Abstract:

Aims Invasive plants can alter soil physicochemical properties by changing the soil microbial community (which is closely related to plant growth and development) and thus further promote the invasion process. Our objectives were to (a) compare changes in soil bacterial diversity with cultivation of four replacement plants (Sorghum bicolor × S. sudanense, Helianthus annuus, Medicago sativa and Lolium perenne) mixed with Flaveria bidentis in different growth period and (b) determine the responses of the soil bacterial community to F. bidentis invasion and replacement.
Methods Total soil bacterial DNA was extracted by PowerSoil^® DNA Isolation Kit, 16S rRNA V3 fragments were amplified with bacterial universal primers, and purified fragments were cloned into pGEM-T-Easy vector. Sequence results were aligned on NCBI.
Important findings Soil bacterial diversity was decreased in F. bidentis monoculture and was lower than in the soils of the monocultures of the four replacement plants and in the soils of the replacement plants and F. bidentis. There were Hsignificant differencesH in soil bacterial 16S rRNA denaturing gradient gel electrophoresis (DGGE) fingerprinting patterns between the mixed- and monoculture soils. Also, there were characteristic bacterial communities with each mixed culture soil on different dates. The Shannon diversity index of soil bacteria peaked in July and decreased starting in August, and this change was synchronous with plant growth. Soil bacterial diversity was reduced following the invasion of F. bidentis, and that the diversity level was increased by cultivating replacement plants with F. bidentis. Therefore, we proposed that soil bacteria play an important role in F. bidentis invasion and control.

Key words: diversity, Flaveria bidentis, invasive plant, invasion ecology, replacement control, soil bacteria