Can Functional Micro-organisms Associated with Pumpkin Sizes Be Sought Out from the Soil?-A Comparison of Soil Microbial Community Structures in Rhizospheres between Giant- and Small-Sized Pumpkin Varieties.

To elucidate the biological mechanisms driving the growth of various pumpkin varieties to different sizes under identical management conditions while in the same field, the soil microbial community structures in the rhizospheres of giant-pumpkin (GP) and small-pumpkin (SP) varieties were analyzed. The results revealed that a significantly higher abundance of bacterial communities could be detected in the rhizospheres of the giant pumpkin varieties, such as Gemmatimonadota, , , , , , and , than in those of the small-sized pumpkins. Additionally, , , , and were unique dominant soil bacteria genera in the rhizospheres of the giant pumpkins. By contrast, , , , , , , and were the unique dominant soil bacterial genera in the rhizospheres of the small pumpkins. Moreover, at the fungal genus level, , and presented significant differences between the giant-pumpkin (GP) and small-pumpkin (SP) rhizospheres. In addition, , , , and were unique dominant soil fungal genera in the rhizospheres of the giant pumpkins (GPs). By contrast, , , , , , , and were the unique dominant soil fungal genera in the rhizospheres of the small pumpkins (SPs). PICRUSt and FUNGuild functional prediction analyses revealed that the giant-pumpkin rhizosphere microbial community had significantly increased translation, ribosomal structure and biogenesis, nucleotide transport and metabolism, defense mechanisms, replication, recombination and repair, wood saprotroph, and undefined saprotroph levels. The above results suggest that the soil microbial compositions differed between the rhizospheres of the giant- (GP) and small-pumpkin (SP) varieties, even though the plants were grown in the same field under identical management conditions. Meanwhile, bacterial genera such as , , , and , in addition to fungal genera such as , , , and , can be speculated as potential soil functional micro-organisms associated with improved pumpkin size.