Abstract:
Anthracnose, caused by Colletotrichum lindemuthianum, is one of the main diseases affecting common bean in Brazil, and field losses can reach 100%. Transmission of this pathogen from seeds to seedlings/plants may vary according to environmental conditions and initial inoculum levels, among other factors. The aim of this study was to quantify the transmission rate of C. lindemuthianum, race 65, from infected bean seeds to seedlings/plants under controlled conditions. Seed inoculation was performed by the water conditioning technique in order to obtain seeds with different inoculum potentials as a result of the exposure time of the seeds to the fungus in pure culture, with the potentials denominated P0, P36, P72, P108, and P144. Inoculated and non-inoculated seeds were individually sown and kept in growth chambers under two temperatures, 20 and 26 °C, for a period of 28 days. There was transmission of the pathogen in both asymptomatic and symptomatic plants. The highest total transmission rate (92%) occurred in plants originating from seeds exposed for 144 hours to the fungus at 20 °C.
Index terms:
transmission; common bean anthracnose; inoculum potential
Resumo:
A antracnose do feijoeiro, causada por Colletotrichum lindemuthianum, é uma das principais doenças que ocorre no feijoeiro e as perdas podem chegar a 100%. A transmissão deste patógeno de sementes para plântulas/plantas pode variar de acordo com as condições ambientais e nível de inóculo, dentre outros fatores. O objetivo deste trabalho foi quantificar a taxa de transmissão de C. lindemuthianum, raça 65, a partir de sementes de feijão infectadas. A inoculação das sementes foi realizada pela técnica de condicionamento hídrico com o intuito de se obter sementes com diferentes potenciais de inóculo, em função do tempo de exposição das sementes com o fungo em cultura pura, sendo os potenciais denominados: P0, P36, P72, P108 e P144. Sementes não inoculadas e inoculadas foram semeadas individualmente e mantidas em câmaras de crescimento vegetal sob duas temperaturas de crescimento, 20 e 26 °C pelo período de 28 dias. Observou-se que, tanto em plantas assintomáticas, quanto nas sintomáticas, houve transmissão do patógeno. A maior taxa de transmissão total (92%) ocorreu nas plantas originadas a partir de sementes expostas por 144 horas ao fungo e a 20 °C.
Termos para indexação:
transmissão; antracnose do feijoeiro; potencial de inóculo
INTRODUCTION
Anthracnose caused by Colletotrichum lindemuthianum (Sacc. & Magn.) Briosi & Cav. is one of the most serious diseases of common bean in Brazil. The fungus is transmitted by seeds, which are responsible for introduction and significant concentrations of the inoculum in growing areas. Seeds are an effective vehicle for dissemination of this organism (Maringoni and Barros, 2002MARINGONI, A.C.; BARROS, E.M. Ocorrência de isolados de Colletotrichum lindemuthianum resistentes a fungicidas benzimidazóis. Summa Phytopathologica, v.28, n.2, p.197-200, 2002. https://www.researchgate.net/profile/Antonio_Maringoni/publication/265231302_Occurrence_of_isolates_of_Colletotrichum_lindemuthianum_resistant_to_benzimidazole_fungicides/links/5405d08e0cf2c48563b1b8b4/Occurrence-of-isolates-of-Colletotrichum-lindemuthianum-resistant-to-benzimidazole-fungicides.pdf
https://www.researchgate.net/profile/Ant...
; Sartori et al., 2004SARTORI, A.F; REIS, E.M.; CASA, R.T. Quantificação da transmissão de Fusarium moniliforme de sementes para plântulas de milho. Fitopatologia Brasileira, v.29, n.4, p.456-458, 2004. https://www.researchgate.net/publication/26393418_Quantificacao_da_transmissao_de_Fusarium_moniliforme_de_sementes_para_plantulas_de_milho
https://www.researchgate.net/publication...
; Vechiato et al., 1997VECHIATO, M.H.; CASTRO, J.L.; ISHIMURA, I.; SABINO, J.C.; MENTEN, J.O.M. Antracnose do feijoeiro: correlação entre severidade em vagens e a incidência do patógeno nas sementes. Fitopatologia Brasileira , v.22, n.2, p.159-163, 1997. http://biologico.agricultura.sp.gov.br/uploads/docs/arq/V68_1/15.pdf
http://biologico.agricultura.sp.gov.br/u...
; Vieira, 1988VIEIRA, C. Doenças e pragas do feijoeiro. Viçosa: UFV, 1988. 231p.; Ferreira et al., 2019FERREIRA, T.F.; CARVALHO, M.V.; FERREIRA, V.F.; MAVAIEIE, D.P.R.; GUIMARÃES, G.C.; OLIVEIRA, J.A. Sanitary quality of soybean seeds treated with fungicides and insecticides before and after storage. Journal of Seed Science , v.41, n.3, p.293-300, 2019.).
This understanding indicates that one of the main strategies for control of anthracnose is the use of pathogen-free seeds, preventing its dissemination to healthy plants of a given population and to other growing regions (Sartori et al., 2004SARTORI, A.F; REIS, E.M.; CASA, R.T. Quantificação da transmissão de Fusarium moniliforme de sementes para plântulas de milho. Fitopatologia Brasileira, v.29, n.4, p.456-458, 2004. https://www.researchgate.net/publication/26393418_Quantificacao_da_transmissao_de_Fusarium_moniliforme_de_sementes_para_plantulas_de_milho
https://www.researchgate.net/publication...
; Vieira, 1988VIEIRA, C. Doenças e pragas do feijoeiro. Viçosa: UFV, 1988. 231p.).
Transmission of C. lindemuthianum from seeds to seedlings is known to occur quickly and effectively. In Rey et al. (2009REY, M.S.; LIMA, N.B.; SANTOS, J.; PIEROBOM, D.R. Transmissão semente-plântula de Colletotrichum lindemuthinum em feijão (Phaseolus vulgaris). Arquivos do Instituto Biológico, v.76, n.3, p.465-470, 2009. http://www.biologico.agricultura.sp.gov.br/uploads/docs/arq/v76_3/rey.pdf
http://www.biologico.agricultura.sp.gov....
), common bean seeds of the cultivar Líder, belonging to the white bean class, were exposed to C. lindemuthianum (races 65, 73, and 81) for 96 hours. Even though the seeds had not been coated across 100% of their area, they showed high transmission rates of the fungus, which ranged from 70 to 80 %. In addition, symptoms typical of the fungus were observed in all parts of the plants, the cotyledons, stems, and leaves.
The presence of the pathogen in seeds constitutes the primary inoculum source, and it may lead to damage in seed performance in a variable manner. The pathogen may affect establishment of the crop and cause reductions in the plant population, reducing its yield. Furthermore, it remains in the crop area, constituting a source of the inoculum for subsequent crops (Talamini et al., 2001TALAMINI, V.; POZZA, E.A.; MACHADO, J.C.; OLIVEIRA, F.A. Epidemiologia de doenças associadas a Colletotrichum spp. transmitidas por sementes. Revisão Anual de Patologia de Plantas , v.10, p.219-248, 2001.).
Studies on C. lindemuthianum transmission in common bean seeds have not taken into account the presence of the pathogen in tissues of asymptomatic emerged plants or in dead seeds or seedlings in pre-emergence. These evaluations, as a complement to recognition of the presence of the pathogen in symptomatic plants, are of extreme importance, particularly from the epidemiological perspective. It is also important to emphasize that the probability of transmission of the fungus increases with colonization of the internal seed tissues, particularly in the embryo (Agarwal and Sinclair, 1987AGARWAL, V.K; SINCLAIR, J. B. Principles of seed pathology. Boca Raton: CRC Press, 1987. 176p.; Neergaard, 1979NEEGARD, P. Seed Pathology. London: The MacMillan Press, 1979. 839p.).
Given this scenario, the aim of this study was to evaluate the transmissibility of C. lindemuthianum (race 65) from common bean seeds to plants based on different levels of inoculum potential and on environmental growing conditions.
MATERIALS AND METHODS
Origin, multiplication of Colletotrichum lindemuthianum (race 65), and seed profile
For this study, the isolate of C. lindemuthianum (LV238), race 65, was used, granted by the Plant Resistance Laboratory of the Department of Biology of the Universidade Federal de Lavras. This isolate was cultivated in M3 medium [10 g of sucrose, 20 g of agar, 2 g of KH2(PO4), 1 g of MgSO47H2O, 6 g of neopeptone/peptone, 4 mL of panvit, and 1 mL of chloramphenicol per liter of distilled water] in 15-cm Petri dishes and kept in a BOD chamber at 20 ± 2 °C and twelve-hour photoperiod for seven days. The Pérola cultivar of the Carioca common bean group, susceptible to C. lindemuthianum, was used, with initial germination percentage of 95.5%, evaluated according to the Rules for Seed Testing (Brasil, 2009aBRASIL. Ministério da Agricultura, Pecuária e Abastecimento. Regras para Análise de Sementes. Ministério da Agricultura, Pecuária e Abastecimento. Secretaria de Defesa Agropecuária. Brasília: MAPA/ACS, 2009a. 395p. https://www.abrates.org.br/files/regras_analise_de_sementes.pdf
https://www.abrates.org.br/files/regras_...
), and incidence of 0.5% of seeds with Aspergillus flavus and 0.5% with Penicillium sp. detected through the seed health test (Brasil, 2009bBRASIL. Ministério da Agricultura, Pecuária e Abastecimento. Manual de Análise Sanitária de Sementes. Ministério da Agricultura, Pecuária e Abastecimento. Secretaria de Defesa Agropecuária. Brasília: MAPA/ACS , 2009b. 202p. https://www.abrates.org.br/files/manual-de-analise-sanitaria-de-sementes.pdf
https://www.abrates.org.br/files/manual-...
).
A randomized block design was used to conduct the experiments, using four replications per treatment, and two cultivation temperatures.
Obtaining seeds infected by Colletotrichum lindemuthianum with different inoculum potentials
To obtain ‘Pérola’ common bean seeds with different levels of pathogen inoculum potential, the water conditioning method was followed (Botelho et al., 2013BOTELHO, L.S.; ZANCAN, W.L.A.; MACHADO, J.C.; BARROCAS, E.N. Performance of common bean seeds infected by the fungus Sclerotinia sclerotiorum. Journal of Seed Science, v.35, n.2, p.153-160, 2013. http://www.scielo.br/pdf/jss/v35n2/03.pdf
http://www.scielo.br/pdf/jss/v35n2/03.pd...
; Machado et al., 2012MACHADO, J.C.; BARROCAS, E.N.; COSTA, M.L.N.; GUIMARÃES, R.M; MACHADO, C. Uso da técnica de restrição hídrica ou condicionamento osmótico em patologia de sementes. Revisão Anual de Patologia de Plantas, v.20, p.37-63, 2012.). The seeds were initially desinfested with 1% sodium hypochlorite for 1 minute and then washed three times in distilled water, with subsequent drying on two sheets of Germitest (germination testing paper) in plastic trays in a laboratory environment for 48 hours. Fungal colonies at seven days of age were obtained in Petri dishes containing M3 medium with the addition of mannitol, with potential adjusted to -1.0 MPa (Michel and Radcliffe, 1995MICHEL, B.E.; RADCLIFFE, D.A. Computer program relating solute potential to solution composition for five solutes. Agronomy Journal, v.87, n.1, p.131-136, 1995. https://doi.org/10.2134/agronj1995.00021962008700010022x
https://doi.org/10.2134/agronj1995.00021...
). Seeds were distributed in a single layer on this agarized medium in a uniform manner. The Petri dishes with seeds were kept in a BOD chamber at 20 ± 2 °C and twelve-hour photoperiod for periods of 0, 36, 72, 108, and 144 hours, which corresponded to the different inoculum potentials denominated P0, P36, P72, P108, and P144, respectively. After each period of contact between fungi and seeds, the seeds were transferred from the Petri dishes to plastic trays containing two sheets of Germitest paper, remaining at ambient temperature for 48 hours.
Sowing under controlled conditions and evaluations
A randomized block experimental design was used to carry out the experiments, with four replications per treatment and two growing temperatures.
For each treatment, 100 inoculated seeds were sown individually in 200 mL plastic cups containing a mixture of Plantmax® commercial substrate, soil and sand at a 1:1:1 proportion. The cups were placed in four plastic trays, 25 cups in each tray, obtaining four replications. The experiment was conducted in two plant growth chambers with temperatures adjusted to 20 ± 2 °C and 26 ± 2 °C, and twelve-hour photoperiod. The plants were kept under these conditions for 28 days after sowing (D.A.S.). Symptomatic and asymptomatic plants were counted daily.
Fragments (2 cm) from symptomatic and asymptomatic plants, removed at the height of the root collar (C) and of the top leaf node (LN), were placed in Petri dishes containing M3 medium at the temperature of 20 °C and 12-hour photoperiod for seven days for confirmation of the presence of C. lindemuthianum in their tissues. The fragments were first desinfested for one minute in each one of the following products: 70% alcohol, 1% sodium hypochlorite, and distilled and sterilized water. They were then dried on sterilized paper at ambient temperature. After this period, the fragments were individually evaluated in a stereoscopic microscope for observation of the characteristic structures of C. lindemuthianum.
Confirmation of fungus transmission from seeds to plants was assumed when at least one of the fragments (C or LN) indicated the presence of C. lindemuthianum. The total transmission rate was calculated considering the symptomatic plants, asymptomatic plants (occurrence of the fungus in parts of the asymptomatic plants), and dead seedlings in pre-emergence (Siqueira et al., 2014SIQUEIRA, C.S.; MACHADO, J.C.; BARROCAS, E.N.; ALMEIDA, M.F. Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions. Journal of Seed Science , v.36, n.2, p.154-161, 2014. http://www.scielo.br/pdf/jss/v36n2/v36n2a03.pdf
http://www.scielo.br/pdf/jss/v36n2/v36n2...
).
The experiment was conducted in a randomized block design with one cultivar, two temperatures, and four inoculum potentials, with four replications per treatment.
Statistical analysis
Statistical analysis was carried out using the Sisvar® 5.6 program (Ferreira, 2011FERREIRA, D.F. Sisvar: a computer statistical analysis system. Ciência e Agrotecnologia, v.35, n.6, p.1039-1042, 2011. http://www.scielo.br/pdf/cagro/v35n6/a01v35n6.pdf
http://www.scielo.br/pdf/cagro/v35n6/a01...
). When the variable was significant in the F test, the mean values among the treatments were compared by the regression test at 5% probability.
RESULTS AND DISCUSSION
Analyses of variance for the variables - death of seeds.seedlings-1 in pre-emergence, transmission rates in symptomatic and asymptomatic plants, and total transmission rate from seeds to emerged plants when the seeds were inoculated with C. lindemuthianum (race 65) - revealed non-significant differences (p ≤ 0.05) among the treatments (Tables 1 and 2).
Incidence of Colletotrichum lindemuthianum, race 65, isolate LV238, in two regions analyzed of asymptomatic plants grown from inoculated seeds with different seed-fungus contact periods, corresponding to the inoculum potentials P0 (0 h), P36 (36 h), P72 (72 h), P108 (108 h), and P144 (144 h).
According to the control treatments, there was no interference from the water restrictor mannitol on seed performance.
The results observed in this study show that the fungus C. lindemuthianum did not cause a significant effect on seed death in pre-emergence and common bean seedlings. However, their effects can be observed afterwards through the appearance of anthracnose symptoms on emerged plants on the cotyledons, stems, and leaves, which constitute sources of inoculum that can disseminate the pathogen in the current crop and in the following crops.
There was an increase in seedling death in pre-emergence related to inoculum potential with the temperature of 20 °C, which is a factor that favors development of anthracnose (Figure 1). Death in pre-emergence of seeds and seedlings ranged from 16 to 30 %. Some pathogens in other pathosystems proved to be more damaging to seeds in pre-emergence, such as Stenocarpella macrospora, which caused death in pre-emergence of maize seeds in a range from 61 to 73.5% at the higher inoculum potentials (Siqueira et al., 2014SIQUEIRA, C.S.; MACHADO, J.C.; BARROCAS, E.N.; ALMEIDA, M.F. Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions. Journal of Seed Science , v.36, n.2, p.154-161, 2014. http://www.scielo.br/pdf/jss/v36n2/v36n2a03.pdf
http://www.scielo.br/pdf/jss/v36n2/v36n2...
). The results of the present study show that C. lindemuthianum does not cause significant death of its host in pre-emergence, bearing in mind that this pathogen is not considered an organism that inhabits the soil (Hall, 1991HALL, R. Compendium of Bean Diseases. Saint Paul: The American Phytopathological Society Press, 1991. 71p.).
Percentage of death in pre-emergence of common bean (‘Pérola’) seeds-seedlings inoculated with the isolate LV238 of Colletotrichum lindemuthianum (race 65) with different seed-fungus contact periods (0 h, 36 h, 72 h, 108 h, and 144 h), corresponding to the inoculum potentials P0, P36, P72, P108, and P144, and grown at two temperatures (20 and 26 °C).
In relation to the C. lindemuthianum transmission rate from seeds to symptomatic plants (Figure 2), the highest rates were observed in the plants grown from seeds with higher inoculum potentials, P108 and P144. Plants grown at the temperature of 20 °C had a higher transmission rate, as observed in symptomatic plants, than plants grown at 26 °C. In addition, the highest inoculum potentials led to higher fungal transmission rates, reaching 29% (P144), whereas the control (P0) did not manifest transmission.
rate of Colletotrichum lindemuthianum (race 65), isolate LV238, in symptomatic plants of common bean (‘Pérola’) grown from inoculated seeds with different seed-fungus contact periods (0 h, 36 h, 72 h, 108 h, and 144 h), corresponding to the inoculum potentials P0, P36, P72, P108, and P144, and grown at two temperatures (20 and 26 °C).
From these results, it is clear that the temperature of 20 °C is more favorable to transmission of the fungus than the temperature of 26 °C. Examples in this same line of research show different patterns of this type of transmission, although there is a tendency similar to the results of this study. In this respect, Venturoso et al. (2015VENTUROSO, L.R.; BACCHI, L.M.A.; GAVASSONI, W.L.; VENTUROSO, L.A.C.; PONTIM, B.C.A.; REIS, G.F. Inoculação de Sclerotinia sclerotiorum em sementes de oleaginosas: transmissão e seus efeitos sobre a emergência de plantas. Ciência Rural, v.45, n.5, p.788-793, 2015. http://www.scielo.br/pdf/cr/v45n5/0103-8478-cr-00-00-cr20140374.pdf
http://www.scielo.br/pdf/cr/v45n5/0103-8...
) found a high rate of transmission of S. sclerotiorum from seeds to seedlings of some oilseed plants. In their studies on transmission of S. macrospora and S. maydis in maize, Siqueira et al. (2014SIQUEIRA, C.S.; MACHADO, J.C.; BARROCAS, E.N.; ALMEIDA, M.F. Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions. Journal of Seed Science , v.36, n.2, p.154-161, 2014. http://www.scielo.br/pdf/jss/v36n2/v36n2a03.pdf
http://www.scielo.br/pdf/jss/v36n2/v36n2...
; 2016SIQUEIRA, C.S.; BARROCAS, E.N.; MACHADO, J.C.; CORRÊA, C.L. Transmission of Stenocarpella maydis by maize seeds. Revista Ciência Agronômica, v.47, n.2, p.393-400, 2016. http://ccarevista.ufc.br/seer/index.php/ccarevista/article/view/2764/1374
http://ccarevista.ufc.br/seer/index.php/...
) observed that the fungal transmission rates were proportionally higher from the first inoculum potential to the last one, and there was a inverse proportionality between the inoculum potentials and the seed performance.
Therefore, a variation can be seen in the patterns of pathogen transmission in accordance with the initial inoculum potentials in the seeds. These variations among values of inoculum potential for each pathosystem lead to consideration of management strategies corresponding to each case of disease.
From examination of asymptomatic plants (Figures 3A and 3B) that emerged from inoculated seeds, C. lindemuthianum was found to be associated with tissues of the root collar region of the plant and tissues of the top leaf node of some plants. This finding confirms the need for more careful examinations in these types of studies since asymptomatic infected tissues can ensure introduction of the fungus in the crop field or in distant fields, with disastrous consequences for the producers involved with this crop.
Transmission rate (A) and incidence of Colletotrichum lindemuthianum (B) (race 65), isolate LV238, in the region of the root collar (C) and top leaf node (LN) in asymptomatic plants of common bean (‘Pérola’) grown from inoculated seeds with different seed-fungus contact periods (0 h, 36 h, 72 h, 108 h, and 144 h), corresponding to the inoculum potentials P0, P36, P72, P108, and P144, and grown at two temperatures (20 and 26 °C).
A noteworthy study conducted by Noetzold et al. (2014NOETZOLD, R.; ALVES, M.C.; CASSETARI-NETO, D.; MACHADO, A.Q. Variabilidade espacial de Colletotrichum truncatum em campo de soja sob três níveis de sanidade de sementes. Summa Phytopathologica , v.40, n.1, p.16-23, 2014. http://www.scielo.br/pdf/sp/v40n1/v40n1a02.pdf
http://www.scielo.br/pdf/sp/v40n1/v40n1a...
) on spatial variability of Colletotrichum truncatum in soybean showed that this pathogen is able to infect the seeds coming from infected seeds, without symptoms appearing throughout the crop cycle.
The highest pathogen transmission rate in asymptomatic plants (28%) was observed in the plants grown at 20 °C and at the higher inoculum potentials. The lowest rate (zero) was observed in the P0 inoculum potential in plants grown at both temperatures used. When comparing only the occurrences in the plant root collar and top leaf node regions, the highest occurrences of the fungus were found in the fragments coming from the root collar region of plants that grew at the temperature of 26 °C, with a value of 97% at the P144 potential, and with a value of 74% at the P144 potential at 20 °C. It was also found that with the increase of the inoculum potentials, the occurrence of the fungus also increased in the fragments examined (C and LN) under the two temperature conditions, 20 and 26 °C. Siqueira et al. (2014SIQUEIRA, C.S.; MACHADO, J.C.; BARROCAS, E.N.; ALMEIDA, M.F. Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions. Journal of Seed Science , v.36, n.2, p.154-161, 2014. http://www.scielo.br/pdf/jss/v36n2/v36n2a03.pdf
http://www.scielo.br/pdf/jss/v36n2/v36n2...
; 2016SIQUEIRA, C.S.; BARROCAS, E.N.; MACHADO, J.C.; CORRÊA, C.L. Transmission of Stenocarpella maydis by maize seeds. Revista Ciência Agronômica, v.47, n.2, p.393-400, 2016. http://ccarevista.ufc.br/seer/index.php/ccarevista/article/view/2764/1374
http://ccarevista.ufc.br/seer/index.php/...
) report that transmission rates of the fungi S. macrospora and S. maydis in asymptomatic plants of maize were higher in the plant root collar region than in the top leaf node region. In contrast, Zancan et al. (2015ZANCAN, W.L.A.; MACHADO, J.C.; BAUTE, N.L.; SOUSA, B.F.M. Relationship between mycelial inoculum of Sclerotinia sclerotiorum and performance of sunflower seeds under controlled conditions. Bioscience Journal, v.31, n.3, p.775-784, 2015. http://www.seer.ufu.br/index.php/biosciencejournal/article/view/26090/16463
http://www.seer.ufu.br/index.php/bioscie...
) did not observe the presence of S. sclerotiorum in tissues of asymptomatic sunflower plants grown from infected seeds.
Examination of emerged plants shows that the mean transmission rate from asymptomatic plants with C. lindemuthianum grown at 20 °C was in the order of 28% and at 26 °C, this value was 11%.
The highest percentage of total transmission of C. lindemuthianum (92%) in common bean seeds occurred at the highest inoculum potential, P144 at the temperature of 20 °C. At the temperature of 26 °C, the total transmission rate was 56% (Figure 4). Pathogens in other pathosystems, such as Sclerotinia sclerotiorum in common bean seeds and S. macrospora and S. maydis in maize seeds, led to total transmission rates at varying levels, depending on the growing temperature and inoculum potential (Siqueira et al., 2014SIQUEIRA, C.S.; MACHADO, J.C.; BARROCAS, E.N.; ALMEIDA, M.F. Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions. Journal of Seed Science , v.36, n.2, p.154-161, 2014. http://www.scielo.br/pdf/jss/v36n2/v36n2a03.pdf
http://www.scielo.br/pdf/jss/v36n2/v36n2...
; Siqueira et al., 2016SIQUEIRA, C.S.; BARROCAS, E.N.; MACHADO, J.C.; CORRÊA, C.L. Transmission of Stenocarpella maydis by maize seeds. Revista Ciência Agronômica, v.47, n.2, p.393-400, 2016. http://ccarevista.ufc.br/seer/index.php/ccarevista/article/view/2764/1374
http://ccarevista.ufc.br/seer/index.php/...
; Zancan et al., 2015ZANCAN, W.L.A.; MACHADO, J.C.; BAUTE, N.L.; SOUSA, B.F.M. Relationship between mycelial inoculum of Sclerotinia sclerotiorum and performance of sunflower seeds under controlled conditions. Bioscience Journal, v.31, n.3, p.775-784, 2015. http://www.seer.ufu.br/index.php/biosciencejournal/article/view/26090/16463
http://www.seer.ufu.br/index.php/bioscie...
).
Total transmission rate of Colletotrichum lindemuthianum (race 65) from common bean seeds (‘Pérola’), inoculated with different seed-fungus contact times (0 h, 36 h, 72 h, 108 h, and 144 h), corresponding to the inoculum potentials P0, P36, P72, P108, and P144 to plants grown at two temperatures (20 and 26 °C), considering the evaluations of deaths in pre-emergence and transmissions rates in symptomatic and asymptomatic plants.
Given these results, it is clear that the transmission rate of pathogens through seeds of host species has variable patterns, which are affected by diverse factors. Among these factors, the initial inoculum potential in the seeds is crucial in this type of interaction.
Although the methods used in other studies to evaluate the transmission of pathogens through seeds were different, as the literature on this matter shows, the transmission rates found in other pathosystems follow a similar pattern, with specific variations for each case. As shown in this study, the temperature factor is also decisive for bringing about transmission of the pathogens in the various pathosystems.
CONCLUSIONS
The transmission rate of C. lindemuthianum from infected common bean seeds is variable and directly proportional to the pathogen inoculum potentials in the seeds under favorable temperature condition for the disease development.
Higher percentages of total transmission rates of the fungus are observed at higher inoculum potentials and in growing seedlings at the temperature of 20 °C.
Under both growing conditions, 20 and 26 °C, C. lindemuthianum was detected in tissues from parts of asymptomatic plants, and the highest transmission rates were observed at the temperature of 20 °C.
The incidence of C. lindemuthianum in the infected seeds was more verified in the region of the root collar in asymptomatic plants at the temperature of 20 °C, and these values increased in proportion to the increase of the inoculum potentials.
ACKNOWLEDGMENTS
Our thanks to the Universidade Federal de Lavras, to the Universidade Pedagógica de Quelimane, to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support through scholarships, to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for support in carrying out this study, and to the SEPROTEC for providing seeds for this study.
REFERENCES
- AGARWAL, V.K; SINCLAIR, J. B. Principles of seed pathology Boca Raton: CRC Press, 1987. 176p.
- BOTELHO, L.S.; ZANCAN, W.L.A.; MACHADO, J.C.; BARROCAS, E.N. Performance of common bean seeds infected by the fungus Sclerotinia sclerotiorum Journal of Seed Science, v.35, n.2, p.153-160, 2013. http://www.scielo.br/pdf/jss/v35n2/03.pdf
» http://www.scielo.br/pdf/jss/v35n2/03.pdf - BRASIL. Ministério da Agricultura, Pecuária e Abastecimento. Regras para Análise de Sementes Ministério da Agricultura, Pecuária e Abastecimento. Secretaria de Defesa Agropecuária. Brasília: MAPA/ACS, 2009a. 395p. https://www.abrates.org.br/files/regras_analise_de_sementes.pdf
» https://www.abrates.org.br/files/regras_analise_de_sementes.pdf - BRASIL. Ministério da Agricultura, Pecuária e Abastecimento. Manual de Análise Sanitária de Sementes Ministério da Agricultura, Pecuária e Abastecimento. Secretaria de Defesa Agropecuária. Brasília: MAPA/ACS , 2009b. 202p. https://www.abrates.org.br/files/manual-de-analise-sanitaria-de-sementes.pdf
» https://www.abrates.org.br/files/manual-de-analise-sanitaria-de-sementes.pdf - FERREIRA, D.F. Sisvar: a computer statistical analysis system. Ciência e Agrotecnologia, v.35, n.6, p.1039-1042, 2011. http://www.scielo.br/pdf/cagro/v35n6/a01v35n6.pdf
» http://www.scielo.br/pdf/cagro/v35n6/a01v35n6.pdf - FERREIRA, T.F.; CARVALHO, M.V.; FERREIRA, V.F.; MAVAIEIE, D.P.R.; GUIMARÃES, G.C.; OLIVEIRA, J.A. Sanitary quality of soybean seeds treated with fungicides and insecticides before and after storage. Journal of Seed Science , v.41, n.3, p.293-300, 2019.
- HALL, R. Compendium of Bean Diseases Saint Paul: The American Phytopathological Society Press, 1991. 71p.
- MACHADO, J.C.; BARROCAS, E.N.; COSTA, M.L.N.; GUIMARÃES, R.M; MACHADO, C. Uso da técnica de restrição hídrica ou condicionamento osmótico em patologia de sementes. Revisão Anual de Patologia de Plantas, v.20, p.37-63, 2012.
- MARINGONI, A.C.; BARROS, E.M. Ocorrência de isolados de Colletotrichum lindemuthianum resistentes a fungicidas benzimidazóis. Summa Phytopathologica, v.28, n.2, p.197-200, 2002. https://www.researchgate.net/profile/Antonio_Maringoni/publication/265231302_Occurrence_of_isolates_of_Colletotrichum_lindemuthianum_resistant_to_benzimidazole_fungicides/links/5405d08e0cf2c48563b1b8b4/Occurrence-of-isolates-of-Colletotrichum-lindemuthianum-resistant-to-benzimidazole-fungicides.pdf
» https://www.researchgate.net/profile/Antonio_Maringoni/publication/265231302_Occurrence_of_isolates_of_Colletotrichum_lindemuthianum_resistant_to_benzimidazole_fungicides/links/5405d08e0cf2c48563b1b8b4/Occurrence-of-isolates-of-Colletotrichum-lindemuthianum-resistant-to-benzimidazole-fungicides.pdf - MICHEL, B.E.; RADCLIFFE, D.A. Computer program relating solute potential to solution composition for five solutes. Agronomy Journal, v.87, n.1, p.131-136, 1995. https://doi.org/10.2134/agronj1995.00021962008700010022x
» https://doi.org/10.2134/agronj1995.00021962008700010022x - NEEGARD, P. Seed Pathology London: The MacMillan Press, 1979. 839p.
- NOETZOLD, R.; ALVES, M.C.; CASSETARI-NETO, D.; MACHADO, A.Q. Variabilidade espacial de Colletotrichum truncatum em campo de soja sob três níveis de sanidade de sementes. Summa Phytopathologica , v.40, n.1, p.16-23, 2014. http://www.scielo.br/pdf/sp/v40n1/v40n1a02.pdf
» http://www.scielo.br/pdf/sp/v40n1/v40n1a02.pdf - REY, M.S.; LIMA, N.B.; SANTOS, J.; PIEROBOM, D.R. Transmissão semente-plântula de Colletotrichum lindemuthinum em feijão (Phaseolus vulgaris). Arquivos do Instituto Biológico, v.76, n.3, p.465-470, 2009. http://www.biologico.agricultura.sp.gov.br/uploads/docs/arq/v76_3/rey.pdf
» http://www.biologico.agricultura.sp.gov.br/uploads/docs/arq/v76_3/rey.pdf - SARTORI, A.F; REIS, E.M.; CASA, R.T. Quantificação da transmissão de Fusarium moniliforme de sementes para plântulas de milho. Fitopatologia Brasileira, v.29, n.4, p.456-458, 2004. https://www.researchgate.net/publication/26393418_Quantificacao_da_transmissao_de_Fusarium_moniliforme_de_sementes_para_plantulas_de_milho
» https://www.researchgate.net/publication/26393418_Quantificacao_da_transmissao_de_Fusarium_moniliforme_de_sementes_para_plantulas_de_milho - SIQUEIRA, C.S.; MACHADO, J.C.; BARROCAS, E.N.; ALMEIDA, M.F. Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions. Journal of Seed Science , v.36, n.2, p.154-161, 2014. http://www.scielo.br/pdf/jss/v36n2/v36n2a03.pdf
» http://www.scielo.br/pdf/jss/v36n2/v36n2a03.pdf - SIQUEIRA, C.S.; BARROCAS, E.N.; MACHADO, J.C.; CORRÊA, C.L. Transmission of Stenocarpella maydis by maize seeds. Revista Ciência Agronômica, v.47, n.2, p.393-400, 2016. http://ccarevista.ufc.br/seer/index.php/ccarevista/article/view/2764/1374
» http://ccarevista.ufc.br/seer/index.php/ccarevista/article/view/2764/1374 - TALAMINI, V.; POZZA, E.A.; MACHADO, J.C.; OLIVEIRA, F.A. Epidemiologia de doenças associadas a Colletotrichum spp. transmitidas por sementes. Revisão Anual de Patologia de Plantas , v.10, p.219-248, 2001.
- VECHIATO, M.H.; CASTRO, J.L.; ISHIMURA, I.; SABINO, J.C.; MENTEN, J.O.M. Antracnose do feijoeiro: correlação entre severidade em vagens e a incidência do patógeno nas sementes. Fitopatologia Brasileira , v.22, n.2, p.159-163, 1997. http://biologico.agricultura.sp.gov.br/uploads/docs/arq/V68_1/15.pdf
» http://biologico.agricultura.sp.gov.br/uploads/docs/arq/V68_1/15.pdf - VENTUROSO, L.R.; BACCHI, L.M.A.; GAVASSONI, W.L.; VENTUROSO, L.A.C.; PONTIM, B.C.A.; REIS, G.F. Inoculação de Sclerotinia sclerotiorum em sementes de oleaginosas: transmissão e seus efeitos sobre a emergência de plantas. Ciência Rural, v.45, n.5, p.788-793, 2015. http://www.scielo.br/pdf/cr/v45n5/0103-8478-cr-00-00-cr20140374.pdf
» http://www.scielo.br/pdf/cr/v45n5/0103-8478-cr-00-00-cr20140374.pdf - VIEIRA, C. Doenças e pragas do feijoeiro Viçosa: UFV, 1988. 231p.
- ZANCAN, W.L.A.; MACHADO, J.C.; BAUTE, N.L.; SOUSA, B.F.M. Relationship between mycelial inoculum of Sclerotinia sclerotiorum and performance of sunflower seeds under controlled conditions. Bioscience Journal, v.31, n.3, p.775-784, 2015. http://www.seer.ufu.br/index.php/biosciencejournal/article/view/26090/16463
» http://www.seer.ufu.br/index.php/biosciencejournal/article/view/26090/16463
Publication Dates
-
Publication in this collection
14 Aug 2020 -
Date of issue
2020
History
-
Received
25 Nov 2019 -
Accepted
26 May 2020