Ambient temperature affects plant growth and even minor changes can substantially impact crop yields. The underlying mechanisms of temperature perception and response are just beginning to emerge. Chromatin remodeling, via the eviction of the histone variant H2A.Z containing nucleosomes, is a critical component of thermal response in plants. However, the role of histone modifications remains unknown. Here, through a forward genetic screen, we identify POWERDRESS (PWR), a SANT-domain containing protein known to interact with HISTONE DEACETYLASE 9 (HDA9), as a novel factor required for thermomorphogenesis in Arabidopsis thaliana. We show that mutations in PWR impede thermomorphogenesis, exemplified by attenuated warm temperature-induced hypocotyl/petiole elongation and early flowering. We show that inhibitors of histone deacetylases diminish temperature-induced hypocotyl elongation, which demonstrates a requirement for histone deacetylation in thermomorphogenesis. We also show that elevated temperature is associated with deacetylation of H3K9 at the +1 nucleosomes of PHYTOCHROME INTERACTING FACTOR4 (PIF4) and YUCCA8 (YUC8), and that PWR is required for this response. There is global misregulation of genes in pwr mutants at elevated temperatures. Meta-analysis revealed that genes that are misregulated in pwr mutants display a significant overlap with genes that are H2A.Z-enriched in their gene bodies, and with genes that are differentially expressed in mutants of the components of the SWR1 complex that deposits H2A.Z. Our findings thus uncover a role for PWR in facilitating thermomorphogenesis and suggest a potential link between histone deacetylation and H2A.Z nucleosome dynamics in plants.

Wild strains of Arabidopsis (Arabidopsis thaliana) exhibit extensive natural variation in a wide variety of traits, including response to environmental changes. Ambient temperature is one of the major external factors that modulates plant growth and development. Here, we analyze the genetic architecture of natural variation in thermal responses of Arabidopsis. Exploiting wild accessions and recombinant inbred lines, we reveal extensive phenotypic variation in response to ambient temperature in distinct developmental traits such as hypocotyl elongation, root elongation, and flowering time. We show that variation in thermal response differs between traits, suggesting that the individual phenotypes do not capture all the variation associated with thermal response. Genome-wide association studies and quantitative trait locus analyses reveal that multiple rare alleles contribute to the genetic architecture of variation in thermal response. We identify at least 20 genomic regions that are associated with variation in thermal response. Further characterizations of temperature sensitivity quantitative trait loci that are shared between traits reveal a role for the blue-light receptor CRYPTOCHROME2 (CRY2) in thermosensory growth responses. We show the accession Cape Verde Islands is less sensitive to changes in ambient temperature, and through transgenic analysis, we demonstrate that allelic variation at CRY2 underlies this temperature insensitivity across several traits. Transgenic analyses suggest that the allelic effects of CRY2 on thermal response are dependent on genetic background suggestive of the presence of modifiers. In addition, our results indicate that complex light and temperature interactions, in a background-dependent manner, govern growth responses in Arabidopsis.Temperature is a critical environmental factor that has major effects on the growth, development, and distribution of plants across the globe (Fitter and Fitter, 2002;Samach and Wigge, 2005, 2013;Kotak et al., 2007;Penfield, 2008). With the predicted increase in global temperatures, and their potential impact on agricultural productivity, there are efforts to understand the genetic basis of temperature responses in plants. Traditionally, temperature effects have been studied in the context of extreme stress responses such as heat shock or cold shock (Kotak et al., 2007;Barrero-Gil and Salinas, 2013;Song et al., 2013;Storey and Storey, 2013). In recent times, there has been an interest in analyzing the response of plants to changes in their growth temperature within the nonstress range of l6°C to 27°C, as even small changes in temperature can have major impacts on plant growth and development (Wigge, 2013;Franklin et al., 2014). In this study, we refer to various phenotypic responses in plants that are attributable to small changes in ambient temperature as temperature/thermal response.A few specific phenotypic responses are often used to uncover the genetic and molecular basis of thermal response in plants. These include temperature-induced chan...

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Despite such challenges as high path loss and equipment cost, THz communication is becoming one of the potentially viable means through which ultra-high data rate can be achieved. To compensate for the high path loss, we present parameter modeling for indoor THz communication. To maximize efficient and opportunistic use of resources, we analyze the potential workarounds for a single access point to satisfy most of the mobile terminals by varying such parameters as humidity, distance, frequency windows, beamwidths, antenna placement, and user mobility type. One promising parameter is antenna beamwidth, where narrower beams results in higher antenna gain. However, this can lead to "beamwidth dilemma" scenario, where narrower beamwidth can result in significant outages due to device mobility and orientation. In this paper, we address this challenge by presenting a mobility model that performs an extensive analysis of different human mobility scenarios, where each scenario has different data rate demands and movement patterns. We observe that for mobile users, there are optimal beamwidths that are affected by the mobility type (high mobility, constrained mobility, and low mobility) and AP placement.