Preinoculation with Endophytic fungus Phomopsis liquidambaris reduced rice bakanae disease caused by Fusarium proliferatum via enhanced plant resistance.

AIMS: This study evaluated the control effect of the endophytic fungus Phomopsis liquidambaris B3 against rice bakanae disease (RBD) caused by Fusarium proliferatum and the disease control result of different inoculation times of beneficial micro-organisms. METHODS AND RESULTS: Rice seedlings preinoculated, coinoculated and noninoculated with B3 were exposed to F. proliferatum stress and grown under controlled conditions. Greenhouse experimental results showed that rice preinoculation with B3 significantly reduced rice bakanae disease by 21.45%, inhibited the colonization of F. proliferatum, increased defence-related enzyme activities, upregulated the expression of defence genes and promoted plant photosynthesis. However, bakanae disease in rice coinoculation with B3 increased by 11.45%, resulted in excessive reactive oxygen species (ROS) bursts and plant cell death. CONCLUSIONS: Preinoculation with the endophytic fungus P. liquidambaris B3 significantly reduced rice bakanae disease by triggering the SA-dependent defence pathways of plants, and promoted plant growth. However, coinoculatiton with P. liquidambaris B3 activated excessive defence responses, resulting in plants cell death and aggravation of bakanae disease. SIGNIFICANCE AND IMPACT OF THE STUDY: This study indicated that P. liquidambaris B3 was an effective method for agricultural control against rice bakanae disease caused by F. proliferatum, and provides an experimental basis for the development of sustainable endophytic fungal resources to effectively control plant diseases caused by pathogenic fungi, and suggests that precise application of beneficial micro-organisms may be become a key factor in farmland crop disease management.

Distribution, abundance, and risk assessment of selected antibiotics in a shallow freshwater body used for drinking water, China.

With rapid improvements in industrialization and urbanization, antibiotics are now extensively used to prevent and treat human and animal diseases and husbandry and aquaculture. Some research has been conducted to assess the environmental distribution and risk level of antibiotics, but their distribution remains largely uncharacterized. Thus, this study investigated the distribution and abundance of 39 antibiotics belonging to five groups, and their associated risks in surface water around Luoma Lake in the north of Jiangsu province, China. Nineteen antibiotics were detected, at a detection frequency (DF) ranging from 2.27% to 100%. The total antibiotics (ΣABs) concentrations ranged from 34.91 to 825.93 ng/L, with a median concentration of 195.45 ng/L. Among these antibiotics, chlortetracycline (DF: 100%; median: 172.02 ng/L) was the dominant antibiotic, accounting for a median percentage of 91.0% of ΣABs concentrations. Spearman rank correlation method found a significant correlation between clindamycin (DF: 72.7%; median: 2.01 ng/L) and lincomycin (DF: 79.5%; median: 4.58 ng/L). The ecological risk quotient (RQ) values for two out of 44 sampling sites were higher than 1, indicating a high risk; 11.4% of the RQ values fell between 0.1 and 1, indicating a medium risk. Moreover, roxithromycin was found to be the dominant contributor to the ecological risk, accounting for a median of 79.7% of ΣABs. However, the total non-carcinogenic (<6.54 × 10-4) and carcinogenic risks (<1.64 × 10-7) of ΣABs were negligible at the detected concentrations.

Distribution of the entomopathogenic fungus Beauveria bassiana in rice ecosystems and its effect on soil enzymes.

Fungal entomopathogens, especially Beauveria bassiana, are often studied within the context of their use in biological pest control; however, there is limited knowledge of their distributions in host plants and soil ecosystem. We examined the distribution of B. bassiana and its influence on rice plants and paddy soils. B. bassiana could only be detected on the foliar surfaces of rice plants within 15 days under Bb-4 (7.5 × 10(4) conidia/mL) and Bb-7 (7.5 × 10(7) conidia/mL) treatments. The endophytic colonization of B. bassiana could not be found in stems, roots, or seeds of rice plants under Bb-4 and Bb-7 treatments. The fungus was found only in the leaves of rice plants under Bb-4 and Bb-7 treatments at 15 days after inoculation. Moreover, B. bassiana was absent from paddy soils under Bb-4 and Bb-7 treatments at all times. Enzyme activity (urease and phosphatase) in the paddy soils of Bb-4 and Bb-7 treatments showed no significant difference from the control. It is possible that B. bassiana was not able to colonize paddy soil. Detailed understanding of distribution and ecological interactions of B. bassiana is helpful for understanding and predicting the effects of fungal entomopathogens on host populations, and the interactions among fungal entomopathogens and other organisms in the community.

[Occurrence Characteristics and Risk Assessment of Antibiotics in the Surface Water of Luoma Lake and Its Main Inflow Rivers].

The concentration levels of 39 antibiotics, including sulfonamides (SAs), quinolones (QUs), tetracyclines (TCs), macrolides (MLs), and penicillins (PLs), in the surface water of Luoma Lake, and its main inflow rivers were analyzed using SPE-UPLC-MS/MS. The contribution rates of pollution of major rivers entering the lake were analyzed, and the potential ecological and health risks of antibiotics were assessed. The results showed that ρ(antibiotics)in 42 sampling sites was between 30.10 ng·L-1 and 582.37 ng·L-1, and a total of four classes of 23 antibiotics were detected. Among them, the average detection concentration of enrofloxacin (ERX) was the highest (88.05 ng·L-1), and the detection rate of lincomycin (LIN) was the highest (100%). The average concentration of antibiotics in the northern region of Luoma Lake was higher than that in the south, and among the two main rivers entering the lake, Yihe River was the main river contributing to the pollution of antibiotics in Luoma Lake, with a contribution rate of 53.91%. The results of risk assessment showed that ERX had the largest risk quotient. For the cumulative risk quotient (RQcum), RQcum of L6, R30, R31, R32, R33, and R42 was between 0.1 and 1, which is considered medium risk, and RQcum of other points was>1, which is considered high risk. The health risk assessment of 11 antibiotics showed that the health risk quotient (RQH) of adults and children ranged from 4.16×10-6 to 2.46×10-3, and there was no health risk to the human body.