Affiliations: School of Life Sciences, Sun Yat-sen University,
Guangzhou 510275, China | Department of Biology, The Chinese University of Hong
Kong, Shatin, Hong Kong, China
Abstract: Soil properties, microbial communities and enzyme activities were
studied in soil amended with replicase (RP)-transgenic or non-transgenic papaya
under field conditions. Compared with non-transgenic papaya, significant
differences (P<0.05) were observed in total nitrogen in soils grown with
transgenic papaya. There were also significant differences (P<0.05) in the
total number of colony forming units (CFUs) of bacteria, actinomycetes and
fungi between soils amended with RP-transgenic plants and non-transgenic
plants. Compared with non-transgenic papaya, the total CFUs of bacteria,
actinomycetes and fungi in soil with transgenic papaya increased by
0.43–1.1, 0.21–0.80 and 0.46–0.73 times respectively.
Significantly higher (P<0.05) CFUs of bacteria, actinomycetes and fungi
resistant to kanamycin (Km) were obtained in soils with RP-transgenic papaya
than those with non-transgenic papaya in all concentrations of Km. Higher
resistance quotients for Km^r (kanam ycin resistant)
bacteria, actinomycetes and fungi were found in soil planted with RP-transgenic
papaya, and the resistance quotients for KTr bacteria, actinomycetes and fungi
in soils with transgenic papaya increased 1.6–4.46, 0.63–2.5 and
0.75–2.30 times. RP-transgenic papaya and non-transgenic papaya produced
significantly different enzyme activities in arylsulfatase (5.4–5.9x),
polyphenol oxidase (0.7–1.4x), invertase (0.5–0.79x), cellulase
(0.23–0.35x) and phosphodiesterase (0.16–0.2x). The former three
soil enzymes appeared to be more sensitive to the transgenic papaya than the
others, and could be useful parameters in assessing the effects of transgenic
papaya. Transgenic papaya could alter soil chemical properties, enzyme
activities and microbial communities.
