Assessment of the effectiveness of Ty genes in tomato against tomato leaf curl Bangalore virus

Abstract

Tomato leaf curl Bangalore virus (ToLCBaV), a monopartite begomovirus transmitted by the whitefly Bemisia tabaci, has become a major constraint in tomato production in the Indian subcontinent. Earlier breeding efforts in India led to the adoption of tomato cultivars carrying the resistance gene Ty‐2. However, it has been observed recently that such cultivars/hybrids are susceptible to begomoviruses. This requires the identification of additional or new sources of resistance against ToLCBaV. The present study was undertaken to assess the effectiveness of several Ty genes in providing resistance against infection by ToLCBaV. The kinetics of virus multiplication in different Ty resistance gene stocks of tomato were estimated and compared using quantitative PCR data. Accumulation of viral genomic units and symptom severity were lower in tomato lines carrying Ty‐3 and Ty‐2 + Ty‐3 compared with those carrying Ty‐2 alone. All tested lines carrying Ty‐2 showed typical tomato leaf curl disease symptoms. Tomato lines carrying Ty‐2 + ty‐5 and ty‐5 + Ty‐6 combinations had a significantly higher disease severity index and viral genomic units compared to those carrying Ty‐3 and Ty‐2 + Ty‐3 at 30 days postinoculation. The accumulation level of ToLCBaV genomic units serves as a good indicator for resistance selection along with other parameters of disease. We present here a comprehensive overview of the effectiveness of Ty‐2, Ty‐3, and ty‐5 alone as well as the combinations Ty‐2 + Ty‐3 and Ty‐2 + ty‐5 against ToLCBaV.

Twindemic Threats of Weeds Coinfected with Tomato Yellow Leaf Curl Virus and Tomato Spotted Wilt Virus as Viral Reservoirs in Tomato Greenhouses

“…Furthermore, the selected perennial weed roots, such as C. glomeratum ( n = 6), R. crispus ( n = 12), R. palustris ( n = 6), S. aquatica ( n = 12), S. asper ( n = 6), and S. vulgaris ( n = 6), were collected and extracted for viral detection using the above extraction method. The percentage disease incidence (PDI) for infected tomato sample and weed sample were calculated for each of the viral symptom using the following formular ( Kaushal et al, 2020 ).…”