In rice, gene body-localized H2A.Z plays a prominent role in repressing stress-responsive genes under non-inductive conditions, whereas H2A.Z at the transcription start site functions as a positive or negative regulator of transcription.

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One-sentence summary: Combined chromatin structural data reveals specific chromatin-state transitions that correlate with subsets of functionally distinct rice genes differentially expressed under phosphate starvation. Author contributions: M.F. performed the experiments, analyzed the data, and wrote the article; S.Z provided technical assistance; D-H.O. and G.W. provided bioinformatics assistance; M.D. supervised the data analysis; A.S. conceived the project, supervised the experiments and data analysis, complemented the writing, and agrees to serve as the author responsible for contact and to ensure communication.

Phosphorus (P) is an essential plant macronutrient vital to fundamental metabolic processes. Plant-available P is low in most soils, making it a frequent limiter of growth. Declining P reserves for fertilizer production exasperates this agricultural challenge. Plants modulate complex responses to fluctuating P levels via global transcriptional regulatory networks. Although chromatin structure plays a substantial role in controlling gene expression, the chromatin dynamics involved in regulating P homeostasis have not been determined. Here we define distinct chromatin states across the rice genome by integrating multiple aspects of chromatin structure, including the H2A.Z histone variant, H3K4me3 modification, and nucleosome positioning. In response to P starvation, 40% of all protein-coding genes exhibit a transition from one chromatin state to another at their transcription start site. Several of these transitions are enriched in subsets of genes differentially expressed by P deficiency. The most prominent subset supports the presence of a coordinated signaling network that targets cell wall structure and is regulated in part via a decrease of H3K4me3 at the transcription start site. The P-starvation induced chromatin dynamics and correlated genes identified here will aid in enhancing P-use efficiency in crop plants, benefitting global agriculture.One sentence summaryCombining data for three components of chromatin structure from control and phosphate-starved rice shoots reveals specific chromatin state transitions that correlate with subsets of functionally distinct differentially-expressed genes.

Exposure of phytoplankton to the wateraccommodated fraction of crude oil can elicit a number of stress responses, but the mechanisms that drive these responses are unclear. South Louisiana crude oil was selected to investigate its effects on population growth, chlorophyll a (Chl a) content, antioxidative defense, and lipid peroxidation, for the marine diatom, Ditylum brightwellii, and the dinoflagellate, Heterocapsa triquetra, in laboratory-based microcosm experiments. The transcript levels of several possible stress-responsive genes in D. brightwellii were also measured.

Senescence is a complex process of controlled degradation and nutrient recycling that is modulated by developmental and environmental cues. Beginning in the middle to late vegetative stage of growth, the remobilisation of phosphorus (P) from senescing leaves serves as the major source of P for sink tissues, such as young leaves, reproductive structures and storage organs. Although it is clear that plants are generally efficient at recycling P from senescing leaves, little is known regarding the molecular components involved in the process. Optimising P remobilisation during senescence will likely be a valuable contribution to future improvements in P‐use efficiency of crop species, which is urgently needed to minimise the use of unsustainable P fertilizers.

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