scholarly journals Effect of Volatile Compounds Produced by Selected Bacterial Endophytes in Promoting Plant Growth

HortScience ◽  
2021 ◽  
pp. 1-8
Author(s):  
Maheshwari Asha ◽  
Mmbaga Margaret ◽  
Bhusal Bandana ◽  
Ondzighi-Assoume Christine

Bacterial endophytes selected for their capability to suppress diverse fungal pathogens in vitro and in greenhouse studies have been shown to promote plant growth. The effect of volatile compounds emitted by selected bacteria on plant growth in Arabidopsis thaliana, tomato (Solanum lycopersicum), sweet pepper (Capsicum annuum), and cucumbers (Cucumis sativus) was evaluated on container-grown plants nested above bacterial cultures, with roots exposed to the volatiles without direct contact between bacterial cells and the plant roots. Significant increases in plant growth were observed in plant height, root length, leaf size, fresh weight, and chlorophyll content in all plants tested. Although diverse chemical compounds may be involved in promoting plant growth, including volatile and nonvolatile compounds, observations in this study have implications for the potential role of the selected bacteria in plant production as biofertilizers and biopesticides.

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 349
Author(s):  
Dominik Bleša ◽  
Pavel Matušinský ◽  
Romana Sedmíková ◽  
Milan Baláž

The use of biological control is becoming a common practice in plant production. One overlooked group of organisms potentially suitable for biological control are Rhizoctonia-like (Rh-like) fungi. Some of them are capable of forming endophytic associations with a large group of higher plants as well as mycorrhizal symbioses. Various benefits of endophytic associations were proved, including amelioration of devastating effects of pathogens such as Fusarium culmorum. The advantage of Rh-like endophytes over strictly biotrophic mycorrhizal organisms is the possibility of their cultivation on organic substrates, which makes their use more suitable for production. We focused on abilities of five Rh-like fungi isolated from orchid mycorrhizas, endophytic fungi Serendipita indica, Microdochium bolleyi and pathogenic Ceratobasidium cereale to inhibit the growth of pathogenic F. culmorum or Pyrenophora teres in vitro. We also analysed their suppressive effect on wheat infection by F. culmorum in a growth chamber, as well as an effect on barley under field conditions. Some of the Rh-like fungi affected the growth of plant pathogens in vitro, then the interaction with plants was tested. Beneficial effect was especially noted in the pot experiments, where wheat plants were negatively influenced by F. culmorum. Inoculation with S. indica caused higher dry shoot biomass in comparison to plants treated with fungicide. Prospective for future work are the effects of these endophytes on plant signalling pathways, factors affecting the level of colonization and surviving of infectious particles.


2017 ◽  
Vol 155 (7) ◽  
pp. 1069-1081 ◽  
Author(s):  
T.-C. LIN ◽  
C.-L. LIN ◽  
W.-C. CHUNG ◽  
K.-R. CHUNG ◽  
J.-W. HUANG

SUMMARYPlant defence systems can be induced by biotic and abiotic stress. Experiments were undertaken to explore the feasibility of different fungal proteins for the reduction of vegetable diseases. Total proteins purified from three soil-borne and five foliar fungal pathogens had no fungistatic effects nor did they trigger hypersensitive reactions on test plants. The abilities to promote plant growth and to reduce disease severity varied among test proteins and plants. Depending on test proteins, experiments have demonstrated that exogenous application of fungal proteins could reduce Alternaria brassicicola-induced black spot severity on cabbage, Colletotrichum spp.-induced anthracnose on Chinese cabbage and cucumber, Rhizoctonia solani-induced damping-off on sweet pepper and Chinese cabbage, and powdery mildew on cucumber seedlings. An Alternariaprotein effector 1 (Ape1)-coding gene was cloned from two Alternaria spp. and expressed in Escherichia coli. The expressed Ape1 reduced anthracnose incidence on cucumber leaves, indicating that Ape1 was the primary activator in the crude protein extracts responsible for disease reduction. Application of Alternaria proteins onto Chinese cabbage seedlings caused an increase of phenylalanine ammonia lyase and peroxidase activities in treated seedlings, which may have played a role in host defence.


2020 ◽  
Vol 11 (1) ◽  
pp. 19
Author(s):  
NASRUN NASRUN ◽  
CHRISTANTI CHRISTANTI ◽  
TRIWIDODO ARWIYANTO ◽  
IKA MARISKA

<p>ABSTRAK<br />Penelitian pengendalian penyakit layu bakteri nilam (Ralstonia<br />solanacearum) menggunakan pseudomonad fluoresen di kebun petani<br />nilam Desa Situak Pasaman Barat, Sumatera Barat telah dilakukan pada<br />bulan Oktober 2003 sampai dengan Juni 2004. Penelitian ini bertujuan<br />untuk mendapatkan pseudomonad fluoresen yang berpotensi untuk<br />mengendalikan penyakit layu bakteri, dan meningkatkan pertumbuhan<br />dan produksi nilam. Isolat pseudomonad fluoresen Pf 63, Pf 90, Pf 91, Pf<br />147, dan Pf 180 sebagai perlakuan diisolasi dari rizosfer nilam sehat, dan<br />diseleksi  berdasarkan  kemampuan  antagonistik  terhadap  R.<br />solanacearum secara in vitro di Laboratorium Bakteriologi Tumbuhan<br />Fakultas Pertanian UGM. Isolat pseudomonad fluoresen tersebut<br />diintroduksikan ke nilam dan diadaptasikan selama 1 minggu sebelum<br />ditanam. Tanaman yang telah diperlakukan dengan isolat pseudomonad<br />fluoresen ditanam pada kebun yang telah terinfeksi dengan patogen pada<br />bulan Oktober 2003. Percobaan disusun dalam rancangan acak kelompok<br />(RAK) dengan 6 ulangan. Parameter pengamatan adalah masa inkubasi,<br />intensitas penyakit, pertumbuhan tanaman dan produksi minyak nilam.<br />Hasil penelitian menunjukkan bahwa isolat pseudomonad fluoresen<br />dapat mengendalikan penyakit layu bakteri dengan perpanjangan masa<br />inkubasi 6-52 hari dan penekanan intensitas penyakit 31,11 – 50,56%.<br />Disamping itu isolat pseudomonad fluoresen dapat mempengaruhi<br />peningkatan pertumbuhan tanaman yaitu tinggi tanaman (6,7 – 26,3 cm),<br />jumlah daun (4,6 – 30,1 daun/tanaman) dan berat kering daun (24,5 –<br />154,3 g/tanaman), dan produksi minyak nilam terutama jumlah minyak<br />(4,8 – 22,3 ml/tanaman). Hasil percobaan ini menunjukkan bahwa isolat<br />Pf 91 mempunyai kemampuan antagonistik tertinggi dalam mengen-<br />dalikan penyakit layu bakteri di lapangan.<br />Kata kunci : Nilam, Pogostemon cablin Benth, penyakit layu, bakteri,<br />pengendalian hayati, pseudomonad fluoresen</p><p><br />ABSTRACT<br />Controlling bacterial wilt disease on patchouli plant with<br />fluorescent pseudomonad<br />The study of controlling bacterial wilt disease on patchouli plant<br />(Ralstonia solanacearum) with fluorescent pseudomonad was carried out<br />in a farmer’s field in Situak Village West Pasaman, West Sumatera from<br />October 2003 to June 2004. The aims of the study were to find out the<br />effectiveness of fluorescent pseudomonad for controlling bacterial wilt<br />disease, increasing plant growth and production. Isolates of fluorescent<br />pseudomonad Pf 63, Pf 90, Pf 91, Pf 147 and Pf 180 as treatments were<br />isolated from the rhizosphere of healthy patchouli plant, and selected<br />based on antagonistic activity on R. solanacearum in vitro at the<br />Laboratory of Plant Bacteriology, Faculty of Agriculture, UGM. The<br />isolates were inoculated on patchouli plant and adapted for one week<br />before planting. The plants treated with fluorescent pseudomonad<br />isolates were planted in the field infected with pathogen on October<br />2003. The experiment was arranged in a randomized block design<br />(RBD) with six replications. The assessment parameters were incubation<br />period, disease intensity, plant growth and production of patchouli plants.<br />The results showed that fluorescent pseudomonad isolates could control<br />the bacterial wilt disease and delay the incubation period 6-52 days and<br />decrease the disease intensity 31,11–50,56%. In addition fluorescent<br />pseudomonad isolates could affect the increase of plant growth, i.e. plant<br />height ( 6,7 – 26,3 cm ), leaf numbers (4,6 – 30,1 leaves/plant) and dry<br />weight of leaves (24,5 – 154,3 g/plant), and plant production, especially<br />oil content (4,8 – 22,3 ml/plant). The results of the experiment showed<br />that Pf 91 isolate had the highest antagonistic activity on controlling the<br />bacterial wilt disease on field.<br />Key words : Patchouli, Pogostemon cablin Benth, wilt disease,<br />bacterial, biological control, fluorescent pseudomonad</p>


Author(s):  
Solange da Cunha Ferreira ◽  
Alessandra Keiko Nakasone ◽  
Silvia Mara Coelho do Nascimento ◽  
Danyllo Amaral de Oliveira ◽  
Andrei Santos Siqueira ◽  
...  

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
H. H. Al-Nadabi ◽  
N. S. Al-Buraiki ◽  
A. A. Al-Nabhani ◽  
S. N. Maharachchikumbura ◽  
R. Velazhahan ◽  
...  

Abstract Background Date palm ((Phoenix doctylifera L.) suffers from several fungal diseases. The endophytic microorganisms present in higher plants generally offer protection to their host plants against invading phytopathogenic fungi and bacteria. In the present study, endophytic bacteria associated with date palm leaves were isolated and their in vitro antagonistic potential against fungal pathogens causing leaf spots in date palm was demonstrated. Results Endophytic bacteria were isolated from date palm leaves of 3 different cultivars viz., Nighal, Khalas and Khinaizi and evaluated for their inhibitory activity against leaf spot pathogens of date palm viz., Fusarium solani, Alternaria sp., Nigrospora sp., Thieloviopsis sp., Curvularia subpapendrofii and Tilletiopsis minor using an in vitro dual culture assay. Of the 24 endophytic bacterial strains tested, the endophytes designated B1, B7, B8 and B9 obtained from cv. Nighal showed inhibitory activities (more than 55% mycelial growth inhibition) against F. solani and Alternaria sp. None of the bacterial endophytes inhibited the growth of other fungal pathogens tested. These antagonistic bacterial strains were identified as Pantoea septica on the basis of 16S rRNA gene sequence analysis. The hyphae of F. solani and Alternaria sp. exhibited morphological abnormalities such as shrinkage and disintegration when grown in the presence of antagonistic bacterial endophytes. The cell-free culture filtrates of the bacterial endophytes caused inhibition of mycelial growth and induced leakage of electrolytes from the mycelia of F. solani and Alternaria sp. This is the first study that describes inhibition of the date palm pathogens F. solani and Alternaria sp. by P. septica. Conclusion Endophytic Pantoea septica strains isolated from date palm leaves inhibited the mycelial growth of F. solani and Alternaria sp. and induced morphological changes in their mycelia. The culture filtrates of these bacterial strains also inhibited the mycelial growth and caused leakage of electrolytes from the mycelia of F. solani and Alternaria sp. These promising bacterial strains can be exploited as biocontrol agents to control F. solani and Alternaria sp.-induced leaf spot diseases of date palm.


Author(s):  
Daniel Alonso Pérez Corral ◽  
José de Jesús Ornelas Paz ◽  
Guadalupe Isela Olivas Orozco ◽  
Carlos Horacio Acosta Muñiz ◽  
Miguel Ángel Salas Marina ◽  
...  

Fungi and oomycetes are important plant pathogens that constantly attacked plants, thus compromising the production of foods worldwide. Streptomyces strains might be useful to control fungal pathogens by different mechanism. The in vitro antagonistic activity of non-volatile and volatile metabolites from four Streptomyces strains was evaluated over cultures of phytopathogenic fungi and oomycetes. The non-volatile compounds from Streptomyces strains significantly reduced (44.2 to 92.1%) the growth of aerial mycelium of pathogens. The volatile compounds (VOCs) from Streptomyces strains reduced both aerial mycelium (22.5 to 96.7%) and mycelium growing inside of culture medium (0.0 - 9.4%). The pathogens maintained their capacity to grow normally in fresh culture medium without antagonists after confrontations with antagonist VOCs. The analysis of VOCs by gas chromatography coupled to mass spectrometry revealed different kinds of VOCs included alcohols, aldehydes, ketones, esters, terpenes, terpenoids, thioethers, among others. The most abundant VOCs were trans-1,10-dimethyl-trans-9-decalol (geosmin), 2-methylisoborneol, 2-methyl-2-bornene, 1,4-dimethyladamantane, and 4-penten-1-ol, trifluoroacetate. The antipathogenic activity of nine pure VOCs that had been identified in cultures of the Streptomyces strains alone was evaluated in vitro against phytopathogenic fungi and oomycetes. Trans-2-hexenal was the most effective of these VOCs, inhibiting completely the growth of tested phytopathogens. The volatile and non-volatile compounds from Streptomyces strains effectively reduced the in vitro growth of phytopathogens and they might be used as biological control. Further studies are required to demonstrate this activity on open field conditions.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11194
Author(s):  
Rizwana begum Syed Nabi ◽  
Raheem Shahzad ◽  
Rupesh Tayade ◽  
Muhammad Shahid ◽  
Adil Hussain ◽  
...  

Soilborne fungal diseases are most common among vegetable crops and have major implications for crop yield and productivity. Eco-friendly sustainable agriculture practices that can overcome biotic and abiotic stresses are of prime importance. In this study, we evaluated the ability of plant growth-promoting rhizobacterium (PGPR) Bacillus aryabhattai strain SRB02 to control the effects of tomato wilt disease caused by Fusarium oxysporum f. sp. lycopersici (strain KACC40032) and promote plant growth. In vitro bioassays showed significant inhibition of fungal growth by SRB02. Inoculation of susceptible and tolerant tomato cultivars in the presence of SRB02 showed significant protection of the cultivar that was susceptible to infection and promotion of plant growth and biomass production in both of the cultivars. Further analysis of SRB02-treated plants revealed a significantly higher production of amino acids following infection by F. oxysporum. Analysis of plant defense hormones after inoculation by the pathogen revealed a significantly higher accumulation of salicylic acid (SA), with a concomitant reduction in jasmonic acid (JA). These results indicate that B. aryabhattai strain SRB02 reduces the effects of Fusarium wilt disease in tomato by modulating endogenous phytohormones and amino acid levels.


2020 ◽  
Vol 63 (2) ◽  
pp. 169-179
Author(s):  
Carrie Siew Fang Sim ◽  
Yuen Lin Cheow ◽  
Si Ling Ng ◽  
Adeline Su Yien Ting

Five metal-tolerant endophytic isolates (Bipolaris sp. LF7, Diaporthe miriciae LF9, Trichoderma asperellum LF11, Phomopsis asparagi LF15, Saccharicola bicolor LF22), with known metal-tolerance attributes and biocontrol activities against Ganoderma boninense, were tested for growth-promoting activities independent of (in vitro) and associated with plants (height, weight, root mass and stem circumference) (in vivo). Results revealed that metal-tolerant endophytes did not significantly render benefit to host plants as plant growth was compromised by the presence of metals. Lower production of indole-acetic acid (0.74-21.77 μg mL-1), siderophores (8.82-90.26%), and deaminase activities of 1-aminocyclopropane carboxylic acid (3.00-69.2 μmol mg protein-1 hr-1) were observed.


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