Biocontrol potential of endophytic fungi originated from grapevine leaves for management of anthracnose disease caused by Colletotrichum gloeosporioides.

In the present study, 51 fungal endophytes (FEs) were isolated, purified and identified from the healthy leaf segments of ten grapevine varieties based on the spore and colony morphologies and ITS sequence information. The FEs belonged to the Ascomycota division comprising eight genera viz., Alternaria, Aspergillus, Bipolaris, Curvularia, Daldinia, Exserohilum, Fusarium and Nigrospora. The in vitro direct confrontation assay against Colletotrichum gloeosporioides revealed that six isolates viz., VR8 (70%), SB2 (83.15%), CS2 (88.42%), MN3 (88.42%), MS5 (78.94%) and MS15 (78.94%) inhibited the mycelial growth of test pathogen. The remaining 45 fungal isolates showed 20-59.9% growth inhibition of C. gloeosporioides. Indirect confrontation assay manifested that the isolates MN1 and MN4a showed 79.09% and 78.18% growth inhibition of C. gloeosporioides followed by MM4 (73.63%) and S5 (71.81%) isolates. Isolate S5 and MM4 were found to produce azulene and 1,3-Cyclopentanedione, 4,4-dimethyl as antimicrobial volatile organic compounds, respectively. The 38 FEs showed PCR amplification using internal transcribed spacer universal primers. The BLAST search revealed highest similarity with the existing sequences in the database. The phylogenetic analysis revealed the occurrence of seven distinct clusters each corresponding to single genus. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03675-z.

Impact of chitosan seed treatment of fenugreek for management of root rot disease caused by Fusarium solani under in vitro and in vivo conditions.

The use of chitosan as an alternative for fungicides has received more attention worldwide. Hence, this study aimed to evaluate in vitro and in vivo antifungal activity of chitosan against Fusarium solani causing root rot in fenugreek. Chitosan treatments ranged from 0.1 to 2gL-1 were tested against F. solani on to potato dextrose agar and in potato dextrose broth. The results revealed that increase in concentrations of chitosan significantly reduced growth, dried biomass, sporulation and spore germination of F. solani. The hyphal swellings and distortion of F. solani mycelia were induced by chitosan. Fenugreek seeds treated with chitosan at 2 gL-1 and 0.5 gL-1 showed reduced F. solani infection and increased seed germination, respectively. In pot and field studies, fenugreek seeds treated with chitosan at 2.0 gL-1 greatly reduced root rot disease severity and also enhanced yield parameters. The activity of defence enzymes, such as chitinase, ß-1, 3-glucanase and total phenol were increased in chitosan treated in fenugreek plants. This increased activity offered protection to fenugreek plants against F. solani to a greater extent. The results showed that chitosan could be used as inducer of defense response and has the potential of controlling fenugreek root rot disease.