Screening tomato genotypes for resistance and tolerance to Tomato chlorosis virus

Abstract

Tomato chlorosis virus (ToCV) is an emerging crinivirus in Brazil that causes an economically important disease in tomato (Solanum lycopersicum) and other solanaceous species. ToCV is transmitted predominantly by the whitefly Bemisia tabaci Middle East-Asia Minor 1 (MEAM1, formerly biotype B), in a semipersistent manner. As all cultivated tomato varieties and hybrids are susceptible to this crinivirus, the main alternatives for the control of the disease are the use of healthy seedlings for transplanting and the chemical control of the insect vector. The objective of this work was to evaluate the responses of tomato genotypes to infection with this crinivirus and their tolerance to the disease in order to support the development of other alternatives for disease control. Resistance to infection was evaluated by ToCV inoculation with viruliferous B. tabaciMEAM1 followed by virus detection by RT-PCR and RT-qPCR. To measure tolerance to the disease, plant development and fruit yield of ToCV-infected and healthy plants were compared. Among 56 genotypes, only the lineage IAC-CN-RT (S. lycopersicum ‘Angela Gigante’ × S. peruvianum ‘LA 444-1’) was highly resistant to infection with ToCV. Tolerance to the disease over two trials with different genotypes showed variable results. The effect of ToCV on plant development varied from 2.9% to 71.9% reduction, while yield loss varied from 0.2% to 51.8%. The highly ToCV-resistant lineage IAC-CN-RT, which is also resistant to a Spanish isolate of ToCV, might be useful for tomato breeding programmes.