Production of lytic enzymes by Trichoderma isolates during in vitro antagonism with Aspergillus niger, the causal agent of collar rot of peanut

Abstract

Twelve isolates of Trichoderma (six of T. harzianum, five of T. viride, one of T. virens), which reduced variably the incidence of collar rot disease caused in peanut by Aspergillus niger Van Tieghem, were evaluated for their potential to produce lytic enzymes during in vitro antagonism. T. viride 60 inhibited highest (86.2%) growth of test fungus followed by T. harzianum 2J (80.4%) at 6 days after inoculation (DAI) on PDA media. The specific activities of chitinase, β-1,3-glucanase and protease were 11, 3.46 and 9 folds higher in T6 antagonist (T. viride 60 and A. niger interactions) followed by 8.72, 2.85 and 9 folds in T8antagonist (T. harzianum 2J and A. niger interactions), respectively, compared to the activity produced by control petri plate T13 (A. niger alone) at 6 DAI. Activity of these lytic enzymes induced in antagonists’ plates comprises the growth of Trichoderma isolates. However, cellulase and poly galacturonase were found least amount in these antagonists treatment. A significant positive correlation (p=0.01) between percentage growth inhibition of test fungus and lytic enzymes – (chitinase, β-1,3-glucanase and protease) in the culture medium of antagonist treatment established a relationship to inhibit growth of fungal pathogen by increasing the levels of these enzymes. Among the Trichoderma isolates, T. viride 60 was found best strain to be used in biological control of plant pathogen A. niger.

Isolation of Six Microorganisms from Rotten <i> Dioscorea alata </i> (Water Yam), and Antimicrobial Sensitivity Test with Nine Plant Extracts

“…Also observed was similarity or variance of their occurrence across the two local government areas; this is most probably due to the weather condition at the time of harvest, if the day is dry, windy and the tubers are bruised, it dries easily reducing entry time of the microorganisms but under humid weather, the organisms stick fast and grow causing damages, this type of change can also influence variation in occurrence on a farm. Aspergillus niger showed high occurrence incidence in all the water yam varieties in all the sampled areas, this is most probably due to the fact that the time required for it to survive and cause rot is shorter than most microorganisms found on yam; it creates pre-harvest and post-harvest food rot all over the world for tubers as well as nuts [43] [54] [70]. This was followed by Rhizopus stolonifera, Pseudomonas aeruginosa, Aspergillus flavus, Penicillium marneffei and Erwinia carotovora.…”

“…The fungi; Aspergillus niger, Aspergillus flavus and the bacteria Pseudomonas aeruginosa isolated are known to be human pathogenic or opportunistic human pathogenic organisms [44] [68]. They may even secrete substances that are harmful to humans [43] [69].…”

“…The dried plant extracts show mild or low inhibition in most cases. This could be due to chemical changes brought about by enzyme hydrolysis which could bring about hydrolysis of some compounds which may even induce intra or intermolecular reactions [43]. Some plant extracts could not inhibit other microorganisms but effectively inhibited others; this is probably due to the fact that, the active sites reacting with the various microorganisms were different or there were different substances in extracts inhibiting different microorganisms.…”

Plant Growth Promoting Rhizobacteria (PGPR): Current and Future Prospects for Development of Sustainable Agriculture

“…Inoculation with Trichoderma sp. has been the preferred choice for novel biocontrol agents against Aspergillus niger the causal agent of collar rot of peanut [60]. The use of multistrain inoculants are also be a good strategy that enables organisms to successfully survive, maintain themselves in communities.…”

A comparative study of phenols composition, antioxidant, and antifungal potency of leaves extract from five Moroccan Vitis vinifera L. varieties

“…Trichoderma sp antagonist fungi are potentials capable of producing volatile substances with either a fungistatic effect such as acetaldehyde (Dennis & Webster, 1971) or a fungicidal effect such as alkyl pyrones (Claydon et al, 1987). Gajera and Vakharia (2012) report a significant positive correlation between Trichoderma growth inhibition (80%) and chitinase, glucanase, and protease lytic enzymes. Salman (2005) reports that T. harzianum was effective and has a significant effect in R. stolonifer biological control on apple, pear, and peach trees.…”