Inoculation method and disease evaluation of tomato chlorotic virus (ToCV) in Solanum lycopersicum

Abstract

Tomato chlorosis virus (ToCV) is a worldwide epidemic virus that seriously harms tomato production. However, there is no effective ToCV-inoculated method and relevant disease evaluation criteria in tomato plants. The lack of these basic techniques have severely limited the tomato-ToCV interaction research and ToCV-resistant tomato breeding. Here, we presented a method for constructing the ToCV-infectious clones using binary vector pCass-Rz and Agrobacterium-mediated transformation system. We further used ToCV-infectious clones to develope an improved stem-inoculated method, which can increase the ToCV-inoculated efficiency from less than 40% to more than 90% compared with the traditional leaf-inoculated method. According to characteristics of the tomato ToCV disease, we developed a detailed symptom description and grading plan, including the change degree of leaf color and texture, plant height, and planting value. The symptom description and grading plan was used to calculate the disease index (DI) and further to develop the tomato ToCV disease resistance (DR) of different tomato cultivars. The publication of these new methods will strongly promote related research and breeding in the field of tomato and ToCV.

Keywords

• tomato
• tomato chlorosis virus
• inoculation method
• disease index
• disease resistance
• disease evaluation