Leaf bacterial community structure and variation in wild ruderal plants are shaped by the interaction of host species and defense chemistry with environment

Abstract

Variable phenotypes help plants ensure fitness and survival in the face of unpredictable environmental stresses. Leaf bacteria (bacteriomes) can extend plant phenotypes and are well-known to vary from one plant to the next, but little is known about controls on this variation. Here, we find in 9 populations of Arabidopsis thaliana that core leaf bacteriomes are largely, but not completely, shared with other ground-dwelling ruderal plant species. Strength of differentiation between plant species and between A. thaliana populations shifts from year to year, becoming stronger when plants within populations have more similar leaf bacteriomes (less plant-to-plant variation or stochasticity). Interestingly, across different populations, plants with shared leaf aliphatic glucosinolate chemotypes exhibited strong and specific year-to-year stochasticity shifts. Therefore, stochasticity of leaf bacteriomes in plant populations changes in specific ways and might be controlled by plant traits, with important implications for how plants adapt to complex and shifting environments.

Beyond defense: Glucosinolate structural diversity shapes recruitment of a metabolic network of leaf-associated bacteria

“…S1). We had previously isolated individual plants from these populations, grown them in the laboratory, and characterized their leaf GLS profiles ( 31 ). The chemotype of all the isolates differed from that of the model genotype Col-0, where 4MSOB-GLS is the principal aliphatic GLS (Fig.…”

“…We worked with the widely used reference A. thaliana Col-0, its single and double knock-out mutants myb28 and myb28/myb29 ( 67 ) and the local genotype NG2. The latter was identified and isolated in spring 2018 as one out of five wild A. thaliana populations in Jena, Germany: NG2, PB, SW1, JT1, and Woe ( 31 ). One individual plant of each population was propagated in the lab from a single seed for two generations to generate relatively uniform, homozygous lines for further experiments.…”