Variability in indigenous Pakistani tomato lines and worldwide reference collection for Tomato Mosaic Virus (ToMV) and Tomato Yellow Leaf Curl Virus (TYLCV) infection / Variabilidade em linhagens indígenas de tomate do Paquistão e coleção de referência global para infecção por vírus do mosaico do tomateiro (ToMV) e vírus da folha amarela do tomate (TYLCV)

Local and exotic germplasm of tomato remains a major source for genetic improvement. Assessment of such lines for biotic stresses particularly viral diseases are the most important criteria for selection in Pakistan, where Tomato Yellow Leaf Curl Virus (TYLCV) and Tomato Mosaic Virus (ToMV) are the major diseases/viruses. A set of 40 accessions (including indigenous Pakistani lines and exotic germplasm from Europe, the United States, and Asia) were evaluated for their resistance/infection response to ToMV with artificial inoculation under greenhouse conditions. Infection response was quantified through disease scoring and DAS-ELISA test (for ToMV). A subset of 24 lines, was further screened for TYLCV using disease scoring and TAS-ELISA. The tested lines showed significant variability for resistance to ToMV. Only one accession (Acc-17878) was resistant to the ToMV whereas seven accessions i.e. Acc-17890, AVR-261, CLN-312, AVR-321, EUR-333, CLN-352, and CLN-362 expressed resistance to TYLCV. Correlation between phenotypic evaluation was confirmed by the ELISA results in both diseases, although both tools complemented to assess the viral infection status. In future, tomato breeding programs must consider breeding for ToMV and TYLCV resistance (using identified germplasm in our study) so as to deliver virus resistant tomato varieties.

O germoplasma local e exótico do tomate continua sendo uma importante fonte de melhoramento genético. A avaliação de linhagens para estresses bióticos, particularmente as doenças virais, é o critério mais importantes para seleção no Paquistão, onde o vírus da folha amarela do tomate (TYLCV) e o vírus do mosaico do tomateiro (ToMV) são as principais doenças/vírus. Um conjunto de 40 acessos (incluindo linhagens indígenas do Paquistão e germoplasma exótico da Europa, dos Estados Unidos e da Ásia) foi avaliado quanto à resistência/resposta à infecção ao ToMV com inoculação artificial em casa de vegetação. A resposta à infecção foi quantificada por meio de pontuação da doença e de teste DAS-ELISA (para ToMV). Um subconjunto de 24 linhas foi posteriormente rastreado para TYLCV usando pontuação de doença e TAS-ELISA. As linhas testadas apresentaram variabilidade significativa para resistência ao ToMV. Apenas um acesso (Acc-17878) foi resistente ao ToMV, enquanto sete acessos (Acc-17890, AVR-261, CLN-312, AVR-321, EUR-333, CLN-352 e CLN-362) expressaram resistência ao TYLCV. A correlação entre a avaliação fenotípica foi confirmada pelos resultados do ELISA nas duas doenças, embora ambas as ferramentas tenham se complementado para avaliar o estado da infecção viral. No futuro, os programas de melhoramento de tomate devem considerar aperfeiçoamentos para resistência ao ToMV e TYLCV (usando germoplasma identificado em nosso estudo) de modo a fornecer variedades de tomate resistentes a vírus.

Variability in indigenous Pakistani tomato lines and worldwide reference collection for Tomato Mosaic Virus (ToMV) and Tomato Yellow Leaf Curl Virus (TYLCV) infection

Abstract Local and exotic germplasm of tomato remains a major source for genetic improvement. Assessment of such lines for biotic stresses particularly viral diseases are the most important criteria for selection in Pakistan, where Tomato Yellow Leaf Curl Virus (TYLCV) and Tomato Mosaic Virus (ToMV) are the major diseases/viruses. A set of 40 accessions (including indigenous Pakistani lines and exotic germplasm from Europe, the United States, and Asia) were evaluated for their resistance/infection response to ToMV with artificial inoculation under greenhouse conditions. Infection response was quantified through disease scoring and DAS-ELISA test (for ToMV). A subset of 24 lines, was further screened for TYLCV using disease scoring and TAS-ELISA. The tested lines showed significant variability for resistance to ToMV. Only one accession (Acc-17878) was resistant to the ToMV whereas seven accessions i.e. Acc-17890, AVR-261, CLN-312, AVR-321, EUR-333, CLN-352, and CLN-362 expressed resistance to TYLCV. Correlation between phenotypic evaluation was confirmed by the ELISA results in both diseases, although both tools complemented to assess the viral infection status. In future, tomato breeding programs must consider breeding for ToMV and TYLCV resistance (using identified germplasm in our study) so as to deliver virus resistant tomato varieties.

RESUMO O germoplasma local e exótico do tomate continua sendo uma importante fonte de melhoramento genético. A avaliação de linhagens para estresses bióticos, particularmente as doenças virais, é o critério mais importantes para seleção no Paquistão, onde o vírus da folha amarela do tomate (TYLCV) e o vírus do mosaico do tomateiro (ToMV) são as principais doenças/vírus. Um conjunto de 40 acessos (incluindo linhagens indígenas do Paquistão e germoplasma exótico da Europa, dos Estados Unidos e da Ásia) foi avaliado quanto à resistência/resposta à infecção ao ToMV com inoculação artificial em casa de vegetação. A resposta à infecção foi quantificada por meio de pontuação da doença e de teste DAS-ELISA (para ToMV). Um subconjunto de 24 linhas foi posteriormente rastreado para TYLCV usando pontuação de doença e TAS-ELISA. As linhas testadas apresentaram variabilidade significativa para resistência ao ToMV. Apenas um acesso (Acc-17878) foi resistente ao ToMV, enquanto sete acessos (Acc-17890, AVR-261, CLN-312, AVR-321, EUR-333, CLN-352 e CLN-362) expressaram resistência ao TYLCV. A correlação entre a avaliação fenotípica foi confirmada pelos resultados do ELISA nas duas doenças, embora ambas as ferramentas tenham se complementado para avaliar o estado da infecção viral. No futuro, os programas de melhoramento de tomate devem considerar aperfeiçoamentos para resistência ao ToMV e TYLCV (usando germoplasma identificado em nosso estudo) de modo a fornecer variedades de tomate resistentes a vírus.

Variability in indigenous Pakistani tomato lines and worldwide reference collection for Tomato Mosaic Virus (ToMV) and Tomato Yellow Leaf Curl Virus (TYLCV) infection.

Local and exotic germplasm of tomato remains a major source for genetic improvement. Assessment of such lines for biotic stresses particularly viral diseases are the most important criteria for selection in Pakistan, where Tomato Yellow Leaf Curl Virus (TYLCV) and Tomato Mosaic Virus (ToMV) are the major diseases/viruses. A set of 40 accessions (including indigenous Pakistani lines and exotic germplasm from Europe, the United States, and Asia) were evaluated for their resistance/infection response to ToMV with artificial inoculation under greenhouse conditions. Infection response was quantified through disease scoring and DAS-ELISA test (for ToMV). A subset of 24 lines, was further screened for TYLCV using disease scoring and TAS-ELISA. The tested lines showed significant variability for resistance to ToMV. Only one accession (Acc-17878) was resistant to the ToMV whereas seven accessions i.e. Acc-17890, AVR-261, CLN-312, AVR-321, EUR-333, CLN-352, and CLN-362 expressed resistance to TYLCV. Correlation between phenotypic evaluation was confirmed by the ELISA results in both diseases, although both tools complemented to assess the viral infection status. In future, tomato breeding programs must consider breeding for ToMV and TYLCV resistance (using identified germplasm in our study) so as to deliver virus resistant tomato varieties.