scholarly journals Leaf Cuticle Can Contribute to Non-Host Resistance to Poplar Leaf Rust

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 870 ◽  
Author(s):  
Yu ◽  
Shen ◽  
Newcombe ◽  
Fan ◽  
Chen
Keyword(s):  
Host Resistance ◽  
Populus Deltoides ◽  
Rust Fungus ◽  
Trimethylsilyl Ether ◽  
Populus Tomentosa ◽  
Rust Fungi ◽  
Mesophyll Cells ◽  
Defense Compounds ◽  
Leaf Cuticle ◽  
Poplar Leaf

The plant leaf cuticle is a chemically complex but largely waxy outer shell that limits water loss and also prevents some pathogens from gaining access to internal mesophyll. Rust fungi are obligate parasites, and most bypass the cuticle by thigmotropically locating stomata, growing through the stomatal openings, and then parasitizing mesophyll cells with haustoria. It is thought that even non-hosts of a given rust fungus do not resist until their mesophyll cells are contacted in this way. In other words, it is thought that the cuticle plays no role in non-host resistance. Here, we tested the hypothesis that poplar leaf cuticles might contribute to non-host resistance to rust fungi by chemically impeding the germination and growth of urediniosporelings of Melampsora larici-populina. Following an initial survey in China of the resistance of 36 genotypes of various species and interspecific hybrids of Populus to M. larici-populina, we selected three genotypes for the initial test of hypothesis: (1) A Populus purdomii genotype that is fully susceptible; (2) a Populus deltoides cv. ‘I-69′ that is incompletely resistant (i.e., a resistant host); and (3) a Populus tomentosa genotype that is a non-host to M. larici-populina. Urediniospores were assayed for germination in extracts of the cuticles of the three genotypes. Germination was most reduced by the P. tomentosa non-host cuticular extracts that also reduced the growth of germ tubes to 36 times less than that in controls or in the extract of the susceptible P. purdomii. Four cuticular components were identified as putative defense compounds given greater concentrations in P. tomentosa than in P. purdomii: Aucubin, hexakis(trimethylsilyl) ether, catechol, 7,9-Di-tert-buty l-1-oxaspiro (4,5) deca-6, 9-diene-2,8-dione and trifluoroacetamide. These four compounds were then tested, and they reduced urediniospore germination and uredinial density in inoculations of normally susceptible P. purdomii with Melampsora larici-populina. Thus, the cuticle of P. tomentosa can contribute to pre-haustorial, non-host resistance to M. larici-populina.

scholarly journals Transposon-associated small RNAs involved in plant defense in poplar

2021 ◽  
Author(s):  
Sijia Liu ◽  
xian li ◽  
yiyang zhao ◽  
jianbo xie
Keyword(s):  
Plant Defense ◽  
Small Rnas ◽  
Rust Fungus ◽  
Defense Responses ◽  
Populus Tomentosa ◽  
Rust Fungi ◽  
Plant Colonization ◽  
Pathogen Effector ◽  
Intergenic Regions ◽  
Fungal Genes

Abstract Background: Small RNAs (sRNAs) are hypothesized to contribute to plant defense responses by increasing the overall genetic diversity and regulating gene expression; however, their origins and functional importance in plant defense remain unclear. Here, we use Illumina sequencing to assess how sRNA populations vary in the Chinese white poplar (Populus tomentosa) during a rust fungus (Melampsora larici-populina) infection. We sampled sRNAs from the biotrophic growth phase (T02; 48 h post infection) and the urediniospore formation and release phase (T03; 168 h), two essential stages associated with plant colonization and biotrophic growth in rust fungi. Results: The proportion of siRNA clusters located in pseudogenes and transposons was significantly larger than would be expected by chance and infection-stage-specific differences in siRNAs primarily originated from those in the transposon regions. We also found that the abundance of clusters comprising 24-nt siRNAs located in the transposon and intergenic regions underwent more substantial changes as the infection progressed. A target analysis revealed that 95% of fungal genes were predicted to be targets of Populus sRNAs. Pathogen effector genes were targeted by more sRNAs identified during the biotrophic growth and urediniospores formation and release phases than in the control plants, suggesting a clear selection for sRNA-target interactions. Compared with the miRNAs conserved between different plant species, a significantly higher proportion of Populus-specific miRNAs appeared to target NB-LRR genes. Conclusions: This integrated study on the plant colonization and biotrophic growth in rust fungi profiles could provide evolutionary insights into the origin and potential roles of the sRNAs in plant defense, coevolution with pathogens, and functional innovation.

scholarly journals Specificity of SSR loci for Melampsora species on poplars

Genetika ◽  
2010 ◽  
Vol 42 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Vladislava Galovic ◽  
Sasa Orlovic ◽  
Predrag Pap ◽  
Branislav Kovacevic ◽  
Miroslav Markovic
Keyword(s):  
Leaf Rust ◽  
Ssr Markers ◽  
Populus Deltoides ◽  
Rust Fungi ◽  
Population Composition ◽  
Melampsora Medusae ◽  
Ssr Loci ◽  
Poplar Leaf ◽  
Growing Region ◽  
Poplar Leaf Rust

Two rust fungi, Melampsora larici populina and Melampsora medusae are common in all poplar growing regions worlwide. M. larici populina is native to Eurasia, while M. medusae is endemic to eastern Unated States on Populus deltoides. Poplar leaf rust (Melampsora sp.) is widely spread disease in our country, and can cause significant growing problems. Race that prevails in our growing region is M. Larici populina. This work initiated the research of population composition, i.e. qualitative participation of Melampsora races in popoluation of black poplars hybrid progenies using molecular methods. When five SSR markers were used the results showed that M. larici populina was found in three tested clones, while only M. medusae was determined in clone I-214.

Non-host resistance responses of Arabidopsis thaliana to the coffee leaf rust fungus (Hemileia vastatrix)

Botany ◽  
2010 ◽  
Vol 88 (7) ◽  
pp. 621-629 ◽  
Author(s):  
Helena Gil Azinheira ◽  
Maria do Céu Silva ◽  
Pedro Talhinhas ◽  
Clara Medeira ◽  
Isabel Maia ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Leaf Rust ◽  
Rust Fungus ◽  
Hemileia Vastatrix ◽  
Callose Deposition ◽  
Mesophyll Cells ◽  
Model Plant ◽  
Heterologous System ◽  
Coffee Leaf Rust ◽  
Model Plant Arabidopsis Thaliana

Leaf rust, caused by Hemileia vastatrix Berk & Broome, is the most destructive fungal disease of coffee. In the absence of a suitable gene validation system in coffee, the objective of this study was to investigate whether the model plant Arabidopsis thaliana (L.) Heynh. may be used as a heterologous system for the molecular dissection of coffee responses to leaf rust. Histological examination of A. thaliana (Col-0) leaves inoculated with H. vastatrix (race II) showed that by 24 h after inoculation (hai), H. vastatrix uredospores differentiated appressoria and penetrated the stomata, but failed to form haustoria. Arabidopsis thaliana cellular resistance responses included hypersensitive-like response (HR) of stomata guard cells together with accumulation of phenolic compounds and callose deposition in walls of epidermal and mesophyll cells. Results indicate that H. vastatrix infection triggered the induction of a set of defence-related genes peaking at 18 and 42 hai. The non-host HR triggered by H. vastatrix in the model plant A. thaliana makes it usable to infer the function of coffee genes involved in pre-haustorial rust resistance.

scholarly journals An Investigation into the Involvement of Defense Signaling Pathways in Components of the Nonhost Resistance of Arabidopsis thaliana to Rust Fungi Also Reveals a Model System for Studying Rust Fungal Compatibility

2003 ◽  
Vol 16 (5) ◽  
pp. 398-404 ◽  
Author(s):  
Denny G. Mellersh ◽  
Michèle C. Heath
Keyword(s):  
Arabidopsis Thaliana ◽  
Rust Fungus ◽  
Fungal Growth ◽  
Rust Fungi ◽  
Nonhost Resistance ◽  
Wild Type ◽  
Pr Genes ◽  
Hypersensitive Cell Death ◽  
Defense Signaling ◽  
Infection Hypha

Seventeen accessions of Arabidopsis thaliana inoculated with the cowpea rust fungus Uromyces vignae exhibited a variety of expressions of nonhost resistance, although infection hypha growth typically ceased before the formation of the first haustorium, except in Ws-0. Compared with wild-type plants, there was no increased fungal growth in ndr1 or eds1 mutants defective in two of the signal cascades regulated by the major class of Arabidopsis host resistance genes. However, in the Col-0 background, infection hyphae of U. vignae and two other rust fungi were longer in sid2 mutants defective in an enzyme that synthesizes salicylic acid (SA), in npr1 mutants deficient in a regulator of the expression of SA-dependent pathogenesis related (PR) genes, and in NahG plants containing a bacterial salicylate hydroxylase. Infection hyphae of U. vignae and U. appendiculatus but not of Puccinia helianthi were also longer in jar1 mutants, which are defective in the jasmonic acid defense signaling pathway. Nevertheless, haustorium formation increased only for the Uromyces spp. and only in sid2 mutants or NahG plants. Rather than the hypersensitive cell death that usually accompanies haustorium formation in nonhost plants, Arabidopsis typically encased haustoria in calloselike material. Growing fungal colonies of both Uromyces spp., indicative of a successful biotrophic relationship between plant and fungus, formed in NahG plants, but only U. vignae formed growing colonies in the sid2 mutants and cycloheximide-treated wild-type plants. Growing colonies did not develop in NahG tobacco or tomato plants. These data suggest that nonhost resistance of Arabidopsis to rust fungi primarily involves the restriction of infection hypha growth as a result of defense gene expression. However, there is a subsequent involvement of SA but not SA-dependent PR genes in preventing the Uromyces spp. from forming the first haustorium and establishing a sufficient biotrophic relationship to support further fungal growth. The U. vignae-Arabidopsis combination could allow the application of the powerful genetic capabilities of this model plant to the study of compatibility as well as nonhost resistance to rust fungi.

scholarly journals Putative Rust Fungal Effector Proteins in Infected Bean and Soybean Leaves

2016 ◽  
Vol 106 (5) ◽  
pp. 491-499 ◽  
Author(s):  
Bret Cooper ◽  
Kimberly B. Campbell ◽  
Hunter S. Beard ◽  
Wesley M. Garrett ◽  
Nazrul Islam
Keyword(s):  
Plant Cell ◽  
Crop Production ◽  
Rust Fungus ◽  
Fungal Spores ◽  
Pathogenic Fungi ◽  
Rust Fungi ◽  
Effector Proteins ◽  
Glycoside Hydrolases ◽  
Data Set ◽  
Soybean Leaves

The plant-pathogenic fungi Uromyces appendiculatus and Phakopsora pachyrhizi cause debilitating rust diseases on common bean and soybean. These rust fungi secrete effector proteins that allow them to infect plants, but their effector repertoires are not understood. The discovery of rust fungus effectors may eventually help guide decisions and actions that mitigate crop production loss. Therefore, we used mass spectrometry to identify thousands of proteins in infected beans and soybeans and in germinated fungal spores. The comparative analysis between the two helped differentiate a set of 24 U. appendiculatus proteins targeted for secretion that were specifically found in infected beans and a set of 34 U. appendiculatus proteins targeted for secretion that were found in germinated spores and infected beans. The proteins specific to infected beans included family 26 and family 76 glycoside hydrolases that may contribute to degrading plant cell walls. There were also several types of proteins with structural motifs that may aid in stabilizing the specialized fungal haustorium cell that interfaces the plant cell membrane during infection. There were 16 P. pachyrhizi proteins targeted for secretion that were found in infected soybeans, and many of these proteins resembled the U. appendiculatus proteins found in infected beans, which implies that these proteins are important to rust fungal pathology in general. This data set provides insight to the biochemical mechanisms that rust fungi use to overcome plant immune systems and to parasitize cells.

Notes on rust fungi in China 8. Pucciniastrum tiliae life cycle and new host plants inferred from phylogenetic evidence

Mycotaxon ◽  
2020 ◽  
Vol 135 (3) ◽  
pp. 490-499
Author(s):  
Jing-Xin Ji ◽  
Zhuang Li ◽  
Yu Li ◽  
Makoto Kakishima
Keyword(s):  
Life Cycle ◽  
Northeast China ◽  
Host Plants ◽  
Phylogenetic Analyses ◽  
Rust Fungus ◽  
Rust Fungi ◽  
New Host ◽  
First Time

The life cycle connection between spermogonial and aecial stages of a rust fungus found on Abies holophylla and uredinial and telial stages on Tilia mongolica and T. mandshurica collected in northeast China were confirmed by phylogenetic analyses. The rust, identified as Pucciniastrum tiliae, was confirmed by morphological observations. The life cycle of this rust fungus is reported for the first time in China, and A. holophylla and T. mongolica represent new host plants for the species.

THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: XVIII. DISTRIBUTION OF TRITIUM-LABELLED CYTIDINE, URIDINE, AND LEUCINE IN WHEAT LEAVES INFECTED WITH THE STEM RUST FUNGUS

1967 ◽  
Vol 45 (5) ◽  
pp. 555-563 ◽  
Author(s):  
P. K. Bhattacharya ◽  
Michael Shaw
Keyword(s):  
Stem Rust ◽  
Rust Fungus ◽  
Host Cells ◽  
Fungal Mycelium ◽  
Puccinia Graminis ◽  
Mesophyll Cells ◽  
Wheat Leaves ◽  
Host Parasite

Wheat leaves were detached 6 days after inoculation with the stem rust fungus (Puccinia graminis var. tritici Erikss. and Henn.) and fed with tritiated leucine, cytidine, uridine, or thymidine. Mesophyll cells in infected zones incorporated more leucine into protein and more cytidine and uridine into RNA than did cells in adjacent uninfected tissue. Leucine, cytidine, and uridine were also heavily incorporated by fungal mycelium and developing uredospores. Grain counts over host nuclei in the infected zone were two to three-fold of those over nuclei in adjacent uninfected zones. There was no detectable incorporation of thymidinemethyl-3H into either the fungus or the host cells. The results are discussed.

Effect of intercellular washing fluids on the interactions between bean plants and fungi nonpathogenic on beans

1990 ◽  
Vol 68 (4) ◽  
pp. 934-939 ◽  
Author(s):  
Aimin Li ◽  
Michèle C. Heath
Keyword(s):  
Rust Fungus ◽  
Rust Fungi ◽  
Silica Deposition ◽  
Saprophytic Fungus ◽  
Plant Parasite ◽  
Bean Plants ◽  
Fungal Parasites ◽  
Bean Leaves

Intercellular washing fluids from various compatible plant–parasite interactions were tested for their ability to reduce silica deposition on plant walls and to increase haustorium production in bean leaves following inoculation with the normally incompatible cowpea rust fungus. Only fluids from bean, wheat, and sunflower plants infected with their respective compatible rust fungi exhibited such activity, and no fluid had any similar effect on the nonhost interaction between bean leaves and other rust fungi. Fluids from rusted bean leaves did not increase the intercellular growth of a saprophytic fungus or other fungal parasites nonpathogenic on beans, nor did they affect silica deposition induced by these fungi. These data suggest that some feature of silica induction in bean by the cowpea rust fungus is unique and is affected by components in the intercellular washing fluids from only certain rust-infected plants. Fluids from uninoculated healthy wheat or sunflower plants and a Driselase solution that induces haustoria in vitro all increased haustorium formation by the cowpea rust fungus, but to a lesser extent than fluids from infected plants; silica deposition was not affected in these cases, suggesting that fluids from uninoculated plants may promote haustorium formation rather than prevent silica deposition.

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