Insect Resistance Mechanisms Of KTI Gene Families In Model Plants

Trypsin inhibitors (TIs) play important roles in plant defense against biotic and inbiotic stresses. In this article, we focused on the KTI(Kunitz-type trypsin inhibitor)gene family, which is a sub-family of TI gene family. We first characterized the KTI gene families in the herbaceous model system Arabidopsis thaliana and the woody model system Populus trichocarpa. Then a series of genetic analysis of AtKTIs and PtKTIs using bioinformatic methods had been taken as follows: constructing phylogenetic relationship, gene structure analysis, motif preservation verification and heatmap construction against biotic and inbiotic stresses. In order to assess the defense process of KTI in woody plants, we isolated KTI cDNAs from P. nigra on a genome-wide scale and analyzed their respective response to Apocheima cinerarius Erschoff and mechanical wounding through Semi-quantitative RT-PCR analysis. Our data demonstrated that both of the two treatments rapidly induced PnKTIs except for slight individual difference. So we presumed that PnKTIs had the protential of improving biotic resistance in host plants.Populus, as the model plant of woody model system, has a strong defense system. Based on that, we constructed expressional vetor and made an over-expressing of PnKTIs in transgenic populus using agrobacterium, which can improve its stress resistance. After verifying the active transgenic plants, we concluded that target gene were integrated into populus'genome and can be used as herbivore attack analysis and gene expression in the near further. Populus has significant economic value own to its woods and leaves. However, for the seasonal insect pest, populus may be threatened and grow up weakly. So the transgenetic populous we learned, specifically in herbivore defensed, will bring us values both in economic aspects and social lives.