scholarly journals Mapping Host Plant Resistance Qtls against Three Virulent Isolates of Downy Mildew PathogenIn Pearl Millet (Pennisetum glaucum [L.] R. Br.)

2017 ◽  
Vol 5 (5) ◽  
pp. 1625-1631
Author(s):  
Anishetti Saritha ◽  
Keyword(s):  
Host Plant ◽  
Downy Mildew ◽  
Pearl Millet ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Pennisetum Glaucum ◽  
Resistance Qtls

scholarly journals Resurgence of Pseudoperonospora cubensis: The Causal Agent of Cucurbit Downy Mildew

2015 ◽  
Vol 105 (7) ◽  
pp. 998-1012 ◽  
Author(s):  
Yigal Cohen ◽  
Kyle M. Van den Langenberg ◽  
Todd C. Wehner ◽  
Peter S. Ojiambo ◽  
Mary Hausbeck ◽  
...  
Keyword(s):  
Disease Control ◽  
Host Plant ◽  
Downy Mildew ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Current Status ◽  
Pseudoperonospora Cubensis ◽  
Research Areas ◽  
The Family ◽  
Future Management

The downy mildew pathogen, Pseudoperonospora cubensis, which infects plant species in the family Cucurbitaceae, has undergone major changes during the last decade. Disease severity and epidemics are far more destructive than previously reported, and new genotypes, races, pathotypes, and mating types of the pathogen have been discovered in populations from around the globe as a result of the resurgence of the disease. Consequently, disease control through host plant resistance and fungicide applications has become more complex. This resurgence of P. cubensis offers challenges to scientists in many research areas including pathogen biology, epidemiology and dispersal, population structure and population genetics, host preference, host−pathogen interactions and gene expression, genetic host plant resistance, inheritance of host and fungicide resistance, and chemical disease control. This review serves to summarize the current status of this major pathogen and to guide future management and research efforts within this pathosystem.

scholarly journals Effects of Host Plant Resistance and Fungicides on Severity of Cucumber Downy Mildew

HortScience ◽  
2013 ◽  
Vol 48 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Adam D. Call ◽  
Todd C. Wehner ◽  
Gerald J. Holmes ◽  
Peter S. Ojiambo
Keyword(s):  
Host Plant ◽  
Downy Mildew ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Maximum Yield ◽  
Plant Size ◽  
High Yield ◽  
High Yields ◽  
A Minor ◽  
Moderately Resistant

Cucurbit downy mildew caused by the oomycete Pseudoperonospora cubensis (Berk. And Curt) Rostov is a major disease of cucumber (Cucumis sativus L.) (Palti and Cohen, 1980) globally. Chemical control of downy mildew is necessary to achieve high yields in the absence of adequate host plant resistance. Most of the currently grown cultivars have some resistance to downy mildew. Before the resurgence of the disease in 2004, host plant resistance was sufficient to control the disease without fungicide use, and downy mildew was only a minor problem on cucumber. There are currently no cultivars that show resistance at a level equal to that observed before 2004. However, differences in resistance exist among cultivars, ranging from moderately resistant to highly susceptible. In this study, we evaluated the disease severity and yield of four cucumber cultivars that differed in disease resistance and were treated with fungicide programs representing a range of efficacy levels. The experiment was a split plot design with six replications and four years. Disease was evaluated as chlorosis, necrosis, and reduction in plant size on a 0 to 9 scale. Cultigen had a large effect in all four years. Fungicide has a smaller effect on resistance component traits and a larger effect on yield traits. The effects of cultivar resistance and fungicides appear to be additive until a threshold where maximum yield is reached. Highly resistant cultigens such as PI 197088 required only the least effective fungicides to achieve highest yields, whereas moderately resistant cultigens required a more effective fungicide to reach a similar level of yield. Susceptible cultigens did not achieve high yield even with the most effective fungicide treatments. It is likely that, even as highly resistant cultivars are released, growers will need to continue a minimal fungicide program to achieve maximum yield.

scholarly journals Morphological and Chemical Factors Related to Western Flower Thrips Resistance in the Ornamental Gladiolus

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1384
Author(s):  
Dinar S. C. Wahyuni ◽  
Young Hae Choi ◽  
Kirsten A. Leiss ◽  
Peter G. L. Klinkhamer
Keyword(s):  
Host Plant ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Frankliniella Occidentalis ◽  
Western Flower Thrips ◽  
Resistance Breeding ◽  
Breeding Programs ◽  
Triterpenoid Saponins ◽  
Flower Thrips ◽  
Highly Correlated

Understanding the mechanisms involved in host plant resistance opens the way for improved resistance breeding programs by using the traits involved as markers. Pest management is a major problem in cultivation of ornamentals. Gladiolus (Gladiolus hybridus L.) is an economically important ornamental in the Netherlands. Gladiolus is especially sensitive to attack by western flower thrips (Frankliniella occidentalis (Pergande) (Thysanoptera:Thripidae)). The objective of this study was, therefore, to investigate morphological and chemical markers for resistance breeding to western flower thrips in Gladiolus varieties. We measured thrips damage of 14 Gladiolus varieties in a whole-plant thrips bioassay and related this to morphological traits with a focus on papillae density. Moreover, we studied chemical host plant resistance to using an eco-metabolomic approach comparing the 1H NMR profiles of thrips resistant and susceptible varieties representing a broad range of papillae densities. Thrips damage varied strongly among varieties: the most susceptible variety showed 130 times more damage than the most resistant one. Varieties with low thrips damage had shorter mesophylls and epidermal cells, as well as a higher density of epicuticular papillae. All three traits related to thrips damage were highly correlated with each other. We observed a number of metabolites related to resistance against thrips: two unidentified triterpenoid saponins and the amino acids alanine and threonine. All these compounds were highly correlated amongst each other as well as to the density of papillae. These correlations suggest that papillae are involved in resistance to thrips by producing and/or storing compounds causing thrips resistance. Although it is not possible to distinguish the individual effects of morphological and chemical traits statistically, our results show that papillae density is an easy marker in Gladiolus-breeding programs targeted at increased resistance to thrips.

scholarly journals Comparative TMT Proteomic Analysis Unveils Unique Insights into Helicoverpa armigera (Hübner) Resistance in Cajanus scarabaeoides (L.) Thouars

2021 ◽  
Vol 22 (11) ◽  
pp. 5941
Author(s):  
Abigail Ngugi-Dawit ◽  
Isaac Njaci ◽  
Thomas J.V. Higgins ◽  
Brett Williams ◽  
Sita R. Ghimire ◽  
...  
Keyword(s):  
Host Plant ◽  
Helicoverpa Armigera ◽  
Plant Resistance ◽  
Host Plant Resistance ◽  
Proteomic Analysis ◽  
Artificial Diet ◽  
Growth Stages ◽  
Genetic Base ◽  
Helicoverpa Armígera ◽  
Helicoverpa Armigera Hubner

Pigeonpea [Cajanus cajan (L.) Millspaugh] is an economically important legume playing a crucial role in the semi-arid tropics. Pigeonpea is susceptible to Helicoverpa armigera (Hübner), which causes devastating yield losses. This pest is developing resistance to many commercially available insecticides. Therefore, crop wild relatives of pigeonpea, are being considered as potential sources of genes to expand the genetic base of cultivated pigeonpea to improve traits such as host plant resistance to pests and pathogens. Quantitative proteomic analysis was conducted using the tandem mass tag platform to identify differentially abundant proteins between IBS 3471 and ICPL 87 tolerant accession and susceptible variety to H. armigera, respectively. Leaf proteome were analysed at the vegetative and flowering/podding growth stages. H. armigera tolerance in IBS 3471 appeared to be related to enhanced defence responses, such as changes in secondary metabolite precursors, antioxidants, and the phenylpropanoid pathway. The development of larvae fed on an artificial diet with IBS 3471 lyophilised leaves showed similar inhibition with those fed on an artificial diet with quercetin concentrations with 32 mg/25 g of artificial diet. DAB staining (3,3’-diaminobenzidine) revealed a rapid accumulation of reactive oxygen species in IBS 3471. We conclude that IBS 3471 is an ideal candidate for improving the genetic base of cultivated pigeonpea, including traits for host plant resistance.

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