatment plants were visited less and eaten less than leaves from control plants. We then assessed the differences in physical defenses by comparing the leaf structural components, nutrient and water content, and trichome density between treatment and control plants. For chemical plant defenses, we measured leaf carbon and nitrogen levels in, and volatile organic compounds (VOCs) from treatment and control plants. We found no significant difference between treatment and control plants in: lignin content, most elemental plant nutrients, water content, trichome density, and quantity of carbon and nitrogen. We did see an increase in the VOC Indole, known for plant defense priming, an increase in phosphorous levels and a decrease in cellulose levels in silica treated plants.

scholarly journals The Effectiveness of Physical and Chemical Defense Responses of Wild Emmer Wheat Against Aphids Depends on Leaf Position and Genotype

2021 ◽  
Vol 12 ◽  
Author(s):  
Anuradha Singh ◽  
Brian Dilkes ◽  
Hanan Sela ◽  
Vered Tzin
Keyword(s):  
Chemical Defense ◽  
Defense Mechanisms ◽  
Aphid Resistance ◽  
Wild Emmer ◽  
Leaf Position ◽  
Trichome Density ◽  
Aphid Infestation ◽  
Phloem Sap ◽  
Physical Defense ◽  
Aphid Feeding

The bird cherry-oat aphid (Rhopalosiphum padi) is one of the most destructive insect pests in wheat production. To reduce aphid damage, wheat plants have evolved various chemical and physical defense mechanisms. Although these mechanisms have been frequently reported, much less is known about their effectiveness. The tetraploid wild emmer wheat (WEW; Triticum turgidum ssp. dicoccoides), one of the progenitors of domesticated wheat, possesses untapped resources from its numerous desirable traits, including insect resistance. The goal of this research was to determine the effectiveness of trichomes (physical defense) and benzoxazinoids (BXDs; chemical defense) in aphid resistance by exploiting the natural diversity of WEW. We integrated a large dataset composed of trichome density and BXD abundance across wheat genotypes, different leaf positions, conditions (constitutive and aphid-induced), and tissues (whole leaf and phloem sap). First, we evaluated aphid reproduction on 203 wheat accessions and found large variation in this trait. Then, we chose eight WEW genotypes and one domesticated durum wheat cultivar for detailed quantification of the defense mechanisms across three leaves. We discovered that these defense mechanisms are influenced by both leaf position and genotype, where aphid reproduction was the highest on leaf-1 (the oldest), and trichome density was the lowest. We compared the changes in trichome density and BXD levels upon aphid infestation and found only minor changes relative to untreated plants. This suggests that the defense mechanisms in the whole leaf are primarily anticipatory and unlikely to contribute to aphid-induced defense. Next, we quantified BXD levels in the phloem sap and detected a significant induction of two compounds upon aphid infestation. Moreover, evaluating aphid feeding patterns showed that aphids prefer to feed on the oldest leaf. These findings revealed the dynamic response at the whole leaf and phloem levels that altered aphid feeding and reproduction. Overall, they suggested that trichomes and the BXD 2,4-dihydroxy-7- methoxy-1,4-benzoxazin-3-one (DIMBOA) levels are the main factors determining aphid resistance, while trichomes are more effective than BXDs. Accessions from the WEW germplasm, rich with trichomes and BXDs, can be used as new genetic sources to improve the resistance of elite wheat cultivars.

Function Analysis of Drought Resistance Related Gene TaGAPCs and TaWRKYs in Wheat

2021 ◽  
Author(s):  
Qiuzhu Wang ◽  
Lin Zhang ◽  
Shushen Yang
Keyword(s):  
Transcription Factors ◽  
Drought Stress ◽  
Function Analysis ◽  
Severe Drought ◽  
Primary Metabolism ◽  
Wild Type ◽  
Drought Treatment ◽  
Biological Regulation ◽  
Wheat Seedlings ◽  
Differential Genes

Abstract Backgrounds: Wheat (Triticum aestivum L.) is one of the most important food crops in the world. It faces various abiotic stresses during its growth. Drought is one of the main factors limiting the growth and development of wheat. Severe drought stress will Lead to a decline in wheat production. Cytoplasmic glyceraldehyde-3-phosphate dehydrogenase (GAPC) is an important member of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) family, which is widely present in plant cytoplasm. Plants play an important role in the process of primary metabolism and stress resistance.Result: In this study, a comparative transcriptomic analysis of the TaGAPCs-RNAi strain of Changwu 134 and the wild-type wheat seedlings of Changwu 134 under natural drought conditions was carried out. A total of 30067 differentially expressed genes were screened in RNAi strains and wild-type strains, of which 19,959 genes were up-regulated in RNAi strains and 10,108 genes were down-regulated in transcription. GO analysis shows that differential genes are mainly enriched in biological regulation, cellular processes, metabolic processes, and responses to stimuli. KEGG analysis showed that the differential genes were mainly concentrated in the biosynthesis of phenylpropane, plant hormone signal transduction and flavonoid biosynthesis pathways. By analyzing the expression levels of differential transcription factors, the significantly down-regulated transcription factor WRKY family member TaWRKY2 / 22/28/29/33/40/47/52 in wheat was screened out. The TaWRKY28/33/40/47 gene silencing line was successfully obtained using the barley stripe mosaic virus (BSMV-VIGS) technology. The plants with TaWRKY28/33/40/47 gene silenced were subjected to natural drought treatment, and physiological and biochemical index tests were carried out. The results showed that the growth status of gene-silenced plants was worse than that of wild-type plants, and the relative water content and chlorophyll content decreased. The content of MDA, H2O2 and superoxide anion increases, the activity of antioxidant enzymes (SOD, POD, CAT) decreases, and the content of proline decreases. Conclusion: The results showed that TaGAPCs regulates the expression of some TaWRKYs transcription factors, activates antioxidant pathways, enhances tolerance of wheat to drought stress.

scholarly journals Plant antiherbivore defenses in Fabaceae species of the Chaco

2016 ◽  
Vol 77 (2) ◽  
pp. 299-303 ◽  
Author(s):  
T. E. Lima ◽  
A. L. B. Sartori ◽  
M. L. M. Rodrigues
Keyword(s):  
Protease Inhibitors ◽  
Plant Species ◽  
Reproductive Organs ◽  
Chemical Defenses ◽  
South American ◽  
Defense Proteins ◽  
Climatic Variations ◽  
Physical Defenses ◽  
Physical And Chemical ◽  
First Time

Abstract The establishment and maintenance of plant species in the Chaco, one of the widest continuous areas of forests in the South American with sharp climatic variations, are possibly related to biological features favoring plants with particular defenses. This study assesses the physical and chemical defenses mechanisms against herbivores of vegetative and reproductive organs. Its analyses of 12 species of Fabaceae (Leguminosae) collected in remnants of Brazilian Chaco shows that 75% present structural defense characters and 50% have chemical defense – defense proteins in their seeds, like protease inhibitors and lectins. Physical defenses occur mainly on branches (78% of the species), leaves (67%), and reproductive organs (56%). The most common physical characters are trichomes and thorns, whose color represents a cryptic character since it does not contrast with the other plant structures. Defense proteins occur in different concentrations and molecular weight classes in the seeds of most species. Protease inhibitors are reported for the first time in seeds of: Albizia niopoides, Anadenanthera colubrina, Mimosa glutinosa, Prosopis rubriflora, and Poincianella pluviosa. The occurrence of physical and chemical defenses in members of Fabaceae indicate no associations between defense characters in these plant species of the Chaco.

scholarly journals Model Wheat Genotypes as Tools to Uncover Effective Defense Mechanisms Against the Hemibiotrophic Fungus Bipolaris sorokiniana

2005 ◽  
Vol 95 (5) ◽  
pp. 528-532 ◽  
Author(s):  
Aloysius Ebelechukwu Ibeagha ◽  
Ralph Hückelhoven ◽  
Patrick Schäfer ◽  
Devendra Pal Singh ◽  
Karl-Heinz Kogel
Keyword(s):  
Cell Wall ◽  
Defense Mechanisms ◽  
Bipolaris Sorokiniana ◽  
Field Resistance ◽  
Phytopathogenic Fungus ◽  
Host Genotype ◽  
Wheat Genotypes ◽  
A Cell ◽  
Wall Appositions ◽  
Susceptible Control

We investigated the interaction of several differentially resistant wheatwith the hemibiotrophic phytopathogenic fungus Bipolaris sorokiniana (teleomorph Cochliobolus sativus). Wheat genotypes Yangmai, M 3 (W7976), Shanghai 4, and Chirya 7 showed higher levels of resistancewith cv. Sonalika, used as a susceptible control. In amicroscopic inspection, we found that fungal penetration intoepidermal layer failed mostly through a cell wall-associated defense. In cases where the fungus successfully overcame epidermal, its spread within the mesophyll tissue (necrotrophic phase) wasin the more resistant genotypes. Epidermal cell wall-associated, spreading as well as the extent of electrolyte leakage of infected, correlated well with field resistance. We propose that cellular hostsuch as formation of cell wall appositions as well as the degreeearly mesophyll spreading of fungal hyphae are indicative of thepotential of the respective host genotype and, therefore, could befor the characterization of new spot blotch resistance traits in cereals.

scholarly journals Effects of Targeted Replacement of the Tomatinase Gene on the Interaction of Septoria lycopersici with Tomato Plants

2000 ◽  
Vol 13 (12) ◽  
pp. 1301-1311 ◽  
Author(s):  
A. M. Martin-Hernandez ◽  
M. Dufresne ◽  
V. Hugouvieux ◽  
R. Melton ◽  
A. Osbourn
Keyword(s):  
Plant Defense ◽  
Defense Mechanisms ◽  
Phytopathogenic Fungi ◽  
Chemical Defenses ◽  
Gaeumannomyces Graminis ◽  
Blue Staining ◽  
Wild Type ◽  
Mesophyll Cells ◽  
Isolation And Characterization ◽  
Septoria Lycopersici

Many plants produce constitutive antifungal molecules belonging to the saponin family of secondary metabolites, which have been implicated in plant defense. Successful pathogens of these plants must presumably have some means of combating the chemical defenses of their hosts. In the oat root pathogen Gaeumannomyces graminis, the saponin-detoxifying enzyme avenacinase has been shown to be essential for pathogenicity. A number of other phytopathogenic fungi also produce saponin-degrading enzymes, although the significance of these for saponin resistance and pathogenicity has not yet been established. The tomato leaf spot pathogen Septoria lycopersici secretes the enzyme tomatinase, which degrades the tomato steroidal glycoalkaloid α-tomatine. Here we report the isolation and characterization of tomatinase-deficient mutants of S. lycopersici following targeted gene disruption. Tomatinase-minus mutants were more sensitive to α-tomatine than the wild-type strain. They could, however, still grow in the presence of 1 mM α-tomatine, suggesting that nondegra-dative mechanisms of tolerance are also important. There were no obvious effects of loss of tomatinase on macroscopic lesion formation on tomato leaves, but trypan blue staining of infected tissue during the early stages of infection revealed more dying mesophyll cells in leaves that had been inoculated with tomatinase-minus mutants. Expression of a defense-related basic β-1,3 glucanase gene was also enhanced in these leaves. These differences in plant response may be associated with subtle differences in the growth of the wild-type and mutant strains during infection. Alternatively, tomatinase may be involved in suppression of plant defense mechanisms.

scholarly journals Constitutive and Induced Expression of Total Phenol and Phenol Oxidases in Wheat Genotypes Ranging in Resistance/Susceptibility to the Root-Lesion Nematode Pratylenchus thornei

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 485 ◽  
Author(s):  
Md Motiur Rahaman ◽  
Rebecca S. Zwart ◽  
John P. Thompson
Keyword(s):  
Phenolic Compounds ◽  
Defense Mechanisms ◽  
Oxidative Enzymes ◽  
Total Phenols ◽  
Sources Of Resistance ◽  
Wheat Genotypes ◽  
Phenol Oxidases ◽  
Pratylenchus Thornei ◽  
Root Tissues ◽  
Moderately Resistant

Plant-derived phenolic compounds contribute to the defense against various pathogens, including root-lesion nematodes (Pratylenchus spp.). However, there are no reports on the role of phenolic compounds in wheat (Triticum aestivum) against Pratylenchus thornei. In this study, wheat genotypes ranging from resistant to very susceptible to P. thornei were used to investigate the level of total phenols and phenol oxidases, polyphenol oxidase (PPO), and peroxidase (POD) expressed in root tissues when grown in the presence and absence of P. thornei over time (2–8 weeks). Higher constitutive levels of total phenols were found in resistant synthetic hexaploid wheats CPI133872 (576 µg gallic acid equivalent (GAE)/g root) and CPI133859 (518 µg GAE/g root) at 8 weeks after sowing, compared with moderately resistant and susceptible genotypes (192 to 390 µg GAE/g root). The activity of PPO was induced in resistant (CPI133872) and moderately resistant (GS50a and its derivate QT8343) genotypes, becoming maximal at 4 weeks after P. thornei inoculation. The activity of POD was induced in CPI133872 at 6 weeks after P. thornei inoculation. Different genetic sources of resistance to P. thornei showed diverse defense mechanisms and differences in timing responses. The combined effects of total phenols and oxidative enzymes could be important for defense against P. thornei in some resistant wheat genotypes.

RESTRICTION FRAGMENT LENGTH POLYMORPHISM IN WILD AND CULTIVATED TETRAPLOID WHEAT

1999 ◽  
Vol 47 (4) ◽  
pp. 213-224 ◽  
Author(s):  
Li Huang ◽  
Eitan Millet ◽  
Junkang Rong ◽  
Jonathan F. Wendel ◽  
Yehoshua Anikster ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Triticum Turgidum ◽  
Large Population ◽  
Tetraploid Wheat ◽  
Nuclear Genome ◽  
Wild Emmer ◽  
Long Term Study ◽  
In The Wild

RFLP diversity in the nuclear genome was estimated within and among Israeli populations of wild emmer wheat (Triticum turgidumvar.dicoccoides) from a long-term study site at Ammiad (NE Israel), and from several other geographical locations. Using 55 enzyme-probe combinations, high levels of genetic diversity were revealed in wild emmer in general and within the Ammiad site. In spite of high diversity, observed heterozygosity was low and populations consisted of a patchwork of alternate multilocus homozygotes, consistent with the reproductive biology of a predominant self-fertilizing species. Retention of genetic diversity in wild emmer may be promoted by large population sizes, microhabitat diversity, and occasional gene flow through both pollen and seed. Population genetic structure in wild emmer appears to have been influenced by historical founder events as well as selective factors. Multivariate analyses indicated that individuals tend to cluster together according to their population of origin, and that there is little geographical differentiation among populations. Sampling of 12 domesticated land-races and both primitive and modern cultivars ofT. turgidumrevealed high levels of diversity and a large number of alleles that were not detected in the wild emmer populations. This may reflect a long-term domestication process in which wild, semi-domesticated, and domesticated types grew sympatrically, continuing introgression from wild populations, and perhaps also gene flow from trans-specific sources.

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