Plant-Arthropod Interactions: Effectors and Elicitors of Arthropods and Their Associated Microbes

Editorial

04 November 2020

Editorial: Plant-Arthropod Interactions: Effectors and Elicitors of Arthropods and Their Associated Microbes

Akiko Sugio

Gary W. Felton

David Giron

and

Isgouhi Kaloshian

3,597 views

0 citations

Editors

Gary W Felton

The Pennsylvania State University (PSU)

Giron David

Centre National de la Recherche Scientifique (CNRS)

Akiko Sugio

Institut de Génétique, Environnement et Protection des Plantes, Institut National de la Recherche Agronomique

Isgouhi Kaloshian

University of California, Riverside

Impact

Gene ontology (GO) of putative Cowpea aphid effectors. Cowpea aphid putative effectors were identified by analyzing the salivary proteins with SignalP, SecretomeP, and EffectorP.

Original Research

15 May 2020

AcDCXR Is a Cowpea Aphid Effector With Putative Roles in Altering Host Immunity and Physiology

Jacob R. MacWilliams

, 3 more and

Isgouhi Kaloshian

6,577 views

15 citations

(A) Fisher’s exact test (FET) analysis for significance of SNP allele frequency difference between H5-avirulent and H5-virulent bulks. The average -Log10(FET) values were plotted, and the relative positions of scaffolds on chromosomes are presented as in Figure 2A. A 1.3-Mb region corresponding to a single genome scaffold (A2.7) is highlighted in gray where the -Log10(FET) was statistically significant. (B) FET analysis of scaffold A2.7 (highlighted in panel A). Each dot represents the average -Log10(FET) value for 10-kb sliding-windows (5-kb steps).

Original Research

25 June 2020

BSA-Seq Discovery and Functional Analysis of Candidate Hessian Fly (Mayetiola destructor) Avirulence Genes

Lucio Navarro-Escalante

, 2 more and

Jeffrey Stuart

5,915 views

13 citations

Original Research

10 July 2020

Juvenile Spider Mites Induce Salicylate Defenses, but Not Jasmonate Defenses, Unlike Adults

Jie Liu

, 5 more and

Merijn R. Kant

5,451 views

7 citations

Original Research

02 September 2020

Big Genes, Small Effectors: Pea Aphid Cassette Effector Families Composed From Miniature Exons

Matthew Dommel

, 9 more and

Frank F. White

4,714 views

9 citations

Therefore, plants have developed the ability to use egg deposition as a warning cue to increase defenses against larvae after hatching (Beyaert et al., 2011) or even modify their own phenology to achieve an early flowering and reproduction (Lucas-Barbosa et al., 2013). Indeed, there is a bulk of evidence on the existence of specific plant responses that may endeavor to damage eggs directly or indirectly. Egg elicitors, i.e. 1) chemical substances present on the egg surface (e.g. benzyl cyanide), and possibly 2) egg-associated microorganisms trigger downstream defense responses regulated through hormone signaling pathways of which 3) salicylic acid (SA) plays a pivotal role (Hilfiker et al., 2014). Direct defense strategies include 4) necrotic tissue (HR-like necrosis), 5) ovicidal compounds (H2O2) (Geuss et al., 2017) or 6) callose formation. Lepidopteran egg elicitors can also induce the production of oviposition-induced plant volatiles (OIPVs) enabling the plants 7) to attract egg or larval parasitoids, that upon locating their hosts, inject their own eggs and kill the lepidopteran instars to feed their off-spring (Tamiru et al., 2011; Fatouros et al., 2012; Cusumano et al., 2015; Ponzio et al., 2016) or 8) insectivorous birds (Mrazova et al., 2019). In addition, OIPVs can also prime 9) neighboring plants (Mutyambai et al., 2016; Guo et al., 2019).

Mini Review

30 January 2020

Chemical, Physiological and Molecular Responses of Host Plants to Lepidopteran Egg-Laying

Cinzia Margherita Bertea

, 3 more and

Francesca Barbero

Plant-lepidopteran interactions involve complex processes encompassing molecules and regulators to counteract defense responses they develop against each other. Lepidoptera identify plants for oviposition and exploit them as larval food sources to complete their development. In turn, plants adopt different strategies to overcome and limit herbivorous damages. The insect egg deposition on leaves can already induce a number of defense responses in several plant species. This minireview deals with the main features involved in the interaction between plants and lepidopteran egg-laying, focusing on responses from both insect and plant side. We discuss different aspects of direct and indirect plant responses triggered by lepidopteran oviposition. In particular, we focus our attention on the mechanisms underlying egg-induced plant defenses that can i) directly damage the eggs such as localized hypersensitive response (HR)-like necrosis, neoplasm formation, production of ovicidal compounds and ii) indirect defenses, such as production of oviposition-induced plant volatiles (OIPVs) used to attract natural enemies (parasitoids) able to kill the eggs or hatching larvae. We provide an overview of chemical, physiological, and molecular egg-mediated plant responses induced by both specialist and generalist lepidopteran species, also dealing with effectors, elicitors, and chemical signals involved in the process. Egg-associated microorganisms are also discussed, although little is known about this third partner participating in plant-lepidopteran interactions.

7,501 views

31 citations

TPM of transcripts significantly upregulated in three or more tissues from corn-fed insects. TPM values were calculated with the Trinity suite. (A) Transcripts with significant differences in three pairwise comparisons. (B) Transcripts with significant differences in all pairwise comparisons.

Original Research

08 January 2020

Transcription and Activity of Digestive Enzymes of Nezara viridula Maintained on Different Plant Diets

Pablo Emiliano Cantón

and

Bryony C. Bonning

3,899 views

12 citations

Original Research

22 October 2019

Differential Expression of Candidate Salivary Effector Genes in Pea Aphid Biotypes With Distinct Host Plant Specificity

Hélène Boulain

, 5 more and

Akiko Sugio

Effector proteins play crucial roles in determining the outcome of various plant-parasite interactions. Aphids inject salivary effector proteins into plants to facilitate phloem feeding, but some proteins might trigger defense responses in certain plants. The pea aphid, Acyrthosiphon pisum, forms multiple biotypes, and each biotype is specialized to feed on a small number of closely related legume species. Interestingly, all the previously identified biotypes can feed on Vicia faba; hence, it serves as a universal host plant of A. pisum. We hypothesized that the salivary effector proteins have a key role in determining the compatibility between specific host species and A. pisum biotypes and that each biotype produces saliva containing a specific mixture of effector proteins due to differential expression of encoding genes. As the first step to address these hypotheses, we conducted two sets of RNA-seq experiments. RNA-seq analysis of dissected salivary glands (SGs) from reference alfalfa- and pea-specialized A. pisum lines revealed common and line-specific repertoires of candidate salivary effector genes. Based on the results, we created an extended catalogue of A. pisum salivary effector candidates. Next, we used aphid head samples, which contain SGs, to examine biotype-specific expression patterns of candidate salivary genes. RNA-seq analysis of head samples of alfalfa- and pea-specialized biotypes, each represented by three genetically distinct aphid lines reared on either a universal or specific host plant, showed that a majority of the candidate salivary effector genes was expressed in both biotypes at a similar level. Nonetheless, we identified small sets of genes that were differentially regulated in a biotype-specific manner. Little host plant effect (universal vs. specific) was observed on the expression of candidate salivary genes. Analysis of previously obtained genome re-sequenced data of the two biotypes revealed the copy number variations that might explain the differential expression of some candidate salivary genes. In addition, at least four candidate effector genes that were present in the alfalfa biotype but might not be encoded in the pea biotype were identified. This work sets the stage for future functional characterization of candidate genes potentially involved in the determination of plant specificity of pea aphid biotypes.

5,265 views

30 citations

Phylogenetic analysis of amino acid sequences from cathepsins isolated from WS and SS. The positions of H. halys cathepsins−25, −27, and −57 in different clades are shown. Insect and “other” orders are indicated by color as shown. Branch numbers are bootstrap values (%) of >40%.

Original Research

11 October 2019

The Principal Salivary Gland Is the Primary Source of Digestive Enzymes in the Saliva of the Brown Marmorated Stink Bug, Halyomorpha halys

Sijun Liu

and

Bryony C. Bonning

3,946 views

18 citations

Original Research

10 May 2019

The Arabidopsis Lectin Receptor Kinase LecRK-I.8 Is Involved in Insect Egg Perception

Caroline Gouhier-Darimont

, 2 more and

Philippe Reymond

Plants induce defense responses after insect egg deposition, but very little is known about the perception mechanisms. In Arabidopsis thaliana, eggs of the specialist insect Pieris brassicae trigger accumulation of reactive oxygen species (ROS) and salicylic acid (SA), followed by induction of defense genes and localized necrosis. Here, the involvement of the clade I L-type lectin receptor kinase LecRK-I.8 in these responses was studied. Expression of LecRK-I.8 was upregulated at the site of P. brassicae oviposition and egg extract (EE) treatment. ROS, SA, cell death, and expression of PR1 were substantially reduced in the Arabidopsis knock-out mutant lecrk-I.8 after EE treatment. In addition, EE-induced systemic resistance against Pseudomonas syringae was abolished in lecrk-I.8. Expression of ten clade I homologs of LecRK-I.8 was also induced by EE treatment, but single mutants displayed only weak alteration of EE-induced PR1 expression. These results demonstrate that LecRK-I.8 is an early component of egg perception.