Evaluation of Pochonia chlamydosporia and Purpureocillium lilacinum for Suppression of Meloidogyne enterolobii on Tomato and Banana

Abstract

Meloidogyne enterolobii is one of the most important root-knot nematode in tropical regions, due to its ability to overcome resistance mechanisms of a number of host plants. The lack of new and safe active ingredients against this nematode has restricted control alternatives for growers. Egg-parasitic fungi have been considered as potential candidates for the development of bionematicides. In tissue culture plates, Pochonia chlamydosporia (var. catenulata and chlamydosporia) and Purpureocillium lilacinum strains were screened for their ability to infect eggs of the root-knot nematode M. enterolobii on water-agar surfaces. Reduction in the hatching of J2 varied from 13% to 84%, depending on strain. The more efficacious strains reduced hatchability of J2 by 57% to 84% when compared to untreated eggs, but average reductions were only 37% to 55% when the same strains were applied to egg masses. Combinations of fungal isolates (one of each species) did not increase the control efficacy in vitro. In experiments in which 10,000 nematode eggs were inoculated per plant, reductions in the number of eggs after 12 months were seen in three of four treatments in banana plants, reaching 34% for P. chlamydosporia var. catenulata. No significant reductions were seen in tomato plants after 3 mon. In another experiment with tomato plants using either P. chlamydosporia var. catenulata or P. lilacinum, the number of eggs was reduced by 34% and 44%, respectively, when initial infestation level was low (500 nematode eggs per plant), but tested strains were not effective under a moderate infestation level (5,000 eggs per plant). Under all infestation levels tested in this work, gall and egg mass indexes (MI) did not differ from the untreated controls, bringing concerns related to the practical adoption of this control strategy by farmers. In our opinion, if the fungi P. chlamydosporia and P. lilacinum are to be used as biocontrol tools toward M. entorolobii, they should focus on agricultural settings with low soil infestation levels and within an IPM approach.

Whole Genome Sequencing and Comparative Genomics of Two Nematicidal Bacillus Strains Reveals a Wide Range of Possible Virulence Factors

“…Sequence 'fig|1399.9.peg.2658' showed the highest sequence identity with chitinase ABW96521.1 (33%; E-value = 1.0e-31) from the fungus Pochonia chlamydosporia, while sequence 'fig|1399.9.peg.3724' showed highest sequence identity with chitinase ABP37997.1 (26%; E-value = 1.0e-17) from the fungus Purpureocillium lilacinum. Both fungi are nematophagous and have been shown to parasitize eggs of the RKN Meloidogyne enterolobii (Silva et al 2017). Through a recursive BLAST search, two additional sequences were found in the I-1582 assembly and one in ZZV12-4809 but appeared to lack the catalytic chitinase domain ( Supplementary Table 8).…”

Rapid and Easy Modified Plate-based Screening Methods for Quantitative and Qualitative Detection of Protease Production by Fungi

“…On the contrary, SMA has proven appropriate for detection of protease production in bacteria, because of their immobility on the medium surface (Chantawannakul et al, 2002;Karimi et al, 2012). Proteases production plays prominent role in biocontrol activity of fungal species such as T. longibrachiatum, B. bassiana and P. lilacinum against fungal and nematode pathogens and pests (Sanchez et al, 2007;Zibaee and Bandani, 2009;Silva et al, 2017;Zhang et al, 2017). In viewpoint of the biocontrol of plant pathogens; most BCAs such as Trichoderma spp.…”

Biocontrol potential of Pochonia chlamydosporia var. chlamydosporia isolates against Meloidogyne javanica on pistachio

“…chlamydosporia isolates on Meloidogyne javanica populations, survival of the fungus isolates and their colonization of roots of pistachio after 4 months in the greenhouse (n = 5 means ± S.E) Data in parenthesis were transformed before being subjected to ANOVA; numbers followed by the same letter in the columns are not significantly different at 5% level according to LSD test; Pf/Pi = ratio of final to initial population density, % control: control-treatment/control × 100. Pcc10, Pcc20, Pcc30, Pcc60C = 1 × 10 4 , Pcc60A = 1 × 10 3 and PccB = 5 × 10 3 cfu/g soil and egg mass indexes of M. enterolobii Yang and Eisenback on tomato or banana (Silva et al 2017). Selection of an efficient biocontrol agent is based on whether it kills nematodes or prevents them from causing damage to their hosts.…”