TY  - JOUR
AU  - Falcón-Rodríguez, Alejandro B. 
AU  - Cabrera, Juan C. 
AU  - Ortega, Eduardo 
AU  - Martínez-Téllez, Miguel Ángel 
PY  - 2009
TI  - Concentration and Physicochemical Properties of Chitosan Derivatives Determine the Induction of Defense Responses in Roots and Leaves of Tobacco (Nicotiana tabacum) Plants 
JF  - American Journal of Agricultural and Biological Sciences
VL  - 4
IS  - 3
DO  - 10.3844/ajabssp.2009.192.200
UR  - https://thescipub.com/abstract/ajabssp.2009.192.200
AB  - Problem statement: The chitosan derivatives promote diverse defensive 
responses in plants, which are affected by chitosan chemical features and concentration. 
Glucanase (EC 3.2.1.6), Phenylalanine Ammonia-Lyase (PAL, EC 4.3.1.5) and peroxidase 
(POD, EC 1.11.1.6) are key enzymes in tobacco defense responses. Thus, the aim 
of this study was to know the behavior of their enzymatic activity in leaves and 
roots of whole tobacco plants, previously elicited with chitosan derivatives of 
different molecular weight and acetylating degree. Approach: 
25 day-old tobacco plants were treated with three chitosan derivatives (CH- 63, 
CH-88 and OLG) of different chemical features. True leaves and roots were sampled 
after three, six, nine and 12 days post-treatment for further evaluation of the 
enzymatic activities. Results: Chitosan treatments increased 
the activity of all three studied enzymes depending on the concentration and chemical 
feature of the derivative. The highest enzymatic activities with polymers occurred 
at 1 g L-1 while the oligochitosan mixture achieved good enzymatic levels as compared 
to controls from 0.1 g L-1 onwards. The Degree of Acetylation (DA) affected PAL 
activity; a more acetylated polymer induced a higher activity than a less acetylated 
one. However, the low levels of acetylation favored POD activity. The systemic 
induction of enzymatic activities was detected in leaves of treated plants after 
root application. The effect of the acetylation degree was systemically transmitted 
to the leaves by POD, but not by PAL activity; so the transmission of the acetylating 
degree influence beyond the tissue directly elicited by chitosan polymer depended 
on each enzymatic response tested. Conclusion: This study proved 
that various chitosan derivatives induced and raised lasting β-1,3-glucanase, 
PAL and POD activities in tobacco leaves and roots as local or systemic responses, 
which could lead to the accumulation of secondary metabolites and formation of 
barriers that all together enhance plant resistance against pathogens.