scholarly journals Application of Plant Defense Elicitors Fails to Enhance Herbivore Resistance or Mitigate Phytoplasma Infection in Cranberries

2021 ◽  
Vol 12 ◽  
Author(s):  
Cesar Rodriguez-Saona ◽  
James J. Polashock ◽  
Vera Kyryczenko-Roth ◽  
Robert Holdcraft ◽  
Giovanna Jimenez-Gonzalez ◽  
...  

Synthetic elicitors of the salicylic acid (SA) and jasmonic acid (JA) plant defense pathways can be used to increase crop protection against herbivores and pathogens. In this study, we tested the hypothesis that elicitors of plant defenses interact with pathogen infection to influence crop resistance against vector and nonvector herbivores. To do so, we employed a trophic system comprising of cranberries (Vaccinium macrocarpon), the phytoplasma that causes false blossom disease, and two herbivores—the blunt-nosed leafhopper (Limotettix vaccinii), the vector of false blossom disease, and the nonvector gypsy moth (Lymantria dispar). We tested four commercial elicitors, including three that activate mainly SA-related plant defenses (Actigard, LifeGard, and Regalia) and one activator of JA-related defenses (Blush). A greenhouse experiment in which phytoplasma-infected and uninfected plants received repeated exposure to elicitors revealed that both phytoplasma infection and elicitor treatment individually improved L. vaccinii and L. dispar mass compared to uninfected, untreated controls; however, SA-based elicitor treatments reduced L. vaccinii mass on infected plants. Regalia also improved L. vaccinii survival. Phytoplasma infection reduced plant size and mass, increased levels of nitrogen (N) and SA, and lowered carbon/nitrogen (C/N) ratios compared to uninfected plants, irrespective of elicitor treatment. Although none of our elicitor treatments influenced transcript levels of a phytoplasma-specific marker gene, all of them increased N and reduced C/N levels; the three SA activators also reduced JA levels. Taken together, our findings reveal positive effects of both phytoplasma infection and elicitor treatment on the performance of L. vaccinii and L. dispar in cranberries, likely via enhancement of plant nutrition and changes in phytohormone profiles, specifically increases in SA levels and corresponding decreases in levels of JA. Thus, we found no evidence that the tested elicitors of plant defenses increase resistance to insect herbivores or reduce disease incidence in cranberries.

2021 ◽  
Vol 12 ◽  
Author(s):  
Sanae Mouden ◽  
Johanna A. Bac-Molenaar ◽  
Iris F. Kappers ◽  
Ellen A. M. Beerling ◽  
Kirsten A. Leiss

For a first step integrating elicitor applications into the current IPM strategy increasing plant resilience against pests, we investigated repeated elicitor treatments in a strawberry everbearer nursery and cropping cycle under glass. During nursery methyl-jasmonate (MeJA), testing induction of defenses with plant bioassays was applied every 3 weeks. Thrips damage and reproduction by spider mites, whitefly and aphids were strongly reduced upon elicitor treatment. Subsequently, we applied MeJA every 3 weeks or based on scouting pests during a whole cropping cycle. Thrips leaf bioassays and LC-MS leaf metabolomics were applied to investigate the induction of defenses. Leaf damage by thrips was lower for both MeJA application schemes compared to the control except for the last weeks. While elicitor treatments after scouting also reduced damage, its effect did not last. Thrips damage decreased from vegetative to mature plants during the cropping cycle. At the end of the nursery phase, plants in the elicitor treatment were smaller. Surprisingly, growth during production was not affected by MeJA application, as were fruit yield and quality. LC-MS leaf metabolomics showed strong induction of vegetative plants decreasing during the maturation of plants toward the end of cultivation. Concurrently, no increase in the JA-inducible marker PPO was observed when measured toward the end of cultivation. Mostly flavonoid and phenolic glycosides known as plant defense compounds were induced upon MeJA application. While induced defense decreased with the maturation of plants, constitutive defense increased as measured in the leaf metabolome of control plants. Our data propose that young, relatively small plant stages lack constitutive defense necessitating an active JA defense response. As plants, mature constitutive defense metabolites seem to accumulate, providing a higher level of basal resistance. Our results have important implications for but are not limited to strawberry cultivation. We demonstrated that repeated elicitor application could be deployed as part of an integrated approach for sustainable crop protection by vertical integration with other management tactics and horizontal integration to control multiple pests concurrently. This approach forms a promising potential for long-term crop protection in greenhouses.


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1818
Author(s):  
Francisco Hernández-Aparicio ◽  
Purificación Lisón ◽  
Ismael Rodrigo ◽  
José María Bellés ◽  
M. Pilar López-Gresa

New strategies of control need to be developed with the aim of economic and environmental sustainability in plant and crop protection. Metabolomics is an excellent platform for both understanding the complex plant–pathogen interactions and unraveling new chemical control strategies. GC-MS-based metabolomics, along with a phytohormone analysis of a compatible and incompatible interaction between tomato plants and Fusarium oxysporum f. sp. lycopersici, revealed the specific volatile chemical composition and the plant signals associated with them. The susceptible tomato plants were characterized by the over-emission of methyl- and ethyl-salicylate as well as some fatty acid derivatives, along with an activation of salicylic acid and abscisic acid signaling. In contrast, terpenoids, benzenoids, and 2-ethylhexanoic acid were differentially emitted by plants undergoing an incompatible interaction, together with the activation of the jasmonic acid (JA) pathway. In accordance with this response, a higher expression of several genes participating in the biosynthesis of these volatiles, such as MTS1, TomloxC,TomloxD, and AOS, as well as JAZ7, a JA marker gene, was found to be induced by the fungus in these resistant plants. The characterized metabolome of the immune tomato plants could lead to the development of new resistance inducers against Fusarium wilt treatment.


2021 ◽  
Vol 12 ◽  
Author(s):  
Garima Pal ◽  
Devashish Mehta ◽  
Saurabh Singh ◽  
Kalai Magal ◽  
Siddhi Gupta ◽  
...  

Xanthomonas Oryzae pv. oryzae (Xoo) causes bacterial blight and Rhizoctonia solani (R. solani) causes sheath blight in rice accounting for >75% of crop losses. Therefore, there is an urgent need to develop strategies for the mitigation of these pathogen infections. In this study, we report the antimicrobial efficacy of Cholic Acid-Glycine Conjugates (CAGCs) against Xoo and R. solani. We show that CAGC C6 is a broad-spectrum antimicrobial and is also able to degrade biofilms. The application of C6 did not hamper plant growth and showed minimal effect on the plant cell membranes. Exogenous application of C6 on pre-infection or post-infection of Xoo on rice susceptible genotype Taichung native (TN1) can mitigate the bacterial load and improve resistance through upregulation of plant defense genes. We further demonstrate that C6 can induce plant defense responses when seeds were primed with C6 CAGC. Therefore, this study demonstrates the potential of CAGCs as effective antimicrobials for crop protection that can be further explored for field applications.


Endocrinology ◽  
2013 ◽  
Vol 154 (10) ◽  
pp. 3680-3689 ◽  
Author(s):  
Xiaorui Cao ◽  
Huan Li ◽  
Huiren Tao ◽  
Ning Wu ◽  
Lifeng Yu ◽  
...  

Metformin exhibits diverse protective effects against diabetic complications, such as bone loss. Here, we investigated the effect of metformin on vascular calcification, another type 2 diabetes complication. In female rat aortic smooth muscle cells (RASMCs), we observed that metformin significantly alleviated β-glycerophosphate-induced Ca deposition and alkaline phosphatase activity, corresponding with reduced expression of some specific genes in osteoblast-like cells, including Runx2 and bone morphogenetic protein-2, and positive effects on α-actin expression, a specific marker of smooth muscle cells. Mechanistic analysis showed that phosphorylation levels of both AMP-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS) were increased with NO overproduction. After inhibition of either AMPK or eNOS with the pharmacologic inhibitors, compound C or Nω-Nitro-L-arginine methyl ester, NO production was lowered and metformin-meditated vascular protection against β-glycerophosphate-induced Ca deposition was removed. Our results support that metformin prevents vascular calcification via AMPK-eNOS-NO pathway.


2020 ◽  
Vol 8 (7) ◽  
pp. 992 ◽  
Author(s):  
Laura Toral ◽  
Miguel Rodríguez ◽  
Victoria Béjar ◽  
Inmaculada Sampedro

This study aims to evaluate the use of Bacillus velezensis strain XT1 as a plant growth-promoting rhizobacterium (PGPR) and biocontrol agent against B. cinerea in tomato and strawberry plants. Foliar and radicular applications of strain XT1 increased plant total biomass as compared to the control and B. cinerea-infected plants, with root applications being, on the whole, the most effective mode of treatment. Applications of the bacterium were found to reduce infection parameters such as disease incidence and severity by 50% and 60%, respectively. We analyzed stress parameters and phytohormone content in order to evaluate the capacity of XT1 to activate the defense system through phytohormonal regulation. Overall, the application of XT1 reduced oxidative damage, while the H2O2 and malondialdehyde (MDA) content was lower in XT1-treated and B. cinerea-infected plants as compared to non-XT1-treated plants. Moreover, treatment with XT1 induced callose deposition, thus boosting the response to pathogenic infection. The results of this study suggest that the signaling and activation pathways involved in defense mechanisms are mediated by jasmonic acid (JA) and ethylene hormones, which are induced by preventive treatment with XT1. The study also highlights the potential of preventive applications of strain XT1 to activate defense mechanisms in strawberry and tomato plants through hormone regulation.


2009 ◽  
Vol 11 (1) ◽  
pp. 111-122 ◽  
Author(s):  
Mingtao Zhao ◽  
S. Clay Isom ◽  
Hui Lin ◽  
Yanhong Hao ◽  
Yong Zhang ◽  
...  

2009 ◽  
Vol 21 (1) ◽  
pp. 241
Author(s):  
M. T. Zhao ◽  
C. S. Isom ◽  
J. G. Zhao ◽  
Y. H. Hao ◽  
J. Ross ◽  
...  

Recently neural crest derived multipotent progenitors from skin have attracted much attention as the skin may provide an accessible, autologous source of stem cells available with therapeutic potential (Toma JG et al. 2001 Nat. Cell Biol. 3, 778–784). The multipotent property of stem cells could be tracked back to the expression of specific marker genes that are exclusively expressed in multipotent stem cells rather than any other types of differentiated cells. Here we demonstrate the property of multipotency and neural crest origin of porcine GFP-transgenic skin derived progenitors (termed pSKP) in vitro by marker gene expression analysis. The pSKP cells were isolated from the back skin of GFP transgenic fetuses by serum-free selection culture in the presence of EGF (20 ng mL–1) and bFGF (40 ng mL–1), and developed into spheres in 1–2 weeks (Dyce PW et al. 2004 Biochem. Biophy. Res. Commun. 316, 651–658). Three groups of RT-PCR primers were used on total RNA from purified pSKP cells: pluripotency related genes (Oct4, Sox2, Nanog, Stat3), neural crest marker genes (p75NGFR, Slug, Twist, Pax3, Sox9, Sox10) and lineage specific genes (GFAP, tubulin β-III, leptin). Expression of both pluripotency related genes and neural crest marker genes were detected in undifferentiated pSKP cells. In addition, transcripts for fibronectin, vimentin and nestin (neural stem cell marker) were also present. The percentage of positive cells for Oct4, fibronection and vimentin were 12.3%, 67.9% and 53.7% respectively. Differentiation assays showed the appearance of tubulin β-III positive (39.4%) and GFAP-positive (42.6%) cells in cultures by immunocytochemistry, which share the characteristics of neurons and glial cells, respectively. Thus, we confirm the multiple lineage potentials and neural crest origin of pSKP cells in the level of marker gene expression. This work was funded by National Institutes of Health National Center for Research Resources RR013438.


2020 ◽  
Vol 6 (01) ◽  
pp. 01-08
Author(s):  
Rajesh Bajpai ◽  
D. K. Upreti

Allelopathy is a common biological miracle by which one organism produces biochemicals that affect the growth, existence, development, and reproduction of other organisms. These biochemicals are known as allelochemicals and have advantageous, as well as, harmful effects on target organisms. Lichens produce over a thousand different extracellular biochemical terms as secondary metabolites. The lichen secondary metabolites may show either positive effects, such as, in weed control, crop protection, or crop re-establishment or negative effects, e.g., autotoxicity, biological invasion, competition, deterioration, and eutrophic soil sickness. However, several lichen secondary metabolites can potentially be used as growth regulators, insecticidal, and antimicrobial since dated back. Here, we discuss the application of lichen allelopathy in various agricultural prospects in the near future.


Plant Disease ◽  
2005 ◽  
Vol 89 (9) ◽  
pp. 1000-1008 ◽  
Author(s):  
M. C. Becktell ◽  
M. L. Daughtrey ◽  
W. E. Fry

Factors affecting the management of petunia and tomato late blight, caused by Phytophthora infestans, under greenhouse conditions were investigated. Late blight-infected petunias (Petunia × hybrida) and tomatoes (Lycopersicon esculentum) each produced sporangia that were dispersed throughout the greenhouse via air currents. Infected petunias produced and released fewer sporangia than infected tomatoes, but infected petunias released sporangia two times longer. Surface-directed irrigation reduced disease incidence compared with overhead irrigation that wetted the foliage. The fungicides dimethomorph-mancozeb, fosetyl-Al, azoxystrobin, and dipo-tassium phosphonate/phosphate suppressed late blight development, as did the plant defense activator acibenzolar-S-methyl. All products were applied twice at 7-day intervals. The other plant defense activator (harpin protein) and the bioantagonists (Trichoderma harzianum, Glio-cladium virens, and Bacillus subtilis) were ineffective at the rates tested.


Land ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 34 ◽  
Author(s):  
Ram Meena ◽  
Sandeep Kumar ◽  
Rahul Datta ◽  
Rattan Lal ◽  
Vinod Vijayakumar ◽  
...  

The World Health Organization (WHO) states that in developing nations, there are three million cases of agrochemical poisoning. The prolonged intensive and indiscriminate use of agrochemicals adversely affected the soil biodiversity, agricultural sustainability, and food safety, bringing in long-term harmful effects on nutritional security, human and animal health. Most of the agrochemicals negatively affect soil microbial functions and biochemical processes. The alteration in diversity and composition of the beneficial microbial community can be unfavorable to plant growth and development either by reducing nutrient availability or by increasing disease incidence. Currently, there is a need for qualitative, innovative, and demand-driven research in soil science, especially in developing countries for facilitating of high-quality eco-friendly research by creating a conducive and trustworthy work atmosphere, thereby rewarding productivity and merits. Hence, we reviewed (1) the impact of various agrochemicals on the soil microbial diversity and environment; (2) the importance of smallholder farmers for sustainable crop protection and enhancement solutions, and (3) management strategies that serve the scientific community, policymakers, and land managers in integrating soil enhancement and sustainability practices in smallholder farming households. The current review provides an improved understanding of agricultural soil management for food and nutritional security.


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