Cowpea mild mottle virus em soja: interação vírus x vetor, incidência e vetor associado, variabilidade do vírus e impactos na qualidade fisiológica de sementes
Data
2022-10-27
Autores
Barreto da Silva, Felipe
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Doenças causadas por vírus podem impactar negativamente a cultura da soja (Glycine max L. Merril). Entre elas podemos citar a necrose da haste causada pelo cowpea mild mottle virus (CPMMV), cujo vetor é a mosca-branca Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) atualmente caracterizada como um complexo de espécie crípticas, das quais as mais invasivas são Middle East Asia Minor 1 (MEAM1, também conhecida por biótipo B) e Mediterranean (MED, conhecida por biótipo Q). Com o objetivo de verificar a distribuição destas espécies crípticas em áreas produtoras de soja no Estado de São Paulo, bem como a incidência do CPMMV nestas regiões, foram realizadas coletas de plantas de soja e mosca-branca por três anos consecutivos e avaliada a presença do vírus e caracterizada a espécie críptica de B. tabaci associada a plantas de soja. Isolados representativos de CPMMV tiveram o seu genoma completo sequenciado por sequenciamento de nova geração (HTS). Além disto foram estudados aspectos da transmissão do CPMMV por B. tabaci MED e MEAM1 e o efeito do CPMMV nos aspectos agronômicos e qualidade fisiológica das sementes de soja. Os resultados indicaram que MEAM1 ainda é a espécie predominante em áreas de soja, entretanto algumas áreas, como em Buritãma, tiveram predominância de MED na primeira safra de soja avaliada (2019/2020) com redução nas safras posteriores (2020/2021 e 2021/2022). Em Santa Cruz do Rio Pardo e Óleo houve um aumento de incidência de MED ao longo das safras de soja avaliadas. Os ensaios de transmissão com um único espécimen de mosca-branca revelaram que MED é um melhor vetor de CPMMV comparado com MEAM1, sendo capaz de transmitir o vírus com apenas dois minutos de período de acesso à inoculação. A análise filogenética das sequencias do genoma completo de isolados de CPMMV coletados nos Estados da Bahia e de São Paulo, mostraram que eles pertencem ao grupo BR2, que compreendem os isolados de CPMMV mais representativos do Brasil. O CPMMV afetou drasticamente a qualidade fisiológica das sementes de soja produzidas a partir de plantas infectadas, reduzindo a germinação das sementes. Os resultados deste trabalho reforçam os impactos negativos do CPMMV em soja e a importância do monitoramento de espécies crípticas de B. tabaci como forma de subsidiar as táticas de manejo desta praga e vetor de virus.
Diseases caused by viruses are important constraints to soybean (Glycine max L. Merril) production. Among them, stem necrosis caused by cowpea mild mottle virus (CPMMV), transmitted by the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Two B. tabaci cryptic species were already detected in soybean-growing areas in São Paulo state, the Middle East Asia Minor 1 (MEAM1, formerly known as biotype B) and the Mediterranean (MED, biotype Q). Here we evaluate the distribution of CPMMV and B. tabaci cryptic species in the main soybean growing areas from São Paulo state for three years. CPMMV isolates were also sequenced by High Throughput Sequencing (HTS) and properties of CPMMV transmission by MED and MEAM1, and the effect of CPMMV on the physiologic seed quality in soybean were evaluated. Results indicated that MEAM is still the predominant whitefly species in soybean, but MED was also found in different locations where soybean is produced in the state. Some areas, like Buritãma, evolved to a predominance of MED over the three years but others where MED was previously detected, showed a reduction of the insect during the same period. In Santa Cruz do Rio Pardo and Óleo, MED incidence increased during the evaluated years. Transmission assays with one single insect revealed that MED is a better vector compared to MEAM1, transmitting the virus within two minutes of the inoculation access period. Phylogenetic analysis of the complete genome sequence of CPMMV isolates collected in Sao Paulo and Bahia State showed that they belong to BR2 clade that includes Brazilian CPMMV isolates collected from soybean. Studies of the effects of CPMMV on the agronomic aspects of soybean and its effects on the seed physiology quality showed that there are negative effects of the virus in the plants and in the seeds. Our results suggest that the continuous survey of B. tabaci cryptic species and CPMMV should be frequent to better whitefly and CPMMV management in soybean
Diseases caused by viruses are important constraints to soybean (Glycine max L. Merril) production. Among them, stem necrosis caused by cowpea mild mottle virus (CPMMV), transmitted by the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Two B. tabaci cryptic species were already detected in soybean-growing areas in São Paulo state, the Middle East Asia Minor 1 (MEAM1, formerly known as biotype B) and the Mediterranean (MED, biotype Q). Here we evaluate the distribution of CPMMV and B. tabaci cryptic species in the main soybean growing areas from São Paulo state for three years. CPMMV isolates were also sequenced by High Throughput Sequencing (HTS) and properties of CPMMV transmission by MED and MEAM1, and the effect of CPMMV on the physiologic seed quality in soybean were evaluated. Results indicated that MEAM is still the predominant whitefly species in soybean, but MED was also found in different locations where soybean is produced in the state. Some areas, like Buritãma, evolved to a predominance of MED over the three years but others where MED was previously detected, showed a reduction of the insect during the same period. In Santa Cruz do Rio Pardo and Óleo, MED incidence increased during the evaluated years. Transmission assays with one single insect revealed that MED is a better vector compared to MEAM1, transmitting the virus within two minutes of the inoculation access period. Phylogenetic analysis of the complete genome sequence of CPMMV isolates collected in Sao Paulo and Bahia State showed that they belong to BR2 clade that includes Brazilian CPMMV isolates collected from soybean. Studies of the effects of CPMMV on the agronomic aspects of soybean and its effects on the seed physiology quality showed that there are negative effects of the virus in the plants and in the seeds. Our results suggest that the continuous survey of B. tabaci cryptic species and CPMMV should be frequent to better whitefly and CPMMV management in soybean
Descrição
Palavras-chave
carlavirus, levantamento, transmissão, Bemisia tabaci, survey, transmission