scholarly journals Differential Defense Responses of Upland and Lowland Switchgrass Cultivars to a Cereal Aphid Pest

2020 ◽  
Vol 21 (21) ◽  
pp. 7966
Author(s):  
Lise Pingault ◽  
Nathan A. Palmer ◽  
Kyle G. Koch ◽  
Tiffany Heng-Moss ◽  
Jeffrey D. Bradshaw ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Panicum Virgatum ◽  
Global Analysis ◽  
Defense Responses ◽  
Bioenergy Feedstock ◽  
Cereal Aphid ◽  
Aphid Infestation ◽  
Biotic Stresses ◽  
Panicum Virgatum L ◽  
Sipha Flava

Yellow sugarcane aphid (YSA) (Sipha flava, Forbes) is a damaging pest on many grasses. Switchgrass (Panicum virgatum L.), a perennial C4 grass, has been selected as a bioenergy feedstock because of its perceived resilience to abiotic and biotic stresses. Aphid infestation on switchgrass has the potential to reduce the yields and biomass quantity. Here, the global defense response of switchgrass cultivars Summer and Kanlow to YSA feeding was analyzed by RNA-seq and metabolite analysis at 5, 10, and 15 days after infestation. Genes upregulated by infestation were more common in both cultivars compared to downregulated genes. In total, a higher number of differentially expressed genes (DEGs) were found in the YSA susceptible cultivar (Summer), and fewer DEGs were observed in the YSA resistant cultivar (Kanlow). Interestingly, no downregulated genes were found in common between each time point or between the two switchgrass cultivars. Gene co-expression analysis revealed upregulated genes in Kanlow were associated with functions such as flavonoid, oxidation-response to chemical, or wax composition. Downregulated genes for the cultivar Summer were found in co-expression modules with gene functions related to plant defense mechanisms or cell wall composition. Global analysis of defense networks of the two cultivars uncovered differential mechanisms associated with resistance or susceptibility of switchgrass in response to YSA infestation. Several gene co-expression modules and transcription factors correlated with these differential defense responses. Overall, the YSA-resistant Kanlow plants have an enhanced defense even under aphid uninfested conditions.

scholarly journals Proteomics and Metabolomics Studies on the Biotic Stress Responses of Rice: an Update

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kieu Thi Xuan Vo ◽  
Md Mizanor Rahman ◽  
Md Mustafizur Rahman ◽  
Kieu Thi Thuy Trinh ◽  
Sun Tae Kim ◽  
...  
Keyword(s):  
Stress Responses ◽  
Biotic Stress ◽  
Defense Mechanisms ◽  
Defense Responses ◽  
Global Changes ◽  
Biotic Stresses ◽  
Novel Proteins ◽  
Stress Agent ◽  
Global Food ◽  
Shed Light

AbstractBiotic stresses represent a serious threat to rice production to meet global food demand and thus pose a major challenge for scientists, who need to understand the intricate defense mechanisms. Proteomics and metabolomics studies have found global changes in proteins and metabolites during defense responses of rice exposed to biotic stressors, and also reported the production of specific secondary metabolites (SMs) in some cultivars that may vary depending on the type of biotic stress and the time at which the stress is imposed. The most common changes were seen in photosynthesis which is modified differently by rice plants to conserve energy, disrupt food supply for biotic stress agent, and initiate defense mechanisms or by biotic stressors to facilitate invasion and acquire nutrients, depending on their feeding style. Studies also provide evidence for the correlation between reactive oxygen species (ROS) and photorespiration and photosynthesis which can broaden our understanding on the balance of ROS production and scavenging in rice-pathogen interaction. Variation in the generation of phytohormones is also a key response exploited by rice and pathogens for their own benefit. Proteomics and metabolomics studies in resistant and susceptible rice cultivars upon pathogen attack have helped to identify the proteins and metabolites related to specific defense mechanisms, where choosing of an appropriate method to identify characterized or novel proteins and metabolites is essential, considering the outcomes of host-pathogen interactions. Despites the limitation in identifying the whole repertoire of responsive metabolites, some studies have shed light on functions of resistant-specific SMs. Lastly, we illustrate the potent metabolites responsible for resistance to different biotic stressors to provide valuable targets for further investigation and application.

scholarly journals Carbohydrate and lignin partitioning in switchgrass biomass (Panicum virgatum L.) as a bioenergy feedstock

2013 ◽  
Vol 100 (3) ◽  
pp. 251-260 ◽  
Author(s):  
Bronislava Butkutė ◽  
Nijolė Lemežienė ◽  
Jurgita Cesevičienė ◽  
Žilvinas Liatukas ◽  
Giedrė Dabkevičienė
Keyword(s):  
Panicum Virgatum ◽  
Bioenergy Feedstock ◽  
Panicum Virgatum L

scholarly journals Divergent Switchgrass Cultivars Modify Cereal Aphid Transcriptomes

2019 ◽  
Vol 112 (4) ◽  
pp. 1887-1901
Author(s):  
Kyle G Koch ◽  
Erin D Scully ◽  
Nathan A Palmer ◽  
Scott M Geib ◽  
Gautam Sarath ◽  
...  
Keyword(s):  
Panicum Virgatum ◽  
De Novo ◽  
Expression Profiles ◽  
Schizaphis Graminum ◽  
Detoxification Enzymes ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Bioenergy Grasses ◽  
Sipha Flava ◽  
Transcriptional Changes

Abstract Schizaphis graminum Rondani (Hemiptera: Aphididae) and Sipha flava Forbes (Hemiptera: Aphididae) are two common pests of bioenergy grasses. Despite the fact that they are both considered generalists, they differ in their ability to colonize Panicum virgatum cultivars. For example, S. flava colonizes both P. virgatum cv. Summer and P. virgatum cv. Kanlow whereas S. graminum can only colonize Summer. To study the molecular responses of these aphids to these two switchgrass cultivars, we generated de novo transcriptome assemblies and compared the expression profiles of aphids feeding on both cultivars to profiles associated with feeding on a highly susceptible sorghum host and a starvation treatment. Transcriptome assemblies yielded 8,428 and 8,866 high-quality unigenes for S. graminum and S. flava, respectively. Overall, S. graminum responded strongly to all three treatments after 12 h with an upregulation of unigenes coding for detoxification enzymes while major transcriptional changes were not observed in S. flava until 24 h. Additionally, while the two aphids responded to the switchgrass feeding treatment by downregulating unigenes linked to growth and development, their responses to Summer and Kanlow diverged significantly. Schizaphis graminum upregulated more unigenes coding for stress-responsive enzymes in the Summer treatment compared to S. flava; however, many of these unigenes were actually downregulated in the Kanlow treatment. In contrast, S. flava appeared capable of overcoming host defenses by upregulating a larger number of unigenes coding for detoxification enzymes in the Kanlow treatment. Overall, these findings are consistent with previous studies on the interactions of these two cereal aphids to divergent switchgrass hosts.

scholarly journals Functional analysis of the teosinte branched 1 gene in the tetraploid switchgrass (Panicum virgatum L.) by CRISPR/Cas9-directed mutagenesis

2020 ◽  
Author(s):  
Yang Liu ◽  
Weiling Wang ◽  
Bing Yang ◽  
Christopher Currey ◽  
Shui-zhang Fei
Keyword(s):  
Panicum Virgatum ◽  
Mutant Gene ◽  
Defense Responses ◽  
Yield Component ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Component Trait ◽  
Panicum Virgatum L ◽  
Nodal Culture

AbstractTillering is an important biomass yield component trait in switchgrass (Panicum virgatum L.). Teosinte branched 1 (tb1)/Branched 1 (BRC1) gene is a known regulator for tillering/branching in several plant species; however, its role on tillering in switchgrass remains unknown. Here, we report physiological and molecular characterization of mutants created by CRISPR/Cas9. We successfully obtained non-chimeric Pvtb1a and Pvtb1b mutants from chimeric T0 mutants using nodal culture. The biallelic Pvtb1a-Pvtb1b mutant plants produced significantly more tillers and higher fresh weight biomass than the wild-type plants. The increased tiller production in the mutant plants resulted primarily from hastened outgrowth of lower axillary buds. Increased tillers were also observed in transgene-free T1 monoallelic mutants for either Pvtb1a-Pvtb1b or Pvtb1b gene alone, suggesting Pvtb1 genes act in a dosage-dependent manner. Transcriptome analysis showed 831 genes were differentially expressed in the Pvtb1a-Pvtb1b double knockdown mutant. Gene Ontology analysis revealed downregulation of Pvtb1 genes affected multiple biological processes, including transcription, flower development, cell differentiation, and stress/defense responses in edited plants. This study demonstrates that Pvtb1 genes play a pivotal role in tiller production as a negative regulator in switchgrass and provides opportunities for further research aiming to elucidate the molecular pathway regulating tillering in switchgrass.HighlightSolid non-chimeric mutants were successfully isolated from CRISPR/Cas9-induced chimeric mutants using nodal culture. Teosinte branched 1 (tb1) genes are involved in various pathways to regulate tillering in switchgrass.

scholarly journals Variation Between Three Eragrostis tef Accessions in Defense Responses to Rhopalosiphum padi Aphid Infestation

2020 ◽  
Vol 11 ◽  
Author(s):  
Nathan M. Gyan ◽  
Beery Yaakov ◽  
Nati Weinblum ◽  
Anuradha Singh ◽  
Alon Cna’ani ◽  
...  
Keyword(s):  
Stress Responses ◽  
Defense Mechanisms ◽  
Rhopalosiphum Padi ◽  
Defense Responses ◽  
The Other ◽  
Eragrostis Tef ◽  
Aphid Infestation ◽  
Volatile Analysis ◽  
Insect Order ◽  
Physical Defense

Tef (Eragrostis tef), a staple crop that originated in the Horn of Africa, has been introduced to multiple countries over the last several decades. Crop cultivation in new geographic regions raises questions regarding the molecular basis for biotic stress responses. In this study, we aimed to classify the insect abundance on tef crop in Israel, and to elucidate its chemical and physical defense mechanisms in response to insect feeding. To discover the main pests of tef in the Mediterranean climate, we conducted an insect field survey on three selected accessions named RTC-144, RTC-405, and RTC-406, and discovered that the most abundant insect order is Hemiptera. We compared the differences in Rhopalosiphum padi (Hemiptera; Aphididae) aphid performance, preference, and feeding behavior between the three accessions. While the number of aphid progeny was lower on RTC-406 than on the other two, the aphid olfactory assay indicated that the aphids tended to be repelled from the RTC-144 accession. To highlight the variation in defense responses, we investigated the physical and chemical mechanisms. As a physical barrier, the density of non-granular trichomes was evaluated, in which a higher number of trichomes on the RTC-406 than on the other accessions was observed. This was negatively correlated with aphid performance. To determine chemical responses, the volatile and central metabolite profiles were measured upon aphid attack for 4 days. The volatile analysis exposed a rich and dynamic metabolic profile, and the central metabolism profile indicated that tef plants adjust their sugars and organic and amino acid levels. Overall, we found that the tef plants possess similar defense responses as other Poaceae family species, while the non-volatile deterrent compounds are yet to be characterized. A transcriptomic time-series analysis of a selected accession RTC-144 infested with aphids revealed a massive alteration of genes related to specialized metabolism that potentially synthesize non-volatile toxic compounds. This is the first report to reveal the variation in the defense mechanisms of tef plants. These findings can facilitate the discovery of insect-resistance genes leading to enhanced yield in tef and other cereal crops.

scholarly journals Internode structure and cell wall composition in maturing tillers of switchgrass (Panicum virgatum. L)

2007 ◽  
Vol 98 (16) ◽  
pp. 2985-2992 ◽  
Author(s):  
Gautam Sarath ◽  
Lisa M. Baird ◽  
Kenneth P. Vogel ◽  
Robert B. Mitchell
Keyword(s):  
Cell Wall ◽  
Panicum Virgatum ◽  
Cell Wall Composition ◽  
Panicum Virgatum L

scholarly journals Core RNA Interference Genes Involved in miRNA and Ta-siRNA Biogenesis in Hops and Their Expression Analysis after Challenging with Verticillium nonalfalfae

2021 ◽  
Vol 22 (8) ◽  
pp. 4224
Author(s):  
Urban Kunej ◽  
Jernej Jakše ◽  
Sebastjan Radišek ◽  
Nataša Štajner
Keyword(s):  
Rna Interference ◽  
Expression Analysis ◽  
Cannabis Sativa ◽  
Defense Responses ◽  
Resistant Cultivar ◽  
Post Inoculation ◽  
Biotic Stresses ◽  
Argonaute 2 ◽  
Expression Of Genes ◽  
Verticillium Nonalfalfae

RNA interference is an evolutionary conserved mechanism by which organisms regulate the expression of genes in a sequence-specific manner to modulate defense responses against various abiotic or biotic stresses. Hops are grown for their use in brewing and, in recent years, for the pharmaceutical industry. Hop production is threatened by many phytopathogens, of which Verticillium, the causal agent of Verticillium wilt, is a major contributor to yield losses. In the present study, we performed identification, characterization, phylogenetic, and expression analyses of three Argonaute, two Dicer-like, and two RNA-dependent RNA polymerase genes in the susceptible hop cultivar Celeia and the resistant cultivar Wye Target after infection with Verticillium nonalfalfae. Phylogeny results showed clustering of hop RNAi proteins with their orthologues from the closely related species Cannabis sativa, Morus notabilis and Ziziphus jujuba which form a common cluster with species of the Rosaceae family. Expression analysis revealed downregulation of argonaute 2 in both cultivars on the third day post-inoculation, which may result in reduced AGO2-siRNA-mediated posttranscriptional gene silencing. Both cultivars may also repress ta-siRNA biogenesis at different dpi, as we observed downregulation of argonaute 7 in the susceptible cultivar on day 1 and downregulation of RDR6 in the resistant cultivar on day 3 after inoculation.

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