Chito-oligosaccharide production by chitinase of Streptococcus macrosporeus VTCC 940003 and their inhibition activities on Botrytis cinerea

Detection of chitinase activity after electrophoresis in native polyacrylamide gels containing glycol chitin showed that Streptomyces macrosporeus VTCC 940003 produced several chitinases. Chito-oligosaccharides (COS) were produced from commercial chitosan using these chitinases. The degree of polymerization (DP) of the produced COS was confirmed by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). Moreover, the biological activities of the COS against Botrytis cinerea in vitro and in vivo were assessed. The COS preparation contained a mixture of oligomers with DP ranging from 2 to 10. The COS also showed inhibition activities on spore germination, mycelial growth and infection of B. cinerea on tomato leaves.