Internet applications remain exposed to pervasive Domain Name System (DNS)–based threats. Blockchain technologies provide a new way for tackling DNS vulnerability issues, and have been highlighted recently. However, traditional blockchain is still not well suited for big data applications such as DNS, because the performance of blockchain consensus greatly limits its practical adoption. In this paper, we present DagGridLedger, a sharded directed acyclic graph (DAG) blockchain that provides scalable big data architecture for trustful DNS management. To achieve this goal, DagGridLedger proposes a radical new architecture that combines blockchain sharding and DAG techniques on the DNS resolver side, thereby making it a promising solution to enhance the security and stability of large-scale DNS system. To be specific, DagGridLedger provides a blockchain structure targeting DNS application, which employs a high-performance DAG consensus algorithm named DagGrid. DagGrid consensus realizes a multi-DNS negotiation mechanism through block sharding in generating a block. With an improved asynchronous leaderless Byzantine consensus, DagGrid implements total order determination, which guarantees the trustful DNS management. Further experiments verified the performance of DagGridLedger as well as the applicability of the proposed blockchain architecture in traditional DNS. To this end, DagGridLedger consistently achieves a big data architecture for secure DNS record management, with a novel shared DAG consensus designed for high throughput. This makes DagGridLedger a promising architecture for highly secure and efficient DNS solution.
Glycoside hydrolase family 9 (GH9) is a key member of the hydrolase family in the process of cellulose synthesis and hydrolysis, playing important roles in plant growth and development. In this study, we investigated the phenotypic characteristics and gene expression involved in pollen fertility conversion and anther dehiscence from a genomewide level. In total, 74 wheat GH9 genes (TaGH9s) were identified, which were classified into Class A, Class B and Class C and unevenly distributed on chromosomes. We also investigated the gene duplication and reveled that fragments and tandem repeats contributed to the amplification of TaGH9s. TaGH9s had abundant hormone-responsive elements and light-responsive elements, involving JA–ABA crosstalk to regulate anther development. Ten TaGH9s, which highly expressed stamen tissue, were selected to further validate their function in pollen fertility conversion and anther dehiscence. Based on the cell phenotype and the results of the scanning electron microscope at the anther dehiscence period, we found that seven TaGH9s may target miRNAs, including some known miRNAs (miR164 and miR398), regulate the level of cellulose by light and phytohormone and play important roles in pollen fertility and anther dehiscence. Finally, we proposed a hypothesis model to reveal the regulation pathway of TaGH9 on fertility conversion and anther dehiscence. Our study provides valuable insights into the GH9 family in explaining the male sterility mechanism of the wheat photo-thermo-sensitive genetic male sterile (PTGMS) line and generates useful male sterile resources for improving wheat hybrid breeding. 相似文献
