Genome-wide identification and characterization of the bHLH gene family in an ornamental woody plant Prunus mume

The basic helix-loop-helix(bHLH)transcription factor family is the second-largest family in plants,where it plays essential roles in development,and the responses to multiple abiotic and biotic stressors.However,little information is available about this gene family in Prunus mume,which is widely cultivated in East Asia as an ornamental fruit tree.Here,100 PmbHLH genes were identified,and their evolution and functions were explored in P.mume for the first time.The PmbHLH genes were classified into 21 subfamilies.The chromosomal distribution,physicochemical properties,bHLH domain,conserved motif,and intron/exon compositions were also analyzed.Furthermore,the evolutionary pattern,divergence time of the PmbHLH family,and genetic relationships among P.mume,Arabidopsis thaliana,and Prunus persica and Fragaria vesca of Rosaceae were explored.The functional prediction analysis of these PmbHLHs indicated that their functions varied,and included participating in the formation of organs and tissues,responding to stress,and the biosynthesis and metabolism of hormones and other secondary metabolites.Interestingly,expression analyses of PmbHLHs also revealed diverse expression patterns.Most of the PmbHLH genes were highly expressed in roots and stems,and a few were highly expressed in leaves,buds,and fruits,indicating tissue expression specificity.Eight PmbHLH genes,which were upregulated during low-temperature stress,may have critical roles in the response to cold stress.Ten PmbHLHs were differentially expressed between weeping and upright branches in a P.mume F_(1) population.These results shed light on the structure and evolution of the PmbHLH gene family,and lay a foundation for further functional studies of the bHLH genes.

Design optimization of a wind turbine gear transmission based on fatigue reliability sensitivity

Fatigue failure of gear transmission is one of the key factors that restrict the performance and service life of wind turbines.One of the major concerns in gear transmission under random loading conditions is the disregard of dynamic fatigue reliability in conventional design methods.Various issues,such as overweight structure or insufficient fatigue reliability,require continuous improvements in the reliability-based design optimization(RBDO)methodology.In this work,a novel gear transmission optimization model based on dynamic fatigue reliability sensitivity is developed to predict the optimal structural parameters of a wind turbine gear transmission.In the model,the dynamic fatigue reliability of the gear transmission is evaluated based on stress–strength interference theory.Design variables are determined based on the reliability sensitivity and correlation coefficient of the initial design parameters.The optimal structural parameters with the minimum volume are identified using the genetic algorithm in consideration of the dynamic fatigue reliability constraints.Comparison of the initial and optimized structures shows that the volume decreases by 3.58%while ensuring fatigue reliability.This work provides new insights into the RBDO of transmission systems from the perspective of reliability sensitivity.