Endophytes Aspergillus caespitosus LK12 and Phoma sp. LK13 of Moringa peregrina produce gibberellins and improve rice plant growth

Two new strains of endophytic fungi were isolated from the bark of Moringa peregrina and identified as Aspergillus caespitosus LK12 and Phomasp. LK13. These endophytes were identified through amplifying polymerase chain reaction (PCR) and sequencing the 18S internal transcribed spacer of DNA extracted from both endophytes. Pure cultures of endophytic fungi were subjected to extract and isolate gibberellins (GAs). Deuterated standards of [17,17-²H₂]-GA₁, [17,17-²H₂]-GA₃, [17, 17-²H₂]-GA₄ and [17, 17-²H₂]-GA₇ were used to quantify the endophytic fungal GAs. The analysis revealed that both the endophytes are producing bioactive GAs in various quantities (ng mL^-1). A. caespitosus LK12 was producing GA₁ (54.51 ± 1.23), GA₄ (26.5 ± 0.65), and GA₇ (2.87 ± 1.23) while Phomasp. LK13 was secreting GA₁ (4.8 ± 0.12), GA₃ (8.65 ± 0.21), GA₄ (23.7 ± 0.98), and GA₇ (22.7 ± 0.73). The culture filtrate (CF) of A. caespitosusand Phomasp. significantly increased the shoot length of GAs-deficient mutant waito-cand normal Dongjin-beyo rice seedlings as compared to control. Application of such growth-promoting and GAs-producing endophytes can ameliorate poorly growing crop plants.