Bio-control of Stem Rot in Jerusalem Artichoke (Helianthus tuberosus L.) in Field Conditions

Stem rot is a serious disease in Jerusalem artichoke (JA). To reduce the impact of this disease on yield and quality farmers often use fungicides, but this control method can be expensive and leave chemical residues. The objective of this study was to evaluate the efficacy of two biological control agents, Trichoderma harzianum T9 and Bacillus firmus BSR032 for control of Sclerotium rolfsii under field conditions. Four accessions of JA (HEL246, HEL65, JA47, and JA12) were treated or notreated with T. harzianum T9 and B. firmus BSR032 in a 4 × 2 × 2 factorial experiment in two fields (environments), one unfertilized and one fertilized. Plants were inoculated with S. rolfsii and disease was evaluated at 3-day intervals for 46 days. T. harzianum T9 and B. firmus BSR032 reduced disease incidence by 48% and 49%, respectively, whereas T. harzianum T9 + B. firmus BSR032 reduced disease incidence by 37%. The efficacy of T. harzianum T9 and B. firmus BSR032 for control of S. rolfsii was dependent on environments and genotypes. The expression of host plant resistance also depended on the environment. However, HEL246 showed consistently low disease incidence and severity index in both environments (fertilized and unfertilized). Individually, T. harzianum T9, B. firmus BSR032, or host plant resistance control stem rot caused by S. rolfsii in JA. However, no combination of these treatments provided more effective control than each alone.

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Management of Dry Root Rot in Chickpea (Cicer arietinum L.) Caused By Macrophomina phaseolina by Utilizing Host Plant Resistance, Fungicides and Bioagents

Legume Research - An International Journal ◽

10.18805/lr-3820 ◽

2020 ◽

Author(s):

H. Manjunatha ◽

M. Saifulla

Keyword(s):

Host Plant ◽

Plant Resistance ◽

Host Plant Resistance ◽

Root Rot ◽

Disease Incidence ◽

Macrophomina Phaseolina ◽

Resistant Varieties ◽

Paper Technique ◽

Blotter Paper ◽

Cent Disease

Background: For the management of soil borne disease like dry root rot of chickpea caused by Macrophomina phaseolina, by using fungicides alone is not feasible due to environmental and health hazards. Hence integrated management of the disease by using resistant varieties, fungicides and bio-control agents is the best alternative. So the present study was aimed to identify resistant varieties, best fungicide and bioagent for management of dry root rot in chickpea. Methods: Two hundred and twelve genotypes were screened using blotter paper technique for identifying resistant genotypes for dry root rot. The experiment on management of dry root rot was conducted during Kharif and Rabi of 2013-14 using a susceptible chickpea variety JG-11 with 14 treatments including control with 3 replications. Result: Of two hundred and twelve chickpea genotypes screened for host plant resistance against Macrophomina phaseolina by blotter paper technique only one genotype ie. PBG-5 showed moderately resistant reaction. Among fourteen treatments including fungicides and bioagents imposed for the management of dry root rot, seed treatment with tebuconazole @ 2 g/kg recorded lowest per cent disease incidence of 9.43, with a highest yield of 722.81 kg/ha compared to untreated control which recorded the highest per cent disease incidence (40.10) with a lowest mean yield of 362.02 kg/ha.

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Characterization of Strawberry Host Plant Resistance to Powdery Mildew caused by Podosphaera aphanis

Plant Health Progress ◽

10.1094/php-12-20-0107-rs ◽

2021 ◽

Author(s):

Michael Palmer ◽

Gerald Holmes

Keyword(s):

Powdery Mildew ◽

Host Plant ◽

Plant Resistance ◽

Host Plant Resistance ◽

Disease Incidence ◽

Strawberry Cultivar ◽

Plant Disease Management ◽

Relative Differences ◽

Moderately Resistant

Host plant resistance is an essential tool in plant disease management worldwide. Evaluations of strawberry cultivar resistance to powdery mildew were done previously in California, but many new cultivars have been released since the last evaluation in 1996 and merit evaluation for today’s growers. Two studies were conducted over the winter and summer of 2020, evaluating ten commonly grown cultivars. Powdery mildew-free plants were established in 3 L pots under high plastic tunnels and after three weeks (four- to five-leaf stage) moved into a powdery mildew-infested greenhouse. Disease incidence and severity ratings were taken weekly beginning at the first sign of disease. Ratings taken at 40 (winter) and 41 (summer) days after transfer to the greenhouse were used to make comparisons among cultivars. Significant differences were found in foliar disease severity among cultivars, but none were totally free of disease. Moderately resistant cultivars were ‘San Andreas’ and ‘Sweet Ann’. Highly susceptible cultivars were ‘BG 3.324’ and ‘Royal Royce’. Two field evaluations of the ten cultivars confirmed the observed relative differences in host resistance under field conditions. This information is valuable to California strawberry growers who select cultivars based in part on their susceptibility to economically important diseases such as powdery mildew.

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Transcriptional Responses of Resistant and Susceptible Wheat Exposed to Wheat Curl Mite

International Journal of Molecular Sciences ◽

10.3390/ijms22052703 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2703

Author(s):

Mahnaz Kiani ◽

Becky Bryan ◽

Charles Rush ◽

Adrianna Szczepaniec

Keyword(s):

Host Plant ◽

Plant Resistance ◽

Host Plant Resistance ◽

Triticum Aestivum L ◽

Defense Responses ◽

Transcriptional Responses ◽

Wheat Curl Mite ◽

Yield And Quality ◽

The Impact

(1) Background: The wheat curl mite (Aceria tosichella Keifer) is a key pest of wheat (Triticum aestivum L.) worldwide. While a number of wheat cultivars resistant to the mites have been employed to minimize the impact on the yield and quality of grain, little is known regarding the mechanisms underlying host plant resistance. Therefore, the goal of this study was to explore changes in transcriptome of resistant and susceptible wheat in order to quantify the molecular changes that drive host plant resistance. (2) Methods: Two varieties, wheat curl mite-susceptible (Karl 92) and wheat curl mite-resistant (TAM112) wheat, both at 2-week postemergence, were used in this study. Half of the plants were exposed to wheat curl mite herbivory and half remained mite-free and served as controls. Transcriptome changes were quantified using RNA-seq and compared among treatments to identify genes and pathways affected by herbivores. (3) Results: We identified a number of genes and pathways involved in plant defenses against pathogens, herbivores, and abiotic stress that were differentially expressed in the resistant wheat exposed to wheat curl mite herbivory but were unaffected in the susceptible wheat. (4) Conclusions: Our outcomes indicated that resistant wheat counteracts wheat curl mite exposure through effective induction of genes and pathways that enhance its defense responses.

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Host plant resistance and biological control: A test of the movement-risk hypothesis

10.1603/ice.2016.109191 ◽

2016 ◽

Author(s):

Cory Straub

Keyword(s):

Biological Control ◽

Host Plant ◽

Plant Resistance ◽

Host Plant Resistance

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

Plants ◽

10.3390/plants10071384 ◽

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.

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

International Journal of Molecular Sciences ◽

10.3390/ijms22115941 ◽

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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