Sarocladium Oryzae Research Articles

Effectiveness of Bacteria Isolated from Peat Swamp Forests to Control Rice Dirty Panicle Fungi in Thailand

Rice dirty panicle disease is one of the most important problems in Thailand. The fungal pathogens were reported to be many species including Curvularia lunata, Bipolaris oryzae, Fusarium incarnatum, Sarocladium oryzae, Trichoconis padwickii and Cercospora oryzae. Biological control is an alternative method for controlling this disease and reducing the application of fungicides. Therefore, this study aimed to evaluate the antagonistic potential of bacteria isolated from peat swamp forests in Thailand. A total of 513 bacterial isolates were collected and screened in the laboratory using the dual culture method. The results revealed that three of the 513 bacterial strains (IBK-4, IBK-8 and IBK-5) were highly inhibitory to the fungal pathogens including C. lunata, B. oryzae and F. incarnatum. These three strains were identified as Bacillus (IBK-4 and IBK-8) and Brevibacillus (IBK-5) based on 16S rRNA sequencing. Then, these three strains were evaluated on a susceptible rice variety by inoculation with three fungal pathogens. The results indicated that Bacillus strain IBK-8 had the highest efficiency to control the disease development as observed in the disease severity and index. The results of this study indicated that bacterial strains from peat swamp forests have the potential to be antagonistic to plant pathogens.

Combination on endophytic fungal as the Plant Growth-Promoting Fungi (PGPF) on cucumber (Cucumis sativus)

Abstract. Syamsia S, Idhan A, Firmansyah AP, Noerfitryani N, Rahim I, Kesaulya H, Armus R. 2021. Combination on endophytic fungal as the Plant Growth-Promoting Fungi (PGPF) on Cucumber (Cucumis sativus). Biodiversitas 22: 1194-1202. Endophytic fungi are known to stimulate plant growth by producing secondary metabolites, including phytohormones (IAA and Gibberellins), siderophore, phosphate-solubilizing metabolites. In this study, a total of six endophytic fungi were successfully isolated from local rice plants and showed different abilities in producing secondary metabolites, during single isolates testing. These six isolates were then combined to obtain 15 combinations for analysis, to determine the best combination for application as a plant growth promoter. Subsequently, each combination was tested for phytohormones (IAA, gibberellins) and siderophore (quantitatively)-producing activity, phosphate-solubilizing ability, and the effect on cucumber (Cucumis sativus L) plant growth. F13 showed activity in producing IAA and produced the highest gibberellin levels, while F1 exhibited the highest phosphate-solubilizing activity. In addition, F11 (Na-salicylate) and F1 (catechol) showed the highest siderophore activity, while a combination of F6, F8, F9, and F12 successfully increased plant height growth. Also, F4 increased the root growth, while the fresh weight of cucumber was increased by F8 treatment, under controlled conditions. Molecular analysis showed the tested isolates have close similarity to Daldinia eschscholtzii, Sarocladium oryzae, Rhizoctonia oryzae, Penicillium allahabadense, and Aspergillus foetidus. The combination of endophyte fungal isolates showed potential as plant growth promoters, however, further testing on several plant types is required before the combination is to be widely applied.

Genetic diversity of the pathogenic fungus Sarocladium oryzae causing sheath rot on rice using rep-PCR

Rice becomes the main commodity cultivated in Asia. Sheath rot disease becomes one of the challenges in increasing rice production. Sarocladium oryzae is known to be one of the major pathogens in causing sheath rot disease. This pathogen has been reported in several rice production countries, such as Brazil, India, Taiwan, Philippines, Thailand, including Indonesia, and causing yield loss of up to 85%. The study of genetic diversity is important to investigate the rapid shift in genetic structures. A total of six S. oryzae strains showed diverse in molecular using repetitive-PCR (rep-PCR). The isolate SO8 and SO13 isolate SO2 and SO11 and isolate SO3, and SO5 has the relatively same the band patterns in BOX, ERIC, and REP sets of primers. The results of the UPGMA analysis show that S. oryzae in the various primers can be divided into three different group consistency. This result indicates that the rep-PCR method can genetically distinguish S. oryzae. The use of the three main sets, BOX, ERIC, and REP, suggested differentiating the other fungal species.

Fungicidal Activity of Volatile Organic Compounds Emitted by Burkholderia gladioli Strain BBB-01.

A Burkholderia gladioli strain, named BBB-01, was isolated from rice shoots based on the confrontation plate assay activity against several plant pathogenic fungi. The genome of this bacterial strain consists of two circular chromosomes and one plasmid with 8,201,484 base pairs in total. Pangenome analysis of 23 B. gladioli strains suggests that B. gladioli BBB-01 has the closest evolutionary relationship to B. gladioli pv. gladioli and B. gladioli pv. agaricicola. B. gladioli BBB-01 emitted dimethyl disulfide and 2,5-dimethylfuran when it was cultivated in lysogeny broth and potato dextrose broth, respectively. Dimethyl disulfide is a well-known pesticide, while the bioactivity of 2,5-dimethylfuran has not been reported. In this study, the inhibition activity of the vapor of these two compounds was examined against phytopathogenic fungi, including Magnaporthe oryzae, Gibberella fujikuroi, Sarocladium oryzae, Phellinus noxius and Colletotrichum fructicola, and human pathogen Candida albicans. In general, 2,5-dimethylfuran is more potent than dimethyl disulfide in suppressing the growth of the tested fungi, suggesting that 2,5-dimethylfuran is a potential fumigant to control plant fungal disease.

Efficiency of a new Waitea circinata extract against rice pathogens

ABSTRACT Waitea circinata (Warcup & Talbot) is an orchid antagonist mycorrhizal fungus with biocontrol potential against rice pathogens. This study aimed to optimize the extraction method, obtain a new extract and evaluate its efficiency against rice pathogens in vitro and in vivo, as well as to compare it with other extraction methods and W. circinata. The extracts were obtained and screened for in vitro growth inhibition against the pathogens Cochliobolus miyabeanus, Monographella albescens and Sarocladium oryzae, using the following extracts: mycelial, crude, lyophilized and mycelial mass. An additional in vitro assay was performed with the principal rice pathogen (Magnaporthe oryzae), in order to evaluate the conidial germination and appressorium formation. Based on this evaluation, the lyophilized and mycelial mass extracts were tested in vivo against rice blast (M. oryzae) and compared to the W. circinata mycelial suspension, in different application forms (simultaneous and previous). The mycelial mass extract inhibited all the pathogens, and the crude and lyophilized extracts inhibited C. miyabeanus and M. albescens, respectively. The mycelial mass extract inhibited the M. oryzae conidial germination and appressorium formation by 80 %, and the simultaneous and previous applications suppressed the rice blast by 94 %. These results indicate that the new extract can be used to control rice pathogens.

Survival of the fittest: how the rice microbial community forces Sarocladium oryzae into pathogenicity.

The fungus Sarocladium oryzae (Sawada) causes rice sheath rot and produces the phytotoxins cerulenin and helvolic acid. Both toxins show antimicrobial activity but only helvolic acid production in the rice sheath correlates with virulence. Sarocladium oryzae isolates that differ in their toxin production were used to study their interaction with the rice culturable bacterial endophyte community. The diversity and community structure was defined in the edge of sheath rot lesions, followed by a null model-based co-occurrence analysis to discover pairwise interactions. Non-random pairs were co-cultured to study the nature of the interactions and the role of the toxins herein. Compared to healthy sheaths, endophyte diversity strongly increased when infected with the least virulent S. oryzae isolates producing low amounts of toxins. Virulent S. oryzae isolates did not affect diversity but caused strong shifts in species composition. The endophyte community of healthy rice plants was dominated by B. cereus. This bacterium was enriched in lesions produced by low-virulent S. oryzae isolates and caused hyphal lysis. Contrarily, helvolic acid producers eliminated this bacterium from the sheath endosphere. We conclude that S. oryzae needs to produce antibiotics to defend itself against antagonistic rice endophytes to successfully colonize and infect the rice sheath.

Screening of Rice Germplasms for Their Resistance against Sheath Rot Disease (Sarocladium oryzae) at Fogera, Ethiopia

Sheath rot of rice, Sarocladium oryzae [(Sawada) W. Gams & D. Hawksw], is currently regarded as one of the most serious rice diseases in Fogera plains. Varietal resistance is the most cost-effective and eco-friendly management strategy for the small-scale farmers. An investigation was conducted to identify resistant sources among rice germplasm introductions that could be employed in varietal development program. Eighty germplasms along four checks were evaluated in field trials for two years at two locations arranged in an augmented design. Results indicated that three immune germplasms (SCRID014-1-1-1-1, SCRID037-4-2-2-5-2 and YUNLU N0.33) were found to be suitable for resistant variety development. The remaining, germplasms were found to exhibit different levels of reactions, of which 27 resistant, 35 moderately resistant, 13 moderately susceptible and two susceptible, with PSI ranging between 1.48–56.17%. The immune germplasms perform better than the standard check varieties in all agronomic and phenological traits considered. Based on these results, the high yielder immune germplasms could be used to develop resistant varieties so as to meet the farmers’ requirement, as far as rice production is concerned.

Pathobiomes Revealed that Pseudomonas fuscovaginae and Sarocladium oryzae Are Independently Associated with Rice Sheath Rot.

Rice sheath rot has been mainly associated with the bacterial pathogen Pseudomonas fuscovaginae and in some cases to the fungal pathogen Sarocladium oryzae; it is yet unclear if they are part of a complex disease. The bacterial and fungal community associated with rice sheath rot symptomatic and asymptomatic rice plants was determined/studied with the main aim to shed light on the pathogen(s) causing rice sheath rot. Plant samples were collected from different rice varieties in two locations (highland and lowland) in two rice-growing seasons (wet and dry season) in Burundi. Our results showed that the bacterial Pseudomonas genus was prevalent in highland in both rice-growing seasons and was not affected by rice plant varieties. Pseudomonas sequence reads displayed a significant high similarity to Pseudomonas fuscovaginae indicating that it is the causal agent of rice sheath rot as previously reported. The fungal Sarocladium genus was on the other hand prevalent in lowland only in the wet season; the sequence reads were most significantly similar to Sarocladium oryzae. These studies showed that plant microbiome analysis is very useful in determining the microorganisms involved in a plant disease. P. fuscovaginae and S. oryzae were prevalent in symptomatic samples in highland and lowland respectively being present independently and hence are not part of a complex disease. The significant presence of other bacterial and fungal taxa in symptomatic samples is also discussed possibly making this disease more complex. Finally, we also report the microbial communities that are associated with the plant sheath in symptomatic and asymptomatic plants from the same rice fields.

Effect of Organic Amendments, Biofertilizer Consortia and Microbial Antagonists on the Survival of Sheath Rot Pathogen (Sarocladium oryzae (sawada) Gams and Hawksw

Effect of Organic Amendments, Biofertilizer Consortia and Microbial Antagonists on the Survival of Sheath Rot Pathogen (Sarocladium oryzae (sawada) Gams and Hawksw

Short Communication: Sarocladium oryzae associated with sheath rot disease of rice in Indonesia

Abstract. Pramunadipta S, Widiastuti A, Wibowo A, Suga H, Priyatmojo A. 2020. Short Communication: Sarocladium oryzae associated with sheath rot disease of rice in Indonesia. Biodiversitas 21: 1243-1249. One of the obstacles in increasing rice production is the presence of sheath rot pathogen infection, which causes changes in color on the rice sheath to brown or reddish-brown, sometimes does not produce rice grain. The major fungal pathogens that cause sheath rot disease are Sarocladium oryzae and Fusarium spp. The loss of rice yields reaches 85%. The disease found in six provinces, some of which are the largest rice-producing centers in Indonesia. A total of twenty-four Sarocladium sp. were isolated from leaf sheath symptom on potato dextrose agar and water agar medium. Sheath rot pathogen identification based on molecular method was performed using internal transcribed spacer (ITS) rDNA gene sequencing. Necrosis occurs after artificial inoculation in Ciherang rice variety was observed and showed that all isolates were pathogenic. Morphological characterization of the isolates identified them as Sarocladium sp. Molecular identification showed that six representatives isolates belonging to S. oryzae. These findings are important information about the fungal pathogen that causes sheath rot disease in Indonesia, and in studies for formulating control measures of the pathogen in the future to prevent the disease epidemic on rice. This is the first report about the existence of sheath rot disease, morphological characterization and molecular identification of S. oryzae in various rice fields in Indonesia.

Morphological, Pathogenic and Toxigenic Variability in the Rice Sheath Rot Pathogen Sarocladium Oryzae.

Sheath rot is an emerging rice disease that leads to considerable yield losses. The main causal agent is the fungus Sarocladium oryzae. This pathogen is known to produce the toxins cerulenin and helvolic acid, but their role in pathogenicity has not been clearly established. S. oryzea isolates from different rice-producing regions can be grouped into three phylogenetic lineages. When grown in vitro, isolates from these lineages differed in growth rate, colour and in the ability to form sectors. A diverse selection of isolates from Rwanda and Nigeria, representing these lineages, were used to further study their pathogenicity and toxin production. Liquid chromatography high-resolution mass spectrometry analysis was used to measure cerulenin and helvolic acid production in vitro and in planta. The three lineages clearly differed in pathogenicity on the japonica cultivar Kitaake. Isolates from the least pathogenic lineage produced the highest levels of cerulenin in vitro. Helvolic acid production was not correlated with the lineage. Sectorisation was observed in isolates from the two least pathogenic lineages and resulted in a loss of helvolic acid production. In planta, only the production of helvolic acid, but not of cerulenin, correlated strongly with disease severity. The most pathogenic isolates all belonged to one lineage. They were phenotypically stable, shown by the lack of sectorisation, and therefore maintained high helvolic acid production in planta.

Morphological characterization of seed-borne fungi associated with BRRI rice varieties in Bangladesh

Twenty five fungal species, representing 13 genera were found to be associated with seeds of 20 varieties of rice (BRRI dhan 56 to BRRI dhan 75). Fungi were isolated following "Tissue planting" method and "Blotter method". The isolated fungi were Alternaria alternata, A. tenuissima, Aspergillus flavus, A. fumigatus, A. niger, A. ochraceus, A. terreus, Bipolaris multiformis, B. oryzae, B. sorokiniana, Chaetomium globosum, Curvularia lunata, Fusarium equiseti, F. fugikuroi, F. oxysporum, F. proliferatum, Microdochium fisheri, Nigrospora oryzae, Penicillium sp., Pestalotiopsis oxyanthi, Phanerochaete chrysosporium, Rhizopus stolonifer, Sarocladium oryzae, Syncephalastrum racemosum and Trichoderma viride.
 Dhaka Univ. J. Biol. Sci. 29(1): 75-86, 2020 (January)

Endophytic plant growth promoting bacteria (EPGPB) for the management of sheath rot of rice caused by Sarocladium oryzae

Endophytic plant growth promoting bacteria (EPGPB) for the management of sheath rot of rice caused by Sarocladium oryzae

Sarocladium species associated with rice in Taiwan

Sarocladium oryzae is a common plant pathogen causing rice sheath rot worldwide. Sarocladium attenuatum has been identified as one of the causal agents of rice sheath rot and was synonymized under S. oryzae. The analysis of 102 Sarocladium strains associated with rice in Taiwan, based on morphological features and multilocus molecular phylogeny, reveals that these two species are distinct and that two other species, S. sparsum sp. nov. and S. spirale sp. nov., can be identified. Sarocladium sparsum is phylogenetically closely related to S. attenuatum and S. oryzae and causes the same disease symptom in pathogenicity tests. Sarocladium spirale, a sister taxon of S. hominis and S. spinificis, is not pathogenic to rice. All strains of S. attenuatum and some S. sparsum strains show fluorescence emission ability under 365-nm UV light, while S. oryzae does not.

Molecular characterization of Sarocladium oryzae isolates causing sheath rot in paddy (Oryza sativa)

Sheath rot, caused by Sarocladium oryzae (Sawada) W. Gams & D. Hawksw, is an important seed borne fungal disease of paddy (Oryza sativa L.). In the present investigation, diseased specimens were collected in kharif 2016 and 2017 from more than 55 different geographical locations spread across 15 states of the country and variability in 30 isolates of Sarocladium oryzae was studied by molecular methods. The molecular characterization using two marker systems, i.e. Inter-Simple Sequence Repeat (ISSR) and Random Amplified Polymorphic DNA (RAPD) was carried out which revealed differences in isolates collected from different geographical locations. After preliminary screening, out of 22 ISSR and 24 RAPD primers, 8 ISSR and 7 RAPD primers were used against all the isolates. Percent polymorphic ranging between 53.1–100% in ISSR and 61.4–100% in RAPD was recorded with all the isolates. The average number of bands in ISSR markers was 63.3, and 71.8 in RAPD markers. All RAPD primers showed 100% polymorphism except OPS13 (61.4%) and OPD5 (74%). Among ISSR primers ISSR5 and ISSR18 showed 100% polymorphism. Cluster analysis of individual and combined primers was done. In the combined cluster analysis of RAPD and ISSR markers, the isolates from same geographical region were in same cluster as evident from the cluster I that includes Kadapa, Ragolu, Maruteru, West Godavari and Adutharai, which are from southern plain region of the country. Similar observations were recorded when data analysis of individual marker system was carried out which revealed that the two different marker systems applied complement each other in characterizing various isolates.

Extending the Metabolite Diversity of the Endophyte Dimorphosporicola tragani.

Fungi are one of the most prolific sources of microbial secondary metabolites. The production of new metabolites can be achieved using multiple fermentation conditions and by adding small-molecule effectors, including epigenetic modifiers. In the framework of our Natural Product screening programme targeting the discovery of new antimicrobial compounds, we applied multiple fermentation conditions and adsorptive polymeric resins on a large collection of fungal endophytes, to increase and stimulate their fungal secondary metabolite production. During this work the endophytic fungus Dimorphosporicola tragani CF-090383 showed antimicrobial activity only when grown in presence of adsorptive polymeric resins. In addition, seven epigenetic modifiers were added to fermentations of this endophytic fungus, in an attempt to activate its cryptic pathways as well as to analyse the metabolites produced under these conditions. D. tragani was seen to produce three different mycotoxin dendrodolides when the epigenetic modifiers 5-azacytidine and valproic acid were added to the fermentations, and these compounds were further characterized. However, the fungus produced the fatty acid synthesis inhibitor cerulenin, a molecule not previously described to be produced by this fungal species, only when cultivated in presence of the XAD-16 resin. We have found that the addition of XAD-16 resin resulted in four-fold higher titers in the production of cerulenin when compared to the best production conditions described in literature for the original fungal producer strain, Cephalosporium caerulens KF-140 (=Sarocladium oryzae), in a zeolite-based fermentation, used as an ammonium ion-trapping agent. The production of cerulenin by this strain of D. tragani, represents an alternative source for the improved production of cerulenin with better yields.

Potassium deficiency aggravates yield loss in rice by restricting the translocation of non-structural carbohydrates under Sarocladium oryzae infection condition.

Sheath rot disease (ShR) caused by Sarocladium oryzae (S. oryzae) infection is an emerging disease that causes severe yield loss by restricting the translocation of non-structural carbohydrates (NSC). Potassium (K) nutrition plays a critical role in disease resistance and the exportation of NSC. However, the physiological mechanisms of K with respect to ShR have not been thoroughly elucidated to date. The objectives of this study were to reveal the mechanisms by which K increases ShR resistance by regulating NSC translocation of rice, therefore, a field experiment combined with an inoculation experiment was conducted. We demonstrate that ShR disease incidence and disease index decreased dramatically with an increasing K application. K deficiency sharply induced the accumulation of NSC in the flag leaf (FL) and flag leaf sheath (FLS) under S. oryzae infection condition, which reduced the contribution of transferred NSC to final yield. A permutational multivariate analysis showed that K deficiency had a greater (49.0%, P <0.001) effect on the NSC content variation in FL than that of S. oryzae infection (15.0%, P <0.001). S. oryzae infection dramatically increased the difference in apparent transferred mass of NSC and cell membrane injury of diseased organs between K-deficient and K-sufficient rice. Finally, we demonstrate that cell membrane injury was a limiting factor imposed by K deficiency, which restricts the export of NSC from source organs. This work highlights the importance of K in improving ShR resistance by regulating NSC translocation (particularly the stem NSC).

Seed Health and Quality of Rice Seeds Produced by Farmer and Growing in Cho Moi District, An Giang Province, Vietnam

This study was conducted at Laboratory in An Giang University; the varieties examined were collected from farmer households in 2018 – they were varieties that the farmer stored for the next crop (Winter-Spring) from Autumn-Winter crop in Cho Moi district, An Giang Province, Vietnam. The research evaluated the quality of seed rice, which is provided and planted by the farmer. As a result, this study showed that almost all of the varieties of seed rice from farmer households indicated the ratio of filled-grain, the germination, and the determination of seedling healthy, which are lower than certified variation. Besides, the samples of seed rice from farmer household have more infected fungal; especially the samples with higher in a filled-grain ratio is less infected by fungi, there were 12 types of seed borne-fungi in rice varieties from the farmer (in Cho Moi district), included: Alternaria padwickii, Rhizoctonia solani, Aspergillus oryzae, Bipolaris oryzae, Cercospora janseana, Curvularia lunata, Fusarium moniliforme, Pyricularia oryzae, Sarocladium oryzae, Tilletia barclayana, Fusarium graminearum, and Ustilaginoidea virens

Combination of different marine algal extracts as biostimulant and biofungicide

ABSTRACTThis study investigates the efficiency of seaweed liquid fertilizer (SLF) prepared from combinations of different seaweeds (Sargassum polyphyllum, Turbinaria ornata, Gelidiopsis sp., Padina tetrastomatica, Gracilaria corticata) as a stimulant for the growth of Vigna radiata (Mung) as well as its antagonistic activity against fungal pathogens (Alternaria solani, Rhizoctonia solani., Sarocladium oryzae). 100% SLF was prepared, which was further diluted to 60%, 40%, and 20%. Seeds were soaked in four different concentrations of the SLF (20%, 40%, 60%, and 100%) for 12 hr and planted. After 60 d, the root and shoot length were increased by 14% and 16%, respectively, with SLF (100%). The carbohydrate and protein concentrations were also increased by 70% and 86%, respectively, at 100% SLF. The concentration of chlorophyll a, chlorophyll b, and carotenoids were found to be increased by 20%, 43%, and 28%, respectively, with 100% SLF. Further, the SLF (60% and 100%) successfully inhibited the growth of fungal pathogen A. solani but the other tested strains were found to be resistant. The present study indicates that 100% SLF concentration acts as both biostimulant and biofungicide for A. solani and thus, this SLF could be used as a potential alternative to the chemical fertilizers.

Molecular characterization of Sarocladium oryzae (Sawada) through RAPD technique: causal agent of sheath rot disease of Rice

Sarocladium oryzae isolates were characterized on various culture media, pathogenic virulence on susceptible variety and genetic variability by Random Amplified Polymorphic DNA (RAPD) technique. The radial growth of Sarocladium isolates was non-significantly differing on Potato Dextrose Agar (PDA) medium followed by Kirchhoffs medium. For the pathogenic virulence estimation, the maximum lesion length was recorded with isolates SR-8 (7.86cm). For genetic variability detection among the isolated Sarocladium isolates, it was recorded that in RAPD analysis, a total 23 bands appeared during gel electrophoresis and of those 17 bands were polymorphic and 6 bands were monomorphic pattern. The size of the amplicons was obtained and ranged from 100bp (minimum) to 2000bp (maximum). The phylogenetic tree/dendogram was prepared using NT-SYS software version 2.11W version. It separated Sarocladium isolates into two major clusters. Cluster I was comprised of 16 isolates except 2 isolates (SR-1 & SR-2). Average Polymorphic Information Content (PIC) value was calculated 0.161 and recorded that there is no much variation in isolated Sarocladium isolates. This research activity was done to find out genetic variability of the sheath rot causing fungus (Sarocladium oryzae) so that it may be used for rice improvement programme, economic and sustainable disease management strategies.