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| Plant growth-promoting characteristics of A10(Paecilomyces lilacinus)and effects of its fermentation broth on Cs+ accumulation in Brassica juncea L. seedlings |
| Received:April 07, 2018 |
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| KeyWord:Paecilomyces lilacinus;cesium;indian mustard (Brassica juncea L.)seedling;plant-microbial interaction |
| Author Name | Affiliation | E-mail | | HAN Na | Life Science College, Sichuan Normal University, Chengdu 610101, China | | | TAO Zong-ya | Life Science College, Sichuan Normal University, Chengdu 610101, China | | | DAI Wen-xiu | Life Science College, Sichuan Normal University, Chengdu 610101, China | | | HUANG Pan | Life Science College, Sichuan Normal University, Chengdu 610101, China | | | LIU Qiao | Life Science College, Sichuan Normal University, Chengdu 610101, China | | | LAI Jin-long | Life Science College, Sichuan Normal University, Chengdu 610101, China | | | WU Guo | Life Science College, Sichuan Normal University, Chengdu 610101, China | | | LU Hong | Life Science College, Sichuan Normal University, Chengdu 610101, China | 154194719@qq.com |
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| Abstract: |
| In the present study, a strain of the fungus Paecilomyces lilacinus, named A10, was isolated from potted soil with a cesium (Cs+) content (ρ[Cs+]) of 10 mmol·kg-1. A10 was studied in order to investigate its plant growth-promoting characteristics and the effects of A10 fermentation broth on Cs+ bioaccumulation in Indian mustard (Brassica juncea L.) seedlings, by measuring the secretion of auxin (IAA) analogs, the content of soluble phosphorus, the effective potassium in media with different Cs+ concentrations, and the Cs+ content in seedlings. The following results were obtained. A10 had strong tolerance and Cs+-enrichment traits, although the phosphorus solubilization ability of A10 was significantly inhibited when the ρ[Cs+] in the medium was 50~100 mg·L-1 (P<0.05). Treatments in which either Cs+ or exogenous tryptophan was added to the medium could significantly increase the secretion of IAA analogs induced by A10. A10 fermentation broth was diluted (dilution ratio 5x, 35x, 55x) with 1/2-strength Hoagland nutrient solution, formulated to yield solutions containing ρ (Cs+) 25~100 mg·L-1, and then used as culture solutions to cultivate Brassica juncea seedlings. At ρ (Cs+) 0 mg·L-1 (CK), the dilute solution of A10 fermentation broth clearly affected root growth, and the secretion of IAA initially increased and subsequently decreased. Optimal root-promoting effects were observed in seedlings treated with the 35x dilutions of fermentation broth. When seedling were cultured in 5x, 35x, and 55x diluted broth containing ρ (Cs+) 100 mg·L-1, the amounts of Cs+ bioaccumulated increased significantly in the aboveground parts of seedlings, with maximum values of 8.86 mg·g-1 DW in the aboveground parts and 16.76 mg·g-1 DW in the belowground parts being recorded in seedlings cultured in the 35x diluted broth. Furthermore, we detected a significant negative correlation between the accumulated Cs+ and K+ content in the aboveground parts of seedlings. Collectively, these results indicate that A10 has distinct plant growth-promoting properties, whereas treatments with A10 fermentation broth can promote Cs+ bioaccumulation in Indian mustard seedlings. |
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