In eukaryotes, histone acetylation and methylation have been known to be involved in regulating diverse developmental processes and plant defense. These histone modification events are controlled by a series of histone modification gene families. To date, there is no study regarding genome-wide characterization of histone modification related genes in citrus species. Based on the two recent sequenced sweet orange genome databases, a total of 136 CsHMs (Citrus sinensis histone modification genes), including 47 CsHMTs (histone methyltransferase genes), 23 CsHDMs (histone demethylase genes), 50 CsHATs (histone acetyltransferase genes), and 16 CsHDACs (histone deacetylase genes) were identified. These genes were categorized to 11 gene families. A comprehensive analysis of these 11 gene families was performed with chromosome locations, phylogenetic comparison, gene structures, and conserved domain compositions of proteins. In order to gain an insight into the potential roles of these genes in citrus fruit development, 42 CsHMs with high mRNA abundance in fruit tissues were selected to further analyze their expression profiles at six stages of fruit development. Interestingly, a numbers of genes were expressed highly in flesh of ripening fruit and some of them showed the increasing expression levels along with the fruit development. Furthermore, we analyzed the expression patterns of all 136 CsHMs response to the infection of blue mold (Penicillium digitatum), which is the most devastating pathogen in citrus post-harvest process. The results indicated that 20 of them showed the strong alterations of their expression levels during the fruit-pathogen infection. In conclusion, this study presents a comprehensive analysis of the histone modification gene families in sweet orange and further elucidates their behaviors during the fruit development and the blue mold infection responses.

No abstract

Lithium-ion batteries (LIBs) are receiving considerable attention as storage devices in the renewable and sustainable energy developments. However, facile fabrication of long-life and high-rate cathode materials for LIBs is required to facilitate practical application. Here we report a favourable way to synthesize a Li3V2(PO4)3/C nanosphere cathode with three-dimensional (3D) continuous electron pathways by synergistically utilizing polyethyleneglycol (PEG) and acetylene black for carbon coating and conductive network construction. The as-prepared cathode material has a discharge capacity of 142 mA h g(-1) at 1 C rate, approaching its theoretical value (150 mA h g(-1)), and can even be cycled at a rate as high as 30 C without capacity fading. After 1000 cycles at a rate of 5 C, the as-prepared material has a capacity retention of up to 83%, and can also tolerate 5000 cycles with a considerable capacity, demonstrating excellent cycling stability. Our work shows that this material has great potential for high-energy and high-power energy storage applications, and this rational method can be applied to synthesize high-performance cathode materials on a large scale.

No abstract

No abstract