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Background Pistachio ( Pistacia vera ), one of the most important commercial nut crops worldwide, is highly adaptable to abiotic stresses and is tolerant to drought and salt stresses. Results Here, we provide a draft de novo genome of pistachio as well as large-scale genome resequencing. Comparative genomic analyses reveal stress adaptation of pistachio is likely attributable to the expanded cytochrome P450 and chitinase gene families. Particularly, a comparative transcriptomic analysis shows that the jasmonic acid (JA) biosynthetic pathway plays an important role in salt tolerance in pistachio. Moreover, we resequence 93 cultivars and 14 wild P. vera genomes and 35 closely related wild Pistacia genomes, to provide insights into population structure, genetic diversity, and domestication. We find that frequent genetic admixture occurred among the different wild Pistacia species. Comparative population genomic analyses reveal that pistachio was domesticated about 8000 years ago and suggest that key genes for domestication related to tree and seed size experienced artificial selection. Conclusions Our study provides insight into genetic underpinning of local adaptation and domestication of pistachio. The Pistacia genome sequences should facilitate future studies to understand the genetic basis of agronomically and environmentally related traits of desert crops.

H2A.Z is a highly conserved histone variant in all species. The chromatin deposition of H2A.Z is specifically cata- lyzed by the yeast chromatin remodeling complex SWR1 and its mammalian counterpart SRCAP. However, the mechanism by which H2A.Z is preferentially recognized by non-histone proteins remains elusive. Here we identified Anp32e, a novel higher eukaryote-specific histone chaperone for H2A.Z. Anp32e preferentially associates with H2A. Z-H2B dimers rather than H2A-H2B dimers in vitro and in vivo and dissociates non-nucleosomal aggregates formed by DNA and H2A-H2B. We determined the crystal structure of the Anp32e chaperone domain （186-232） in complex with the H2A.Z-H2B dimer. In this structure, the region containing Anp32e residues 214-224, which is absent in other Anp32 family proteins, specifically interacts with the extended H2A.Z aC helix, which exhibits an unexpected confor- mational change. Genome-wide profiling of Anp32e revealed a remarkable co-occupancy between Anp32e and H2A. Z. Cells overexpressing Anp32e displayed a strong global H2A.Z loss at the ＋1 nucleosomes, whereas cells depleted of Anp32e displayed a moderate global H2A.Z increase at the ＋1 nucleosomes. This suggests that Anp32e may help to resolve the non-nucleosomal H2A.Z aggregates and also facilitate the removal of H2A.Z at the ＋1 nucleosomes, and the latter may help RNA polymerase II to pass the first nucleosomal barrier.

Three types of Ti–Si binary oxides have been prepared by sol-gel processes. The effects of SiO 2 addition and annealing temperature on the grain size, phase transition, dispersion, and microstructure of nanocrystalline (nc) TiO 2 anatase in the three Ti–Si oxide structures have been comparatively investigated by X-ray diffraction (XRD) analysis and high-resolution transmission electron microscopy (HRTEM). The grain growth and anatase-rutile transformation (ART) of ncTiO 2 were found to depend not only on the SiO 2 content and annealing temperature, but also on the composite structure. Both the grain growth and the ART of ncTiO 2 proved to be significantly inhibited with increasing SiO 2 content for all of the Ti–Si samples, but the structure of intimately mixed Ti–Si binary oxide showed the best inhibiting ability under high-temperature annealing. This result might be attributed to variations in the large lattice strains in ncTiO 2 , which were mainly induced by the substitution of Ti 4+ by Si 4+ . Plausible mechanisms for the grain growth and ART of ncTiO 2 are proposed. To inhibit the grain growth of ncTiO 2 , the addition of 10 and 30 mol% SiO 2 proved to be optimal for Ti–Si samples annealed at 773 K and 1273 K, respectively.

Selenium at a low concentration has a chemopreventive role against cancer, while at a high concentration, it exerts a direct antitumor effect. However, the mechanisms remain elusive. In this article, we discovered that Na(2)SeO(3) at 20 micromol/l concentration could significantly inhibit the proliferation of NB4 cells, affect the cell cycle distribution of cell population, and induce cellular changes characteristic of apoptotic cells, while this same compound at 2 micromol/l concentration had no such effects. The mechanisms underlying these overt differences caused by treatment of different concentrations of selenium were further investigated. cDNA microarray analysis showed that after treatment by 20 micromol/l Na(2)SeO(3), 34 genes were changed in expression, while treatment by 2 micromol/l Na(2)SeO(3) resulted in the changes of 29 genes. Nine genes were regulated in both groups, among which three showed opposite changes caused by 2 and 20 micromol/l Na(2)SeO(3). The majority of regulated genes did not coincide between the two experiment groups. In conclusion, 2 and 20 micromol/l Na(2)SeO(3) could have different effects on NB4 cells, and some genes might be involved in the underlying mechanisms. Our findings could provide basis for further uncovering the molecular mechanisms of the chemopreventive and antitumor effects of selenium and, in turn, for probing the rationality of treating leukemia with selenium.

Three types of Ti-Si binary oxides have been prepared by sol-gel processes. The effects of SiO sub(2) addition and annealing temperature on the grain size, phase transition, dispersion, and microstructure of nanocrystalline (nc) TiO sub(2) anatase in the three Ti-Si oxide structures have been comparatively investigated by X-ray diffraction (XRD) analysis and high-resolution transmission electron microscopy (HRTEM). The grain growth and anatase-rutile transformation (ART) of ncTiO sub(2) were found to depend not only on the SiO sub(2) content and annealing temperature, but also on the composite structure. Both the grain growth and the ART of ncTiO sub(2) proved to be significantly inhibited with increasing SiO sub(2) content for all of the Ti-Si samples, but the structure of intimately mixed Ti-Si binary oxide showed the best inhibiting ability under high-temperature annealing. This result might be attributed to variations in the large lattice strains in ncTiO sub(2), which were mainly induced by the substitution of Ti super(4+) by Si super(4+). Plausible mechanisms for the grain growth and ART of ncTiO sub(2) are proposed. To inhibit the grain growth of ncTiO sub(2), the addition of 10 and 30 mol% SiO sub(2) proved to be optimal for Ti-Si samples annealed at 773 K and 1273 K, respectively.