The Raf-like MAPKKK INTEGRIN-LINKED KINASE 5 regulates purinergic receptor-mediated innate immunity in Arabidopsis.

Mitogen-activated protein (MAP) kinase signaling cascades play important roles in eukaryotic defense against various pathogens. Activation of the extracellular ATP (eATP) receptor P2K1 triggers MAP kinase 3 and 6 (MPK3/6) phosphorylation, which leads to an elevated plant defense response. However, the mechanism by which P2K1 activates the MAPK cascade is unclear. In this study, we show that in Arabidopsis thaliana, P2K1 phosphorylates the Raf-like MAP kinase kinase kinase (MAPKKK) INTEGRIN-LINKED KINASE 5 (ILK5) on serine 192 in the presence of eATP. The interaction between P2K1 and ILK5 was confirmed both in vitro and in planta and their interaction was enhanced by ATP treatment. Similar to P2K1 expression, ILK5 expression levels were highly induced by treatment with ATP, flg22, Pseudomonas syringae pv. tomato DC3000, and various abiotic stresses. ILK5 interacts with and phosphorylates the MAP kinase MKK5. Moreover, phosphorylation of MPK3/6 was significantly reduced upon ATP treatment in ilk5 mutant plants, relative to wild-type (WT). The ilk5 mutant plants showed higher susceptibility to P. syringae pathogen infection relative to WT plants. Plants expressing only the mutant ILK5S192A protein, with decreased kinase activity, did not activate the MAPK cascade upon ATP addition. These results suggest that eATP activation of P2K1 results in transphosphorylation of the Raf-like MAPKKK ILK5, which subsequently triggers the MAPK cascade, culminating in activation of MPK3/6 associated with an elevated innate immune response.

Agronomic performance and genetic diversity among lines and soybean cultivars / Desempenho agronômico e diversidade genética em linhagens e cultivares de soja

Knowledge of genetic diversity is of great importance to the contribution of plant breeding, as it helps plant breeders to better selecting parents for establishment of segregating populations. This knowledge is especially important to crops that presents a narrow genetic base as soybean. The objective of this work was to assess agronomic performance and genetic diversity of lines and soybean cultivars, in order to find those ones with potential to be used as parents in breeding programs. Experiment was carried out during 2015/2016 season in the Federal University of Uberlândia farm known as Capim Branco. A randomized complete block designed was applied in order to assess twentythree morpho-agronomic features on twenty-four soybean genotypes. Significant genetic variability for all agronomic traits was found. Genotypes UFU B7, UFU B14, UFU B16, Msoy 6101 and UFUS 7910 were set as early maturity soybean, with life cycle duration ranging from 107.3 to 111 days. Genotypes UFU B1, UFU B3, UFU B8 and UFU B16 presented productivity values higher than national average of 2.870 kg ha-1. Genotypes were clustered by UPGMA, Tocher and canonical variables methods. Both UPGMA and Tocher methods formed four groups. NDF was the major contributor to genetic diversity. Hybridizations between UFU B3, UFU B8, UFU B16 genotypes with UFU B1 genotype might be promising for establishment of segregating populations shown superior genetic variability. Under these circumstances, it was concluded that agronomic features assessed were useful on detection of parents with potential to UFU's soybean breeding program.

O conhecimento da diversidade genética é de grande importância para o melhoramento de plantas, pois auxiliam os melhoristas na escolha de genitores para formação de populações segregantes, especialmente na cultura da soja que é de base genética estreita. O objetivo do trabalho foi avaliar o desempenho agronômico e a diversidade genética de linhagens e cultivares de soja, com potencial de serem utilizados como genitores em programas de melhoramento genético. O experimento foi conduzido em uma área experimental localizada na Fazenda Capim Branco pertencente à Universidade Federal de Uberlândia na safra de 2015/2016. Foram avaliados 24 genótipos de soja, em delineamento de blocos completos casualizados, nos quais foram avaliados 23 caracteres morfo-agronômicos. Foi verificada variabilidade genética para todos os caracteres agronômicos. Os genótipos UFU B7, UFU B14, UFU B16, Msoy 6101 e UFUS 7910 foram classificados como genótipos de ciclo precoce, com duração variando de 107,3 a 111 dias. Os genótipos UFU B1, UFU B3, UFU B8 e UFU B16 apresentaram produtividade elevadas em relação aos demais com valores superiores à média nacional, que é de 2.870 kg ha-1. Os genótipos foram agrupados pelos métodos UPGMA, Tocher e variáveis canônicas. Pelos métodos UPGMA e Tocher foram formados quatro grupos distintos. O NDF foi o caractere que mais contribuiu com a diversidade genética. Hibridações dos genótipos UFU B3, UFU B8 e UFU B16 com o genótipo UFU B1 são promissoras para obtenção de populações segregantes com variabilidade genética superior. Desse modo concluiu-se que o uso de caracteres agronômicos permitiu detectar genitores potenciais para o programa de melhoramento de soja da UFU.