Heckman Robert W, Aspinwall Michael J, Taylor Samuel H, Lowry David B, Khasanova Albina, Bonnette Jason E, Razzaque Samsad, Fay Philip A, Juenger Thomas E
Department of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA.
Formation Environmental LLC, Sacramento, CA, 95816, USA.
New Phytol. 2025 May;246(4):1583-1596. doi: 10.1111/nph.70089. Epub 2025 Mar 28.
The leaf economics spectrum (LES) describes a suite of functional traits that consistently covary at large spatial and taxonomic scales. Despite its importance at these larger scales, few studies have examined the major drivers of intraspecific variation in the LES - phenotypic plasticity and standing genetic variation. Using experimental precipitation manipulations, we examined whether covariation among leaf economics traits and selection on leaf economics traits and trait combinations change as diverse genotypes of the widespread perennial grass Panicum virgatum are exposed to differences in precipitation. We also used RNA-Seq to examine whether groups of co-expressed genes that align with leaf economics traits function in processes hypothesized to underlie the LES. Water availability impacted leaf economics trait covariation in important ways - covariation between leaf economics traits and selection on covariation between traits (i.e. correlational selection) tended to be strongest when water availability was high. Additionally, many genes associated with leaf economics traits functioned in processes that may explain how the LES originates, such as chloroplasts, cell walls, and nitrogen metabolism. Water availability is likely an important modulator of selection and evolution of the LES in P. virgatum that can be better understood by examining gene expression.
叶经济谱（LES）描述了一系列在大空间和分类尺度上始终共同变化的功能性状。尽管其在这些较大尺度上很重要，但很少有研究探讨LES种内变异的主要驱动因素——表型可塑性和现存遗传变异。通过实验性降水操纵，我们研究了广泛分布的多年生草本植物柳枝稷不同基因型在面临降水差异时，叶经济性状之间的协变以及对叶经济性状和性状组合的选择是否会发生变化。我们还使用RNA测序来研究与叶经济性状相关的共表达基因群是否在假定构成LES基础的过程中发挥作用。水分有效性以重要方式影响叶经济性状的协变——当水分有效性较高时，叶经济性状之间的协变以及对性状间协变的选择（即相关选择）往往最强。此外，许多与叶经济性状相关的基因在可能解释LES如何起源的过程中发挥作用，如叶绿体、细胞壁和氮代谢。水分有效性可能是柳枝稷中LES选择和进化的重要调节因子，通过研究基因表达可以更好地理解这一点。
