Induced systemic resistance and growth promotion in tomato by an indole‐3‐acetic acid‐producing strain of Paenibacillus polymyxa

Abstract

Paenibacillus polymyxa strain CF05, a plant-growth-promoting rhizobacterium (PGPR) showed inhibitory effect on Fusarium oxysporum f. sp. lycopersici in vitro, causal agent of Fusarium-wilt of tomato. In the greenhouse experiments, tomatoes inoculated with strain CF05 promoted the significant growth. Meanwhile, strain CF05 suppressed the Fusarium-wilt with 78.24% in control efficiency, which was similar to the carbendazim treatment. The bacterial culture supernatant was found to have the presence of indole-3-acetic acid (IAA), which could be accumulated throughout the growth. Furthermore, strain CF05 could greatly stimulate the activities of phenylalanine ammonialyase (PAL), polyphenol oxidase (PPO), peroxidase (POD) and superoxide dismutase (SOD) in either the absence or the presence of fungal pathogen, and the stimulation stayed throughout the entire experimental assessment. Activities of POD and SOD reached the maximum amount at the second day post-inoculation (dpi) after inoculation while activities of PAL and PPO reached the maximum amount at the third dpi and the fourth dpi, respectively. Moreover, strain CF05 could stimulate the H 2 O 2 and phenol contents in the initial phase after pathogen inoculation. These results suggest that the sustained and timely induction of defence enzymes and accumulation of H 2 O 2 and phenolics treated with P. polymyxa might have contributed to restriction of invasion of fungal pathogen in tomato roots. In summary, P. polymyxa strain CF05, which elicited both plant growth promotion and induction of defence response, could be potential agent to improve the yield of tomato and manage Fusarium-wilt disease.

Evaluation of Paenibacillus polymyxa carboxymethylcellulose/poly (vinyl alcohol) formulation for control of Carya cathayensis canker caused by Botryosphaeria dothidea

“…In addition, inoculation with P. polymyxa led to accumulation of phenolic compounds, which, together with induced defence enzymes, could defend C. cathayensis trunks against infection by the canker‐causing pathogen. Similar patterns of induction by bacteria have been reported in other plants, including tomato roots (Mei et al., ), Arabidopsis thaliana (Timmusk & Wagner, ) and cucumber (Benhamou, Gagne, Quere, & Dehbi, ; Chen et al., ). This study, however, is the first report in which antagonistic bacteria induced plant defences on the tree trunk.…”

“…Paenibacillus polymyxa strain CF05 was isolated from the interior of an ancient Cryptomeria fortunei (syn. Cryptomeria japonica) tree growing on Tianmu Mountain, Zhejiang, China, and stored at −80°C (Mei, Liang, Zhang, Wang, & Guo, 2014). The pathogenic fungus B. dothidea CK16 was isolated from typical symptoms of Chinese hickory trunk canker.…”

“…Paenibacillus polymyxa strain CF05 was grown in nutrient broth (Difco, USA) supplemented with 0.1M MgSO 4 at 23 ± 2°C on a rotary shaker for 2 days to produce endospores (Mei et al, 2014), which were harvested by centrifuging at 2,100 g for 30 min. Pelleted endospores were washed twice in sterilized 0.05 M phosphate buffer saline (PBS, pH 7.0) and resuspended in PBS solution, followed by centrifugation at 2,100 g for 30 min.…”

Improved iron acquisition ofAstragalus sinicusunder low iron-availability conditions by soil-borne bacteriaBurkholderia cepacia

“…The supernatant was used to measure Fe content by inductively coupled plasma-atomic emission spectroscopy according to the method reported by Lei et al (2014). Additionally, the production of indole acetic acid (IAA) by bacteria in the culture medium was detected according to the method of Mei et al (2014). The content of IAA in plants was examined by gas chromatography as reported by Ljung et al (2005).…”

Evaluation of Paenibacillus spp. isolates for the biological control of black rot in Brassica oleracea var. capitata (cabbage)

“…Many parameters such as age, temperature, pH, and in particular nutrient composition of the media affect metabolite production by an organism and can result in different bioactivity outcomes to an in vitro study. On the other hand, antibiosis is only one of the mechanisms involved in the biocontrol activity of Paenibacillus spp.. Competition, root colonization (Haggag and Timmusk, 2008), and induced systemic resistance (Mei et al, 2014) have also been reported as possible modes of action of Paenibacillus spp., and these cannot be determined using a dual culture assay. Hence, the high biocontrol activity that P16 exhibited against black rot disease in cabbage, despite the lack of bioactivity in vitro, appears to be due to mechanisms other than antibiosis.…”