the role of fungal chitinases in biological control of plant root-knot nematode meloidogyne incognita on cucumber

[...]... from M incognita egg-parasitic fungus P variotii DG-3, (4) analysis of the mode of action of these chitinases on chitooligomers, (5) extraction of chitin from F solani cell walls and analysis of hydrolysis products from fungal chitin by Chi32 and Chi46, (6) initial elucidation of the role of the 37kDa chitinases from L antillanum B-3 in the infection process to M incognita eggs, (7) suppression of root-knot. .. ml xvii THE ROLE OF FUNGAL CHITINASES IN BIOLOGICAL CONTROL OF PLANT ROOT-KNOT NEMATODE Meloidogyne incognita ON CUCUMBER NGUYEN VAN NAM Department of Agricultural Chemistry Graduate School, Chonnam National University, Gwangju, 500-757, Korea (Directed by Professor Ro-Dong Park) ABSTRACT Chitin layer, a major composition of fungal cell walls of Fusarium solani and eggshells of Meloidogyne incognita. .. al 2005) 1.4.2 Roles of chitinases in biological control of plant diseases Among the chitinase-producing organisms, fungi are believed to produce various isoforms of chitinases with different biophysical functions In fungi, chitinases play an important roles in biological and physiological such as lysis of the cell walls (separation of cells after division, hyphal autolysis), nutritional requirements,... fungi, eggshells of nematode eggs, exoskeletons of insects) The protection of plant roots against infection by any microbial agents and plant nematodes is mainly dependent upon the introduction of hazardous pesticides into environment (El-Fiky et al 2003) Applications of fungicides and nematicide fumigants can have drastic effects on the environment and consumer and they are often applied in lager quantities... chitinases Chitinases (EC 3.2.1.14) are glycosyl hydrolases that catalyze the degradation of chitin, a component chemical in nematode eggshells and fungal cell walls Chitinolytic enzymes are found in a variety of organisms, not only fungi and insects, but also bacteria and higher plants Recently chitinases have received renewed attention since they play a role in plant defense against chitin-containing pathogens... information is not known For that purpose, the objectives of our study are about: (1) isolation of chitinolytic fungi having antifungal activity and nematode- egg parasitism, (2) characterization of H aureoviride DY-59 and R microsporus VS-9 chitinases and elucidating the role of DY-59 and VS-9 chitinases on the suppression of a F solani fungus (3) purification and characterization of two chitinases (Chi32... disease-causing factors of root galls of cucumber, is a target for fungal chitinases considered to be involved in the parasitism process This study was focused on an important function and elucidation of fungal chitinases in parasitism process Among fungal chitinases, chitinases produced from Hypocrea aureoviride DY-59 and Rhizopus microsporus VS-9 were used for antifungal activity against F solani Chitinase... nematode M incognita on cucumber by chitinolytic fungi L psalliotae A-1 and L antillanum B-3 in pot experiment - 11 - CHAPTER II ISOLATION AND SCREENING OF ANTAGONISTICCHITINOLYTIC FUNGI FROM SOIL ABSTRACT Chitinases play an important role in parasitism of fungi into some plant pathogens containing chitin in cell walls such as fungi, nematodes, or insects This chapter describes procedure of screening... and 47.4% in B-3, A-1 plus B-3, and A-1 treated cucumber roots, respectively In addition, nematode population of cucumber root was reduced by 79.8%, 62.0%, and 37.9% in B-3, A-1 plus B-3, and A-1 treatments after 7 weeks of growth period The results demonstrate that the fungus B-3 showed effectiveness of biological control of M incognita on cucumber in pot experiment In conclusion, chitinase of 51.9... comprise proteins of 30-50 kDa whereas about a molecular mass of 140-170 kDa is typical for subgroup C These chitinases contain Nterminal signal peptides, which suggest that they are targeted to the secretive pathway They contain a chitin-binding domain (CBM 18 according to the CAZy classification) and tandem lysin motifs (LysMs), which are short peptide domains implicated in binding of peptidoglycan . Doctor of Philosophy Dissertation The Role of Fungal Chitinases in Biological Control of Plant Root-Knot Nematode Meloidogyne incognita on Cucumber Department of Agricultural. characteristics of plant root-knot nematode 4 1.3. Biological control of plant parasitic nematode 5 1.4. Chitinases 7 1.4.1. Property and molecular structure of chitinases 7 1.4.2. Roles of chitinases in. Chonnam National University Nguyen Van Nam Directed by Professor Ro-Dong Park February, 2009 The Role of Fungal Chitinases in Biological Control of Plant Root-Knot Nematode