Glucanase Gene Research Articles

Complete genome sequence of the acidic cellulase producer Bacillus amyloliquefaciens ATC6

Here we report the complete genome sequence of Bacillus amyloliquefaciens ATC6, which produces acidic cellulase, isolated from pig feces. The genome is 4,062,817 bp in length and has a guanine-cytosine (GC) content of 46.27%. Among the predicted 3,913 protein-coding genes, two glucanase genes, which are involved in lichenan and cellulose degradation, were found. This genome analysis helps clarify the mechanism involved in cellulose biodegradation and support its application for efficient use of livestock feeds.

Sugar-regulated susceptibility of tomato fruit to Colletotrichum and Penicillium requires differential mechanisms of pathogenicity and fruit responses.

Colletotrichum gloeosporioides and Penicillium expansum cause postharvest diseases in tropical and deciduous fruit. During colonization, C. gloeosporioides and P. expansum secrete ammonia in hosts with low sugar content (LowSC) and gluconic acid in hosts with high sugar content (HighSC), respectively, as a mechanism to modulate enhanced pathogenicity. We studied the pathogens interactions with tomato lines of similar genetic background but differing in their sugar content. Colletotrichum gloeosporioides showed enhanced colonization of the LowSC line with differential expression response of 15% of its genes including enhanced relative expression of glycosyl hydrolases, glucanase and MFS-transporter genes. Enhanced colonization of P. expansum occurred in the HighSC line, accompanied by an increase in carbohydrate metabolic processes mainly phosphoenolpyruvate carboxykinase, and only 4% of differentially expressed genes. Gene response of the two host lines strongly differed depending on the sugar level. Limited colonization of HighSC line by C. gloeosporioides was accompanied by a marked alteration of gene expression compared the LowSC response to the same pathogen; while colonization by P. expansum resulted in a similar response of the two different hosts. We suggest that this differential pattern of fungal/host responses may be the basis for the differential of host range of both pathogens in nature.

Comparative transcriptomic analyses of powdery mildew resistant and susceptible cultivated cucumber (Cucumis sativus L.) varieties to identify the genes involved in the resistance to Sphaerotheca fuliginea infection.

BackgroundCucumber (Cucumis sativus L.) is a widely cultivated vegetable crop, and its yield and quality are greatly affected by various pathogen infections. Sphaerotheca fuliginea is a pathogen that causes powdery mildew (PM) disease in cucumber. However, the genes involved in the resistance to PM in cucumber are largely unknown.MethodsIn our study, a cucumber PM resistant cultivated variety “BK2” and a susceptible cultivated variety “H136” were used to screen and identify differential expressed genes (DEGs) under the S. fuliginea infection.ResultsThere were only 97 DEGs between BK2 and H136 under the control condition, suggesting a similarity in the basal gene expression between the resistant and susceptible cultivated varieties. A large number of hormone signaling-related DEGs (9.2% of all DEGs) between resistant and susceptible varieties were identified, suggesting an involvement of hormone signaling pathways in the resistance to PM. In our study, the defense-related DEGs belonging to Class I were only induced in susceptible cultivated variety and the defense-related DEGs belonging to Class II were only induced in resistant cultivated variety. The peroxidase, NBS, glucanase and chitinase genes that were grouped into Class I and II might contribute to production of the resistance to PM in resistant cultivated variety. Furthermore, several members of Pathogen Response-2 family, such as glucanases and chitinases, were identified as DEGs, suggesting that cucumber might enhance the resistance to PM by accelerating the degradation of the pathogen cell walls. Our data allowed us to identify and analyze more potential genes related to PM resistance.

Biolistic-mediated oil palm transformation with alfalfa glucanase (AGLU1) and rice chitinase (RCH10) genes for increasing oil palm resistance towards Ganoderma boninense

Basal stem rot (BSR) caused by Ganoderma boninense, a white-rot fungus is the most devastating disease in oil palm. In addition to the available methods that have been used to control this disease, genetic engineering was explored to produce fungal resistant transgenic oil palm. In this study, oil palm embryogenic calli were co-bombarded with a construct carrying the AGLU1 and RCH10 genes and a construct carrying the Basta® resistance gene (bar). After selection with the herbicide Basta®, 25 plants from seven events were regenerated, transferred onto soil and grown in the fully contained biosafety screen house. Polymerase chain reaction (PCR) analysis for the plants demonstrated that only eight plants were positive for the presence of three transgenes, the bar, AGLU1, and RCH10 genes. The quantitative reverse transcription PCR (RT-qPCR) demonstrated the expression of both AGLU1 and RCH10 genes in five out of eight plants tested. The infection of these plants with the G. boninense fungus resulted in only two plants exhibited resistance to the fungus. The results from this study demonstrated that fungal resistant oil palm could be produced via biolistic using alfalfa β-1,3-glucanase (AGLU1) and rice chitinase (RCH10) genes.

Heterologous gene expression in the human gut bacteria Eubacterium rectale and Roseburia inulinivorans by means of conjugative plasmids

Commensal butyrate-producing bacteria in the Firmicutes phylum are abundant in the human intestine and are important for maintaining health. However, understanding of the metabolism and host interaction of these bacteria is limited by the lack of genetic modification techniques. Here we establish a protocol enabling the transfer of autonomously-replicating shuttle vectors by conjugative plasmid transfer from an Escherichia coli donor into representatives of an important sub-group of strictly anaerobic human colonic Firmicutes. Five different plasmid shuttle vectors were tested, each carrying a different origin of replication from Gram-positive bacteria. Plasmid pMTL83151 (pCB102 replicon) were successfully transferred into two strains of Eubacterium rectale, while pMTL83151 and pMTL82151 (pBP1 replicon) were transferred into Roseburia inulinivorans A2-194. Plasmids that carried a Streptococcus bovis JB1 glycoside hydrolase family 16 β-(1,3-1,4)-glucanase gene were constructed and conjugated into Roseburia inulinivorans A2-194 and Eubacterium rectale T1-815, resulting in successful heterologous expression of this introduced enzymatic activity in these two strains of butyrate-producing Firmicutes.

Оптимизация экспрессии гена 1,3-1,4-β-глюканазы Rhizomucor miehei в дрожжах Komagataella kurtzmanii

Key functional elements of the vector (promoter, leader and terminator regions) that provide the expression of a target l,3-l,4-(3-glucanase gene from Rhizomucor miehei in the Komagataella kurtzmanii yeast have been optimized. It was shown that the promoter regions of the gene AOX1 from the Pichia pastoris yeast currently reclassified as Komagataella phaffti and from К. kurtzmanii yeast as parts of a vector provided equal levels of expression of the target gene in the cells of the recipient strain К. kurtzmanii Y727his4, i.e. they were completely interchangeable. This means that genetic constructs that were previously developed for the biosynthesis of recombinant proteins in К. phajfii are able to provide an effective expression in the К kurtzmanii yeast. The leader peptide MF4I (used as a variant of mif4I containing one amino acid substitution) and the leader peptide maxHH (containing the double proregion of the Hspl50 protein from Saccharomyces cerevisiae) confirmed the status of the most powerful elements among the five leader sequences analyzed. Their efficiency was 1.7 times higher than that of the standard leader from the yeast alpha-factor, and by 20% higher than the characteristics of the second group of artificial leaders. At the same time, it was found that, the choice of the terminator region had the strongest influence on the expression of the target gene among all of the vector functional elements. The best terminator elements were variants derived from the transcription termination region of the AOX1 gene, and the difference in the expression level of the target gene using different terminators was approximately 4.5 times. Based on the analysis of the obtained data, the optimal composition of the key functional elements of the expression vector was determined ; it included the promoter and terminator regions of the AOX1 yeast gene and one of the artificial leaders, mif4I or maxHH. β-glucanase, Komagataella kurtzmanii, yeast, secretion, strain producer The work was financially supported by the Ministry of Science and Higher education of the Russian Federation (Unique Project Identifier RFMEFI60717X0179) using the Unique Scientific Facility of the National Bio-Resource Center «All-Russian Collection of Industrial Microorganisms», NRC «Kurchatov Institute» - GOSNIIGENETIKA

An endophytic strain of genus Paenibacillus isolated from the fruits of Noni (Morinda citrifolia L.) has antagonistic activity against a Noni's pathogenic strain of genus Aspergillus

Endophytes are microbes capable of colonizing the tissues of healthy plants and subsequently establishing a harmonious relationship with their hosts. In this research, the endophytic strain Paenibacillus sp. NEB was isolated from fruits of healthy Noni (Morinda citrifolia L.). Strain NEB was identified as Paenibacillus polymyxa using MALDI-TOF Mass Spectrometry. Pathogenic fungal strain NP-1 was isolated from Noni fruits infected by smut, and was identified as Aspergillus aculeatus by polyphasic taxonomy basing on morphological identification, and ITS-5.8S rDNA and β-tubulin gene phylogenetic analyses. Through the antagonistic test against the pathogenic strain Aspergillus aculeatus NP-1, the results showed that strain NEB had a good antagonistic activity against smut pathogen of Noni. By sequencing with Illumina HiSeq 2000, the draft genome of Paenibacillus sp. NEB was acquired, and 3 CDSs for glucanases were annotated and potentially correlated to the antagonistic activity of this strain. Using realtime-PCR method with specific primers to amplify the biocontrol gene, β-1,3-1,4- glucanase gene (gluB), it was found in Paenibacillus polymyxa NEB. This study would provide a theoretical and microbial basis for the rationally developing and using Noni beneficial microbial inoculants against its pathogenic strain in the future.

Identification and comprehensive evaluation of a novel biocontrol agent Bacillus atrophaeus JZB120050

Bacillus spp. have long been used as biocontrol agents because of their efficient broad-spectrum antimicrobial activity. We identified a novel strain of Bacillus atrophaeus, named JZB120050, from soil. B. atrophaeus JZB120050 had a strong inhibitory effect against Botrytis cinerea and many other phytopathogens. Gas chromatography-mass spectrometry showed that B. atrophaeus JZB120050 produced many secondary metabolites, such as alkanes, alkenes and acids; some of which were related to pathogen inhibition. Enzyme activity analysis showed that B. atrophaeus JZB120050 secreted cell-wall-degrading enzymes, including chitinase, glucanase and protease, which degraded fungal cell walls. Both the novel glucanase gene bglu and chitinase gene chit1 were cloned and heterologously expressed in Escherichia coli and the products showed strong enzyme activity. In addition, B. atrophaeus JZB120050 secreted siderophores and formed a significant biofilm. Future studies should focus on these antimicrobial factors to facilitate widespread application in the field of agricultural biocontrol.

Differential Induction of β-1,3-Glucanase Gene in Expression of Partial Resistance to Rust (Uromyces fabae (Pers.) de-Bary) in Pea (Pisum sativum L.)

The present study highlights differential induction of pathogenesis related protein PR-2 (β-1,3- glucanases) in expression of rust resistance in pea using different resistant and susceptible recombinant inbred lines of pea (Pisum sativum L.). The enhanced levels of glucanase expression was noted in resistant genotypes at 24 h post inoculations that was negatively correlated (–0.54) with Area Under Disease Progress Curve (AUDPC) and positively correlated (0.67) with lignin accumulations. A significant role of structural defence mechanism in rust resistance in pea was evident from reduced colony size and lesser number of haustorium per colony in resistant lines as well as their negative correlations with lignin accumulation and AUDPC. Gene specific markers indicated constitutive nature of glucanase and peroxidase genes in test genotypes, though differential expression of the glucanase activity was observed in the resistant and susceptible genotypes. However, association of peroxidases with resistance to pea rust is yet to be established due to its non-specific role in slow rusting in pea. The result showed a significant role of β-1,3-glucanase in expression of rust resistance in pea.

Expression of an endo α-1, 3-Glucanase gene from Trichoderma harzianum in rice induces resistance against sheath blight

Transformation of rice was done through Agrobacterium mediated, utilizing a binary vector pBS, harboring a fungal gene endo α-1, 3-glucanase from Trichoderma harzianum under rice constitutive promoter actin2 and Agrobacterium nopaline synthase (nos) transcriptional terminator in a T-DNA. Likewise, a selectable marker gene hygromycin phosphotransferese (hpt) resistant to Hygromycin B was cloned in the middle of actin2 and nos terminator in a similar T-DNA. The expression of endo α-1, 3-glucanase was affirmed by cloning gfp gene after the fungal gene in the transformation DNA cassette. In the first generation of transgenic rice lines, out of 912 just 209 plants were false positive affirmed through PCR based screening for the transgene. The positive transgenic lines were tried with fungal infection by leaf cut test in vitro and foliar leaf shower technique in vivo. They demonstrated an exceptional protection against sheath blight disease. Further, seeds of all positive transgenic plants of the first generation were developed and screened in next generation. Just 62 plants were false positive out of 873 transgenic lines in this generation. In the comparative way, they were tried against the fungal disease and they demonstrated the exceptional protection once more. In this way, in this investigation, a fungal gene endo α-1, 3-glucanase was transformed into rice (IR 64) effectively which demonstrated protection against fungus Rhizoctonia solani.

Heterologous expression and characterization of a cold-adapted endo-1,4−β−glucanase gene from Bellamya chinensis laeta

An endo-1,4-β-glucanase from Bellamya chinensis laeta (BC-EG70a) was expressed in Pichia pastoris GS115. The molecular masses of the mature recombinant BC-EG70a enzyme (rBC-EG70amature), the rBC-EG70a catalytic domain (rBC-EG70aCatD), and the rBC-EG70a cellulose binding domain (rBC-EG70aCBD) were 65 kDa, 50 kDa, and 15 kDa, respectively. While the optimum pH and temperature of rBC-EG70amature and rBC-EG70aCatD were pH 5.5 and 50 °C, rBC-EG70amature was more stable within a range of pHs and temperatures compared to rBC-EG70aCatD. The major hydrolysis products from cellohexaose using rBC-EG70amature and rBC-EG70aCatD were cellobiose and cellopentaose during the early stages of the hydrolysis reaction. At lower temperature (30 °C), the specific activity of rBC-EG70amature using carboxymethyl cellulose as the substrate was 5 to 20-fold higher than those of Trichoderma reesei and T. viride cellulases. rBC-EG70acatD demonstrated higher activity than rBC-EG70amature in 10%, 15%, and 20% (v/v) ethanol solutions. rBC-EG70aCBD showed specific adsorption toward Avicel, powder cellulose, and phosphoric acid swollen cellulose.

TRANSFER OF GLUCANASE GENE TO RESIST LATE BLIGHT DISEASE IN POTATO (Solanum tuberosum L.)

Potato late blight is a pandemic disease caused by the highly virulent (Phytophthora infestans) fungus. The regeneration capacity was done among three tested potato cultivars (Spunta, Diamont and Desiree). Two different types of explants (inter-node and leaf) were cultured for calli induction and plant regeneration .The highest value of leaf explants was for Desiree cultivar (80%), which induced from developed callus in the 2,4-D medium. The best value of maximum shoot regeneration was also for Desiree cultivar in the BA, IAA and GA3 media from leaf which proved to be more effective. Then cloning of glucanase gene in pRI plasmid which carrying kanamycin resistance (nptII) gene was perfomed and followed by transformation in Agrobacterium tumefaciens LBA4404 strain which used for plant transfection. Nucleotide and amino acid sequences of transformed Agrobacterium were analyzed. The putative transgenic plantlets genomes and cDNA of the isolated RNA for glucanase gene.

Improvement of cellulose degradation by cloning of endo-β-1, 3-1, 4 glucanase (bgls) gene from Bacillus subtilis BTN7A strain.

The aim of this study is to construct a new recombinant strain able to degrade cellulose efficiently. The endo-β-1, 3-1, 4 glucanase (bgls) gene was cloned from Bacillus subtilis BTN7A strain by using PCR technique. The specific primers of bgls gene were deduced. Optimization of PCR mixture and program were identified. The nucleotide sequence of bgls was placed in the public domain (GenBank accession number KM009051.1). The obtained bgls DNA was cloned with pGEM®-T Easy Vector. The recombinant plasmid designated as Bgls-NRC-1 was transformed into E. coli DH5α. The successful cloning of the bgls gene was tested either by PCR or by evaluating its expression in its new bacterial host. The bgls gene was expressed efficiently in E. coli and the enzyme activity of the transformant was compared to the enzyme activity of the donor bacterial strain. The new constructs produce much higher enzyme yields than the donor bacterial strain, they produce about 29% and about 57% higher cellulase specific activity at 37 °C and 55 °C respectively. Optimization of cellulolytic activity of the new recombinant strain were described. The effect of minimal medium supplemented with CMC or cellulose, or complete medium (LB) on bgls expression were tested, the order of cellulase activity production was CMC27.2 > cellulose 21.9 > LB 19.8 U/mg protein, respectively at 24 h. CMC was proved to be the best medium for cellulase production. Results also showed that double the initial inoculum resulted in more cellulase activities in all media.

Identification of Anther-Specific Genes from Sesame and Functional Assessment of the Upstream Region of a Tapetum-Specific β-1,3-glucanase Gene

Sesamum indicum is widely cultivated in India for its superior agronomic characters like adaptation to the warm climate of India and resistance to drought and pathogen attack. However, the yield of sesame per unit area of land is quite low. In this context, the genes involved with reproductive tissue development is very important since they are directly involved with crop productivity. Therefore, identification and isolation of anther-specific genes through PCR-Select cDNA subtraction between cDNAs of anthers and leaves was carried out. Sequencing of ~ 700 clones from the cDNA subtraction library followed by BLASTX analysis using sesame database resulted in the identification of 163 annotated unique transcripts, of which 18 transcripts showed homology with the genes of exclusive anther-/pollen-specific functions. Furthermore, anther-specific expression of some of the sesame transcripts as well as already identified anther-specific genes of Arabidopsis and rice have been monitored during development of sesame anthers. Subsequently, full-length cDNA sequence and the upstream sequence of an anther-specific β-1 3-glucanase gene was isolated. Transgenic tobacco plants were developed with GUS gene under the control of a 437-bp upstream sequence along with the first exon and first intron of the gene. Monitoring of GUS gene expression pattern indicated exclusive expression of the promoter in the tapetal cell layer before tetrad formation in the anther. Interestingly, upon treatment with ABA as well as drought stress, GUS was found to express in the vegetative parts of the plant such as leaves and roots as well.

Central carbon metabolism influences cellulase production in Bacillus licheniformis.

Cellulase is very important in the field of agriculture and bioenergy because of its degrading effect on cellulosic biomass. This study presented the effect of central carbon metabolism on cellulase production in Bacillus licheniformis. The study also provided a holistic view of the physiological status in B. licheniformis. The shifted metabolism provided a quantitative evaluation of the biosynthesis of cellulase and a priority ranked target list for further strain engineering.

Functional Analysis of a Novel β-(1,3)-Glucanase from Corallococcus sp. Strain EGB Containing a Fascin-Like Module.

A novel β-(1,3)-glucanase gene designated lamC, cloned from Corallococcus sp. strain EGB, contains a fascin-like module and a glycoside hydrolase family 16 (GH16) catalytic module. LamC displays broad hydrolytic activity toward various polysaccharides. Analysis of the hydrolytic products revealed that LamC is an exo-acting enzyme on β-(1,3)(1,3)- and β-(1,6)-linked glucan substrates and an endo-acting enzyme on β-(1,4)-linked glucan and xylan substrates. Site-directed mutagenesis of conserved catalytic Glu residues (E304A and E309A) demonstrated that these activities were derived from the same active site. Excision of the fascin-like module resulted in decreased activity toward β-(1,3)(1,3)-linked glucans. The carbohydrate-binding assay showed that the fascin-like module was a novel β-(1,3)-linked glucan-binding module. The functional characterization of the fascin-like module and catalytic module will help us better understand these enzymes and modules.IMPORTANCE In this report of a bacterial β-(1,3)(1,3)-glucanase containing a fascin-like module, we reveal the β-(1,3)(1,3)-glucan-binding function of the fascin-like module present in the N terminus of LamC. LamC displays exo-β-(1,3)/(1,6)-glucanase and endo-β-(1,4)-glucanase/xylanase activities with a single catalytic domain. Thus, LamC was identified as a novel member of the GH16 family.

Genetic engineering strategies for biotic and abiotic stress tolerance and quality enhancement in horticultural crops: a comprehensive review.

Genetic engineering technique offers myriads of applications in improvement of horticultural crops for biotic and abiotic stress tolerance, and produce quality enhancement. During last two decades, a large number of transgenic horticultural crops has been developed and more are underway. A number of genes including natural and synthetic Cry genes, protease inhibitors, trypsin inhibitors and cystatin genes have been used to incorporate insect and nematode resistance. For providing protection against fungal and bacterial diseases, various genes like chitinase, glucanase, osmotin, defensin and pathogenesis-related genes are being transferred to many horticultural crops world over. RNAi technique has been found quite successful in inducing virus resistance in horticultural crops in addition to coat protein genes. Abiotic stresses such as drought, heat and salinity adversely affect production and productivity of horticultural crops and a number of genes encoding for biosynthesis of stress protecting compounds including mannitol, glycine betaine and heat shock proteins have been employed for abiotic stress tolerance besides various transcription factors like DREB1, MAPK, WRKY, etc. Antisense gene and RNAi technologies have revolutionized the pace of improvement of horticultural crops, particularly ornamentals for color modification, increasing shelf-life and reducing post-harvest losses. Precise genome editing tools, particularly CRISPR/Cas9, have been efficiently applied in tomato, petunia, citrus, grape, potato and apple for gene mutation, repression, activation and epigenome editing. This review provides comprehensive overview to draw the attention of researchers for better understanding of genetic engineering advancements in imparting biotic and abiotic stress tolerance as well as on improving various traits related to quality, texture, plant architecture modification, increasing shelf-life, etc. in different horticultural crops.

Identification of endophytic bacterial strain RSE1 from seeds of super hybrid rice Shenliangyou 5814 (Oryza sativa L.,) and evaluation of its antagonistic activity

Endophytes are related with health and growth of plants. In this study, the endophytic bacterial strain RSE1 was isolated from seeds of super hybrid rice Shenliangyou 5814 (Oryza sativa L.,). Strain RSE1 was identified as Paenibacillus polymyxa by polyphasic taxonomy identification. Through the antagonistic test with the pathogenic strain of rice false smut, Ustilaginoidea oryzae CICC 2710, it showed that the strain RSE1 had an effective antagonistic activity against this pathogen. The draft genome of strain RSE1 was sequenced by Illumina HiSeq 2000, and 3 CDSs for glucanase gene were annotated and correlated to antagonistic activity. Using specific primers to amplify the biocontrol gene in glucanase family, β-1,3-1,4-glucanase gene (gluB) was found. This study laid a scientific foundation for developing and utilizing biological bio-control bacteria agent preventing the suffering from rice false smut.

利用子房注射法进行西瓜遗传转化

利用子房注射法，在西瓜自交系W1-4和W1-12自花授粉后的不同时间，分别导入几丁质酶基因和葡聚糖酶基因。果实成熟后对坐果率进行调查，结果显示，在授粉后20h进行子房注射坐果率最高。对T0代植株进行田间卡那霉素筛选和PCR检测，结果表明，不同西瓜自交系子叶期对卡那霉素敏感性存在显著基因型差异，西瓜自交系W1-4和W1-12卡那霉素临界筛选浓度分别为75mg∙L−1和50mg∙L−1；西瓜自交系在自交授粉后20h进行外源DNA导入有最高的阳性率，几丁质酶基因和葡聚糖酶基因对W1-4的转化率分别为2.15%和3.19%，几丁质酶基因和葡聚糖酶基因对W1-12的转化率分别为5.56%和6.74%。本试验为进一步研究子房注射法转基因技术在西瓜育种中的应用提供了参考依据。 Several fungal pathogens have been identified in the past and have caused serious economic losses in watermelon. The expression of both chitinase and glucanase genes was attempted to achieve higher levels of fungal resistance and to broaden the spectrum of resistance against many fungal pathogens. Chitinase and glucanase genes were successfully transferred into two inbred line of watermelon W1-4 and W1-12 in different time by ovary injection in the greenhouse. The harvested rate is in the highest at 20h after self-pollination, but the harvested rate is zero at 4h after self-pollination. Transgenic plants were obtained by kanamycin screening and PCR amplification. The result of kanamycin screening showed that the sensitivity of seedling to kanamycin was significantly different between W1-4 and W1-12. In cotyledon stage, the optimal screening concentration of W1-4 and W1-12 were 75 mg∙L−1 and 50 mg∙L−1, respectively. Chitinase and β-1,3-gluco- sanase genes were confirmed to integrate into watermelon by PCR. The highest transformation efficiency for Chitinase and glucanase genes of W1-4 was 2.15% and 3.19% at 20 h after self-pollina- tion, respectively. And the highest transformation efficiency for Chitinase and glucanase genes of W1-12 was 5.56% and 6.74% at 20h after self-pollination, respectively. The research provided some references for the application of ovary injection transformation technology in watermelon.

Investigating Disease Controlling Ability of Brassica Volatiles and Their Compatibility with Trichoderma harzianum

The present investigation aimed to test the in vitro toxicity of Brassica volatiles against soil-borne plant pathogens (Rhizoctonia solani Kuhn, Sclerotium rolfsii Sacc., Fusarium oxysporum f.sp. ciceris (Padwick) Matuo & K. Sato and Sclerotinia sclerotiorum (Lib.) de Bary) and biocontrol fungus Trichoderma harzianum Rifai. Moreover, the response of T. harzianum to toxic volatiles was also studied in terms of glucanase and chitinase gene expression. A strong fungistatic effect of B. alba treatment was recorded against all the test pathogens. Noticeably, S. sclerotiorum manifested least sensitivity among all the tested pathogens. All T. harzianum isolates were less sensitive as compared to the assayed pathogens. Based on the in vitro study involving 6 T. harzianum isolates, T55 and Th-R showed least, while T39 showed highest sensitivity to the volatiles. Interestingly, the patterns relating to the effect of volatiles on inoculum density of T. harzianum isolates were similar to their effect on fungus growth in vitro. More importantly, expression of chitinase and glucanase genes in different Trichoderma isolates was up-regulated, which could improve the biocontrol activity of T. harzianum. Therefore, here the authors envisage that combining biocontrol and biofumigation has the potential to provide sustainable and cost-effective strategies to manage soil-borne plant pathogens.