Characterization of rust, early and late leaf spot resistance in wild and cultivated peanut germplasm

Abstract

Groundnut (Arachis hypogaea) has an AB genome and is one of the most important oil crops in the world. The main constraints of crop management in Brazil are fungal diseases. Several species of the genus Arachis are resistant to pests and diseases. The objective of our experiments was to identify wild species belonging to the taxonomic section Arachis with either A or B (or "non-A") genomes that are resistant to early leaf spot (Cercospora arachidicola), late leaf spot (Cercosporidium personatum) and rust (Puccinia arachidis). For the identification of genotypes resistant to fungal diseases, bioassays with detached leaves were done in laboratory conditions, with artificial inoculation, a controlled temperature of 25°C and a photoperiod of 10 h light/14 h dark, for 20-42 days, depending on the fungi species. Most of the accessions of wild species were more resistant than accessions of A. hypogaea for one, two or all three fungi species studied. Arachis monticola, considered to be a possible tetraploid ancestor or a derivative of A. hypogaea, was also more susceptible to Cercosporidium personatum and Puccinia arachidis, as compared to most of the wild species. Therefore, wild germplasm accessions of both genome types are available to be used for the introgression of resistance genes against three fungal diseases of peanut. Key words: Puccinia arachidis, Cercospora arachidicola, Cercosporidium personatum, groundnut, Arachis spp. CARACTERIZAÇÃO DA RESISTÊNCIA À FERRUGEM, MANCHA PRETA E MANCHA CASTANHA EM GERMOPLASMA SILVESTRE E CULTIVADO DE AMENDOIMRESUMO: O amendoim (Arachis hypogaea) possui genoma AB e é uma das mais importantes culturas oleaginosas em todo o mundo. Os principais problemas da cultura no Brasil são as doenças fúngicas. Várias espécies do gênero Arachis são resistentes a pragas e doenças. Este trabalho visou a identificar espécies silvestres pertencentes à seção Arachis associadas aos genomas A ou B (ou "não-A") do amendoim que são resistentes à mancha castanha (Cercospora arachidicola), mancha preta (Cercosporidium personatum) e ferrugem (Puccinia arachidis). Para a identificação de genótipos resistentes a doenças fúngicas, bioensaios utilizando folhas destacadas foram realizados em condições de laboratório, com inoculação artificial, temperatura controlada de 25°C e fotoperíodo de 10h luz/14h escuro, por 20-42 dias, de acordo com a espécie fúngica. A maioria dos acessos das espécies silvestres foram mais resistentes que os acessos de A. hypogaea para uma, duas ou todas as espécies fúngicas estudadas. Arachis monticola, considerada como o possível ancestral tetraplóide ou como um derivativo de A. hypogaea, também mostrou-se mais suscetível a Cercosporidium personatum e Puccinia arachidis, quando comparado à maioria das espécies silvestres. Portanto, acessos de germoplasma silvestre com genoma A ou B estão disponíveis para serem utilizados na introgressão de genes de resistência a doenças fúngicas no amendoim.

Research Article Coupled transcript and metabolite identification: insights on induction and synthesis of resveratrol in peanut, wild relatives and synthetic allotetraploid.

“…Data showed that accessions of A. ipaënsis and A. duranensis have higher concentrations of resveratrol than the two allotetraploids, which is a surprising result since many other studies showed differences between diploids and polyploids, the latter having better characteristics than the former (Fávero et al, 2009;Xu et al, 2014;Michelotto et al, 2015;Leal-Bertioli et al, 2015, 2017. The lack of polyploidy superiority has been previously observed for Arabidopsis thaliana and Pyrus communis, in which only a few metabolites differ between diploids and synthetic autotetraploids.…”

“…Sequences RSArAs01, RSArAs02, RSArAs06, RSArAhT05, RSArAhT06 were placed in different clusters as it can be seen in Figure 1. A. hypogaea and A. stenosperma sequences were chosen to primer design among the species that had amplicons sequenced since the first is the cultivated and previous data on RS expression is available (Chung et al, 2003;Zhu et al, 2014) and the second is a source of genes for A. hypogaea, since some of its accessions had more resistance to some diseases that affect the cultivated one (Fávero et al, 2009). Figure 1.…”

“…Section Arachis species are found in different environments and because of that they may harbor resistant genes related to abiotic and biotic stress that are not found in cultivated peanut (Pande and Rao, 2001). The variation in many important traits have been evaluated in Arachis species to verify their value in peanut breeding programs, mainly in Brazil, which possesses the largest gene bank of wild species of Arachis (Fávero et al, 2009).…”

<b>Resistance to <i>Enneothrips flavens</i> Moulton and genetic parameters estimation in interspecific genotypes of peanut

“…Pre-breeding research on crossings of A. hypogaea L. with wild germplasm has been conducted in Brazil with the aim of identifying sources of resistance to major pests and foliar diseases (Fávero, Simpson, Valls, & Vello, 2006;Fávero, Moraes, Garcia, Valls, & Vello, 2009;Janini, Boiça Júnior, Godoy, Michelotto, & Fávero, 2010;Michelotto et al, 2015;Santos et al, 2011;Santos, Godoy, Michelotto, & Fávero, 2013). One of the crosses made involved an elite cultivar from the Instituto Agronômico de Campinas (IAC 503) and the amphidiploid (A. magna x A. cardenasii) 4x .…”

Research Article Morphological, cytogenetic, and molecular characterization of Arachis kuhlmannii Krapov. & W.C. Greg. (Leguminosae).

“…A previous study has demonstrated that A. kuhlmannii accessions V 8889 and V 7639 display resistance to fungal diseases including late and early leaf spot and rust (Fávero et al, 2009) and insects such as thrips and red-necked peanutworm (Michelotto et al, 2013). Therefore, understanding the complex set of plants currently grouped as A. kuhlmannii and related accessions would shed light on the taxonomy of this species, and provide potentially useful information for breeding programs.…”