Effects of <i>Piriformospora indica</i> and arbuscular mycorrhizal fungus on growth and physiology of <i>Moringa oleifera</i> under low-temperature stress

<i>Moringa</i> is a perennial tree with high nutritional value, and it is drought tolerant and barren but has poor cold resistance during the seedling stage. This study selected <i>Piriformospora indica</i> (PI) and arbuscular mycorrhizal fungus (AM) as inoculants, <i>Moringa</i> seedlings were inoculated, and their growth and physiological responses were evaluated under different low-temperature stress times. The research results show that PI and AM can symbiotically associate with <i>Moringa</i> successfully and promote their nutritional growth. At low temperature, Moringa inoculated with PI and AM exhibited better physiological resistance. However, the effect of mixed inoculation of PI and AM is not as significant as that of single inoculation of any strain. Inoculating plant growth-promoting rhizobia (PGPR) reduced the richness of fungal communities and the number of unique operational taxonomic units (OTUs), with PI being the most prominent. Vaccination with PGPR also increased bacterial diversity, richness, and the number of unique OTUs, with AM inoculation showing the most prominent performance. This suggests that <i>Moringa</i> seedling growth and responsiveness to low-temperature stress are significantly influenced by PGPR, and there may be interactions between different bacterial strains. The results suggest that PGPR can improve the yield and quality of <i>Moringa</i> by promoting growth and regulating stress resistance.