Methods for Analysis of Disease Resistance and the Defense Response in Arabidopsis

Vitamin B6 (VB6), an essential cofactor for numerous metabolic enzymes, has recently been shown to act as a potent antioxidant and play important roles in developmental processes and stress responses. However, little is known about the possible function of VB6 in plant disease resistance response against pathogen infection. In the present study, we explored the possible involvement of VB6 in defense response against Botrytis cinerea through functional analysis of tomato VB6 biosynthetic genes. Three de novo VB6 biosynthetic genes (SlPDX1.2, SlPDX1.3, and SlPDX2) and one salvage pathway gene (SlSOS4) were identified and the SlPDX1.2, SlPDX1.3, and SlPDX2 genes were shown to encode functional enzymes involved in de novo biosynthesis of VB6, as revealed by complementation of the VB6 prototrophy in yeast snz1 and sno1 mutants. Expression of SlPDX1.2, SlPDX1.3, and SlSOS4 genes was induced by infection with B. cinerea. Virus-induced gene silencing-mediated knockdown of SlPDX1.2 or SlPDX1.3 but not SlPDX2 and SlSOS4 led to increased severity of disease caused by B. cinerea, indicating that the VB6 de novo biosynthetic pathway but not the salvage pathway is involved in tomato defense response against B. cinerea. Furthermore, the SlPDX1.2- and SlPDX1.3-silenced tomato plants exhibited reduced levels of VB6 contents and reactive oxygen species scavenging capability, increased levels of superoxide anion and H2O2 generation, and increased activity of superoxide dismutase after infection by B. cinerea. Our results suggest that VB6 and its de novo biosynthetic pathway play important roles in regulation of defense response against B. cinerea through modulating cellular antioxidant capacity.

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Endophytic Streptomyces hygroscopicus OsiSh-2-Mediated Balancing between Growth and Disease Resistance in Host Rice

mBio ◽

10.1128/mbio.01566-21 ◽

2021 ◽

Author(s):

Yan Gao ◽

Qing Ning ◽

Yuanzhu Yang ◽

Ying Liu ◽

Shuqi Niu ◽

...

Keyword(s):

Disease Resistance ◽

Defense Response ◽

Streptomyces Hygroscopicus ◽

Growth And Yield ◽

Crop Breeding ◽

Trade Off ◽

Endophytic Streptomyces ◽

The Cost ◽

Stress Activation

Under disease stress, activation of defense response in plants often comes with the cost of a reduction in growth and yield, which is referred as the growth-defense trade-off. The microorganisms which can be recruited by plants to mitigate the growth-defense trade-off are of great value in crop breeding.

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GT Factor ZmGT-3b Is Associated With Regulation of Photosynthesis and Defense Response to Fusarium graminearum Infection in Maize Seedling

Frontiers in Plant Science ◽

10.3389/fpls.2021.724133 ◽

2021 ◽

Vol 12 ◽

Author(s):

Qianqian Zhang ◽

Tao Zhong ◽

Lizhu E ◽

Mingliang Xu ◽

Weixing Dai ◽

...

Keyword(s):

Disease Resistance ◽

Plant Growth ◽

Fusarium Graminearum ◽

Seedling Growth ◽

Defense Response ◽

Resistance Mechanism ◽

Defense Responses ◽

In Planta ◽

Trade Off ◽

Tf Gene

It is of critical importance for plants to correctly and efficiently allocate their resources between growth and defense to optimize fitness. Transcription factors (TFs) play crucial roles in the regulation of plant growth and defense response. Trihelix TFs display multifaceted functions in plant growth, development, and responses to various biotic and abiotic stresses. In our previous investigation of maize stalk rot disease resistance mechanism, we found a trihelix TF gene, ZmGT-3b, which is primed for its response to Fusarium graminearum challenge by implementing a rapid and significant reduction of its expression to suppress seedling growth and enhance disease resistance. The disease resistance to F. graminearum was consistently increased and drought tolerance was improved, while seedling growth was suppressed and photosynthesis activity was significantly reduced in the ZmGT-3b knockdown seedlings. Thus, the seedlings finally led to show a kind of growth–defense trade-off phenotype. Moreover, photosynthesis-related genes were specifically downregulated, especially ZmHY5, which encodes a conserved central regulator of seedling development and light responses; ZmGT-3b was confirmed to be a novel interacting partner of ZmHY5 in yeast and in planta. Constitutive defense responses were synchronically activated in the ZmGT-3b knockdown seedlings as many defense-related genes were significantly upregulated, and the contents of major cell wall components, such as lignin, were increased in the ZmGT-3b knockdown seedlings. These suggest that ZmGT-3b is involved in the coordination of the metabolism during growth–defense trade-off by optimizing the temporal and spatial expression of photosynthesis- and defense-related genes.

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JMJ704 positively regulates rice defense response against Xanthomonas oryzae pv. oryzae infection via reducing H3K4me2/3 associated with negative disease resistance regulators

BMC Plant Biology ◽

10.1186/s12870-015-0674-3 ◽

2015 ◽

Vol 15 (1) ◽

Cited By ~ 22

Author(s):

Yuxuan Hou ◽

Liyuan Wang ◽

Ling Wang ◽

Lianmeng Liu ◽

Lu Li ◽

...

Keyword(s):

Disease Resistance ◽

Defense Response ◽

Xanthomonas Oryzae

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Identification of Key Transcription Factors Related to Bacterial Spot Resistance in Pepper through Regulatory Network Analyses

Genes ◽

10.3390/genes12091351 ◽

2021 ◽

Vol 12 (9) ◽

pp. 1351

Author(s):

Qingquan Zhu ◽

Shenghua Gao ◽

Wenli Zhang

Keyword(s):

Transcription Factor ◽

Disease Resistance ◽

Resistance Genes ◽

Defense Response ◽

Regulatory Network ◽

Xanthomonas Campestris ◽

Economic Benefits ◽

Multiple Time ◽

Bacterial Spot ◽

Network Analyses

Bacterial spot (BS), caused by Xanthomonas campestris pv. Vesicatoria (Xcv), severely affects the quality and yield of pepper. Thus, breeding new pepper cultivars with enhanced resistance to BS can improve economic benefits for pepper production. Identification of BS resistance genes is an essential step to achieve this goal. However, very few BS resistance genes have been well characterized in pepper so far. In this study, we reanalyzed public multiple time points related to RNA-seq data sets from two pepper cultivars, the Xcv-susceptible cultivar ECW and the Xcv-resistant cultivar VI037601, post Xcv infection. We identified a total of 3568 differentially expressed genes (DEGs) between two cultivars post Xcv infection, which were mainly involved in some biological processes, such as Gene Ontology (GO) terms related to defense response to bacterium, immune system process, and regulation of defense response, etc. Through weighted gene co-expression network analysis (WGCNA), we identified 15 hub (Hub) transcription factor (TF) candidates in response to Xcv infection. We further selected 20 TFs from the gene regulatory network (GRN) potentially involved in Xcv resistance response. Finally, we predicted 4 TFs, C3H (p-coumarate 3-hydroxylase), ERF (ethylene-responsive element binding factor), TALE (three-amino-acid-loop-extension), and HSF (heat shock transcription factor), as key factors responsible for BS disease resistance in pepper. In conclusion, our study provides valuable resources for dissecting the underlying molecular mechanism responsible for Xcv resistance in pepper. Additionally, it also provides valuable references for mining transcriptomic data to identify key candidates for disease resistance in horticulture crops.

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Chitin in strawberry cultivation: foliar growth and defense response promotion, but reduced fruit yield and disease resistance by nutrient imbalances

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-08-20-0223-r ◽

2020 ◽

Author(s):

Caroline De Tender ◽

Bart Vandecasteele ◽

Bruno Verstraeten ◽

Sarah Ommeslag ◽

Tim De Meyer ◽

...

Keyword(s):

Disease Resistance ◽

Defense Response ◽

Fruit Yield ◽

Nutrient Concentrations ◽

Shoot Biomass ◽

Optimal Range ◽

Disease Symptoms ◽

Foliar Disease ◽

Positive Effects ◽

Nutrient Imbalances

Strawberry cultivation is associated with high mineral fertilizer doses and extensive use of chemical plant protection products. Based on previous research, we expected that chitin application to peat substrate would increase the nutrient availability and activate the plant’s systemic defense response, resulting in higher strawberry yields and less disease symptoms. We set up two experiments in which the temporal variability and differences in initial nutrient concentrations of the growing media were taken into account. Chitin treatment resulted in the attraction of plant-growth promoting fungal genera towards the plant root, such as Mortierella and Umbelopsis. In addition, by the end of the experiments 87 mg mineral N/L substrate was mineralized, which can be related to the observed increase in plant shoot biomass. This however led to nutrient imbalances in plant shoots and fruits: N concentration in the leaves increased over 30%, exceeding the optimal range, while P and K deficiencies occurred, with concentrations lower than 50% of the optimal range. This may explain the decreased fruit yield and disease resistance of the fruits towards Botrytis cinerea. In contrast, chitin caused a clear defense priming effect in the strawberry leaves, with a strong induction of the jasmonic acid response, resulting in less foliar disease symptoms. Chitin causes positive effects on shoot growth and foliar disease resistance, but caution needs to be taken for nutrient imbalances leading to negative influences on root growth, fruit production and disease susceptibility towards B. cinerea.

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