RESUMEN
Protoporphyrinogen IX (Protogen IX) oxidase (PPO) catalyzes the oxidation of Protogen IX to Proto IX. PPO is also the target site for diphenyl ether-type herbicides. In plants, there are two PPO encoding genes, PPO1 and PPO2. To date, no PPO gene or mutant has been characterized in monocotyledonous plants. In this study, we isolated a spotted and rolled leaf (sprl1) mutant in rice (Oryza sativa). The spotted leaf phenotype was sensitive to high light intensity and low temperature, but the rolled leaf phenotype was insensitive. We confirmed that the sprl1 phenotypes were caused by a single nucleotide substitution in the OsPPO1 (LOC_Os01g18320) gene. This gene is constitutively expressed, and its encoded product is localized to the chloroplast. The sprl1 mutant accumulated excess Proto(gen) IX and reactive oxygen species (ROS), resulting in necrotic lesions. The expressions of 26 genes associated with tetrapyrrole biosynthesis, photosynthesis, ROS accumulation, and rolled leaf were significantly altered in sprl1, demonstrating that these expression changes were coincident with the mutant phenotypes. Importantly, OsPPO1-overexpression transgenic plants were resistant to the herbicides oxyfluorfen and acifluorfen under field conditions, while having no distinct influence on plant growth and grain yield. These finding indicate that the OsPPO1 gene has the potential to engineer herbicide resistance in rice.
Asunto(s)
Herbicidas , Oryza , Resistencia a los Herbicidas/genética , Herbicidas/farmacología , Mutación , Oryza/genética , Oryza/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Protoporfirinógeno-Oxidasa/genética , Protoporfirinógeno-Oxidasa/metabolismo , Especies Reactivas de OxígenoRESUMEN
The iron-sulfur subunit (SDH2) of succinate dehydrogenase plays a key role in electron transport in plant mitochondria. However, it is yet unknown whether SDH2 genes are involved in leaf senescence and yield formation. In this study, we isolated a late premature senescence mutant, lps1, in rice (Oryza sativa). The mutant leaves exhibited brown spots at late tillering stage and wilted at the late grain-filling stage and mature stage. In its premature senescence leaves, photosynthetic pigment contents and net photosynthetic rate were reduced; chloroplasts and mitochondria were degraded. Meanwhile, lps1 displayed small panicles, low seed-setting rate and dramatically reduced grain yield. Gene cloning and complementation analysis suggested that the causal gene for the mutant phenotype was OsSDH2-1 (LOC_Os08g02640), in which single nucleotide mutation resulted in an amino acid substitution in the encoded protein. OsSDH2-1 gene was expressed in all organs tested, with higher expression in leaves, root tips, ovary and anthers. OsSDH2-1 protein was targeted to mitochondria. Furthermore, reactive oxygen species (ROS), mainly H2O2, was excessively accumulated in leaves and young panicles of lps1, which could cause premature leaf senescence and affect panicle development and pollen function. Taken together, OsSDH2-1 plays a crucial role in leaf senescence and yield formation in rice.
Asunto(s)
Envejecimiento/genética , Proteínas Hierro-Azufre/genética , Oryza/genética , Desarrollo de la Planta/genética , Hojas de la Planta/genética , Subunidades de Proteína/genética , Succinato Deshidrogenasa/genética , Cloroplastos/ultraestructura , Grano Comestible , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Proteínas Hierro-Azufre/metabolismo , Mutación , Oryza/crecimiento & desarrollo , Oryza/metabolismo , Fenotipo , Fotosíntesis/genética , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Subunidades de Proteína/metabolismo , Carácter Cuantitativo Heredable , Especies Reactivas de Oxígeno/metabolismo , Reproducción , Succinato Deshidrogenasa/metabolismoRESUMEN
Study the suitability of organic film for salvianolic acid in the ultrafiltration process of Danshen Dizhuye. UPLC was used to analyze the migration of nine phenolic active ingredients in Danshen Dizhuye during ultrafiltration of PES hollow fiber membrane and PS hollow fiber membrane. The structural composition of multi-components was analyzed by three different batches of Danshen Dizhuye before and after ultrafiltration of the two membranes. The results showed that 9 phenolic active ingredients in Danshen Dizhuye did not change significantly after ultrafiltration through PES membrane. However, after ultrafiltration through PS membrane, the content of sodium danshensu, protocatechualdehyde, caffeic acid, 3-hydroxy-4-methoxycinnamic acid and rosmarinic acid in Danshen Dizhuye did not change significantly, while salvianolic acid D, salvianolic acid B and lithospermic acid decreased by about 20%, and the content of salvianolic acid A decreased significantly. The final content in equilibrium was only about 20% of the original solution. Therefore, an in-depth study on the migration particularity of salvianolic acid A in ultrafiltration membrane was the focuse. The results showed that the loss of salvianolic acid A was caused by both membranes during ultrafiltration, and salvianolic acid A was lost more in PS membrane. When the membrane was washed and regenerated, it was found that salvianolic acid A was detected in the ethanol washing solution, but not in the washing liquid, indicating that the loss of salvianolic acid A during the ultrafiltration was mainly adsorptive action. The results suggested that the migration of phenolic active ingredients in Danshen Dizhuye during the membrane ultrafiltration process did not completely follow the molecular weight passing rule of the membrane pore size. At the same time, it may be affected by factors, such as the structure of the membrane material, and the interaction between the membrane structure and the structure of components, and exhibit different migration behaviors during the ultrafiltration of the membrane.