Volume 2 Issue 11, November 2016

The mechanism for T-DNA integration, a critical step of Agrobacterium-mediated transgenesis, remains poorly understood. Now, a study based on mutant analysis shows that Pol θ controls T-DNA integration and generates error-prone footprints at integration sites.

A new study uncovers thousands of RNA-directed DNA methylation target sites masked by the active removal of methylated cytosines by a demethylating enzyme.

A recent survey of transcript abundance in wheat grains found accumulation of mRNAs encoding key enzymes of C₄ photosynthesis. However, this is not the same as showing that the C₄ pathway operates in these tissues.

A Review discusses the currently known non-canonical RNA-directed DNA methylation mechanisms, their diversity and interconnections, and puts forward the key unanswered questions in this field.

The authors identify novel NEGATIVE GRAVITROPIC RESPONSE OF ROOTS genes in Medicago and Arabidopsis. Mutants display a spectacular phenotype: gravity is still perceived, but the direction of growth is reversed: roots always grow upwards.

C₄ photosynthesis has evolved independently in over 60 plant lineages. This study shows expression of key C₄ enzymes being controlled by light and the chloroplast in C₃ leaves, potentially facilitating repeated evolution of C₄ traits.

Many plants exhibit iridescence but no link has been demonstrated between this phenomenon and photosynthesis. This study shows the epidermal chloroplasts of Begonia to have photonic properties that increase both light capture and quantum yield.

The mechanism for T-DNA integration, a critical step of Agrobacterium-mediated transgenesis, remains elusive. Now, a study shows that polymerase θ controls T-DNA integration and generates the error-prone sequences at the sites of integration.

Plants can regenerate tissues after injury. The heterodimeric transcription factor complex ERF115–PAT1 is activated by the cell death of neighbouring cells, and is crucial for stem cell replenishment and the high regenerative potential of plants.

The legume–Rhizobium symbiosis allows nitrogen fixation. Development of nodules is a finely regulated developmental process that involves a DNA demethylase called DEMETER, linking epigenetic regulation and symbiosis.

By assembling the genome of Cardamine hirsuta and conducting comparative genomic and transcriptomic analyses, a study reveals the prevalent role of transcription factors and gene duplication in morphological evolution.

The Arabidopsis ROS1 is the first characterized DNA demethylase in eukaryotes. Now, an epigenomic study has revealed the features of ROS1-targeted genomic loci and identified a new class of RNA-directed DNA methylation (RdDM) targets.

The evolution of sex-biased gene expression in plants is elusive. By comparing the transcriptomes of two closely related species of different mating systems, a study has found that the change in expression preferentially occurred in females and in sex-linked genes.