A Morpho-Biochemical and functional comparison of Arbuscular Mycorrhizal Fungal spores cultured in two distinct conditions

The present investigation was conducted to compare between Arbuscular Mycorrhizal Fungal spores generated in vitro through Root Organ Culture and those obtained in vivo through conventional pot culture method.Our study conducts a comprehensive analysis of four AMF species viz., Rhizophagus irregularis, Rhizophagus clarus, Entrophospora etunicata, and Funneliformis mosseae cultured both in in vitro and in vivo conditions regarding their morphology, Fatty Acid Methyl Ester (FAME) profiles and infectivity potential.Morphological analysis showed that in vitro-produced spores tend to be smaller in size with smooth surface in comparison to their in vivo counterparts.The observed spore surface irregularities can be attributed to the sloughing off of the outer layer, the adhesion of Rhizobia, Pseudomonads, and the adherence of soil particles due to the release of Glomalin.FAME profiles showed the presence of marker fatty acids indicative of Glomalean nature in all AMF species.Notably, variations in the fatty acid profiles, especially the presence of Neutral Lipid Fatty Acid (NFLA) C16:ù5c, differentiate in vitro and in vivo spores, indicating the influence of growth conditions on the biochemical composition of these AMF species.It is also crucial to identify the disparities in colonization percentages between in vivo and in vitro spores when extrapolating research findings from AMF grown in controlled conditions (in vitro) to those cultured in association with plants (in vivo).In vivo cultivated spores of R. irregularis, R. clarus, and F. mosseae exhibited higher infectivity potential while E. etunicata showed higher infectivity potential among all the in vitro cultivated AMF species.These findings suggest interesting opportunities for further exploration for optimizing their use as bioinoculants.