Evaluation of herbicidal potential of depsides from Cladosporium uredinicola, an endophytic fungus found in Guava fruit

Abstract

Dois produtos naturais produzidos por Cladosporium uredinicola, um fungo endofítico isolado da goiaba, tiveram seus efeitos sobre a fotossíntese avaliados. Os compostos inibiram o fluxo de elétrons (basal, fosforilante e desacoplado) de água a metilviologênio (MV). Esses compostos atuam como inibidores da reação de Hill em tilacóides de espinafre frescos. Esses policetídeos pertencem à classe dos depsídeos e inibiram o fluxo de elétrons das reações parciais do fotossistema II (PS II) de água a 2,5-dicloro-1,4-benzoquinona (DCBQ), de água a silicomolibdato de sódio (SiMo Na + ), e ainda inibiram parcialmente de 1,5-difenilcarbazida (DPC) a 2,6-dicloroindofenol (DCPIP). Esses resultados estabeleceram que os sítios de inibição dos depsídeos estão localizados tanto no lado doador quanto no aceptor do PS II, entre P 680 e Q A . Medidas de fluorescência da clorofila a corroboraram para elucidar esse mecanismo de ação. Nenhum dos compostos inibiu o fluxo de elétrons no fotossistema I (PS I).Two natural products produced by Cladosporium uredinicola, an endophytic fungus isolated from guava fruit, were evaluated for their effects on photosynthesis. Both of them inhibited electron flow (basal, phosphorylating, and uncoupled) from water to methylviologen (MV), acting as Hill reaction inhibitors in freshly lysed spinach thylakoids. These polyketides, belonging to depsides class, inhibited partial reactions of photosystem II (PS II) electron flow from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), from water to sodium silicomolybdate (SiMo Na + ), and partially inhibited electron flow from 1,5-diphenylcarbazide (DPC) to 2,6-dichloroindophenol (DCPIP). These results established that the depsides sites of inhibition are located on the donor and acceptor sides of PS II, between P 680 and Q A . Chlorophyll a fluorescence measurements corroborated this mechanism of action. None of the tested compounds inhibited photosystem I (PS I) electron transport.Keywords: endophyte, Cladosporium, depsides, Hill reaction inhibitors, photosystem II IntroductionExtensive research has been carried out worldwide to find new effective and ecologically natural friendly alternatives due to ecological restrictions in applying synthetic herbicides. A possible solution is the use of weed pathogens for biological control, using fungal metabolites to produce new selective herbicides such as biolaphos. 1 Therefore, these compounds could act as communicators between plants and fungi. 2,3 The interests of chemical ecology are to describe the ecological interactions mediated by natural products and their potential application. 3 The interactions depend on the organisms involved and their environments.Natural products have an enormous diversity of chemical structures and could show modes of action different than the commercial herbicides, suggesting that they are ideal leads for new herbicide discovery. 2,4,5 Recently, herbicidal activity of many natural products isolated from fungi, like stagonalide, 6 stagonolide H, 2 alternethanoxin A and B, 7 lasiodiplodi...

<i>In Vitro</i> and <i>In Silico</i> Antioxidant, Anti-Diabetic, Anti-HIV and Anti-Alzheimer Activity of Endophytic Fungi, <i>Cladosporium uredinicola</i> Phytochemicals

“…The methanol extract of C. uredinicola shows important phytochemicals viz., flavonoids, tannins, alkaloids, glycosides, phenols and coumarins but it not shown the saponin, anthraquinones ( Table 1). The C. uredinicola reported as endophytic fungi from Tinospora cordifolia [19], Psidium guajava [20], Guava fruit [21]. Similar kinds of phytochemicals were noticed from endophytic fungi, Neurospora crassa [22] and Penicillium species [23].…”

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“…The endophytic fungi from Psidium species produce natural products with different biological activities [63][64][65][66][67] . The natural products have been known for their enormous potencies such as antimicrobial agents, 68,62 anticancer, 69 and herbicides 70 . The result of our study indicated that the endophytic F. oxysporum extract from P. guajava showed broad-spectrum antimicrobial activities against the tested bacterial pathogens.…”

Hongos endófitos: fuente potencial de metabolitos secundarios bioactivos con utilidad en agricultura y medicina

“…Por otra parte se aislaron dos policétidos de la familia de los dépsidos, la uredinina A y el 4-[(2,4-dihidroxi-3,6-dimetilbenzoil)oxi]-2-hidroxi-3,6-dimetilbenzoato de 3-hidroxi-2,5-dimetilfenilo, del hongo Cladosporium uredinicola, un endófito de la guayaba (Psidium guajava, Rosaceae). Ambos dépsidos presentan actividad herbicida inhibiendo el flujo de electrones del agua al metilviológeno, actuando como inhibidores de la reacción de Hill en tilacoides de espinaca 44 .…”

“…Estas evaluaciones preliminares permiten detectar extractos naturales apropiados para la obtención de agentes terapéuticos o agroquímicos 4,5 . En general, los extractos que demuestran respuestas positivas en los ensayos de fitoinhibición o como inhibidores del crecimiento de microorganismos, se consideran candidatos adecuados para la realización de otras pruebas biológicas dirigidas a un blanco de acción específico en la fisiología o en el metabolismo vegetal o de los microorganismos, respectivamente 17,44 .…”