A promising growth promoting Meyerozyma caribbica from Solanum xanthocarpum alleviated stress in maize plants.

Fungal endophytes are known to secrete a large array of secondary metabolites (phenols, flavonoids, IAA etc.) that facilitate crops under stress conditions. Considering this, a potent plant growth promoting endophyte (SXSp1) from the spines and leaves of Solanum xanthocarpum L has been isolated. The isolated strain ably secreted high quantities of indole-3-acetic acid, phenols, and flavonoids. Also, it exhibited phosphate solubalization, siderophore and having 2, 2 diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. The SXSp1 has also resisted the salinity stress up to 150 mM. LC/MS analysis of SXSp1 culture filtrate revealed the presence of p-hydroxyl benzoic acid, diadzein, genistien, myricetin and caffeoyl-d-glucose. Moreover, the inoculation of maize plants with SXSp1 has significantly (P = 0.05) promoted the chlorophyll and carotenoid contents, root and shoot lengths, plant fresh and dry weights, catalase and peroxidase activity, proline, phenolics, flavonoids, and relative water contents under salinity. More interestingly, SXSp1 associated plants showed lower endogenous ABA and higher endogenous IAA contents that helped the plants to resist salinity stress up to 100 mM. After sequencing, internal transcribed spacer regions (ITS1 and ITS4) and phylogenetic analysis, the SXSp1 was identified as Meyerozyma caribbica.