Search

Fungal endophytes are not widely known for their role in bioactive metabolite production and salinity stress alleviation in different crop plants. Presently, we investigated the salt stress (NaCl, KCl, and H2SO4) mitigation capabilities of fungal endophyte Candida membranifaciens (FH15) isolated from Euphorbia milii L. The pure culture filtrate (CF) of C. membranifaciens revealed siderophore production and solubilization of phosphate, with high levels of indoleacetic acid (IAA: 35.8µg/mL), phenolics (70 µg/mL), and flavonoids (50 µg/mL) by using a UV spectrophotometer. The LC/MS analysis of the CF showed different phenols and flavonoids that were identified as Salicylic acid, Baicalein, Aconitic acid, Feruloylquinic acid, Coniferyl aldehyde hexoside, Pentose, Chlorogenic acid, Myricetin, Propoxyphene, and Amino-flunitrazepam. Inoculation of maize seedlings with C. membranifaciens significantly (p = 0.05) enhanced the fresh and dry biomass, carotenoid, and chlorophyll contents under 100 mM salt stress conditions. Similarly, the catalase, peroxidase activity, phenols, proline flavonoids and relative water contents (RWC) of the maize plants were enhanced. More interestingly, the inoculation of C. membranifaciens on maize revealed a higher endogenous IAA level as compared to non-inoculated control plants. Endophyte C. membranifaciens inoculation on maize seedlings under salt stress revealed a 20.87% and 16.60% increase in fresh and dry biomass, as well as significantly enhanced root shoot length and allied growth attributes, in addition to an alleviation of the adverse effects of salinity stress. Conclusively, endophytic C. membranifaciens significantly enhanced the growth attributes of maize and mitigated the adverse effects of salinity stress. Such endophytic fungal strain could be used for further field trails to enhance agricultural productivity and facilitate sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

The association between microbes and plant roots involves a complex chemical dialogue featured by IAA and flavonoids in addition to other signals. Current study is focused on the role of IAA and flavonoids as essential elements of the chemical dialogue between an endophytic fungus and maize roots. The strain was isolated from the leaves of Withania somnifera and was identified as Aspergillus fumigatus greenish by 18S rDNA sequence. Culture filtrate of the strain contained phyotstimulant (IAA, ammonia and ACC) and signaling compounds including IAA, flavonoids and flavonols. The strain effectively colonized the maize roots and enhanced its growth. In order, to determine the effect of IAA and flavonoids on the ability of the endophyte to colonize maize roots, we inhibited the release of IAA and flavonoids in maize separately which reduced the colonization of endophyte in maize root to 66% and 55% of the untreated control. Similarly, application of IAA in combination with endophyte enhanced root colonization by 90% in zone of cell division, 66% in the zone of elongation and 30% in the zone of maturation. These findings determined that IAA and flavonoids are among the key players of the complex chemical dialogue between plant root and fungal endophyte. [ABSTRACT FROM AUTHOR]

Abstract Cinnamic acid (CA) is an allelochemical that inhibits the growth of root promoting soil microorganisms. To prevent the growth of soil microbes, CA modulates several metabolic pathways in host plants and soil microbes. The aim of the current study was to investigate the effect of CA on maize root growth, exudation of secondary metabolites and its interaction with beneficial endophyte Pz11. The endophyte Pz11 was isolated from the roots of drought stressed Asphodelus tenuifolius (wild onion). The Pz11 strain was identified as Fusarium culmorum by homology of the internal transcribed spacer (ITS) region of 18 S rDNA sequence. The F. culmorum Pz11 produced phytostimulants and signaling compounds, such as indole-3-acetic acid (IAA), flavonoids and sugars. Moreover, the strain have effectively colonized the roots of maize and subsequently enhanced the growth of its host plants. On the contrary, application of CA has reduced root growth in maize seedlings as well as root colonization ability of F. culmorum Pz11. Also, maize seedlings exposed to CA exude low quantities of flavonoids and polyphenols. In conclusion, CA reduces the maize root growth and exudation of secondary metabolites, which may affects its ability to attract plant growth promoting endophytic fungi. Highlights • Endophytic fungi Fusarium culmorum has been shown to enhance growth of maize seedlings. • Cinnamic acid inhibits growth of maize root and exudation of flavonoids. • Growth of endophytic fungus and its colonization in maize root are compromised under cinnamic acid. [ABSTRACT FROM AUTHOR]