Effects Of Gossypol And Extracts From Agrimonia Pilosa On Tomato Yellow Leaf Curl Virus

Plant viruses cause damage to crop plants with estimates of yield loss of 10-15%around the world.Most efforts to control these viruses have focussed on vector management through pesticide applications and cultural practices to remove virus infested material from the field,but these methods have limitations,resulting in an increased focus on engineering resistance in host plants and understanding the molecular basis of virus-vector interactions.Another novel avenue for controlling plant viruses is to suppress their potential to persist in plants.Tomato yellow leaf curl virus(TYLCV)is a major threat to tomato production in the temperate regions of the world,and it is the most common begomovirus causing disease in tomato crops in China.It also infects other crop plants,including tobacco,common bean,sesame,and various weeds.TYLCV is transmitted exclusively by Bemisia tabaci,which acquires TYLCV from virus-infected tomato plants.Here we investigated the effect of gossypol and extracts from Agrimonia pilosa on the disease severity and virus content of TYLCV in tomato plants.The main results of this paper are as follows:1.Effect of gossypol and extracts from Agrimonia pilosa on developemnt of tomato plant.Greenhouse trials showed that gossypol and extracts from Agrimonia pilosa all had an adverse effect on TYLCV occurrence.Ten weeks after root-drenching of tomato plants with 200 mg/L acetate gossypol or 0.1g/ml and extracts from Agrimonia pilosa,the height of tomato plants and disease severity were all affected,and symptoms of TYLCV in tomato plants with were lightened relative to the controls.Gossypol or extracts from Agrimonia pilosa treatment of tomato plants attacked by viruliferous whiteflies decrease disease severity.2.Effect of gossypol and extracts from Agrimonia pilosa on TYLCV infection in tomato plant.Six weeks after root-drenching of tomato plants with 200 mg/L acetate gossypol,TYLCV level in plants were affected.Diagnostic PCR showed that the TYLCV infection rate decreased with the treatment of gossypol and extracts from Agrimonia pilosa.qPCR indicated that gossypol or extracts from Agrimonia pilosa of tomato plants significantly decreased the level of TYLCV in plants;the log 10 value of the virus in plants treated with gossypol or extracts from Agrimonia pilosa significantly lower than that of the control without gossypol or extracts from Agrimonia pilosa treatemnt.The results showed that both extracts from Agrimonia pilosa and gossypol treatment of tomato plants attacked by viruliferous whiteflies decrease disease severity and TYLCV DNA,which suggest that the direct application of gossypol or extracts from Agrimonia pilosa will be novel management practices in controlling plant virus.