Study On The Effect Of Water Retention And Mechanism Of Rice By OsABA8ox2 Overexpression

Abscisic acid(ABA) is a kind of traditional plant hormones, endogenous active ABA is not only cell signal but also stress response. The level of endogenous ABA content depends on both the ABA synthesis rate and its decomposition rate. OsABA8ox1, OsABA8ox2 and OsABA8ox3 are three coding ABA ’hydroxylase genes. ABA 8 ’- hydroxylase catalytic hydroxylation is referred to as the key steps in the process of ABA catabolism. So far, about how to regulate stomatal movement of ABA catabolism to maintain the balance of plant water related or relative lack of evidence. This study by Realtime qPCR methods to deeply investigate OsABA8ox2- OE gm rice seedlings, identification of genetically modified(gm) positive strain, and the transgenic rice in ABA related gene expression level and phenotypic observation and statistics, to identify Os ABA8ox2 genes in the ABA provides the theory basis for the role of metabolic pathway, but also explores OsABA8ox2 genetic influence on rice water retention.The main results were as follows:1. By PCR detection, identified OsABA8ox2- OE positive strains of transgenic rice. Realtime q-PCR results show that OsABA8ox2- OE OsABA8ox2 gene expression in transgenic rice rise, and ABA/GA metabolic pathways increased the expression of gene OsZEP, SDR and endogenous ABA content also decreased.2. Realtime q-PCR results show that in rice, OsABA8ox2 genes were expressed in root, stem and leaf. Among them, in the highest amount of expression in the blade, the second is not after earing flowering in the ear, in booting stage is the lowest amount of expression in the ear.3. Through the experiment of maize protoplast instantaneous expression showed OsABA8ox2 protein localization in the endoplasmic reticulum(ER), and OsABA8ox1 protein orientation is consistent.4. OsABA8ox2- OE the phenotype of genetically modified(gm) rice has obvious changes, including seed germination delay, low germination rate and seed setting rate is reduced, at the same time to show high levels of water shortage status, present a wilting phenotype and even hard to survive, but under the condition of high humidity environment can better survive.5. Based on the transgenic rice leaves and wild type blade of scanning electron microscope(SEM), and the determination of physiological index, excessive OsABA8ox2 gene can promote stomatal opening, at the same time it can increase the stomatal conductance and transpiration rate to speed up the phenomenon also gradually revealed.