Cloning Of MeLAR And MeANR,Key Genes For The Synthesis Of Cassava Tannin And Its Function In Cassava Resistance To Tetranychus Cinnabarinus

Cassava is a staple food and an important industrial raw material for nearly 800 million people in the world.T.cinnabarinus is one of the four major pests of cassava,and it is difficult to control in pesticides.Cultivating and using insect-resistant varieties is the most economical,effective,and simple way to control pests.Tannins are recognized as secondary metabolites with direct insect resistance.LAR and ANR are the two most important enzymes regulating tannin content,but the ability to encode key genes MeLAR and MeANR to regulate tannin content and increase crop insect resistance still lacks direct molecular evidence.Therefore,based on the comparative analysis of the differences in tannin content,LAR and ANR activities,MeLAR and MeANR gene expression levels in different leaves tissues of mite-resistant C1115and mite-susceptible BRA900 cassava cultivars when damaged by T.cinnabarinus,the MeLAR and MeANR clones were systematically developed and its anti-spasmodic function research.The main findings are as follows:1.It was found that the tannic acid content was significantly positively correlated with the resistance of cassava.It was initially proved that the effect of tannic acid on the resistance to cassava and the significant decrease in the content of tannic acid was one of the important reasons why T.cinnabarinus tends to damage the middle and base leaves of cassava.The content of tannin in rolled leaves,unfolded young leaves,the third leaves below the bud leaves,the middle and base leaves of C1115 cultivars damaged by T.cinnabarinus increased by more than twice times as compared with that before the injury,which was significantly higher than that of BRA900.After BRA900 damaged by T.cinnabarinus,except that the activities of tannic acid content in the middle and base leaves was significantly reduced on the 8th day,there was no significant difference in the content of tannic acid in leaves at different stages of development.2.The activities of LAR and ANR was found to be significantly positively correlated with the resistance of cassava.It was initially proved that the effect of these two enzymes on the resistance of cassava and the significant decrease of its activities were the important reasons why T.cinnabarinus tends to damage the middle and base leaves of cassava.The LAR and ANR enzymes in rolled leaves,unfolded young leaves,the third leaves below the bud leaves,the middle and base leaves of C1115 cultivars damaged by T.cinnabarinus increased by more than twice times as compared with that before the injury,which was significantly higher than that of BRA900.After BRA900 damaged by T.cinnabarinus,except that the activities of LAR and ANR enzymes in the middle and base leaves was significantly reduced on the 8th day,there was no significant difference in the activity of LAR and ANR enzymes in leaves at different stages of development.3.It was found that the gene expression levels of MeLAR and MeANR were positively correlated with the resistance of cassava.The function of these two genes in the resistance of cassava and the significant decrease of their expression resulted in a significant decrease of LAR and ANR enzyme activity was the important reasons why T.cinnabarinus tends to damage the middle and base leaves of cassava.The MeLAR and MeANR gene expression levels of C1115 in rolled leaves,unfolded young leaves,the third leaves below the bud leaves,the middle and base leaves of C1115 cultivars damaged by T.cinnabarinus increased by more than twice times as compared with that before the injury,which was significantly higher than that of BRA900.After BRA900 damaged by T.cinnabarinus,except that the gene expression of MeLAR and MeANR in the middle and base leaves was significantly reduced on the 8th day,there was no significant difference in the gene expression of MeLAR and MeANR in leaves at different stages of development.4.the MeLAR and MeANR genes were cloned,and the MeLAR and MeANR transgenic lines with anti-spawning function were obtained,which provided a theoretical basis for deep mining and innovative utilization of MeLAR and MeANR genes.Indoor locust resistance results showed that the MeLAR and MeANR gene expression levels,LAR and ANR enzyme activity,and tannic acid content of the transgenic lines and C1115 were significantly increased when damaged by T.cinnabarinus,and the survival rate of the F0 generation of T.cinnabarinus was significantly reduced.The leaves did not show obvious symptoms and showed similar resistance to C1115.The MeLAR and MeANR expression levels,LAR and ANR activity,and tannic acid content in the non-transgenic TMS60444(WT)and BRA900 were significantly lower than before damaged by T.cinnabarinus.