Morphological and Molecular Analyses of Host and Nonhost Interactions Involving Barley and Wheat and the Covered Smut Pathogen Ustilago hordei

Ustilago hordei interactions on coleoptiles of barley host cultivars Odessa (compatible), Hannchen (incompatible, carrying the Ruh1 resistance gene), and on nonhost Neepawa wheat were studied using light and fluorescent microscopy. Autofluorescence, mainly caused by callose accumulation, was more rapidly expressed in nonhost wheat at 30 to 72 h compared with the incompatible reaction between 72 and 144 h. Microarray results demonstrated that more than half of the 893 differentially regulated genes were observed in Neepawa; of these genes, 45% fell into the defense- and stress-related classes in Neepawa compared with 25 and 37% in Odessa and Hannchen, respectively. Their expression coincided with the early morphological defense responses observed and were associated with the jasmonic acid and ethylene (JA/ET) signaling pathway. Expression patterns in Odessa and Hannchen were similar, involving fewer genes and coinciding with later morphological defense responses of these varieties. Although no visible hypersensitive response was apparent in Hannchen or Neepawa, specific upregulation of hypersensitivity-related proteins was observed, such as beta-VPE at 48 h. Expression levels of the callose synthase gene were closely associated with callose accumulation. Differential responses in defense-gene expression among disease reaction types included upregulation of PR-1.1b and downregulation of a nonspecific lipid transfer protein in the incompatible and compatible interactions, respectively. Transcript levels of EDS1 and PAD4, involved in both basal resistance and R-mediated resistance to avirulent pathogens, were up-regulated during both nonhost and Ruh1-mediated resistance. Application of methyl-jasmonate, salicylic acid and ET to leaves revealed that only PR1.1b is strongly up-regulated by all three compounds, while the majority of the defense-related genes are only slightly up-regulated by these signaling compounds.

Download Full-text

Formate Dehydrogenase (FDH1) Localizes to Both Mitochondria and Chloroplast to Play a Role in Host and Nonhost Disease Resistance

10.20944/preprints202007.0272.v1 ◽

2020 ◽

Author(s):

Seonghee Lee ◽

Ramu S. Vemanna ◽

Sunhee Oh ◽

Clemencia M. Rojas ◽

Youngjae Oh ◽

...

Keyword(s):

Disease Resistance ◽

Plant Defense ◽

Formate Dehydrogenase ◽

Bacterial Pathogens ◽

Expression Patterns ◽

Defense Responses ◽

Metabolic Enzyme ◽

Marker Genes ◽

Ros Generation ◽

Basal Resistance

Nonhost disease resistance is the most common type of plant defense mechanism against potential pathogens. In this study, the metabolic enzyme formate dehydrogenase (FDH1) was identified to be involved in nonhost disease resistance in Nicotiana benthamiana and Arabidopsis thaliana. In Arabidopsis, AtFDH1 was highly upregulated in response to both host and nonhost bacterial pathogens. Arabidopsis Atfdh1 mutants were compromised in nonhost resistance, basal resistance, and gene-for-gene resistance. The expression patterns of salicylic acid (SA) and jasmonic acid (JA) marker genes after pathogen infections in Atfdh1 mutant indicated that SA is most likely involved in the FDH1-mediated plant defense response to both host and nonhost bacterial pathogens. Previous studies reported that FDH1 localizes to only mitochondria, or both mitochondria and chloroplasts. Our results showed that the AtFDH1 localized to mitochondria and the amount of FDH1 localized to mitochondria increased upon infection with host or nonhost pathogens. Interestingly, the subcellular localization of FDH1 was observed in both mitochondria and chloroplasts after infection with a nonhost pathogen in Arabidopsis. We speculate that FDH1 plays a role in cellular signaling networks between mitochondria and chloroplasts to produce coordinated defense responses such as SA-induced reactive oxygen species (ROS) generation and hypersensitive response (HR)-induced cell death against nonhost bacterial pathogens.

Download Full-text

Wheat Apoplast-Localized Lipid Transfer Protein TaLTP3 Enhances Defense Responses Against Puccinia triticina

Frontiers in Plant Science ◽

10.3389/fpls.2021.771806 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jiaojie Zhao ◽

Weishuai Bi ◽

Shuqing Zhao ◽

Jun Su ◽

Mengyu Li ◽

...

Keyword(s):

Leaf Rust ◽

Lipid Transfer Protein ◽

Puccinia Triticina ◽

Defense Responses ◽

Transgenic Wheat ◽

Lipid Transfer ◽

Transfer Protein ◽

Pathogenesis Related ◽

Rust Pathogen ◽

Wheat Lines

Plant apoplast serves as the frontier battlefield of plant defense in response to different types of pathogens. Many pathogenesis-related (PR) proteins are accumulated in apoplastic space during the onset of plant–pathogen interaction, where they act to suppress pathogen infection. In this study, we found the expression of Triticum aestivum lipid transfer protein 3 (TaLTP3) gene was unregulated during incompatible interaction mediated by leaf rust resistance genes Lr39/41 at the early infection stage. Stable transgenic wheat lines overexpressing TaLTP3 exhibited enhanced resistance to leaf rust pathogen Puccinia triticina. Transcriptome analysis revealed that overexpression of TaLTP3 specifically activated the transcription of pathogenesis-related protein 1a (TaPR1a) and multiple plant hormone pathways, including salicylic acid (SA), jasmonic acid (JA), and auxin, in response to the infection of the model bacterial pathogen Pseudomonas syringae pv. tomato DC3000. Further investigation indicated that TaLTP3 physically associated with wheat TaPR1a protein in the apoplast. Transgenic wheat lines overexpressing TaLTP3 and TaPR1a showed higher accumulations of reactive oxygen species (ROS) during plant defense responses. All these findings suggested that TaLTP3 is involved in wheat resistance against leaf rust pathogen infection and forming a TaLTP3-TaPR1a complex in apoplast against this pathogen, which provides new insights into the functional roles of PR proteins.

Download Full-text

A second member of the Nicotiana glauca lipid transfer protein gene family, NgLTP2, encodes a divergent and differentially expressed protein

Functional Plant Biology ◽

10.1071/fp05170 ◽

2006 ◽

Vol 33 (2) ◽

pp. 141 ◽

Cited By ~ 3

Author(s):

Kimberly D. Cameron ◽

William A. Moskal ◽

Lawrence B. Smart

Keyword(s):

Gene Family ◽

Cdna Library ◽

Dna Sequences ◽

Guard Cell ◽

Genomic Library ◽

Lipid Transfer Protein ◽

Expression Patterns ◽

Lipid Transfer ◽

Nicotiana Glauca ◽

Transfer Protein

Multiple, highly similar members of the lipid transfer protein (LTP) family have been identified in Nicotiana glauca L. Here we describe four new members of the NgLTP gene family and further characterise one member. Three genes were isolated from a guard cell cDNA library and one (NgLTP2) was isolated from a genomic library. These four NgLTPs, as well as one described previously, NgLTP1, share >83% amino acid similarity, but the deduced protein sequence of NgLTP2 lacks the last five residues compared with other LTPs. Since the DNA sequences of the five genes are nearly identical, techniques based on nucleic acid hybridisation or PCR amplification were not sufficient to resolve the expression of the individual genes with confidence. Therefore, we characterised the expression pattern of NgLTP2, the only NgLTP gene that was not found in the guard cell cDNA library, using an NgLTP2 promoter–GUS reporter assay. GUS activity driven by the NgLTP2 promoter was assayed in three species of transgenic plants as an indicator of the endogenous pattern of expression of this gene. GUS was strongly induced upon wounding, whereas NgLTP1 was induced by drought stress. Sequence analysis of the NgLTP2 promoter revealed cis-acting motifs associated with induction by wounding. Differential expression of the NgLTP gene family, revealed by the different expression patterns of NgLTP1 and NgLTP2, is further evidence that these genes have multiple functions in N. glauca.

Download Full-text

EIL2 Transcription Factor and Glutathione Synthetase Are Required for Defense of Tobacco Against Tobacco Blue Mold

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-19-0399 ◽

2006 ◽

Vol 19 (4) ◽

pp. 399-406 ◽

Cited By ~ 16

Author(s):

Orlando Borrás-Hidalgo ◽

Bart P. H. J. Thomma ◽

Cyrelys Collazo ◽

Osmany Chacón ◽

Carlos J. Borroto ◽

...

Keyword(s):

Transcription Factor ◽

Lipid Transfer Protein ◽

Expression Patterns ◽

Differentially Expressed ◽

Glutathione Synthetase ◽

Lipid Transfer ◽

Virus Induced Gene Silencing ◽

Incompatible Interaction ◽

Blue Mold ◽

Mold Resistance

In order to identify tobacco (Nicotiana megalosiphon) genes involved in broad-spectrum resistance to tobacco blue mold (Peronospora hyoscyami f. sp. tabacina), suppression subtractive hybridization was used to generate cDNA from transcripts that are differentially expressed during an incompatible interaction. After differential screening by membrane-based hybridization, clones corresponding to 182 differentially expressed genes were selected, sequenced, and analyzed. The cDNA collection comprised a broad repertoire of genes associated with various processes. Northern blot analysis of a subset of these genes confirmed the differential expression patterns between the compatible and incompatible interaction. Subsequent virus-induced gene silencing (VIGS) of four genes that were found to be differentially induced was pursued. While VIGS of a lipid transfer protein gene or a glutamate decarboxylase gene in Nicotiana megalosiphon did not affect blue mold resistance, silencing of an EIL2 transcription factor gene and a glutathione synthetase gene was found to compromise the resistance of Nicotiana megalosiphon to P. hyoscyami f. sp. tabacina. Potentially, these genes can be used to engineer resistance in blue mold-susceptible tobacco cultivars.

Download Full-text