Cultivar-Dependent Suppression of Tomato Leaf Curl Palampur Virus by Foliar-Applied Trichoderma zelobreve and Bacillus subtilis in Tomato

Articles in Press

Document Type : Original Article

Authors
Roya Kazemi
Naser Safaie
M. R. Atighi
Masoud Shams-Bakhsh
Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran, Islamic Republic of Iran.
Abstract
Tomato (Solanum lycopersicum L.) is a globally important vegetable crop whose quality and yield are affected by tomato leaf curl Palampur virus (ToLCPalV; Begomovirus solanumpalampurense). This study investigated the effectiveness of foliar applications of Trichoderma zelobreve T20 and Bacillus subtilis 6m, applied individually and in combination, in enhancing resistance of two tomato cultivars, Moneymaker and Tabas, to ToLCPalV under greenhouse conditions. Although responses varied considerably with cultivar and application timing, B. subtilis consistently reduced relative viral DNA accumulation in both cultivars. In Moneymaker, T. zelobreve was the most effective treatment, reducing ToLCPaLV DNA accumulation by up to 99.9%. By comparison, B. subtilis reduced viral levels by up to 89.2% in Tabas relative to virus-inoculated controls. The combined treatment did not improve protection in Moneymaker and offered only limited additional benefit in Tabas. Induced resistance was associated with increased antioxidant enzyme activity, including guaiacol peroxidase, polyphenol oxidase, and catalase, as well as increased proline accumulation, maintenance of chlorophyll content, and improved plant growth in plants treated with either T. zelobreve or B. subtilis, compared with infected controls. Re-isolation of T. zelobreve and B. subtilis from newly emerged upper leaves after spraying indicated their presence in distal tissues and suggested a possible contribution to systemic defense responses. These results highlight the potential of foliar microbial priming as a sustainable strategy for managing ToLCPalV, with efficacy dependent on host genotype and treatment timing.
Keywords
Antioxidant enzymes
Microbial priming
Symptom severity
Viral DNA accumulation
Subjects
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Available Online from 13 September 2026