Endophytic Penicillium oxalicum CX-1 prevented Phytophthora cactorum blight on Salvia miltiorrhiza and promoted plant growth.

Abstract

The main purpose of this study was to study the preventive effect of Penicillium sp. CX-1 on Phytophthora cactorum causing Salvia miltiorrhiza blight and its positive effect on plant growth. The endophytic strain CX-1 was isolated from the medicinal plant Corydalis saxicola Bunting and identified as Penicillium oxalicum. The growth inhibitory capacity of CX-1 against Ph. cactorum was 74.4% in the strain co-culture test and 86.2% in filtrate-modified plates. In the pot experiment, the in vivo control of CX-1 against Ph. cactorum in S. miltiorrhiza was 36.0%, which was higher than that of an anti-Phytophthora fungicide (23.4%). In addition, CX-1 had a potent ability to solubilize phosphate and also showed the ability to produce the plant hormone indole-3-acetic acid (IAA) and siderophores, which increase the bioavailability of iron to plants. It was demonstrated through pot experiments that CX-1 could significantly promote plant growth. As determined by real-time quantitative PCR, the expression of some S. miltiorrhiza tanshinone-related biosynthesis genes was significantly upregulated following colonization by CX-1. Strain CX-1 could effectively inhibit Ph. cactorum, the causative agent of S. miltiorrhiza blight, and significantly promoted the growth of plants through several different routes.