Estimates of genetic parameters related to chitinase production by the entomopathogenic fungus Metarhizium anisopliae

Abstract

Chitinolytic activity and dry mass production were determined in culture filtrates from 17 Metarhizium anisopliae strains grown in liquid medium containing chitin as the only carbon source. The objectives were to estimate parameters such as genetic variance among strains, heritability and expected gain from selection, as well as correlations between tested traits. Wide genotypic variability was observed among strains in chitinolytic activity, permitting the exploitation of this property in selection. The high heritability suggests that progress can be made through phenotypic selection. The genotypic correlation coefficient between dry mass production and chitinolytic activity detected in the filtrates was negative (<img src="http:/img/fbpe/gmb/v21n2/pg171-1.jpg" alt="wpe1.jpg (777 bytes)" align="absmiddle">= - 0.588). One of the isolates was also investigated for variation in the two traits as a function of culture growth time. The results showed an increase in enzyme activity up to the 8th (and last) day of the experiment and a decrease in dry mass from the 4th day on.<br>Foi determinada a atividade quitinolítica apresentada pelos filtrados de culturas de 17 genótipos de Metarhizium anisopliae crescidos em meio líquido, tendo quitina como única fonte de carbono. O objetivo foi a estimativa de parâmetros como a variância genética, a herdabilidade e o ganho esperado na seleção. Uma grande variabilidade genotípica foi verificada na atividade quitinolítica, permitindo sua exploração no melhoramento. Os altos coeficientes de herdabilidade permitem esperar um grande progresso na seleção fenotípica. Para uma das linhagens foi também determinada a variação na atividade enzimática, em função do tempo de crescimento das culturas. Os resultados mostraram um aumento na atividade enzimática até o oitavo dia da avaliação

Chitinase genes from Metarhizium anisopliae for the control of whitefly in cotton

“…The chitinolytic activity of 17 isolates of M. anisopliae was evaluated by Braga et al . [48] in different culture media and activity was found to vary from 0.0261 to 0.1340 U ml −1 . Kang et al .…”

Cuticle degrading enzyme production by some isolates of the entomopathogenic fungus, Metarhizium anisopliae (Metsch.)

“…in early works chitinase activity 0.01-0.0398U/ml was recorded for various M. anisopliae isolates studied by Nahar et al (2004). Braga et al (1998) evaluated chitinolytic activity of seventeen isolates of M. anisopliae isolates and reported the activity to vary from 0.0261 to 0.1340U/ml. Similarly St.…”

“…Fungi are widely recognized as preferable lipase sources. Braga et al (1998) carried out chitinolytic activity together with estimates of the genetic parameters of such activities and suggested that these parameters help in improving these traits in M. anisopliae. Mustafa and Kaur (2009) studied in-vitro production of cuticle-degrading enzymes, such as chitinase, proteinase, caseinase, lipase and amylase in fourteen isolates of M. anisopliae and suggested that the enzyme production exhibited significant natural isolate variability.…”

Optimization of the Chitinase Production by Different &lt;i&gt;Metarhizium anisopliae&lt;/i&gt; Strains under Solid-State Fermentation with Silkworm Chrysalis as Substrate Using CCRD

“…The conditions observed in SSF is much closer to the conditions found in nature by the fungus. The chitinase production in both fermentation conditions has been reported for M. anisopliae [17,21]. Usually, the conditions of the SSF are simple and the substrate used has the necessary nutrients for the growth of microorganism.…”