Rice cytoplasmic APX2 is a pleiotropic protein, densely distributed around chloroplasts. It plays key roles in HO homeostasis and chloroplast protection, and is related to plant architecture and fertility regulation. Ascorbate peroxidases (APXs) catalyze the conversion of HO into HO. In this report, we systematically investigated the function of cytosolic APX2 using a T-DNA knockout mutant. Loss of OsAPX2 altered rice architecture including shoot height and leaf inclination, resulting in shoot dwarfing, leaf dispersion and fertility decline. Sixty-five differentially expressed proteins were identified in flag leaves of the milk-ripe stage, mainly involved in photosynthesis, glycolysis and TCA cycle, redox homeostasis, and defense. The absence of APX2 severely impacted the stability of chloroplast proteins, and dramatically reduced their expression levels. Subcellular localization showed that APX2 was enriched around each chloroplast to form a high concentration sphere, highlighting chloroplasts as key targets protected by the protein. Accumulation of HO was suppressed in the KO-APX2 mutant, which may benefit from increased CAT activity and functional complementation of APX family members. Unexpectedly, the accumulation of soluble sugar, especially sucrose increased significantly, suggesting that APX2 was involved in regulation of sugar metabolism. Obviously, roles of the cytosolic APX2 are very profound and complex in rice. It can be concluded that the cytosolic APX2 is a pleiotropic protein and an important regulator in ROS homeostasis, chloroplast protection, carbohydrate metabolism as well as plant architecture and fertility maintenance.
Reactive oxygen species (ROS) are produced by plants. Hydrogen peroxide (H2O2) is one important component of ROS and able to modulate plant growth and development at low level and damage plant cells at high concentrations. Ascorbate peroxidase (APX) shows high affinity towards H2O2 and plays vital roles in H2O2-scavenging. In order to explore the differences of APXs from selected plant species, bioinformatics methods and public databases were used to evaluate the physicochemical properties, conserved motifs, potential modifications and cis-elements in all the APXs, and protein-protein network and expression profiles of rice APXs. The results suggested that APXs in the selected plant species showed high evolutionary conservation and were able to divide into seven groups, group I to VII. Members in the groups contained abundant phosphorylation sites. Interestingly, group I and VII had only PKC site. Additionally, promoters of the APXs contained abundant stress-related cis-elements. APXs in rice plant were able to interact with dehydroascorbate reductase 2. The eight APXs expressed differently in root, leaf, panicle, anther, pistil and seed. Drought, Pi-free, Cd and Xanthomonas oryzae pv. oryzicola B8-12 treatments were able to significantly alter the expression profiles of rice APXs. This study increases our knowledge to further explore functions and mechanisms of APXs and also guides their applications.
Quinoa is a kind of pseudocereal with rich nutrient, unique flavor and antioxidant ingredients. In recent years, it has received widespread attention all over the world, however, the problem of single quinoa product is increasingly prominent. Tea is one of the most popular functional beverages globally, so the development of quinoa tea has a broad market prospect. In the present review, the preparation methods of quinoa seed tea, quinoa malt tea, quinoa leaf tea, quinoa whole plant tea, quinoa fermented tea and quinoa compound tea were summarized, and the current situation and existing problems were analyzed. Based on the above investigations, some suggestions for improving the product performance were put forward.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.