HighlightDetermination of mesophyll and bundle sheath cell-specific transcriptomes for the monocot NAD-ME C4 plant switchgrass reveals both evolutionary divergence and common elements in C4 establishment.

Proanthocyanidins (PAs) are plant natural products important for agriculture and human health. They are polymers of flavan-3-ol subunits, commonly (−)-epicatechin and/or (+)-catechin, but the source of the in planta extension unit that comprises the bulk of the polymer remains unclear, as does how PA composition is determined in different plant species. Anthocyanidin reductase (ANR) can generate 2,3-cis-epicatechin as a PA starter unit from cyanidin, which itself arises from 2,3-trans-leucocyanidin, but ANR proteins from different species produce mixtures of flavan-3-ols with different stereochemistries in vitro. Genetic and biochemical analyses here show that ANR has dual activity and is involved not only in the production of (−)-epicatechin starter units but also in the formation of 2,3-cis-leucocyanidin to serve as (−)-epicatechin extension units. Differences in the product specificities of ANRs account for the presence/absence of PA polymerization and the compositions of PAs across plant species.

A new approach to one-dimensionally organize the quantum dot Au 55 (PPh 3 ) 12 Cl 6 is described by using poly(vinyl-pyrrolidone) (PVP) molecules as templates. AFM investigations indicate chemisorption of the nanoclusters at the surface of the polymers. Using Langmuir−Blodgett techniques, networks of cluster-loaded polymer chains on mica or silicon are generated. The pattern of the networks can be designed from widely distributed but often interconnecting filaments, up to almost densely packed structures, depending on the surface pressure. Those networks are rigid enough to be transferred from the water surface onto solid substrates without degradation. Bare PVP molecules do not give comparable networks under equivalent conditions, indicating that the nanoclusters act as junctions between the chains.

BackgroundCatalpa bungei is an important tree species used for timber in China and widely cultivated for economic and ornamental purposes. A high-density linkage map of C. bungei would be an efficient tool not only for identifying key quantitative trait loci (QTLs) that affect important traits, such as plant growth and leaf traits, but also for other genetic studies.ResultsRestriction site-associated DNA sequencing (RAD-seq) was used to identify molecular markers and construct a genetic map. Approximately 280.77 Gb of clean data were obtained after sequencing, and in total, 25,614,295 single nucleotide polymorphisms (SNPs) and 2,871,647 insertions-deletions (InDels) were initially identified in the genomes of 200 individuals of a C. bungei (7080) × Catalpa duclouxii (16-PJ-3) F1 population and their parents. Finally, 9072 SNP and 521 InDel markers that satisfied the requirements for constructing a genetic map were obtained. The integrated genetic map contained 9593 pleomorphic markers in 20 linkage groups and spanned 3151.63 cM, with an average distance between adjacent markers of 0.32 cM. Twenty QTLs for seven leaf traits and 13 QTLs for plant height at five successive time points were identified using our genetic map by inclusive composite interval mapping (ICIM). Q16–60 was identified as a QTL for five leaf traits, and three significant QTLs (Q9–1, Q18–66 and Q18–73) associated with plant growth were detected at least twice. Genome annotation suggested that a cyclin gene participates in leaf trait development, while the growth of C. bungei may be influenced by CDC48C and genes associated with phytohormone synthesis.ConclusionsThis is the first genetic map constructed in C. bungei and will be a useful tool for further genetic study, molecular marker-assisted breeding and genome assembly.