SummaryWe surveyed differential gene expression patterns during early photomorphogenesis in both wild-type and mutant Arabidopsis defective in HY5, an influential positive regulator of the responses of gene expression to a light stimulus, to identify light-responsive genes whose expression was HY5 dependent. These geneexpression data identified light-regulated zinc finger protein 1 (LZF1), a gene encoding a previously uncharacterized C2C2-CO B-box transcriptional regulator. HY5 has positive trans-activating activity toward LZF1 and binding affinity to LZF1 promoter in vivo. HY5 is needed but not sufficient for the induction of LZF1 expression. Anthocyanin content is significantly diminished in lzf1 under far red, which is the most efficient light for the induction of LZF1. The expression of PAP1/MYB75 is elevated in plants overexpressing LZF1, which leads to the hyperaccumulation of anthocyanin in transgenic Arabidopsis. The transition from etioplast to chloroplast and the accumulation of chlorophyll were notably compromised in the lzf1 mutant. We provide molecular evidence that LZF1 influences chloroplast biogenesis and function via regulating genes encoding chloroplast proteins. In the absence of HY5, mutation of LZF1 leads to further reduced light sensitivity for lightregulated inhibition of hypocotyl elongation and anthocyanin and chlorophyll accumulation. Our data indicate that LZF1 is a positive regulator functioning in Arabidopsis de-etiolation.

To date molecular data have not revealed the exact phylogenetic position of Balanophoraceae in relation to hemiparasitic Santalales. To elucidate the phylogeny of Santalales and the position of Balanophoraceae, three plastid genes (matK, rbcL, accD), three nuclear genes (SSU and LSU rDNA and RPB2) and one mitochondrial gene (matR) from 197 Santalales samples (including 11 Balanophoraceae species) were analyzed with parsimony, maximum likelihood and Bayesian inference methods. Our results demonstrate that Balanophoraceae is composed of two well‐supported clades: a relatively slow‐evolving one including Dactylantus, Hachettea, and Mystropetalon (Mystropetalaceae) and an extremely fast‐evolving one composed of the remaining Balanophoraceae s.str. Support for monophyly of the two clades was low, thus it appears holoparasitism has arisen twice independently in Santalales. These two clades appeared during a time of great change in the order (ca. 100 Ma) when several major evolutionary innovations emerged, e.g., the root hemiparasites of Santalaceae s.l., the first aerial parasites (Misodendraceae), herbaceous root parasites (Schoepfiaceae), root parasitic Loranthaceae (the ancestors of aerial parasitic mistletoes), as well as the holoparasites in Balanophoraceae and Mystropetalaceae.

The nanovirus

Ardisia is a basal asterid genus well known for its medicinal values and has the potential for development of novel phytopharmaceuticals. In this genus of nearly 500 species, many ornamental species are commonly grown worldwide and some have become invasive species that caused ecological problems. As there is no completed plastid genome (plastome) sequence in related taxa, we sequenced and characterized the plastome of Ardisia polysticta to find plastid markers of potential utility for phylogenetic analyses at low taxonomic levels. The complete A. polysticta plastome is 156,506 bp in length and has gene content and organization typical of most asterids and other angiosperms. We identified seven intergenic regions as potentially informative markers with resolution for interspecific relationships. Additionally, we characterized the diversity of asterid plastomes with respect to GC content, plastome organization, gene content, and repetitive sequences through comparative analyses. The results demonstrated that the genome organizations near the boundaries between inverted repeats (IRs) and single-copy regions (SCs) are polymorphic. The boundary organization found in Ardisia appears to be the most common type among asterids, while six other types are also found in various asterid lineages. In general, the repetitive sequences in genic regions tend to be more conserved, whereas those in noncoding regions are usually lineage-specific. Finally, we inferred the whole-plastome phylogeny with the available asterid sequences. With the improvement in taxon sampling of asterid orders and families, our result highlights the uncertainty of the position of Gentianales within euasterids I.

Background: The evolution of type II MADS box genes has been extensively studied in angiosperms. One of the best-understood subfamilies is that of the Arabidopsis gene APETALA3 (AP3). Previous work has demonstrated that the ancestral paleoAP3 lineage was duplicated at some point within the basal eudicots to give rise to the paralogous TM6 and euAP3 lineages. This event was followed in euAP3 orthologs by the replacement of the C-terminal paleoAP3 motif with the derived euAP3 motif. It has been suggested that the new motif was created by an eight-nucleotide insertion that produced a translational frameshift.