Caterpillar feeding drives patterns of induced defenses and herbivore resistance in wild Pinus tabuliformis

Abstract

The defense mechanisms induced in wild Chinese pine (Pinus tabuliformis) in response to herbivores are not well characterized, especially in the field. To address this knowledge gap, we established a biological model system to evaluate proteome variations in pine needles after feeding by the Chinese pine caterpillar (Dendrolimus tabulaeformis), a major natural enemy and dominant herbivore. Quantitative tandem mass tag (TMT) proteomics and bioinformatics were utilized to systematically identify differentially abundant proteins implicated in the induced defense response of Chinese pine. We validated key protein changes using parallel reaction monitoring (PRM) technology. Pathway analysis revealed that the induced defenses involved phenylpropanoid, coumarin, and flavonoid biosynthesis, among other processes. To elucidate the regulatory patterns underlying pine resistance, we determined the activities of defense enzymes and levels of physiological and biochemical compounds. In addition, the expression of upstream genes for key proteins was validated by qRT-PCR. Our results provide new molecular insights into the induced defense mechanisms in Chinese pine against this caterpillar in the field. A better understanding of these defense strategies will inform efforts to breed more-resistant pine varieties.

Keywords

Pinus tabuliformis / Dendrolimus tabulaeformis / Proteomics / Induced / Defensive responses