The effect of white grub (Maladera Verticalis) larvae feeding on rhizosphere microbial characterization of aerobic rice (Oryza sativa L.) in Puer City, Yunnan Province, China.

BACKGROUND

Rhizosphere microorganisms are vital in plants' growth and development and these beneficial microbes are recruited to the root-zone soil when experiencing various environmental stresses. However, the effect of white grub (Maladera verticalis) larvae feeding on the structure and function of rhizosphere microbial communities of aerobic rice (Oryza sativa L.) is unclear.

RESULTS

In this study, we compared physicochemical properties, enzyme activities, and microbial communities using 18 samples under healthy and M. verticalis larvae-feeding aerobic rice rhizosphere soils at the Yunnan of China. 16 S rRNA and ITS amplicons were sequenced using Illumina high throughput sequencing. M. verticalis larvae feeding on aerobic rice can influence rhizosphere soil physicochemical properties and enzyme activities, which also change rhizosphere microbial communities. The healthy and M. verticalis larvae-feeding aerobic rice rhizosphere soil microorganisms had distinct genus signatures, such as possible_genus_04 and Knoellia genera in healthy aerobic rice rhizosphere soils and norank_f__SC - I-84 and norank_f__Roseiflexaceae genera in M. verticalis larvae-feeding aerobic rice rhizosphere soils. The pathway of the metabolism of terpenoids and polyketides and carbohydrate metabolism in rhizosphere bacteria were significantly decreased after M. verticalis larvae feeding. Fungal parasite-wood saprotroph and fungal parasites were significantly decreased after M. verticalis larvae feeding, and plant pathogen-wood saprotroph and animal pathogen-undefined saprotroph were increased after larvae feeding. Additionally, the relative abundance of Bradyrhizobium and Talaromyces genera gradually increased with the elevation of the larvae density. Bacterial and fungal communities significantly correlated with soil physicochemical properties and enzyme activities, respectively.

CONCLUSIONS

Based on the results we provide new insight for understanding the adaptation of aerobic rice to M. verticalis larvae feeding via regulating the rhizosphere environment, which would allow us to facilitate translation to more effective measures.