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Starch synthesis is a key process that influences crop yield and quality, though little is known about the regulation of this complex metabolic pathway. Here, we present the identification of ZmbZIP91 as a candidate regulator of starch synthesis via co-expression analysis in maize (Zea mays L.). ZmbZIP91 was strongly associated with the expression of starch synthesis genes. Reverse tanscription-PCR (RT-PCR) and RNA in situ hybridization indicated that ZmbZIP91 is highly expressed in maize endosperm, with less expression in leaves. Particle bombardment-mediated transient expression in maize endosperm and leaf protoplasts demonstrated that ZmbZIP91 could positively regulate the expression of starch synthesis genes in both leaves and endosperm. Additionally, the Arabidopsis mutant vip1 carried a mutation in a gene (VIP1) that is homologous to ZmbZIP91, displayed altered growth with less starch in leaves, and ZmbZIP91 was able to complement this phenotype, resulting in normal starch synthesis. A yeast one-hybrid experiment and EMSAs showed that ZmbZIP91 could directly bind to ACTCAT elements in the promoters of starch synthesis genes (pAGPS1, pSSI, pSSIIIa, and pISA1). These results demonstrate that ZmbZIP91 acts as a core regulatory factor in starch synthesis by binding to ACTCAT elements in the promoters of starch synthesis genes. [ABSTRACT FROM AUTHOR]

* Background and Aims To understand the link between species diversity and phenotype developmental evolution is an important issue in evolutionary biology. Yarrows in the genus Achillea (Asteraceae) show a great diversity in leaf serrate or pinnate dissection patterns. In Arabidopsis thaliana, the development of leaf serration requires the activity of the transcription factor CUC2. Does this regulator also work for leaf dissections of the Asteraceae plants? If so, how do the conserved regulatory 'tools' work differently to produce diverse leaf forms? * Methods Seedling leaf morphology was observed, and morphogenesis of leaf serration or lobes was examined by scanning electron microscopy (SEM). NAM genes, orthologues of arabidopsis CUC2, were isolated from A. acuminata with serrate leaves and A. asiatica with three-pinnatisect leaves, respectively. By means of wholemount in situ mRNA hybridization and two quantitative gene expression assays, the droplet digital PCR (ddPCR) and quantitative real-time PCR (qPCR), expression patterns of the NAM genes during leaf dissection development were checked in both species for comparison. * Key Results For both species, the development of leaf dissection initiated when a leaf blade was about 300-400 µm long. In A. acuminata, in situ hybridization showed NAM expression signals at leaf margins where teeth are growing, or later on, in the sinuses of the teeth, whilst in A. asiatica, hybridization signals appear not only on leaf margins but further on the margins of leaf lobes. Both ddPCR and qPCR revealed a continuous decline of AacNAM expression from the early to the late developmental stages of a single leaf of A. acuminata, whereas a relatively long maintenance and fluctuation of AasNAM expression was seen in a leaf of A. asiatica. * Conclusions Differential spatiotemporal patterns of NAM expression were found between the two yarrow species during development of leaf dissection. This study provides the first evidence for NAM activity in the development of leaf dissection of the Asteraceae plants, and demonstrates that leaf form diversity is correlated to the altered NAM expression dynamic. [ABSTRACT FROM AUTHOR]

Objectives Vitexin-2″- O-rhamnoside ( VOR) and vitexin-4″- O-glucoside ( VOG) are the two main flavonoid glycosides of the leaves of C ratagus pinnatifida Bge. var. major N. E. Br. that has been widely used for the treatment of cardiovascular system diseases. In this study, we simultaneously investigated the influence of VOR and VOG on human adipose-derived stem cells (h ADSCs) injury induced by hydrogen peroxide ( H2O2) to further characterize their anti-oxidative and anti-apoptotic activity. Methods h ADSCs were isolated, cultured in vitro and pretreated with 62.5 μ m VOR or 120 μ m VOG for 24 h and then exposed to 500 μ m H2O2 for an additional 4 h. Key findings Pretreatment of h ADSCs with VOR and VOG was demonstrated to significantly ameliorate the toxicity and apoptosis effects, such as morphological distortion, nuclear condensation, decreased intracellular caspase-3 activity and percentage of cells in apoptosis/necrosis by using morphological assay, immunocytochemistry and flow cytometric evaluation. In addition, VOR and VOG caused no cytotoxic effect on hADSCs at concentrations up to 250 and 480 μ m, respectively. Conclusions Our results indicated that both VOR and VOG contribute to the protection against H2O2-mediated oxidative stress damage and could be safely used for a wide range of concentrations. [ABSTRACT FROM AUTHOR]

The plastidic caseinolytic protease (CIp) of higher plants is an evolutionarily conserved protein degradation apparatus composed of a proteolytic core complex (the P and R rings) and a set of accessory proteins (ClpT, ClpC, and CIpS). The role and molecular composition of Clps in higher plants has just begun to be unraveled, mostly from studies with the model dicotyledonous plant Arabidopsis (Arabidopsis thaliana). In this work, we isolated a virescent yellow leaf (vyl) mutant in rice (Oryza sativa), which produces chlorotic leaves throughout the entire growth period. The young chlorotic leaves turn green in later developmental stages, accompanied by alterations in chlorophyll accumulation, chloroplast ultrastructure, and the expression of chloroplast development- and photosynthesis-related genes. Positional cloning revealed that the VYL gene encodes a protein homologous to the Arabidopsis ClpP6 subtmit and that it is targeted to the chloroplast. VYL expression is constitutive in most tissues examined but most abundant in leaf sections containing chloroplasts in early stages of development. The mutation in wdl causes premature termination of the predicted gene product and loss of the conserved catalytic triad (serine-histidine-aspartate) and the polypeptide-binding site of VYL. Using a tandem affinity purification approach and mass spectrometry analysis, we identified OsCIpP4 as a VYL-associated protein in vivo. In addition, yeast two-hybrid assays demonstrated that VYL directly interacts with OsClpP3 and OsClpP4. Furthermore, we found that OsCIpP3 directly interacts with OsClpT, that OsClpP4 directly interacts with OsClpP5 and OsCIpT, and that both OsClpP4 and OsClpT can homodimerize. Together, our data provide new insights into the function, assembly, and regulation of Clps in higher plants. [ABSTRACT FROM AUTHOR]