Surveillance of Pathogenicity of Rhizoctonia solani Japanese Isolates with Varied Anastomosis Groups and Subgroups on Arabidopsis thaliana

Rhizoctonia solani is a necrotrophic plant pathogen with a wide host range. R. solani is a species complex consisting of thirteen anastomosis groups (AGs) defined by compatibility of hyphal fusion reaction and subgroups based on cultural morphology. The relationship between such classifications and host specificity remains elusive. Here, we investigated the pathogenicity of seventeen R. solani isolates (AG-1 to 7) in Japan towards Arabidopsis thaliana using leaf and soil inoculations. The tested AGs, except AG-3 and AG-6, induced symptoms in both methods with variations in pathogenicity. The virulence levels differed even within the same AG and subgroup. Some isolates showed tissue-specific infection behavior. Thus, the AGs and their subgroups are suggested to be not enough to define the virulence (host and tissue specificity) of R. solani. We also evaluated the virulence of the isolates on Arabidopsis plants pretreated with salicylic acid, jasmonic acid, and ethylene. No obvious effects were detected on the symptom formation by the virulence isolates, but ethylene and salicylic acid slightly enhanced the susceptibility to the weak and nonvirulent isolates. R. solani seems to be able to overcome the induced defense by these phytohormones in the infection to Arabidopsis.

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Rhizoctonia Web Blight—A New Disease on Mint in Israel

Plant Disease ◽

10.1094/pdis-04-11-0271 ◽

2012 ◽

Vol 96 (3) ◽

pp. 370-378 ◽

Cited By ~ 3

Author(s):

Nadav Nitzan ◽

David Chaimovitsh ◽

Rachel Davidovitch-Rekanati ◽

Michal Sharon ◽

Nativ Dudai

Keyword(s):

Relative Humidity ◽

Rhizoctonia Solani ◽

Quadratic Model ◽

Unknown Etiology ◽

New Disease ◽

Disease Symptoms ◽

Anastomosis Groups ◽

Web Blight ◽

Relationship Of ◽

The Relationship

Mentha longifolia is produced in and exported from Israel with annual revenue of US$16 million. In 2010, a severe epidemic of unknown etiology reduced growers' returns up to 50%. Disease symptoms included water-soaked lesions, necrosis, and web-like mycelia on plants. Two isolates (JV-1 and BS-1) from randomly selected symptomatic plants were identified as members of Rhizoctonia solani anastomosis groups 1-IB and 4HG-I, respectively. The fitness of JV-1 and BS-1 interacted with temperatures between 17 and 35°C: JV-1 grew faster and was more aggressive (P < 0.05) at lower temperatures (<24°C), BS-1 grew faster and was more aggressive at higher temperatures (>30°C), and the two isolates performed similarly at intermediate temperatures. Disease developed fastest at 24 to 28°C. Yield was reduced between 46 and 100%. In all, 77.5% fewer plants recovered from disease developing at 24 to 28°C than at 17 to 23 or 30 to 35°C. The relationship of disease to relative humidity (RH) fit a quadratic model (P < 0.0015, R2 = 0.98). Disease was most severe at 100% RH, decreasing by 1.3-, 1.9-, 3-, 4.5-, and 10.5-fold with the reduction of RH from 100% to 88, 76, 69, 55, or 49%, respectively. This is the first report of Rhizoctonia web blight in mint in Israel.

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Tissue specificity of expression of heat shock gene ATHSP70-10 in Arabidopsis thaliana seedlings under normal and stress conditions

Vìsnik Harkìvsʹkogo nacìonalʹnogo agrarnogo unìversitetu. Serìâ Bìologiâ ◽

10.35550/vbio2020.03.037 ◽

2020 ◽

Vol 2020 (3) ◽

pp. 37-47

Author(s):

L.Ye. Kozeko ◽

◽

E.L. Kordyum ◽

Keyword(s):

Arabidopsis Thaliana ◽

Heat Shock ◽

Water Deficit ◽

Tissue Specificity ◽

Abiotic Factors ◽

Root Apex ◽

Stress Conditions ◽

Heat Shock Gene ◽

Organ Specificity ◽

Pcr Analysis

Mitochondrial heat shock proteins of HSP70 family support protein homeostasis in mitochondria under normal and stress conditions. They provide folding and complex assembly of proteins encoded by mitochondrial genome, as well as import of cytosolic proteins to mitochondria, their folding and protection against aggregation. There are reports about organ-specificity of mitochondrial HSP70 synthesis in plants. However, tissue specificity of their functioning remains incompletely characterized. This problem was studied for mitochondrial AtHSP70-10 in Arabidopsis thaliana seedlings using a transgenic line with uidA signal gene under normal conditions, as well as high temperature and water deficit. Under normal conditions, histochemical GUS-staining revealed the expression of AtHSP70-10 in cotyledon and leaf hydathodes, stipules, central cylinder in root differentiation and mature zones, as well as weak staining in root apex and root-shoot junction zone. RT-PCR analysis of wild-type seedlings exposed to 37°C showed rapid upregulation of AtHSP70-10, which reached the highest level within 2 h. In addition, the gradual development of water deficit for 5 days caused an increase in transcription of this gene, which became more pronounced after 3 days and reached a maximum after 5 days of dehydration. Histochemical analysis showed complete preservation of tissue localization of AtHSP70-10 expression under both abiotic factors. The data obtained indicate the specific functioning of mitochondrial chaperone AtHSP70-10 in certain plant cellular structures.

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Molecular biology of enzyme adaptations in higher eukaryotes

Genome ◽

10.1139/g89-045 ◽

1989 ◽

Vol 31 (1) ◽

pp. 272-283 ◽

Cited By ~ 7

Author(s):

Donal A. Hickey ◽

Bernhard F. Benkel ◽

Charalambos Magoulas

Keyword(s):

Molecular Biology ◽

Tissue Specificity ◽

Enzyme System ◽

Direct Interaction ◽

Evolutionary Genetics ◽

Short Term ◽

Eukaryotic Genes ◽

Higher Eukaryotes ◽

The Relationship

Multicellular eukaryotes have evolved complex homeostatic mechanisms that buffer the majority of their cells from direct interaction with the external environment. Thus, in these organisms long-term adaptations are generally achieved by modulating the developmental profile and tissue specificity of gene expression. Nevertheless, a subset of eukaryotic genes are still involved in direct responses to environmental fluctuations. It is the adaptative responses in the expression of these genes that buffers many other genes from direct environmental effects. Both microevolutionary and macroevolutionary patterns of change in the structure and regulation of such genes are illustrated by the sequences encoding α-amylases. The molecular biology and evolution of α-amylases in Drosophila and other higher eukaryotes are presented. The amylase system illustrates the effects of both long-term and short-term natural selection, acting on both the structural and regulatory components of a gene–enzyme system. This system offers an opportunity for linking evolutionary genetics to molecular biology, and it allows us to explore the relationship between short-term microevolutionary changes and long-term adaptations.Key words: gene regulation, molecular evolution, eukaryotes, Drosophila, amylase.

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Systemic Acquired Resistance in Canola Is Linked with Pathogenesis-Related Gene Expression and Requires Salicylic Acid

Phytopathology ◽

10.1094/phyto-97-7-0794 ◽

2007 ◽

Vol 97 (7) ◽

pp. 794-802 ◽

Cited By ~ 29

Author(s):

Shobha D. Potlakayala ◽

Darwin W. Reed ◽

Patrick S. Covello ◽

Pierre R. Fobert

Keyword(s):

Salicylic Acid ◽

Pseudomonas Syringae ◽

Systemic Acquired Resistance ◽

Induced Defense ◽

Acquired Resistance ◽

Microbial Pathogens ◽

Broad Host Range ◽

Avirulent Strain ◽

Enhanced Resistance ◽

Pathogenesis Related

Systemic acquired resistance (SAR) is an induced defense response that confers long-lasting protection against a broad range of microbial pathogens. Here we show that treatment of Brassica napus plants with the SAR-inducing chemical benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) significantly enhanced resistance against virulent strains of the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Leptosphaeria maculans. Localized preinoculation of plants with an avirulent strain of P. syringae pv. maculicola also enhanced resistance to these pathogens but was not as effective as BTH treatment. Single applications of either SAR-inducing pretreatment were effective against P. syringae pv. maculicola, even when given more than 3 weeks prior to the secondary challenge. The pretreatments also led to the accumulation of pathogenesis-related (PR) genes, including BnPR-1 and BnPR-2, with higher levels of transcripts observed in the BTH-treatment material. B. napus plants expressing a bacterial salicylate hydroxylase transgene (NahG) that metabolizes salicylic acid to catechol were substantially compromised in SAR and accumulated reduced levels of PR gene transcripts when compared with untransformed controls. Thus, SAR in B. napus displays many of the hallmarks of classical SAR including long lasting and broad host range resistance, association with PR gene activation, and a requirement for salicylic acid.

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Anastomosis Groups and Pathogenicity of Rhizoctonia solani and Binucleate Rhizoctonia from Potato in South Africa

Plant Disease ◽

10.1094/pdis-02-15-0236-re ◽

2015 ◽

Vol 99 (12) ◽

pp. 1790-1802 ◽

Cited By ~ 17

Author(s):

N. Muzhinji ◽

M. Truter ◽

J. W. Woodhall ◽

J. E. van der Waals

Keyword(s):

South Africa ◽

Rhizoctonia Solani ◽

Stem Canker ◽

Black Scurf ◽

Bootstrap Support ◽

Internal Transcribed Spacer Region ◽

Binucleate Rhizoctonia ◽

Anastomosis Groups ◽

Potato Plants ◽

Comprehensive Survey

A survey of anastomosis groups (AG) of Rhizoctonia spp. associated with potato diseases was conducted in South Africa. In total, 112 Rhizoctonia solani and 19 binucleate Rhizoctonia (BNR) isolates were recovered from diseased potato plants, characterized for AG and pathogenicity. The AG identity of the isolates was confirmed using phylogenetic analysis of the internal transcribed spacer region of ribosomal DNA. R. solani isolates recovered belonged to AG 3-PT, AG 2-2IIIB, AG 4HG-I, AG 4HG-III, and AG 5, while BNR isolates belonged to AG A and AG R, with frequencies of 74, 6.1, 2.3, 2.3, 0.8, 12.2, and 2.3%, respectively. R. solani AG 3-PT was the most predominant AG and occurred in all the potato-growing regions sampled, whereas the other AG occurred in distinct locations. Different AG grouped into distinct clades, with high maximum parsimony and maximum-likelihood bootstrap support for both R. solani and BNR. An experiment under greenhouse conditions with representative isolates from different AG showed differences in aggressiveness between and within AG. Isolates of AG 2-2IIIB, AG 4HG-III, and AG R were the most aggressive in causing stem canker while AG 3-PT, AG 5, and AG R caused black scurf. This is the first comprehensive survey of R. solani and BNR on potato in South Africa using a molecular-based approach. This is the first report of R. solani AG 2-2IIIB and AG 4 HG-I causing stem and stolon canker and BNR AG A and AG R causing stem canker and black scurf on potato in South Africa.

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