Fungal Endophyte Diversity and Bioactivity in the Indian Medicinal Plant Ocimum sanctum Linn

Abstract

Endophytic mycopopulation isolated from India’s Queen of herbs Tulsi (Ocimum sanctum) were explored and investigated for their diversity and antiphytopathogenic activity against widespread plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani and Fusarium oxysporum. 90 fungal isolates, representing 17 genera were recovered from 313 disease-free and surface sterilised plant segments (leaf and stem tissues) from three different geographic locations (Delhi, Hyderabad and Mukteshwar) during distinct sampling times in consequent years 2010 and 2011 in India. Fungal endophytes were subjected to molecular identification based on rDNA ITS sequence analysis. Plant pathogens such as F. verticillioides, B. maydis, C. coarctatum, R. bataticola, Hypoxylon sp., Diaporthe phaseolorum, Alternaria tenuissima and A. alternata have occurred as endophyte only during second sampling (second sampling in 2011) in the present study. Bi-plot generated by principal component analysis suggested tissue specificity of certain fungal endophytes. Dendrogram revealed species abundance as a function of mean temperature of the location at the time of sampling. Shannon diversity in the first collection is highest in Hyderabad leaf tissues (H' = 1.907) whereas in second collection it was highest from leaf tissues of Delhi (H' = 1.846). Mukteshwar (altitude: 7500 feet) reported least isolation rate in second collection. Nearly 23% of the total fungal isolates were considered as potent biocontrol agent. Hexane extract of M. phaseolina recovered from Hyderabad in first collection demonstrated highest activity against S. sclerotiorum with IC50 value of 0.38 mg/ml. Additionally, its components 2H-pyran-2-one, 5,6-dihydro-6-pentyl and palmitic acid, methyl ester as reported by GC-MS Chromatogram upon evaluation for their antiphytopathogenic activity exhibited IC50 value of 1.002 and 0.662 against respectively S. sclerotiorum indicating their significant role in antiphytopathogenic activity of hexane extract. The production of 2H-pyran-2-one, 5,6-dihydro-6-pentyl from M. phaseolina, an endophytic fungus is being reported for the first time.

Influence of fertilizers and rice cultivation methods on the abundance and diversity of phyllosphere microbiome

“…However, the values of Menhinick index, which is an index of species richness was much lower in our samples with higher values of 0.450 in conventional control. The Pielou's evenness index did not show any significant differences among the treatments in our study, but much higher values ranging from 0.85–0.94 were recorded as compared to those of 0.4–0.7 in the earlier investigations . Our data corroborate the earlier work exhibiting a similar range of Shannon Weiner indices and much higher and narrower range of Pielou indices (0.85–0.94, as against 0.25–1.00).…”

“…Shannon-H values ranged from 2.9 to 3.0 for bacteria 16S rDNA sequences, which were similar to our results, with indices of 2.1-2.9 for the rice phyllosphere microbial communities. Chowdhary and Kaushik [42] observed a greater influence of temperature, precipitation and other climatic factors on the endophytic community, than geography of the medicinal plant Ocimum sanctum Linn. The Simpson index showed significant differences not only among the methods of rice cultivation but also as a result of fertilization; SRI-RDF recorded higher values reflective of more number of distinct species.…”

Identification of endophytic fungi from leaves of Pandanaceae based on their morphotypes and DNA sequence data from southern Thailand

“…Endophytic fungi are beneficial to their host plants and have the ability to produce bioactive compounds that have applied uses (Fisher et al 1994;Strobel et al 2004;Gunatilaka 2006;Arnold et al 2007;Saikkonen et al 2010;Aly et al 2010;Lin et al 2010;Rajulu et al 2011;Chowdhary et al 2015). Research on endophytic fungi began approximately 30 years ago and has intensified over the past 20 years (Thomson et al 1997;Arnold et al 2000;Stone et al 2000;Hyde and Soytong 2008;Lumyong et al 2009).…”

“…The high species diversity of endophytic fungi makes their study a pressing research area. Globally, endophytic fungi were estimated to comprise 7 % of the 1.5 million species of fungi (Hawksworth 2001;Chowdhary et al 2015). The actual numbers may be far higher.…”

A novel bioactive molecule 5-β-Hydroxyltridecanyl benzoate identified in Pedalium Murex L. (Gokhru) fruit extracts showed antifungal activity against Sclerotinia sclerotiorum

“…Growth Inhibition (GI%) was calculated using the following formula: GI= [(A-B)/A]x 100 Where A= diameter of fungi in the solvent only; B= diameter of fungi in fruit extract intoxicated plates at various concentrations. Inhibitory concentration (IC 50 ) was calculated by regression equation analysis (Chaudhary and Kaushik, 2015).…”