Screening and Expression Characteristics of Plant Type Regulatory Genes in Salix psammophila

Abstract

Salix psammophila is an important tree species adapted to sand-fixing afforestation in arid areas, and its different plant type characteristics can have different ecological functions. To identify the genes affecting the plant type of S. psammophila, this study used RT-qPCR and RNA-seq technology to establish a method for screening the candidate genes of the S. psammophila plant type based on the correlation coefficient of the crown–height ratio. We then screened out the gene combination that can best control the expression of the S. psammophila plant type. The results show the following: (1) The expression levels of the FHY1 and TAC2 genes were positively correlated with the crown–height ratio, whereas those of the ATX1, RFK1, PYL1, ABF2, SPA2, TB1, ZFP4, and LAZY1b genes were negatively correlated with the crown–height ratio. (2) The ATX1 + FHY1 gene combination had the greatest influence on the plant type traits of S. psammophila, and the correlation between the gene combination and the crown–height ratio reached 0.74. (3) The double- gene combination screening method improved the screening efficiency and accuracy, as well as the sensitivity and specificity, indicating certain universality. This strategy can be used for the determination of other plants or other traits, providing a theoretical basis for the directional breeding of forest trees.