Molecular and physiological insights into the role played by boron in the soybean- Phakopsora pachyrhizi interaction

• Ano de defesa: 2020
• Autor(a) principal: Picanço, Bárbara Bezerra de Menezes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Ferrugem-da-soja; Fotossístense; Soja-Nutrição; Soja- Resistência a doenças e pragas; Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br//handle/123456789/27899

Considering the potential of Asian Soybean Rust (ASR), caused by the fungus Phakopsora pachyrhizi, to reduce soybean yield, this study investigated the effect of boron (B) on soybean resistance against ASR. The photosynthetic performance (chlorophyll a fluorescence and concentration of photosynthetic pigments), the concentration of total soluble phenolics compounds (TSP) and lignin-thioglycolic acid (LTGA) derivatives as well as the expression of defense- and B-related genes were analyzed. The supply of B to plants grown hydroponically with nutrient solutions containing 0.25 or 1.0 mM B did not show reduction in ASR severity. Confirming this result, the expression of TEF1 gene (translation elongation factor 1α of P. pachyrhizi) increased regardless of B rates. Additionally, higher B foliar concentration occurred for inoculated plants supplied with 1.0 mM B. The photosynthetic process was impaired during the infection process of P. pachyrhizi regardless of B rates. The TSP concentration was significantly high at 15 dai for non-inoculated plants supplied with 1.0 mM B in contrast to non-inoculated plants receiving 0.25 mM B. The LTGA derivatives concentration was higher for inoculated plants regardless of B supply. Defense-related genes were up-regulated in inoculated plants, regardless of B supply. Genes encoding for nitrate and nitrite reductase were more expressed at ideal B rate at 10 and 15 dai, and at high B rate at 3 and 5 dai, for inoculated plants. Genes encoding for rhamnogalacturonan II were more expressed at ideal B rate at 15 dai, and at high B rate at 10 dai, for non-inoculated plants. There was no changes in the expression of the genes coding for phenylalanine ammonia-lyase (PAL2.1) as well as isochorismate synthase (ICS1 and ICS2) regardless of B rates and P. pachyrhizi infection. In conclusion, the supply of high B rate to soybean plants did not result in an increase in their resistance against ASR independently of B supply. Keywords: Asian soybean rust. Photosynthesis. Plant nutrition. Host defense responses.