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Molecular weight‐dependent antifungal activity and action mode of chitosan against Fulvia fulva (cooke) ciffrri
Author(s) -
Li Meiqin,
Chen Xiguang,
Liu Jianmin,
Zhang Weifen,
Tang Xuexi
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.31831
Subject(s) - hypha , chitosan , mycelium , allyl isothiocyanate , conidium , fluorescein isothiocyanate , in vivo , fluorescence microscope , fluorescein , spore germination , scanning electron microscope , in vitro , mode of action , antifungal , biology , biophysics , germination , nuclear chemistry , chemistry , botany , fluorescence , microbiology and biotechnology , biochemistry , materials science , physics , quantum mechanics , composite material
Antifungal activities of chitosans (CTS) with different molecular weights ( M w ) and different concentrations against Fulvia fulva (cooke) ciffrri ( F. fulva ) causing leaf mold in tomato plants were studied in vitro and in vivo ; the action mode and its inhibition at different stages during the life cycle of F. fulva were observed. The results showed that: (1) in vitro , CTS exhibited strong antifungal activity against F. fulva , especially for the medium M w (213 and 499 KDa) CTS. Almost complete inhibition of F. fulva conidia germination and mycelia colony radial growth was found when CTS was at concentration of 0.5 and 2 mg mL −1 , respectively; however, inhibitory effect on sporulation was not very obvious for all CTSs tested in this experiment. In vivo , CTS of 213 KDa CTS at 6 mg mL −1 concentration produced stronger antifungal effect than others. (2) The morphological study by scanning electron microscope (SEM) showed that CTS could induce the hyphal swelling, and the surface of hypha which was treated with low M w (82 KDa) chitosan was smooth, but was rough treated with high M w (1320 KDa) chitosan. The further study using a confocal laser scanning microscopy (CLSM) coupled with fluorescein isothiocyanate (FITC)‐fluorescence detection system showed fluorescence of the FITC‐labeled chitosans of which M w s were below 500 KDa could enter into the inner of hypha; however, 1320 KDa chitosan was blocked off the outer of hypha. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2011