A viral protein promotes host SAMS1 activity and ethylene production for the benefit of virus infection

Abstract

Ethylene plays critical roles in plant development and biotic stress response, but the mechanism of ethylene in host antiviral response remains unclear. Here, we report that Rice dwarf virus (RDV) triggers ethylene production by stimulating the activity of S-adenosyl-L-methionine synthetase (SAMS), a key component of the ethylene synthesis pathway, resulting in elevated susceptibility to RDV. RDV-encoded Pns11 protein specifically interacted with OsSAMS1 to enhance its enzymatic activity, leading to higher ethylene levels in both RDV-infected and Pns11-overexpressing rice. Consistent with a counter-defense role for ethylene, Pns11-overexpressing rice, as well as those overexpressing OsSAMS1, were substantially more susceptible to RDV infection, and a similar effect was observed in rice plants treated with an ethylene precursor. Conversely, OsSAMS1-knockout mutants, as well as an osein2 mutant defective in ethylene signaling, resisted RDV infection more robustly. Our findings uncover a novel mechanism which RDV manipulates ethylene biosynthesis in the host plants to achieve efficient infection.

Cotton Leaf Curl Multan virus C4 protein suppresses both transcriptional and post-transcriptional gene silencing by interacting with SAM synthetase

“…benthamiana leaves were inoculated with CLCuMuV or CLCuMuV-C4 R13A . At 21 days post inoculation (dpi), SAM was extracted from systemically infected leaves with 5% (w/v) trichloroacetic acid, and its level was analysed by LC-MS/MS [ 43 ]. CLCuMuV infected plants showed a reduced level of SAM (2.4 nmol/g) compared to CLCuMuV-C4 R13A (4.9 nmol/g) and healthy control plants (5.6 nmol/g) ( Fig 2C ).…”

“…In this scenario, we cannot exclude the possible involvement of polyamines and viral protein methylation in CLCuMuV infection, because SAM is also the methyl donor for various methylation. Recently, a viral protein was shown to promote ethylene production for the benefit of virus infection by enhancing host SAMS1 activity [ 43 ]. It will need further investigation whether CLCuMuV C4 contributes to viral infection by inhibiting the biosynthesis of polyamines and ethylene or viral proteins.…”

Arabidopsis Transcription Factor MYB102 Increases Plant Susceptibility to Aphids by Substantial Activation of Ethylene Biosynthesis

“…The production of ET can be triggered by pathogen and herbivores, but the role of ET for plant defense responses to aphids is largely controversial [ 23 , 27 , 28 , 29 ]. Elevation of ET levels activates host defense pathways, as well as promotes viral infection efficiency [ 5 , 30 ]. Induction of ET synthesis by virus or aphid infestation occurs in Arabidopsis and tomato, leading to increased host susceptibility to the aphids [ 5 , 25 , 29 ].…”

Plant immunity and sustainable control of pests in China: Advances, opportunities and challenges

“…OsIAA10相互作用, 抑制OsIAA10的降解从而阻断生 长素信号通路, 参与RDV介导的水稻矮化表型的形 成 [271] ; 而另一个蛋白Pns11则通过刺激乙烯合成途径 中的SAMS酶活, 增强其感染能力 [272] . 中国农业科学 院植物保护研究所研究组和浙江大学研究组合作发 现, 中国番茄黄化曲叶病毒(TYLCCNV)的致病因子 βC1蛋白通过上调rgs-CaM表达, 抑制植物RDR6促进…”