Lant Growth Promoting Endophytic Yeast Geotrichum Candidum (Jx 477426) From Roots of Bruguiera Cylindrica

Abstract

Dynamic mangrove ecosystems are fascinating sources of microorganisms which serve as an extraordinary habitat for the growth and development of many endophytic microorganisms. In this study, we isolated 16 endophytic fungi thriving in the mangrove species Bruguiera cylindrica, collected from Ayiramthengu in the state of Kerala, India. All the isolated endophytes were screened for their plant growth promoting activities (IAA, siderophore and HCN production, ACC deaminase activity) and enzyme production. Among the isolates, seven displayed only a single trait from the total plant growth promoting traits evaluated, although IAA production was a common trait observed amongst the lot. When IAA concentration was quantified in the culture medium, the isolate MEF 21 showed the highest IAA production (>45 µg/mL). The ability of MEF 21 isolate to produce IAA, both in the presence and absence of L-Tryptophan was confirmed by TLC and GC-MS analysis. The isolate also produced siderophores and displayed ACC deaminase activity. The fungus exhibited high extracellular enzyme activity such as amylase, cellulase and protease. Vigna radiata seeds were treated with culture filtrates of MEF 21 to determine its plant growth promoting ability by vigor index method. A germination percentage of 93% and a vigor index of 337.59 were displayed by MEF 21 alone. In vitro antagonistic activity was also exhibited by MEF 21 against the plant pathogen Xanthomonas campestris with a growth inhibition zone of 35 ± 1.5 mm diameter in the dual culture plate. This efficient plant growth promoting isolate, MEF 21, was further identified using morphological, biochemical and phylogenetic methods. Molecular identification included ITS-PCR utilizing universal primers. The PCR products were sequenced and submitted to GenBank. The isolate thus identified was Geotrichum candidum with an accession number JX 477426. These findings revealed the efficacy of the endophytic yeast, isolated from the surface sterilized root of the mangrove plant, to promote plant growth, development and protection.

Enhanced Yield of Pepper Plants Promoted by Soil Application of Volatiles From Cell-Free Fungal Culture Filtrates Is Associated With Activation of the Beneficial Soil Microbiota

“…In addition, all CF and DE treatments strongly enriched the populations of C. subhashii , a yeast antagonist of filamentous fungal phytopathogens ( Hilber-Bodmer et al, 2017 ), and that of G. candidum. Although the latter fungus is known to be the causal agent of decays of numerous fruits ( Palou et al, 2009 ; Talibi et al, 2012 ), it has been shown to promote growth when inoculated in plants ( Waqas et al, 2017 ) probably due to its capacity to synthesize IAA, solubilize mineral phosphate and produce VOCs that inhibit microbial phytopathogens ( Wu et al, 2012 ; Fu et al, 2016 ; George et al, 2019 ; Chen et al, 2020 ). It is worth noting that the relative abundances of most of the above microbial species were very low in the microbial populations of non-treated soils and became very high after the CF and DE treatments.…”

Identification endophytic fungi of Nutgrass (Cyperus rotundus L.) as solubilizing phosphate and indole-3-acetic acid producers

“…Besides, the use of long-term chemical phosphate fertilizers above normal dosage has negative impacts on the environment, such as a decrease in soil quality, soil fertility, and crop yield (Jiao et al, 2012;Kaur & Reddy, 2015;Ning et al, 2017). George et al (2019) and Simarmata et al (2020), stated that endophytic microorganisms have great potential to promote growth and do not cause any pathogenic reaction to the host plant. Furthermore, phosphate-solubilizing microorganisms synthesize phosphates which are chemically and biologically undissolved.…”

“…Endophytic fungi are microorganisms with higher phosphate solubility compared to other microorganisms (Klaic et al, 2017;Mehta et al, 2019). George et al (2019) reported that rhizome endophytic fungi produce useful active compounds for plant growth and development, such as dissolving phosphate and releasing IAA phytohormones. However, the potential of rhizome endophytic fungi in nutgrass as phosphate solvents and IAA producers has never been analyzed and published.…”