scholarly journals Trehalose induces tomato defenses and increases drought tolerance and bacterial wilt disease resistance

2021 ◽  
Author(s):  
April M MacIntyre ◽  
Valerian Meline ◽  
Zachary Gorman ◽  
Steven P Augustine ◽  
Carolyn J Dye ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Stomatal Conductance ◽  
Water Use ◽  
Bacterial Wilt ◽  
Xylem Sap ◽  
Wilt Disease ◽  
Tomato Plants ◽  
Bacterial Wilt Disease ◽  
Infected Tomato ◽  
Use Efficiency

Ralstonia solanacearum causes plant bacterial wilt disease, leading to severe crop losses. Xylem sap from R. solanacearum-infected tomato is enriched in host produced trehalose. Water stressed plants accumulate the disaccharide trehalose, which increases drought tolerance via abscisic acid (ABA) signaling networks. Because infected plants have reduced water flow, we hypothesized that bacterial wilt physiologically mimics drought stress, which trehalose could mitigate. Transcriptomic responses of susceptible vs. resistant tomato plants to R. solanacearum infection revealed differential expression of drought-associated genes, including those involved in ABA and trehalose metabolism. ABA was enriched in xylem sap from R. solanacearum-infected plants. Treating roots with ABA lowered stomatal conductance and reduced R. solanacearum stem colonization. Treating roots with trehalose increased ABA in xylem sap and reduced plant water use by reducing stomatal conductance and temporarily improving water use efficiency. Further, trehalose-treated plants were more resistant to bacterial wilt disease. Trehalose treatment also upregulated expression of salicylic acid (SA)-dependent defense genes, increased xylem sap levels of SA and other antimicrobial compounds, and increased wilt resistance of SA-insensitive NahG tomato plants. Additionally, trehalose treatment increased xylem concentrations of jasmonic acid and related oxylipins. Together, these data show that exogenous trehalose reduced both water stress and bacterial wilt disease and triggered systemic resistance. This suite of responses revealed unexpected linkages between plant responses to biotic and abiotic stress and suggests that that R. solanacearum-infected tomato plants produce more trehalose to improve water use efficiency and increase wilt disease resistance. In turn, R. solanacearum degrades trehalose as a counter-defense.

scholarly journals Revisiting the source of wilt symptoms: X-ray microcomputed tomography provides direct evidence that Ralstonia biomass clogs xylem vessels

2021 ◽  
Author(s):  
Brian Ingel ◽  
Denise Caldwell ◽  
Fiona Duong ◽  
Dilworth Y. Parkinson ◽  
Katherine A. McCulloh ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Light Microscopy ◽  
Bacterial Wilt ◽  
Xylem Sap ◽  
Physiological Mechanism ◽  
Bacterial Biomass ◽  
Microcomputed Tomography ◽  
Wilt Disease ◽  
X Ray ◽  
Bacterial Wilt Disease

AbstractPlant pathogenic Ralstonia cause wilt diseases by colonizing xylem vessels and disrupting water transport. Due to the abundance of Ralstonia cells in vessels, the dogma is that bacterial biomass clogs vessels and reduces the flow of xylem sap. However, the physiological mechanism of xylem disruption during bacterial wilt disease is untested. Using a tomato and Ralstonia pseudosolanacearum GMI1000 model, we visualized and quantified the spatiotemporal dynamics of xylem disruption during bacterial wilt disease. First, we measured stomatal conductance of leaflets on mock-inoculated and wilt-symptomatic plants. Wilted leaflets had reduced stomatal conductance, as did turgid leaflets located on the same petiole as wilted leaflets. Next, we used X-ray microcomputed tomography (X-ray microCT) and light microscopy to differentiate between mechanisms of xylem disruption: blockage by bacterial biomass, blockage by vascular tyloses, or sap displacement by gas embolisms. We imaged stems on plants with intact roots and leaves to quantify embolized vessels. Embolized vessels were rare, but there was a slight trend of increased vessel embolisms in infected plants with low bacterial population sizes. To test the hypothesis that vessels are clogged during bacterial wilt, we imaged excised stems after allowing the sap to evaporate during a brief dehydration. Most xylem vessels in mock-infected plants emptied their contents after excision, but non-conductive clogged vessels were abundant in infected plants by 2 days post infection. At wilt onset when bacterial populations exceeded 5×108 cfu/g stem tissue, approximately half of the xylem vessels were clogged with electron-dense bacterial biomass. We found no evidence of tyloses in the X-ray microCT reconstructions or light microscopy on the preserved stems. Bacterial blockage of vessels appears to be the principal cause of vascular disruption during Ralstonia wilt.

Disease Resistance Against a Broad-Host-Range Pathogen

2013 ◽  
Vol 14 (1) ◽  
pp. 32
Author(s):  
Jonathan M. Jacobs ◽  
Caitilyn Allen
Keyword(s):  
Disease Resistance ◽  
Host Range ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Pathogenic Bacteria ◽  
Resistance Breeding ◽  
Wilt Disease ◽  
Family Type ◽  
Broad Host Range ◽  
Bacterial Wilt Disease

The bacterial wilt pathogen Ralstonia solanacearum causes major agricultural losses on many crop hosts worldwide. Resistance breeding is the best way to control bacterial wilt disease, but the biological basis for bacterial wilt resistance is unknown. We found that R. solanacearum uses an AvrE-family, Type III-secreted effector called PopS to overcome plant defenses and cause disease on tomato. Orthologs of PopS are widely conserved across distinct classes of plant pathogenic bacteria and could provide novel, durable targets for resistance. Accepted for publication 25 September 2013. Published 25 November 2013.

scholarly journals Bacterial Tomato Pathogen Ralstonia solanacearum Invasion Modulates Rhizosphere Compounds and Facilitates the Cascade Effect of Fungal Pathogen Fusarium solani

2020 ◽  
Vol 8 (6) ◽  
pp. 806
Author(s):  
Lv Su ◽  
Lifan Zhang ◽  
Duoqian Nie ◽  
Eiko E. Kuramae ◽  
Biao Shen ◽  
...  
Keyword(s):  
Phenolic Acids ◽  
Bacterial Wilt ◽  
Fusarium Solani ◽  
Ralstonia Solanacearum ◽  
High Throughput Sequencing ◽  
Rhizosphere Soil ◽  
Wilt Disease ◽  
Tomato Plants ◽  
Bacterial Wilt Disease ◽  
Pathogen Invasion

Soil-borne pathogen invasions can significantly change the microbial communities of the host rhizosphere. However, whether bacterial Ralstonia solanacearum pathogen invasion influences the abundance of fungal pathogens remains unclear. In this study, we combined high-throughput sequencing, qPCR, liquid chromatography and soil culture experiments to analyze the rhizosphere fungal composition, co-occurrence of fungal communities, copy numbers of functional genes, contents of phenolic acids and their associations in healthy and bacterial wilt-diseased tomato plants. We found that R. solanacearum invasion increased the abundance of the soil-borne pathogen Fusarium solani. The concentrations of three phenolic acids in the rhizosphere soil of bacterial wilt-diseased tomato plants were significantly higher than those in the rhizosphere soil of healthy tomato plants. In addition, the increased concentrations of phenolic acids significantly stimulated F. solani growth in the soil. Furthermore, a simple fungal network with fewer links, nodes and hubs (highly connected nodes) was found in the diseased tomato plant rhizosphere. These results indicate that once the symptom of bacterial wilt disease is observed in tomato, the roots of the wilt-diseased tomato plants need to be removed in a timely manner to prevent the enrichment of other fungal soil-borne pathogens. These findings provide some ecological clues for the mixed co-occurrence of bacterial wilt disease and other fungal soil-borne diseases.

scholarly journals The linkage of SSR markers with bacterial wilt disease resistance in peanut

2016 ◽  
Vol 38 (2) ◽  
Author(s):  
Ngo Thi Thuy Linh ◽  
Nguyen Van Tru ◽  
Le Thi Bich Thuy ◽  
Nguyen Van Thang ◽  
Nguyen Thi Van ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Ssr Markers ◽  
Bacterial Wilt ◽  
Wilt Disease ◽  
Bacterial Wilt Disease

scholarly journals Activity test of Bacillus Spp against bacterial wilt (R. solanacearum) on tomatoes by in vitro

2021 ◽  
Vol 883 (1) ◽  
pp. 012027
Author(s):  
G N C Tuhumury ◽  
J V Hasinu ◽  
H Kesaulya
Keyword(s):  
Bacterial Wilt ◽  
Pathogenic Bacteria ◽  
Wilt Disease ◽  
Tomato Plants ◽  
Bacterial Wilt Disease ◽  
Activity Test ◽  
Resistant Varieties ◽  
Bacillus Spp ◽  
Chemical Pesticides

Abstract Ralstonia solanocearum is a pathogenic bacteria that attacks tomatoes and causes wilt disease. Many efforts have been made to control this disease through cultivation, use of chemical pesticides, and development of resistant varieties, but bacterial wilt disease remains a serious problem economically. Nowadays, many biological controls are being developed using microbes. The use of Bacillus spp as an unfriendly microbe is very potential to control because it has pathogenic inhibitory activity. This study aims to obtain bacterial isolates of Bacillus spp which can suppress the development of bacterial wilt disease in tomato plants. The research was conducted in vitro at the Laboratory of Plant Physiology in the Agriculture Faculty, Unpatti. The results showed that Bacillus niabensis strain PT-32-1 and Bacillus subtilis strain SW116b could inhibit Ralstonia solanacearum, wilt disease in tomato plants in vitro.

scholarly journals Potensi Cendawan Endofit dari Bunga Bawang Dayak untuk Menekan Pertumbuhan Ralstonia solanacearum pada Tanaman Tomat

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Putri Wulan Cahyani ◽  
Noor Laili Aziza ◽  
Yusriadi Marsuni
Keyword(s):  
Biological Control ◽  
Growth Rate ◽  
Endophytic Fungi ◽  
Bacterial Wilt ◽  
Wilt Disease ◽  
Plant Diseases ◽  
Tomato Plants ◽  
Bacterial Wilt Disease ◽  
Randomized Design ◽  
Completely Randomized Design

Cultivation of tomato plants (Lycopesicum esculentum Mill.) Is often exposed to plant diseases. One of the diseases that often attacks tomato plants is bacterial wilt disease caused by R. solanacearum. Therefore, it is necessary to have biological control with the application of an antagonistic agent, namely the provision of endophytic fungi from dayak onion flowers. This study aims to determine the types of endophytic fungi in dayak onion flowers and to determine the potential of endophytic fungi in suppressing the growth of R. solanacearum. This research was conducted from February to May 2020, taking samples of dayak onion flowers in the Experimental Field of the Faculty of Agriculture and samples of symptomatic tomato plants on the Karang Anyar Farmer Group's land then continued with isolation, purification, identification, and antagonistic testing at the Production Laboratory of the Faculty of Agriculture, Lambung Mangkurat University, Banjarbaru. The method used in this study was a one-factor completely randomized design (CRD) with nine treatments, namely C1 = endophytic fungi A + R. solanacearum, C2 = endophytic fungi B + R. solanacearum, C3 = endophytic fungi F + R. solanacearum, C4 = endophytic fungi G + R. solanacearum, C5 = endophytic fungi I + R. solanacearum, C6 = endophytic fungi J + R. solanacearum, C7 = endophytic fungi K + R. solanacearum, C8 = fungi endophytic N + R. solanacearum, and C9 = endophytic fungi P + R. solanacearum and repeated three times. This study used a comparison, namely control with three replications, in order to obtain 30 experimental units. The results of this study that endophytic fungi from dayak onion flowers have the potential to suppress the growth of R. solanacearum. Based on the research, there were 17 endophytic fungi from dayak onion flowers with nine endophytic fungi which had the fastest growth rate of radius. Fungi with the genus Colletotrichum sp., Mucor sp., and Papulaspora sp. has the potential to suppress the growth of R. solanacearum with moderate to strong percentage of inhibition.

scholarly journals Sustainable Management of Soil-Borne Bacterium Ralstonia solanacearum In Vitro and In Vivo through Fungal Metabolites of Different Trichoderma spp.

2021 ◽  
Vol 13 (3) ◽  
pp. 1491
Author(s):  
Yancui Guo ◽  
Zhenyu Fan ◽  
Xiong Yi ◽  
Yuhong Zhang ◽  
Raja Asad Ali Khan ◽  
...  
Keyword(s):  
Bacterial Wilt ◽  
Bacterial Population ◽  
Sem Analysis ◽  
Wilt Disease ◽  
Fungal Metabolites ◽  
Trichoderma Spp ◽  
Tomato Plants ◽  
Bacterial Wilt Disease

The efficacy of traditional control measures for the management of plant pathogens is decreasing, and the resistance of these pathogens to pesticides is increasing, which poses a serious threat to global food security. The exploration of novel and efficient management measures to combat plant disease is an urgent need at this time. In this study, fungal metabolites from three Trichoderma spp. (T. harzianum, T. virens and T. koningii) were prepared on three different growth media (STP, MOF and supermalt (SuM)). The fungal metabolites were tested in vitro and in vivo from March–April 2020 under greenhouse conditions in a pot experiment utilizing completely randomized design to test their management of the bacterial wilt disease caused by R. solanacearum in tomato plants. The effect of the fungal metabolites on bacterial cell morphology was also investigated through scanning electron microscopy (SEM) analysis. In vitro investigation showed that the fungal metabolites of T. harzianum obtained on the STP medium were the most effective in inhibiting in vitro bacterial growth and produced a 17.6 mm growth inhibition zone. SEM analysis confirms the rupture of the cell walls and cell membranes of the bacterium, along with the leakage of its cell contents. Generally, fungal metabolites obtained on an STP medium showed higher activity than those obtained on the other two media, and these metabolites were then evaluated in vivo according to three application times (0 days before transplantation (DBT), 4 DBT and 8 DBT) in a greenhouse trial to examine their ability to manage R. solanacearum in tomato plants. Consistent with in vitro results, the results from the greenhouse studies showed a level of higher anti-bacterial activity of T. harzianum metabolites than they did for the metabolites of other fungi, while among the three application times, the longest time (8 DBT) was more effective in controlling bacterial wilt disease in tomato plants. Metabolites of T. harzianum applied at 8 DBT caused the maximum decrease in soil bacterial population (1.526 log cfu/g), resulting in the lowest level of disease severity (area under disease progressive curve (AUDPC) value: 400), and maximum plant freshness (with a resulting biomass of 36.7 g, a root length of 18.3 cm and a plant height of 33.0 cm). It can be concluded that T. harzianum metabolites obtained on an STP medium, when applied after 8 DBT, can suppress soil bacterial population and enhance plant growth, and thus can be used as a safe, environmentally-conscious and consumer-friendly approach to managing bacterial wilt disease in tomato plants and possibly other crops.

scholarly journals Rhizobacterial community structure in grafted tomato plants infected by Ralstonia solanacearum

2020 ◽  
Vol 21 (10) ◽  
Author(s):  
Lisa Navitasari ◽  
TRI JOKO ◽  
RUDI HARI MURTI ◽  
TRIWIDODO ARWIYANTO
Keyword(s):  
Community Structure ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Wilt Disease ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Distinct Region ◽  
Tomato Plants ◽  
Bacterial Wilt Disease ◽  
Significant Difference

Abstract. Navitasari L, Joko T, Murti RH, Arwiyanto T. 2020. Rhizobacterial community structure in grafted tomato plants infected by Ralstonia solanacearum. Biodiversitas 21: 4888-4895. Bacterial wilt disease caused by Ralstonia solanacearum is a devastating soil-borne vascular disease of tomato leading to a 100% yield loss. One of the alternatives to suppress the infestation of R. solanacearum infestation is the application of grafting techniques, which has been studied and successfully practiced by tomato growers. However, the infestation mode of R. solanacearum and the rhizobacterial community structure in grafted tomato plants are poorly reported. In this study, the rhizobacterial community structure in grafted tomato plants infected by R. solanacearum was investigated. The experiment was conducted on tomato germplasms with the implementation of tube grafting using resistant rootstocks (Amelia from Indonesia, H.7996 from Asian Vegetable Research Development Center/AVRDC) and susceptible scion (Servo from Indonesia). The rhizobacterial community structure was analyzed by metagenomic study under 16S rRNA genes sequencing with a distinct region (16SV3-V4) that was amplified using a specific primer (16SV4: 515F-806R) 5’-GTGCCAGCMGCCGCGGTAA and 5’GGACTACHVHHHTWTCTAAT. The results indicated that the grafted tomato plants and resistant rootstocks that were infected by R. solanacearum showed significantly lower intensity of bacterial wilt disease compared to the susceptible scion. The rhizobacterial community structure in the grafted tomato plants infected by R. solanacearum was indicated by predominant phyla of Proteobacteria, Firmicutes, and Actinobacteria with dominant genera of Pseudomonas and Bacillus. Besides, significant difference was also indicated by species of Geitlerinema sp. in the grafted tomatoes infected by R. solanacearum.

scholarly journals Trehalose Synthesis Contributes to Osmotic Stress Tolerance and Virulence of the Bacterial Wilt Pathogen Ralstonia solanacearum

2020 ◽  
Vol 33 (3) ◽  
pp. 462-473 ◽  
Author(s):  
April M. MacIntyre ◽  
John X. Barth ◽  
Molly C. Pellitteri Hahn ◽  
Cameron O. Scarlett ◽  
Stéphane Genin ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Type Strain ◽  
Wild Type Strain ◽  
Xylem Sap ◽  
Wilt Disease ◽  
Wild Type ◽  
Tomato Plants ◽  
Trehalose Synthesis

The xylem-dwelling plant pathogen Ralstonia solanacearum changes the chemical composition of host xylem sap during bacterial wilt disease. The disaccharide trehalose, implicated in stress tolerance across all kingdoms of life, is enriched in sap from R. solanacearum–infected tomato plants. Trehalose in xylem sap could be synthesized by the bacterium, the plant, or both. To investigate the source and role of trehalose metabolism during wilt disease, we evaluated the effects of deleting the three trehalose synthesis pathways in the pathogen: TreYZ, TreS, and OtsAB, as well as its sole trehalase, TreA. A quadruple treY/treS/otsA/treA mutant produced 30-fold less intracellular trehalose than the wild-type strain missing the trehalase enzyme. This trehalose-nonproducing mutant had reduced tolerance to osmotic stress, which the bacterium likely experiences in plant xylem vessels. Following naturalistic soil-soak inoculation of tomato plants, this triple mutant did not cause disease as well as wild-type R. solanacearum. Further, the wild-type strain out-competed the trehalose-nonproducing mutant by over 600-fold when tomato plants were coinoculated with both strains, showing that trehalose biosynthesis helps R. solanacearum overcome environmental stresses during infection. An otsA (trehalose-6-phosphate synthase) single mutant behaved similarly to ΔtreY/treS/otsA in all experimental settings, suggesting that the OtsAB pathway is the dominant trehalose synthesis pathway in R. solanacearum.

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