The constant struggle between plants and microbes has driven the evolution of multiple defense strategies in the host as well as offense strategies in the pathogen. To defend themselves from pathogen attack, plants often rely on elaborate signaling networks regulated by phytohormones. In turn, pathogens have adopted innovative strategies to manipulate phytohormone-regulated defenses. Tactics frequently employed by plant pathogens involve hijacking, evading, or disrupting hormone signaling pathways and/or crosstalk. As reviewed here, this is achieved mechanistically via pathogen-derived molecules known as effectors, which target phytohormone receptors, transcriptional activators and repressors, and other components of phytohormone signaling in the host plant. Herbivores and sap-sucking insects employ obligate pathogens such as viruses, phytoplasma, or symbiotic bacteria to intervene with phytohormone-regulated defenses. Overall, an improved understanding of phytohormone intervention strategies employed by pests and pathogens during their interactions with plants will ultimately lead to the development of new crop protection strategies.

Intervention of Phytohormone Pathways by Pathogen Effectors

http://sippe.ac.cn/zuhuahe/publication/Yang%20DL-MP%202013.pdf

Roles of plant hormones and their interplay in rice immunity.

https://www.cell.com/molecular-plant/pdf/S1674-2052(14)60799-1.pdf

Connecting Growth and Defense: The Emerging Roles of Brassinosteroids and Gibberellins in Plant Innate Immunity

https://www.cell.com/trends/plant-science/pdf/S1360-1385(13)00129-5.pdf

Hormone defense networking in rice: tales from a different world

Phytohormones are not only essential for plant growth and development but also play central roles in triggering the plant immune signaling network. Historically, research aimed at elucidating the defense-associated role of hormones has tended to focus on the use of experimentally tractable dicot plants such as Arabidopsis thaliana. Emerging from these studies is a picture whereby complex crosstalk and induced hormonal changes mold plant health and disease, with outcomes largely dependent on the lifestyle and infection strategy of invading pathogens. However, recent studies in monocot plants are starting to provide additional important insights into the immune-regulatory roles of hormones, often revealing unique complexities. In this review, we address the latest discoveries dealing with hormone-mediated immunity in rice, one of the most important food crops and an excellent model for molecular genetic studies in monocots. Moreover, we highlight interactions between hormone signaling, rice defense and pathogen virulence, and discuss the differences and similarities with findings in Arabidopsis. Finally, we present a model for hormone defense networking in rice and describe how detailed knowledge of hormone crosstalk mechanisms can be used for engineering durable rice disease resistance.

https://biblio.ugent.be/publication/5764861/file/5764913.pdf

Making sense of hormone-mediated defense networking: from rice to Arabidopsis.

Gibberellin (GA) 20-oxidase (GA20ox) catalyses consecutive steps of oxidation in the late part of the GA biosynthetic pathway. A T-DNA insertion mutant (17S-14) in rice, with an elongated phenotype, was isolated. Analysis of the flanking sequences of the T-DNA insertion site revealed that an incomplete T-DNA integration resulted in enhanced constitutively expression of downstream OsGA20ox3 in the mutant. The accumulation of bioactive GA(1) and GA(4) were increased in the mutant in comparison with the wild-type plant. Transgenic plants overexpressing OsGA20ox3 showed phenotypes similar to those of the 17S-14 mutant, and the RNA interference (RNAi) lines that had decreased OsGA20ox3 expression exhibited a semidwarf phenotype. Expression of OsGA20ox3 was detected in the leaves and roots of young seedlings, immature panicles, anthers, and pollens, based on β-glucuronidase (GUS) activity staining in transgenic plants expressing the OsGA20ox3 promoter fused to the GUS gene. The OsGA20ox3 RNAi lines showed enhanced resistance against rice pathogens Magnaporthe oryzae (causing rice blast) and Xanthomonas oryzae pv. oryzae (causing bacterial blight) and increased expression of defense-related genes. Conversely, OsGA20ox3-overexpressing plants were more susceptible to these pathogens comparing with the wild-type plants. The susceptibility of wild-type plants to X. oryzae pv. oryzae was increased by exogenous application of GA(3) and decreased by S-3307 treatment. Together, the results provide direct evidence for a critical role of OsGA20ox3 in regulating not only plant stature but also disease resistance in rice.

https://apsjournals.apsnet.org/doi/pdf/10.1094/MPMI-05-12-0138-R

Gibberellin 20-Oxidase Gene OsGA20ox3 Regulates Plant Stature and Disease Development in Rice

This paper proposes a miniaturized microwave microfluidic sensor based on quarter-mode 2.5-D spoof localized surface plasmons for detecting liquid permittivity. An active amplification circuit is inherited to increase the resonance quality factor and thereby improve the sensor resolution. The sensor has a double-layer structure and uses microstrip feed. The quarter-mode structure is only one quarter of the full-mode case, and the liquid amount is reduced. The introduction of 2.5-D structure can further reduce the resonator size, improve the slow-wave effect and enhance the field confinement. A polydimethylsiloxane chip with a microfluidic channel is placed directly above the resonator. The injected liquid sample flowing through the channel would induce resonant frequency shift, thus achieving the ability of detecting the liquid permittivity. The prototype is manufactured using printed circuit board technology, and the measured sensor sensitivity for characterizing water reaches 0.16% on average, which is in general agreement with the simulated result. The proposed sensor can be expected to play an important role in biomedicine, environmental monitoring, food hygiene and other fields. Schematic of the proposed sensor. • The application of SLSP makes the electric field highly concentrated, and the quarter-mode design reduces the size while avoiding excessively chaotic modes, which is more beneficial to engineering applications. • The 2.5-D SLSP design has stronger slow-wave effect compared to the normal structure and further reduces the electrical size of the sensor. • An amplifier circuits is introduced to improve the quality factor from 56 to 4247, which can distinguish more subtle environmental changes. 

Miniaturized Microwave Microfluidic Sensor Based on Quarter-Mode 2.5-D Spoof Plasmons

This letter proposes two compact folded spoof surface plasmon polariton (SSPP) transmission lines (TL) with single-sided grooves (Type A) and double-sided grooves (Type B), and their cut-off frequencies are 17.55 GHz and 19.52 GHz, respectively. Due to large number of units, the proposed SSPP TLs have steep sideband and excellent upper band suppression (< −48 dB). The compact folding solution could reduce the lateral size to nearly 2/5 of the original one, and to a certain extent solve the layout difficulties associated with traditional SSPP TLs due to their slender structure. The cut-off frequency can be independently regulated by stub length and width. The proposed components are fabricated and tested. The experimental results are in good agreement with the simulated results, demonstrating the possibility of compact folded SSPP TLs and greatly improving the potential of SSPP use in miniaturized and highly integrated circuit systems.

Compact Folded SSPP Transmission Line and Its Applications in Low-Pass Filters

In this paper, a two-dimensional (2D) displacement sensor based on the diagonal symmetry complementary split-ring resonator (CSRR) structure is proposed. The one-dimensional (1D) displacement sensor is initially developed by etching a ring on the ground plane, and a triangle metal patch is used as the mover. When the mover is attached, a CSRR is formed, thereby inducing a resonant frequency. The displacement of the mover can be retrieved by the variation in the resonant frequency. Then, the structure is extended for designing a 2D displacement sensor. To further reduce the error caused by the lateral displacement, the shape of the sensor is further optimized using the particle swarm algorithm. Finally, the structure of the CSRR displacement sensor is simulated and analyzed, and a physical prototype is made. The measured results are consistent with the theoretical analysis, and its sensitivity is 160 MHz/mm.

/pdf/a-complementary-split-ring-resonator-csrr-based-2d-3nrqf0l6.pdf

A Complementary Split-Ring Resonator (CSRR)-Based 2D Displacement Sensor

Based on the wafer level packaging technology, different widths and lengths of the strip line was designed, fabricate and measured. Meanwhile, to characterize the high frequency characteristics of the strip line, the skin effect has been considered to the transmission line theory equivalent circuit model. The proposed model is in good agreement with the measured data of the strip line in the frequency range of 10 GHz – 110 GHz. The proposed model can effectively support the co-simulation of the active device model and passive device model in heterogeneous integrated package, accelerate the optimization speed of circuit design iteration, and help reduce the time cost of the EM simulation of layout.

Jun Hua Liu

Papers

Gibberellin 20-Oxidase Gene OsGA20ox3 Regulates Plant Stature and Disease Development in Rice

Miniaturized Microwave Microfluidic Sensor Based on Quarter-Mode 2.5-D Spoof Plasmons

Compact Folded SSPP Transmission Line and Its Applications in Low-Pass Filters

A Complementary Split-Ring Resonator (CSRR)-Based 2D Displacement Sensor

Equivalent Circuit Model of Strip Line up to 110GHz