The production relationship of destruxins and blastospores of Metarhizium anisopliae with virulence against Plutella xylostella

Abstract

Metarhizium anisopliae as an essential entomopathogenic fungus has been known to produce destruxins (a kind of cyclo-peptidic mycotoxins) and blastospores in submerged culture. Blastospores and destruxins are candidates for insecticides, but the relations of both productions and the impact factors are unclear yet. In this study, we investigated the effects of inoculums, rotation, dissolved oxygen (DO) on the production of blastospores and destruxins A and B (DA and DB) in submerged culture of M. anisopliae strain MaQ01. The results indicated that DO levels were regulated by inoculum amounts and rotation speeds, meanwhile, the production of DA, DB and blastospores was also closely influenced by those factors. Totally, when DO value was more than 40%, the higher productions of destruxins and blastospores were achieved, by contrast, lower than 40% of DO values resulted in lower productions. The regression analysis suggested that the production of DA, DB and blastospores was positively correlated with the DO levels. Meanwhile, the positive correlations between the productions of DA or DB and blastospores were also found. Briefly, when the rotation is 150 r min-1 and the inoculum is 1.0×10 6 spore mL-1 , the DA, DB and blastospores achieved the best production of 61.81 mg mL-1 , 24.74 mg mL-1 and 5.73×10 6 spore mL-1 , respectively. In addition, the pathogenicities of blastospores and conidia against Plutella xylostella were bioassayed. The higher mortalities of P. xylostella were totally recorded in blastospore treatments than in conidia treatments, especially in lower dosages and earlier periods. Our research will give some new insights to production of destruxins and blastospores by using M. anisopliae.

Acetamiprid Affects Destruxins Production but Its Accumulation in Metarhizium sp. Spores Increases Infection Ability of Fungi

“…It cannot be said that the low concentrations of dtxs in M. robertsii ARSEF727 and M. globosum were caused by the poor growth of these fungi, because their growth rate was similar to that of M. brunneum and M. robertsii IM6519, which turned out to be the species with the highest content of dtxs in the biotic controls. Interestingly, M. anisopliae, in which the synthesis of dtxs has been accurately described, did not turn out to be the best producer [21]. M. robertsii IM2358 was also found to have higher levels of dtxs than M. anisopliae.…”

Advances in >i<Metarhizium>/i< blastospores production and formulation and transcriptome studies of the yeast and filamentous growth

“…Obtaining stabilized blastospores is a crucial step for the further development of commercial fungal formulations. It should be noted that no attempts to dry and stabilize these fungal structures prior to effectiveness assays against different pests had been reported earlier (Alkhaibari et al, , 2017Dong et al, 2016;Fargues et al, 2002;Ramle and Kamarudin, 2014;. As far as we know, our results are therefore the first evidence that air-dried blastospores of M. robertsii are as effective in killing cattle tick larvae at the same rate and concentration as that observed for conidia.…”

“…Although naturally produced in the insect hemolymph, blastospores can be produced artificially in vitro in a balanced liquid culture medium, within a short period of time and under specific growth conditions already described in many earlier studies Mascarin et al, 2015a;. Blastospores of the fungus Metarhizium have already been shown to be as infectious as aerial conidia to different arthropod hosts (Ramle and Norman, 2014;Alkhaibari et al 2017) or even more virulent Dong et al, 2016). However, compared to aerial conidia, blastospores are more sensitive to osmotic and oxidative stresses induced by dehydration or other environmental stresses; thus, they require cautious manipulation during drying and formulation steps of the microbial biopesticide development process (Jaronski and Mascarin, 2016).…”

Synthesis of Metarhizium anisopliae–Chitosan Nanoparticles and Their Pathogenicity against Plutella xylostella (Linnaeus)

“…Several strains of fungi have been isolated and used to control various insect pests, including P. xylostella [3][4][5][6][7]. Of these entomopathogenic fungi, Metarhizium anisopliae (Cordycipitaceae; Hypocreales) has been documented as an effective pathogen of P. xylostella [8][9][10]. Wu et al [8] studied the pathogenicity of M. anisopliae against P. xylostella.…”