Increasing studies have demonstrated that virus quotient (VQ) proteins play crucial roles in modulating plant defense responses. However, direct evidence for their associations with defense responses remains largely limited. Investigating specific functions of VQ proteins and VQ-mediated signaling pathways may provide new insight on the molecular basis of plant defense responses.

Prof. YU Diqiu and his team of Xishuangbanna Tropical Botanical Garden (XTBG) conducted a study to further clarify the functions of Arabidopsis VQ genes in plant defense. They chose VQ12 and VQ29 for further investigation, which showed that VQ12 andVQ29 were highly responsive to the necrotrophic fungal pathogen Botrytis cinerea.

By using an artificial miRNA approach, the researchers generated amiR-vq12 transgenic plants to suppress the expression of VQ12, and isolated a loss-of-function mutant of VQ29 to characterize the roles of VQ12 and VQ29 in plant defense. The analysis of expression showed that VQ12 and VQ29 mainly responded to methyl jasmonate (MeJA) and B. cinerea-infection and might be involved in disease resistance against B. cinerea. Phenotypic analysis showed that decreasing the expression of VQ12 and VQ29simultaneously rendered the amiR-vq12 vq29 double mutant plants resistant against B. cinerea, which enhanced plant resistance against B. cinerea infection.

Moreover, decreasing the expression of VQ12 and VQ29 simultaneously conferred the amiR-vq12 vq29double mutant plants even greater resistance against B. cinerea. In contrast, the transgenic plants overexpressing VQ12 or VQ29 were much more susceptible to B. cinerea. Further investigation revealed that the C-terminal parts of VQ12 and VQ29 interacted with themselves or each other in plant cells to form homodimers and heterodimer. The B. cinerea-induced expression of VQ12 and VQ29 may be partially dependent on the JA-signaling pathway.

The researchers thus concluded that the JA-responsive VQ12 and VQ29 proteins functioned as negative regulators in plant basal defense against B. cinerea.

The study entitled “Arabidopsis VQ motif-containing proteins VQ12 and VQ29 negatively modulate basal defense against Botrytis cinerea” has been published in Scientific Reports.

Contact:
YU Diqiu, Ph.D Principal Investigator 
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences,
Mengla, Yunnan 666303, China 
Tel: 86-871-65178133
E-mail: ydq@xtbg.ac.cn