Synthesized nanochitosan induced rice chitinase isozyme expression; application in brown planthopper (BPH) control

Abstract

Chitosan nanoparticles were prepared by ionic gelation of chitosan solution with anionic sodium tripolyphosphate.?? The XRD pattern of chitosan exhibited broad diffraction peaks at an angle 2?? of 10?? and 21?? which were the two characteristic peaks of chitosan.?? Moreover, there was no impurity peaks observed in the XRD pattern.?? The FESEM image confirmed that the nanoparticle products were spherical in shape with a size of 100???200 nm.?? When the concentration of chitosan increased, the primary particles became more aggregated.?? The functional group confirmations of the prepared samples were obtained by FTIR spectroscopy analysis.?? It was found that the FTIR spectrum of chitosan exhibited O???H, C???H, C???N, C???O???C band stretching and N???H bending which were in good agreement with the previous reported.. Nanochitosan at?? 10, 50, 100 ppm promote rice growth when compared to the control. While,rice seedling did not growth in high concentration of chitosan at 500, 1000 ppm. The protein content and chitinase enzyme activity were induced expression in rice seedling after nanochitosan application. Protein content and chitinase activity in rice treated with nanochitosan varied depending on the chitosan concentration and rice growing time. Total protein content was up to 23.66 fold, while chitinase enzyme activity found increase to 3.31 when compared to the control. ????Four?? isoforms?? were presented?? in all plant tissue after nanochitosan induction for 2 week. One isoform (18 kDa) was constitutively presented in control, while the other 3 isoform (12 24, 76 kDa) ??were strongly induced by nanochitosan. The?? 3 isoform (12 24, 76 kDa) may be involve in plant agaist to abiotic stress?? such as nanochitosan. The expression of chitinase isoform in specific tissues of rice seedling after nanochitosan induction was investigated. It was found the rice leave contains 3 isoform at molecular weight of 12 kD, 18 kD and 76 kD, respectively. Stem contains 12 kD, 18 kD and 24 kD of isoform.While, root no contain chatinase isoform.?? Chitinase isoform expression in stem and leave may be involved in rice against to pathaogen and insect. Especially, 2 isoform of 12 kD, 18 kD in rice stem may be related to against brown plant hopper which was preferred to sucking phloem of rice stem.?? Therefore, the rice plant treated with nanochitosan in this study can survive from the BPH attack when compared to the control. Synthesized Nanochitosan can successfully induced chitinase isoform expression in rice.