Seed priming with Trichoderma harzianum isolates enhances plant growth and induces resistance against Plasmopara halstedii, an incitant of sunflower downy mildew disease

2012 ◽  
Vol 41 (6) ◽  
pp. 609-620 ◽  
Author(s):  
A. Nagaraju ◽  
J. Sudisha ◽  
S. Mahadeva Murthy ◽  
Shin-ichi Ito
Keyword(s):  
Plant Growth ◽  
Downy Mildew ◽  
Trichoderma Harzianum ◽  
Seed Priming ◽  
Plasmopara Halstedii ◽  
Downy Mildew Disease

scholarly journals Updated Characterization of Races of Plasmopara halstedii and Entomopathogenic Fungi as Endophytes of Sunflower Plants in Axenic Culture

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 268
Author(s):  
Pedro Miranda-Fuentes ◽  
Ana B. García-Carneros ◽  
Leire Molinero-Ruiz
Keyword(s):  
Plant Growth ◽  
Downy Mildew ◽  
Entomopathogenic Fungi ◽  
Genetic Resistance ◽  
Axenic Culture ◽  
Plasmopara Halstedii ◽  
Successful Establishment ◽  
Axenic Conditions ◽  
Highly Virulent

The management of downy mildew (Plasmopara halstedii) in sunflower, is heavily dependent on genetic resistance, whilst entomopathogenic fungi (EF) can reduce other sunflower diseases. In this work, we characterized P. halstedii from Spain and other countries collected in the past few years. Twenty-three races were identified (the most frequent in Spain being 310, 304, 705 and 715), with an increasing proportion of highly virulent races. Five isolates from countries other than Spain overcame the resistance in RHA-340. In addition, we assessed the efficacy of five EF against downy mildew and their effects on sunflower growth in axenic conditions. None of the entomopathogens reduced disease severity, nor did they have any effect on plant growth when applied together with P. halstedii. In contrast, three EF reduced some of the plant growth variables in the absence of the pathogen. Microbiological and molecular diagnostics suggest that the axenic system and the short experimental time used in this study did not favor the successful establishment of EF in the plants or their potential biocontrol effect. Our results show a shift in P. halstedii racial patterns and suggest that soil as a growth substrate and long infection times are needed for EF effectiveness against downy mildew.

scholarly journals Short Communication: Potential tests of plant growth bacteria for the control of Peronosclerospora philipinensis in corn

2020 ◽  
Vol 21 (8) ◽  
Author(s):  
Nurasiah Djaenuddin ◽  
SYAFRUDDIN SYAFRUDDIN ◽  
BAHARUDDIN PATANDJENGI ◽  
TUTIK KUSWINANTI
Keyword(s):  
Plant Growth ◽  
Downy Mildew ◽  
Short Communication ◽  
Pseudomonas Stutzeri ◽  
Disease Suppression ◽  
Bacterial Isolates ◽  
Randomized Design ◽  
Induce Resistance ◽  
Downy Mildew Disease

Abstract. Djaenuddin N, Syafruddin, Patandjengi B, Kuswinanti T. 2020. Short Communication: Potential tests of plant growth bacteria for the control of Peronosclerospora philipinensis in corn. Biodiversitas 21: 3886-3892. The study was conducted at the Laboratory and Screen House of the Indonesian Cereals Research Institute (ICERI). The stages of the study were (i) potential test of bacterial isolates that have the ability to control downy mildew disease in vivo in corn and (ii) molecular identification of the selected bacterial isolates. Experiments were arranged in a Completely Randomized Design (CRD) with treatment of 24 bacteria which suspected to be growth-promoting bacteria. The parameters observed were disease intensity, percent disease suppression, plant height, chlorophyll content, and crop wet weight. The result showed that only five bacterial isolates namely, Bacillus albus strain MCCC 1A02146, Bacillus cereus strain IAM 12605, Bacillus paramycoides strain MCCC 1A04098, Pseudomonas stutzeri strain CCUG 11256, Serratia marcescens subsp. sakuensis strain KRED, have the ability to induce resistance to downy mildew disease caused by Peronosclerospora philipinensis.

scholarly journals Newly Emerged Populations of Plasmopara halstedii Infecting Rudbeckia Exhibit Unique Genotypic Profiles and Are Distinct from Sunflower-Infecting Strains

2016 ◽  
Vol 106 (7) ◽  
pp. 752-761 ◽  
Author(s):  
Yazmín Rivera ◽  
Catalina Salgado-Salazar ◽  
Thomas J. Gulya ◽  
Jo Anne Crouch
Keyword(s):  
Downy Mildew ◽  
Phylogenetic Analyses ◽  
Draft Genome ◽  
The United States ◽  
Plasmopara Halstedii ◽  
Draft Genome Assembly ◽  
Host Origin ◽  
Emergent Pathogen ◽  
Pathogen Populations ◽  
Downy Mildew Disease

The oomycete Plasmopara halstedii emerged at the onset of the 21st century as a destructive new pathogen causing downy mildew disease of ornamental Rudbeckia fulgida (rudbeckia) in the United States. The pathogen is also a significant global problem of sunflower (Helianthus annuus) and is widely regarded as the cause of downy mildew affecting 35 Asteraceae genera. To determine whether rudbeckia and sunflower downy mildew are caused by the same genotypes, population genetic and phylogenetic analyses were performed. A draft genome assembly of a P. halstedii isolate from sunflower was generated and used to design 15 polymorphic simple sequence repeat (SSR) markers. SSRs and two sequenced phylogenetic markers measured differentiation between 232 P. halstedii samples collected from 1883 to 2014. Samples clustered into two main groups, corresponding to host origin. Sunflower-derived samples separated into eight admixed subclusters, and rudbeckia-derived samples further separated into three subclusters. Pre-epidemic rudbeckia samples clustered separately from modern strains. Despite the observed genetic distinction based on host origin, P. halstedii from rudbeckia could infect sunflower, and exhibited the virulence phenotype of race 734. These data indicate that the newly emergent pathogen populations infecting commercial rudbeckia are a different species from sunflower-infecting strains, notwithstanding cross-infectivity, and genetically distinct from pre-epidemic populations infecting native rudbeckia hosts.

Symptoms Development as Tools to Differentiate Dorizontal Resistance in Sunflower

Agrotek ◽  
2018 ◽  
Vol 2 (6) ◽  
Author(s):  
Cipta Meliala ◽  
Felicity Fear ◽  
Denis Tourvieille de Labrouhe
Keyword(s):  
Downy Mildew ◽  
Natural Infection ◽  
Resistance Mechanism ◽  
Good Method ◽  
Vegetative Stage ◽  
Horizontal Resistance ◽  
Symptom Development ◽  
Plasmopara Halstedii ◽  
Controlled Conditions ◽  
Symptom Progression

Downy mildew symptoms caused by Plasmopara halstedii encountered in sunflower plantation are varied. This variation may be related to the resistance mechanism presented by plant to the invasion of the fungus. Our objectives were firstly is to evaluate symptom development after fungus race 710 inoculation on some vegetative stage of susceptible hybrid. Second objective is to evaluate the reaction some sunflower genotypes after fungus inoculation. The study was conducted under controlled conditions or under netting cages in the field. The development of downy mildew symptoms were affected by all factors studied. Shoot inoculation may present a good method to produce downy mildew symptom similar to the natural infection. Downy mildew symptom progression may be used to screen a genotype with a horizontal resistance.

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