Chitosan induces tomato basal resistance against Phytophthora nicotianae and inhibits pathogen development

Author(s):  
Dianevys González-Peña Fundora ◽  
Bernardo Falcón-Rodríguez ◽  
Daimy Costales Menéndez ◽  
Nora A. Foroud ◽  
Daymara Vaillant Flores ◽  
...  
2007 ◽  
Vol 97 (8) ◽  
pp. 958-963 ◽  
Author(s):  
G. C. Colburn ◽  
J. H. Graham

Phytophthora root rot of citrus in Florida is caused by Phytophthora nicotianae and P. palmivora. A naturally occurring isolate of P. nicotianae (Pn117) was characterized as hypovirulent on citrus roots. Pn117 infected and colonized fibrous roots, but caused significantly less disease than the virulent isolates P. nicotianae Pn198 and P. palmivora Pp99. Coincident inoculation of rootstock seedlings of Cleopatra mandarin (Citrus reticulata) or Swingle citrumelo (C. paradisi × Poncirus trifoliata) with the hypovirulent Pn117 and the virulent isolates Pn198 and Pp99 did not reduce the severity of disease caused by the virulent Phytophthora spp. When either rootstock was inoculated with the hypovirulent Pn117 for 3 days prior to inoculation with virulent isolates, preinoculated seedlings had significantly less disease and greater root weight compared with seedlings inoculated with the virulent isolates alone. Recovery of the different colony types of Phytophthora spp. from roots of sweet orange (C. sinensis) or Swingle citrumelo was evaluated on semiselective medium after sequential inoculations with the hypovirulent Pn117 and virulent Pp99. Pn117 was isolated from roots at the same level as the Pp99 at 3 days post inoculation. Preinoculation of Pn117 for 3 days followed by inoculation with Pp99 resulted in greater recovery of the hypovirulent isolate and lower recovery of the virulent compared with coincident inoculation.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 656
Author(s):  
Jing Jin ◽  
Rui Shi ◽  
Ramsey Steven Lewis ◽  
Howard David Shew

Phytophthora nicotianae is a devastating oomycete plant pathogen with a wide host range. On tobacco, it causes black shank, a disease that can result in severe economic losses. Deployment of host resistance is one of the most effective means of controlling tobacco black shank, but adaptation to complete and partial resistance by P. nicotianae can limit the long-term effectiveness of the resistance. The molecular basis of adaptation to partial resistance is largely unknown. RNAseq was performed on two isolates of P. nicotianae (adapted to either the susceptible tobacco genotype Hicks or the partially resistant genotype K 326 Wz/Wz) to identify differentially expressed genes (DEGs) during their pathogenic interactions with K 326 Wz/Wz and Hicks. Approximately 69% of the up-regulated DEGs were associated with pathogenicity in the K 326 Wz/Wz-adapted isolate when sampled following infection of its adapted host K 326 Wz/Wz. Thirty-one percent of the up-regulated DEGs were associated with pathogenicity in the Hicks-adapted isolate on K 326 Wz/Wz. A broad spectrum of over-represented gene ontology (GO) terms were assigned to down-regulated genes in the Hicks-adapted isolate. In the host, a series of GO terms involved in nuclear biosynthesis processes were assigned to the down-regulated genes in K 326 Wz/Wz inoculated with K 326 Wz/Wz-adapted isolate. This study enhances our understanding of the molecular mechanisms of P. nicotianae adaptation to partial resistance in tobacco by elucidating how the pathogen recruits pathogenicity-associated genes that impact host biological activities.


Microbiology ◽  
2009 ◽  
Vol 155 (4) ◽  
pp. 1093-1102 ◽  
Author(s):  
Roberta Provvedi ◽  
Francesca Boldrin ◽  
Francesco Falciani ◽  
Giorgio Palù ◽  
Riccardo Manganelli

In order to gain additional understanding of the physiological mechanisms used by bacteria to maintain surface homeostasis and to identify potential targets for new antibacterial drugs, we analysed the variation of the Mycobacterium tuberculosis transcriptional profile in response to inhibitory and subinhibitory concentrations of vancomycin. Our analysis identified 153 genes differentially regulated after exposing bacteria to a concentration of the drug ten times higher than the MIC, and 141 genes differentially expressed when bacteria were growing in a concentration of the drug eightfold lower than the MIC. Hierarchical clustering analysis indicated that the response to these different conditions is different, although with some overlap. This approach allowed us to identify several genes whose products could be involved in the protection from antibiotic stress targeting the envelope and help to confer the basal level of M. tuberculosis resistance to antibacterial drugs, such as Rv2623 (UspA-like), Rv0116c, PE20-PPE31, PspA and proteins related to toxin–antitoxin systems. Moreover, we also demonstrated that the alternative sigma factor σ E confers basal resistance to vancomycin, once again underlining its importance in the physiology of the mycobacterial surface stress response.


2011 ◽  
Vol 115 (4-5) ◽  
pp. 432-442 ◽  
Author(s):  
Marco Antonio Mammella ◽  
Santa Olga Cacciola ◽  
Frank Martin ◽  
Leonardo Schena

1999 ◽  
Vol 11 (3) ◽  
pp. 229-242 ◽  
Author(s):  
Y. Gautam ◽  
D. M. Cahill ◽  
A. R. Hardham

2010 ◽  
Vol 23 (12) ◽  
pp. 1619-1634 ◽  
Author(s):  
Denis A. Gaudet ◽  
Yuanyuan Wang ◽  
Carolyn Penniket ◽  
Z. X. Lu ◽  
Guus Bakkeren ◽  
...  

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.


2017 ◽  
Vol 284 (1869) ◽  
pp. 20171583 ◽  
Author(s):  
Imroze Khan ◽  
Arun Prakash ◽  
Deepa Agashe

Under strong pathogen pressure, insects often evolve resistance to infection. Many insects are also protected via immune memory (immune priming), whereby sublethal exposure to a pathogen enhances survival after secondary infection. Theory predicts that immune memory should evolve when the pathogen is highly virulent, or when pathogen exposure is relatively rare. However, there are no empirical tests of these hypotheses, and the adaptive benefits of immune memory relative to direct resistance against a pathogen are poorly understood. To determine the selective pressures and ecological conditions that shape immune evolution, we imposed strong pathogen selection on flour beetle ( Tribolium castaneum ) populations, infecting them with Bacillus thuringiensis (Bt) for 11 generations. Populations injected first with heat-killed and then live Bt evolved high basal resistance against multiple Bt strains. By contrast, populations injected only with a high dose of live Bt evolved a less effective but strain-specific priming response. Control populations injected with heat-killed Bt did not evolve priming; and in the ancestor, priming was effective only against a low Bt dose. Intriguingly, one replicate population first evolved priming and subsequently evolved basal resistance, suggesting the potential for dynamic evolution of different immune strategies. Our work is the first report showing that pathogens can select for rapid modulation of insect priming ability, allowing hosts to evolve divergent immune strategies (generalized resistance versus specific immune memory) with potentially distinct mechanisms.


Author(s):  
Martin Solanský ◽  
Kamil Mikulášek ◽  
Martina Zapletalová ◽  
Marek Petřivalský ◽  
Annick Chiltz ◽  
...  

Abstract Successful plant defence against microbial pathogens is based on early recognition and fast activation of inducible responses. Key mechanisms include detection of microbe-associated molecular patterns by membrane-localized Pattern Recognition Receptors that induce a basal resistance response. A well-described model of such responses to pathogens involves interaction between Solanaceae plants with proteinaceous elicitors secreted by oomycetes, called elicitins. It has been hypothesised that elicitins' formation of oligomeric structures could be involved in their recognition and activation of defensive transduction cascades. In tests of this hypothesis reported here, using several approaches, we observed differences in tobacco plant responses induced by the elicitin β-cryptogein (β-CRY) and its homodimer (β-CRY DIM). We also found that the C-terminal domain of elicitins of other ELI clades plays a significant role in stabilization of their oligomeric structure and restraint in the cell wall. In addition, covalently crosslinking β-CRY DIM impaired formation of signalling complexes, thereby reducing its capacity to elicit the hypersensitive response and resistance in the host plant, with no significant changes in pathogenesis-related protein expression. The results illuminate the poorly understood role of elicitins' oligomeric structures in oomycetes' interaction with plants, by revealing details of effects of β-CRY dimerization on tobacco plants' recognition and defence responses.


Author(s):  
G. M. Waterhouse

Abstract A description is provided for Phytophthora nicotianae var. nicotianae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Nicotiana plumbaginifolia, N. tabaci, N. spp., and on Amaranthus sp., Commelina benghalensis, C. nudiflora, Lycopersicon esculentum, Ricinus communis, Solanum melongena; also on wound inoculated Buxus sp., Daucus carota, Hedera helix, Ipomoea batatas and Trema amboensis. DISEASE: Black shank of tobacco. GEOGRAPHICAL DISTRIBUTION: Africa (Malawi, Mauritius, Uganda); Asia (Ceylon, China, Formosa, India, Indonesia, Japan, Java, Malaya, Philippines, Sumatra); Central America & West Indies (Cuba, Jamaica, Puerto Rico, Santo Domingo, Trinidad); Europe (Bulgaria, Germany, Greece, Italy, Poland, Romania, U.S.S.R.); North America (U.S.A.); South America (Brazil, Colombia, Venezuela). TRANSMISSION: Soil-borne, persisting in soil for at least 4 years between tobacco crops, and not eliminated by a 3 year rotation or a 4 year fallow (41: 409; 39: 126). Tobacco leaves have been used to indicate disease potential in infested soil after serial dilution with sterile soil (42: 408). Spread in contaminated pond water used in overhead irrigation also suspected (43, 1413). Wind-borne spread up to 800 ft. has been recorded (39: 500).


Author(s):  
G. M. Waterhouse

Abstract A description is provided for Phytophthora nicotianae var. parasitica. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On a very wide range of host plants comprising 58 families including: avocado, castor, Cinchona spp., citrus, cotton, eggplant, guava, lucerne, papaw, parsley, pineapple, Piper betle, rhubarb, sesame, strawberry, tomato. DISEASES: Damping-off of seedlings (tomato, castor, citrus, cotton); root rot (citrus, avocado, strawberry, lucerne); crown rot (parsley, rhubarb, strawberry, lucerne); brown stem rot of tobacco; stem canker and tip blight of Cinchona spp. ; leaf blight (castor, sesame, pineapple, Piper betle) and fruit rot (citrus, tomato, guava, papaw, eggplant). GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Mali, Madagascar, Mauritius, Morocco, Nigeria, Sierra Leone, Southern Rhodesia, Tanganyika); Asia (Burma, Ceylon, China, Formosa, India, Israel, Japan, Java, Malaya, Philippines); Australia & Oceania (Australia, Hawaii, Tasmania); Europe (Cyprus, France, Germany, Great Britain, Holland, Ireland, Italy, Poland, Portugal, U.S.S.R.); North America (Bermuda, Canada, Mexico, U.S.A.); Central America & West Indies (Costa Rica, Cuba, El Salvador, Guatemala, Jamaica, Montserrat, Puerto Rico, Trinidad);. South America (Argentina, Brazil, British Guiana, Colombia, Paraguay, Peru, Venezuela). TRANSMISSION: Soil-borne, spreading rapidly after heavy rain or where soil remains moist or water-logged (40: 470). Also recorded in drainage water in India and in reservoirs and canals supplying citrus groves in U.S.A. (23: 45; 39: 24). A method for determining a disease potential index in soil using lemon fruit has been described (38: 4). Also present in testas of seeds from diseased citrus fruit which may infect nursery seedbeds (37: 165).


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