Compounds Released by the Biocontrol Yeast Hanseniaspora opuntiae Protect Plants Against Corynespora cassiicola and Botrytis cinerea

Plant diseases induced by fungi are among the most important limiting factors during pre- and post-harvest food production. For decades, synthetic chemical fungicides have been used to control these diseases, however, increase on worldwide regulatory policies and the demand to reduce their application, have led to searching for new ecofriendly alternatives such as the biostimulants. The commercial application of yeasts as biocontrol agents, has shown low efficacy compared to synthetic fungicides, mostly due to the limited knowledge of the molecular mechanisms of yeast-induced responses. To date, only two genome-wide transcriptomic analyses have characterized the mode of action of biocontrols using the plant model Arabidopsis thaliana, missing, in our point of view, all its molecular and genomic potential. Here we describe that compounds released by the biocontrol yeast Hanseniaspora opuntiae (HoFs) can protect Glycine max and Arabidopsis thaliana plants against the broad host-range necrotrophic fungi Corynespora cassiicola and Botrytis cinerea. We show that HoFs have a long-lasting, dose-dependent local, and systemic effect against Botrytis cinerea. Additionally, we performed a genome-wide transcriptomic analysis to identify genes differentially expressed after application of HoFs in Arabidopsis thaliana. Our work provides novel and valuable information that can help researchers to improve HoFs efficacy in order for it to become an ecofriendly alternative to synthetic fungicides

Uso de elementos Terras Raras na agricultura

The Rare Earth Elements (REEs) is a group of 17 chemical elements, where 15 belong to the group of lanthanides, and the other two are scandium and yttrium. The largest mineral deposits of REEs are in China, which dominates over 95% of the world market. Research on crops with the use of compounds based on REEs – performed mostly in China – showed an increase in productivity, plant growth, disease control and other beneficial effects, usually when they are applied in low concentrations. The reasons for these effects are not sufficiently understood, but recently, physiological interactions with calcium, effects on the structure and function   of  the  cytoplasmic  membranes,  changes  in  photosynthesis,  hormone  metabolism, enzyme activity, and increased efficiency on water use have been proposed as possible mechanisms affected by REEs. The positive results of the use of these elements in agriculture, combined with the few researches realized outside of China, are strong indicators of the need for further studies on these substances. Thus, in the present review are shown some of the resulting effects from the use of REEs on crops, emphasizing the used concentrations, and the physiological interactions with plants, among other mechanisms. Still, it contribute to disseminate knowledge involving these substances and also highlight the potential which they assume on the agricultural scenario in the world and, consequently, in increasing food production.O grupo da tabela periódica denominado Terras Raras é formado por 17 elementos químicos, onde 15 pertencem ao grupo dos lantanídeos, e os outros dois são o escândio e o ítrio. Os maiores depósitos minerais de Elementos Terra Raras (ETRs) se encontram na China, que domina mais de 95% do mercado mundial. Pesquisas em culturas agrícolas com o uso de compostos baseados em ETRs, realizadas majoritariamente na China, mostraram um incremento da produtividade e do crescimento das plantas, controle de doenças, além de outros efeitos benéficos, geralmente quando estes são aplicados em baixas concentrações. As razões para a ocorrência destes efeitos não são suficientemente compreendidas, mas, recentemente, interações fisiológicas com o cálcio, efeitos sobre a estrutura e a função das membranas citoplasmáticas, alterações na fotossíntese, no metabolismo dos hormônios, na atividade enzimática, e o aumento da eficiência no uso da água têm sido propostos como possíveis mecanismos de atuação dos ETRs. Os resultados positivos do uso destes elementos na agricultura, aliado às poucas pesquisas realizadas fora da China, são fortes indicativos da necessidade de maiores estudos com estas substâncias. Deste modo, na presente revisão são mostrados alguns dos efeitos advindos do uso dos ETRs nas culturas agrícolas, enfatizando as concentrações utilizadas e as interações fisiológicas com as plantas, entre outros mecanismos. Busca-se, ainda, contribuir para a disseminação do conhecimento envolvendo estas substâncias e evidenciar o potencial que estes podem assumir no cenário agrícola mundial e, consequentemente, no aumento da produção de alimentos

Potential of yeasts in control of Phytophthora sojae

Brazil is the second largest producer and exporter of soybeans, meal and oil in the world, ensuring the country a role of great potential for the product. The soybean crop is attacked by various diseases caused by fungi, bacteria and viruses which burdens the cost of production by the need to adopt measures of preventive and curative control throughout cycle. Among the diseases of Phytophtora root rot caused by Phytophthora sojae, is considered one of the most destructive for causing death of plants in all stages of development. The use of resistant cultivars is the primary measure of control, since there is no chemical control for the specific pathogen. Thus, alternative control Phytophtora presents itself as an important aspect of research, which can bundle other measures of protecting plants against diseases, such as biological control and resistance induction. The objective of this study was to evaluate the potential of yeasts in controlling P. sojae. In vitro, evaluated the inhibition zone formed between pathogen and antagonist in pairing colonies and production of volatile compounds in divided plates. In vivo, induction of resistance was assessed by the activity of peroxidase, catalase, polyphenol oxidase, phenylalanine ammonia lyase and lipoxygenase, after treatment with yeast-like fungi and pathogen inoculation in soybean . We also evaluated the production of phytoalexins in soybean cotyledons and hypocotyls of bean. Disease severity was estimated by lesion length 72 and 120h after pathogen inoculation. In the confrontation between pathogen and antagonist yeast four highlighted by the formation of inhibition zone Debaryomyces etchellsii, Saccharomyces cerevisiae 2, Pichia sp. and an isolated yeast raisin (DRD1). We detected a significant increase in the activity of peroxidase in treatments D. etchellsii, S. cerevisiae 2, EM 21.1 , Hanseniaspora opuntiae 2, potato dextrose (BD) and Pichia sp . 2 precipitate. For polyphenoloxidase the best treatments were D. etchellsii, S. cerevisiae 2, EM 21.1, H. opuntiae 2, Pichia sp. 2 and BD, only the first hours of review. The production of glyceollin in soybean cotyledons was significantly higher in treatments H. opuntiae 1, S. cerevisiae 1, S. cerevisiae 2, EM 21.1, H. opuntiae 2, Pichia sp. 2, DRD1 , and saprobic (CUI) , when compared with the control (water). To phaseolin produced in bean hypocotyls, Pichia sp. was the only treatment that overcame and statistically different from the control. The yeasts showed no efficiency to reduce disease severity.O Brasil é o segundo maior produtor e exportador de soja em grão, farelo e óleo do mundo, garantindo ao país um papel de grande potencial para o produto. A cultura da soja é atacada por diversas doenças causadas por fungos, bactérias e vírus, que oneram o custo de produção pela necessidade de adotar medidas de controle preventivas e curativas durante todo ciclo. Dentre as doenças a podridão radicular de fitóftora, causada por Phytophthora sojae, é considerada uma das mais destrutivas por causar morte das plantas em todas as fases de desenvolvimento. O uso de cultivares resistente é a principal medida de controle, uma vez que não existe controle químico específico para o patógeno. Desse modo, o controle alternativo apresenta-se como importante aspecto para investigação, que pode agrupar outras medidas de proteção das plantas contra as doenças, como controle biológico e a indução de resistência. Assim, o objetivo desse trabalho foi avaliar o potencial de fungos leveduriformes no controle de P. sojae. In vitro, avaliou-se o halo de inibição formado entre patógeno e antagonistas (dez leveduras) no pareamento de colônias e na produção de compostos voláteis em placas divididas. In vivo, a indução de resistência foi avaliada pela atividade das enzimas peroxidase, catalase, polifenoloxidase, fenilalanina amônia-liase e lipoxigenase, após tratamento com os fungos leveduriformes e inoculação do patógeno em plantas de soja. Avaliou-se também a produção de fitoalexinas em cotilédones de soja e em hipocótilos de feijoeiro. A severidade da doença foi estimada pelo comprimento da lesão 72h e 120h após inoculação do patógeno. No confronto entre patógeno e antagonista quatro leveduras destacaram-se pela formação do halo de inibição: Debaryomyces etchellsii, Saccharomyces cerevisiae 2, Pichia sp. e uma levedura isolada de uva passa (DRD1). Detectou-se aumento significativo na atividade da enzima peroxidase nos tratamentos D. etchellsii, S.cerevisiae 2, EM 21.1, Hanseniaspora opuntiae 2, batata dextrose (BD) e o precipitado Pichia sp. 2. Para a polifenoloxidase os melhores tratamentos foram D. etchellsii, S. cerevisiae 2, EM 21.1, H. opuntiae 2, Pichia sp. 2 e batata dextrose, apenas nas primeiras horas de avaliação. A produção de gliceolina em cotilédones de soja foi significativamente maior nos tratamentos H.opuntiae 1, S. cerevisiae 1, S. cerevisiae 2, EM 21.1, H. opuntiae 2, Pichia sp. 2, DRD1 , e Sapróbio (CUI), quando comparados com a testemunha (água). Para faseolina produzida em hipocótilos de feijão, Pichia sp. foi o único tratamento que superou e diferiu estatisticamente da testemunha. Os fungos leveduriformes não apresentaram eficiência para reduzir a severidade da doença.vii, 39

ACCUMULATION OF PHYTOALEXINS IN BEANS, SOYBEANS AND SORGHUM BY FUNGAL FILTRATES

The use of elicitors in plants for disease control is demonstrated by the accumulation of phytoalexins. Among these elicitors, metabolic products from fungi have been shown to be effective in the activation of mechanisms of induced resistance. Thus, this study aimed to evaluate the effects of filtrates from the saprobic fungi Curvularia inaequalis, Pseudobotrytis terrestris, Memnoniella echinata and Curvularia eragrostidis in inducing phaseolin, glyceolin and deoxyanthocyanidins. For this, fungal mycelial disks were liquid-subcultured in potato dextrose (BD) media and maintained in BOD at 25 °C and 12 h of light and darkness. After 20 days, the cultures were filtered and, the filtrates were used in the experiments. Phaseolin was measured in etiolated hypocotyls of bean. For glyceolin evaluation, cotyledons of soybean were used. The deoxyanthocyanidin accumulation was evaluated in etiolated mesocotyls of sorghum. The results were subjected to analysis of variance and compared by regression tests (p < 0.05). The filtrates of the saprobic fungi C. eragrostidis, C. inaequalis, P. terrestris and M. echinata promoted 9, 8, 9 and 7% greater increases in the concentration of phaseolin accumulations, respectively. The glyceolin accumulation varied with the concentration of C. eragrostidis, C. inaequalis and P. terrestris by adjusting the behavior to a cubic model. The deoxyanthocyanidin accumulation increased with concentration, while the filtrates of M. echinata and C. eragrostidis promoted 2 to 3 times more increases than the application of water. The filtrates of P. terrestris, C. eragrostidis, C. inaequalis and M. echinata induced accumulations of phytoalexins in soybean, beans and sorghum

Data_Sheet_1_Compounds Released by the Biocontrol Yeast Hanseniaspora opuntiae Protect Plants Against Corynespora cassiicola and Botrytis cinerea.XLSX

<p>Plant diseases induced by fungi are among the most important limiting factors during pre- and post-harvest food production. For decades, synthetic chemical fungicides have been used to control these diseases, however, increase on worldwide regulatory policies and the demand to reduce their application, have led to searching for new ecofriendly alternatives such as the biostimulants. The commercial application of yeasts as biocontrol agents, has shown low efficacy compared to synthetic fungicides, mostly due to the limited knowledge of the molecular mechanisms of yeast-induced responses. To date, only two genome-wide transcriptomic analyses have characterized the mode of action of biocontrols using the plant model Arabidopsis thaliana, missing, in our point of view, all its molecular and genomic potential. Here we describe that compounds released by the biocontrol yeast Hanseniaspora opuntiae (HoFs) can protect Glycine max and Arabidopsis thaliana plants against the broad host-range necrotrophic fungi Corynespora cassiicola and Botrytis cinerea. We show that HoFs have a long-lasting, dose-dependent local, and systemic effect against Botrytis cinerea. Additionally, we performed a genome-wide transcriptomic analysis to identify genes differentially expressed after application of HoFs in Arabidopsis thaliana. Our work provides novel and valuable information that can help researchers to improve HoFs efficacy in order for it to become an ecofriendly alternative to synthetic fungicides.</p