Biocontrol effect ofTrichoderma harzianumT4 on brassica clubroot and analysis of rhizosphere microbial communities based on T-RFLP

Abstract

2015): Biocontrol effect of Trichoderma harzianum T4 on brassica clubroot and analysis of rhizosphere microbial communities based on T-RFLP, Biocontrol Science and Technology, Abstract Clubroot is a serious threat to cruciferous crops in Shanghai, China, and Trichoderma harzianum T4 (T4) has shown good efficiency for its control. In this study, T4 was applied alone or in combination with the fungicide cyazofamid or Bacillus subtilis XF-1, respectively, in a pot experiment to determine its efficiency of controlling clubroot.The control efficiency of T4 (79.3%) was significantly higher than that of XF-1 (63.1%, p < 0.05), and was similar to that of cyazofamid (93.2%, p > 0.05). Furthermore, T4 could promote the growth of the Chinese cabbage Brassica, particularly with respect to its fresh A c c e p t e d M a n u s c r i p t Downloaded by [University of Nebraska, Lincoln] at 00:05 26 August 2015 Xuexin Yu et al.weight. These results indicated that T4 could be used as a green biofungicide to not only control the incidence of clubroot but also to increase the production of vegetables. The structure of microbial communities changed substantially when T4 was applied to the soil, as revealed by a non-metric multidimensional scaling (nMDS) test. T4 could not only reduce the average abundance of Bacillus sp. and Acidiphilium sp. (terminal restriction fragment 231-TRF231, the most dominant fragment) but could also increase the average abundance of Streptococcus sp. (TRF307, the second most dominant fragment). Therefore, the high control efficiency of T4 against clubroot results not only from its ability to directly inhibit spore germination of P. brassicae but also from its ability to regulate the microbial communities in the rhizosphere soil of B. chinensis, which could then inhibit the growth of P. brassicae in soil indirectly.

Trichoderma harzianum Inoculation Reduces the Incidence of Clubroot Disease in Chinese Cabbage by Regulating the Rhizosphere Microbial Community

“…Our result had similarities with a previous study that found that the abundance of Bacillus was significantly increased after inoculation with Trichoderma [30,58]. It is unknown if this increase is driven by a reduction in the population of other genera or an increase in the population of this genus following inoculation.…”

“…Previous reports of Trichoderma applications for prevention and control of clubroot have found differing effects [30,[48][49][50]. We posited that differences in control effects between studies may be related to the differences in regions and microbial communities.…”

“…T. harzianum [ 28 , 29 ] was found to have a controlling effect on clubroot disease of Chinese cabbage in pot experiments [ 23 ]. The use of biocides usually affects the microbial community including bacteria and fungi [ 30 , 31 ]; however, little detail is available about the effect of T. harzianum on plant roots and microbial communities in the rhizosphere. It has been reported from pot experiments and subsequent non-metric multidimensional scaling tests that T. harzianum alters the rhizosphere bacterial community [ 32 , 33 , 34 ]; however, its interactions with P. brassicae and with the rhizosphere fungal community remain unquantified.…”

Suppression of clubroot (Plasmodiophora brassicae) development in Brassica campestris sp. chinensis L. via exogenous inoculation of Piriformospora indica

“…Several beneficial fungi (including Arbuscular mycorrhiza and Acremonium alternatum) have been reported to confer tolerance against different plant diseases (Fakhro et al, 2010;Kogel, Franken, & Hückelhoven, 2006;Saravanakumar et al, 2016). Several experiments on A. thaliana and Brassica rapa revealed that symptoms of clubroot can be reduced by coinoculation with beneficial fungi or bacteria (Auer & Ludwig-Müller, 2014;Yu, Zhao, Cheng, & Wang, 2015). Here, B. campestris sp.…”

Managing clubroot disease (caused byPlasmodiophora brassicaeWor.) by exploiting the interactions between calcium cyanamide fertilizer and soil microorganisms

“…Consequently, practical fertilizer strategies should aim where possible, at encouraging beneficial microbes, especially those that are antagonists against soil-borne pathogens (such as P. brasicae ) (Lahlali & Peng 2014; Yu et al . 2015).…”