Melatonin is responsible for rice resistance to rice stripe virus infection through a nitric oxide-dependent pathway

Rongfei Lu,Wenbiao Shen,Tong Zhou,Yijun Zhou,Zhiyang Liu,Jin Cui,Feng Sun,Yudong Shao,Yali Zhang

doi:10.1186/s12985-019-1228-3

Abstract

Rice stripe virus (RSV) causes one of the most important rice virus diseases of plants in East Asia. However, the molecular mechanisms controlling rice resistance to RSV infection are largely unknown. Recently, several studies presented a novel model that melatonin (MT) and nitric oxide (NO) participate in the plant-pathogen interaction in a synergetic manner. In this study, there was a difference in MT content between two rice varieties that correlated with one being susceptible and one being resistant to RSV, which suggested that MT is related to RSV resistance. In addition, a test with two NO biosynthesis inhibitors revealed that NO inhibitor were able to increase the disease incidence of RSV. A pharmacological experiment with exogenous MT and NO showed that increased MT and NO in the MT-pretreated plants led to lower disease incidences; however, only NO increased in a NO-releasing reagent [sodium nitroprusside (SNP)] pretreated plants. The expressions level of OsPR1b and OsWRKY 45 were significantly induced by MT and NO. These results suggest that rice resistance to RSV can be improved by increased MT through a NO-dependent pathway.

Highlights

Rice stripe virus (RSV), a typical member of the genus Tenuvirus, is transmitted mainly by the small brown planthopper (Laodelphax striatellus) (SBPH) in a persistent and propagative manner, and can infect many crops, such as rice, wheat, and several other gramineous plants, resulting in a severe loss of grain [1]; in addition, Sun et al reported that the virus can infect Arabidopsis thaliana [2]
RSV Coat protein (CP) specific primers showed that RSV RNA accumulated similar in both RSV-inoculated Zhendao 88 and Nipponbare plants at 7, 14 and 21 dpi, but RSV RNA accumulated in Zhendao 88 plants was much lower than in Nipponbare plants at 30 dpi the expression level of CP was significantly higher in Nipponbare than Zhendao 88 at 28 and 35 dpi (Fig. 1b)
The association between MT and nitric oxide (NO) in disease resistance has been reported in animals and in plants [13, 37]. Consistent with these studies, we found that NO participates in MT triggered rice resistance to RSV

Summary

Introduction

Rice stripe virus (RSV), a typical member of the genus Tenuvirus, is transmitted mainly by the small brown planthopper (Laodelphax striatellus) (SBPH) in a persistent and propagative manner, and can infect many crops, such as rice, wheat, and several other gramineous plants, resulting in a severe loss of grain [1]; in addition, Sun et al reported that the virus can infect Arabidopsis thaliana [2]. Previous reports indicated that the plant chloroplasts were damaged by excessive accumulation of starch, which was triggered by RSV infection, resulting in alternating. Lee et al found that the disease resistance induced by MT correlates with plant hormones in Pst DC3000 [11, 22]. These studies may provide a potential mechanism for the effect of MT and NO in plant against other pathogen infections

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Results

Conclusion