Ultrahigh-activity immune inducer from Endophytic Fungi induces tobacco resistance to virus by SA pathway and RNA silencing

Abstract

Background: Plant viruses cause severe economic losses in agricultural production. An ultrahigh activity plant immune inducer (i.e., ZhiNengCong, ZNC) was extracted from endophytic fungi, and it could promote plant growth and enhance resistance to bacteria. However, the antiviral function has not been studied. Our study aims to evaluate the antiviral molecular mechanisms of ZNC in tobacco. Results: Here, we used Potato X virus (PVX), wild-type tobacco and NahG transgenic tobacco as materials to study the resistance of ZNC to virus. ZNC exhibited a high activity in enhancing resistance to viruses and showed optimal use concentration at 100-150 ng/mL. ZNC also induced reactive oxygen species accumulation, increased salicylic acid (SA) content by upregulating the expression of phenylalanine ammonia lyase (PAL) gene and activated SA signaling pathway. We generated transcriptome profiles from ZNC-treated seedlings using RNA sequencing. The first GO term in biological process was positive regulation of post-transcriptional gene silencing, and the subsequent results showed that ZNC promoted RNA silencing. ZNC-sprayed wild-type leaves showed decreased infection areas, whereas ZNC failed to induce a protective effect against PVX in NahG leaves. Conclusion: All results indicate that ZNC is an ultrahigh-activity immune inducer, and it could enhance tobacco resistance to PVX at low concentration by positively regulating the RNA silencing via SA pathway. The antiviral mechanism of ZNC was first revealed in this study, and this study provides a new antiviral bioagent.

Plant Endophytic Fungus Extract ZNC Improved Potato Immunity, Yield, and Quality

“…Zhinengcong is a crude ethanol extract of the endophyte P. variotii that can promote plant growth and enhance plant resistance to bacterial and viral pathogens indoors ( Lu et al, 2019 ; Peng et al, 2020 ). ZNC also promoted potato immunity, yield, and quality, especially verified in the field ( Figures 1 – 3 and Tables 1 – 3 ).…”

“…The biological control agent zhinengcong (ZNC) is the extract of endophytic Paecilomyces variotii isolated from Hippophae rhamnoides , which is an epiphytic orchid that possesses a great diversity of endophytic fungi ( Lu et al, 2019 ). ZNC promotes plant growth and enhances plant resistance against bacteria and viruses ( Lu et al, 2019 ; Peng et al, 2020 ). However, it has not yet been tested against economically important oomycetes in potato.…”

A Technical System for the Large-Scale Application of Metabolites From Paecilomyces variotii SJ1 in Agriculture

“…UAE was performed at 25°C with a frequency of 20.0 kHz and a stirring speed of 100 × g min –1 . Then, the mycelium residue was removed by a filter press, and the extract was named ZNC as described previously ( Lu et al, 2019 ; Chen et al, 2020 ; Peng et al, 2020 ). The extract (10 mL) was then dried to a constant weight at 40°C in a vacuum rotary concentrator at 1,200 × g min –1 .…”

Synergistically promoting plant health by harnessing synthetic microbial communities and prebiotics

“…Disease-suppressive soils prevent and control soil-borne diseases through specific microbial communities (Latz et al, 2016). Specific microbial communities suppress the occurrence of soil-borne diseases mainly through nutrient competition, antagonism, hyperparasitism and plant resistance induction (Lu et al, 2019;Peng et al, 2020). Microbial function, diversity, and activity in rhizospheric soil are also involved in inhibiting the occurrence of soil-borne diseases and promoting plant growth (Jaiswal et al, 2017).…”