Abstract
Worldwide, rice blast (Pyricularia oryzae) causes more rice crop loss than other diseases. Acid rain has reduced crop yields globally for nearly a century. However, the effects of acid rain on rice-Pyricularia oryzae systems are still far from fully understood. In this study, we conducted a lab cultivation experiment of P. oryzae under a series of acidity conditions as well as a glasshouse cultivation experiment of rice that was inoculated with P. oryzae either before (P. + SAR) or after (SAR + P.) simulated acid rain (SAR) at pH 5.0, 4.0, 3.0 and 2.0. Our results showed that the growth and pathogenicity of P. oryzae was significantly inhibited with decreasing pH treatments in vitro culture. The SAR + P. treatment with a pH of 4.0 was associated with the highest inhibition of P. oryzae expansion. However, regardless of the inoculation time, higher-acidity rain treatments showed a decreased inhibition of P. oryzae via disease-resistance related enzymes and metabolites in rice leaves, thus increasing disease index. The combined effects of high acidity and fungal inoculation were more serious than that of either alone. This study provides novel insights into the effects of acid rain on the plant–pathogen interaction and may also serve as a guide for evaluating disease control and crop health in the context of acid rain.
Highlights
Global food security depends on rice yields, which are significantly negatively impacted each year by blast disease Pyricularia oryzae [1,2,3]
Colony diameter of P. oryzae was significantly inhibited under the acid treatments relative to that in the control (P < 0.05), except at pH 5.0 treatment (P > 0.05, Figure 1A)
P. oryzae did not grow under pH 2.0 treatment (Figure 1B)
Summary
Global food security depends on rice yields, which are significantly negatively impacted each year by blast disease Pyricularia oryzae [1,2,3]. P. oryzae invades rice leaf cells and colonizes adjacent cells through plasmodesmata in two to six days after inoculation [4]. It reduces the green leaf area and the photosynthesis, suppresses the plant protective system and overall plant metabolism, and eventually leads to leaf death [5]. Acid rain is a serious worldwide environmental issue [6]. A large agricultural country, has the third largest acid rain zone in the world, following North America and Europe [7]. There is Plants 2020, 9, 881; doi:10.3390/plants9070881 www.mdpi.com/journal/plants
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
