Genome-Wide Network Analysis of Above- and Below-Ground Co-growth in Populus euphratica.

Tree growth is the consequence of developmental interactions between above- and below-ground compartments. However, a comprehensive view of the genetic architecture of growth as a cohesive whole is poorly understood. We propose a systems biology approach for mapping growth trajectories in genome-wide association studies viewing growth as a complex (phenotypic) system in which above- and below-ground components (or traits) interact with each other to mediate systems behavior. We further assume that trait-trait interactions are controlled by a genetic system composed of many different interactive genes and integrate the Lotka-Volterra predator-prey model to dissect phenotypic and genetic systems into pleiotropic and epistatic interaction components by which the detailed genetic mechanism of above- and below-ground co-growth can be charted. We apply the approach to analyze linkage mapping data of Populus euphratica, which is the only tree species that can grow in the desert, and characterize several loci that govern how above- and below-ground growth is cooperated or competed over development. We reconstruct multilayer and multiplex genetic interactome networks for the developmental trajectories of each trait and their developmental covariation. Many significant loci and epistatic effects detected can be annotated to candidate genes for growth and developmental processes. The results from our model may potentially be useful for marker-assisted selection and genetic editing in applied tree breeding programs. The model provides a general tool to characterize a complete picture of pleiotropic and epistatic genetic architecture in growth traits in forest trees and any other organisms.

The genetic architecture of trait covariation in Populus euphratica, a desert tree.

Introduction: The cooperative strategy of phenotypic traits during the growth of plants reflects how plants allocate photosynthesis products, which is the most favorable decision for them to optimize growth, survival, and reproduction response to changing environment. Up to now, we still know little about why plants make such decision from the perspective of biological genetic mechanisms. Methods: In this study, we construct an analytical mapping framework to explore the genetic mechanism regulating the interaction of two complex traits. The framework describes the dynamic growth of two traits and their interaction as Differential Interaction Regulatory Equations (DIRE), then DIRE is embedded into QTL mapping model to identify the key quantitative trait loci (QTLs) that regulate this interaction and clarify the genetic effect, genetic contribution and genetic network structure of these key QTLs. Computer simulation experiment proves the reliability and practicability of our framework. Results: In order to verify that our framework is universal and flexible, we applied it to two sets of data from Populus euphratica, namely, aboveground stem length - underground taproot length, underground root number - underground root length, which represent relationships of phenotypic traits in two spatial dimensions of plant architecture. The analytical result shows that our model is well applicable to datasets of two dimensions. Discussion: Our model helps to better illustrate the cooperation-competition patterns between phenotypic traits, and understand the decisions that plants make in a specific environment that are most conducive to their growth from the genetic perspective.

[Clinical effects and safety of piperacillin/tazobactam in treating neutropenic febrile patients with malignant hematopathy].

OBJECTIVE: To evaluate the effect and safety of piperacillin/tazobactam on neutropenic febrile patients with Malignant Hematopathy. METHODS: 218 patients with malignant hematopathy complicated by infectious fever, 162 (74.31%) with fever of unknown origin (FUO), 33 (15.14%) with clinically defined infection (CDI), and 23 (10.55%) with microbiologically defined infection (MDI), underwent intravenous drip of piperacillin/tazobactam at the dose of 4.5 g for 30 min every 8 hours till 4 - 5 d after the temperature returned to normal or neutropenia was relieved. Twenty hours before and after treatment blood routine, blood biochemical and electrolytes, and bacteriological examination, chest X-ray examination were conducted. The changes of symptoms and signs were observed. RESULTS: The total effective rate was 65.60%, the bacteria clearance rate was 71.43%, and the adverse reaction rate was 5.04%. The average defervescence time was (2.5 +/- 1.2) days, and the duration of antibiotic therapy was (9.4 +/- 8.1) days. There were not significant differences in the curative effect and defervescence time between the patients undergoing chemotherapy and those undergoing hematopoietic stem cell transplantation (chi2 = 2.058, P > 0.05, and t = 1.892, P > 0.05). After the piperacillin/tazobactam treatment the white blood cell count and absolute neutrophile granulocyte count of the patients significantly increased (t = 4.092, P < 0.01; t = 4.248, P < 0.01). However, the hepatic and renal functions did not change obviously after treatment. CONCLUSIONS: Piperacillin/tazobactam therapy is effective and safe empirical antibacterial therapy in febrile neutropenic patients with hematological malignancies.